Bio-Based Polymers with Potential for Biodegradability

Carcinogenic formaldehyde in U.S. residential buildings: Mass inventories, human health impacts, and associated healthcare costs

Formaldehyde, a human carcinogen, is formulated into building materials in the U.S. and worldwide. We used literature information and mass balances to obtain order-of-magnitude estimates of formaldehyde inventories in U.S. residential buildings as well as associated exposures, excess morbidity, and healthcare costs along with other economic ramifications. Use of formaldehyde in building materials dates to the 1940s and continues today unabated, despite its international classification in 2004 as a human carcinogen. Global production of formaldehyde was about 32 million metric tons (MMT) in 2006. In the U.S., 5.7 ± 0.05 to 7.4 ± 0.125 MMT of formaldehyde were produced annually from 2006 to 2022, with 65 ± 5 % of this mass (3.7 ± 0.03 to 4.8 ± 0.08 MMT) entering building materials. For a typical U.S. residential building constructed in 2022, we determined an average total mass of formaldehyde containing chemicals of 48.2 ± 10.1 kg, equivalent to 207 ± 40 g of neat formaldehyde per housing unit. When extrapolated to the entire U.S. housing stock, this equates to 29,800 ± 5760 metric tons of neat formaldehyde. If the health threshold in indoor air of 0.1 mg/m3 is never surpassed in a residential building, safe venting of embedded formaldehyde would take years. Using reported indoor air exceedances, up to 645 ± 33 excess cancer cases may occur U.S. nationwide annually generating up to US$65 M in cancer treatment costs alone, not counting ~16,000 ± 1000 disability adjusted life-years. Other documents showed health effects of formaldehyde exist, but could not be quantified reliably, including sick building syndrome outcomes such as headache, asthma, and various respiratory illnesses. Opportunities to improve indoor air exposure assessments are discussed with special emphasis on monitoring of building wastewater. Safer alternatives to formaldehyde in building products exist and are recommended for future use.

Advances in Organosulfur-Based Polymers for Drug Delivery Systems

Organosulfur-based polymers have unique properties that make them useful for targeted and managed drug delivery, which can improve therapy while reducing side effects. This work aims to provide a brief review of the synthesis strategies, characterization techniques, and packages of organosulfur-based polymers in drug delivery. More importantly, this work discusses the characterization, biocompatibility, controlled release, nanotechnology, and targeted therapeutic aspects of these important structural units. This review provides not only a good comprehension of organosulfur-based polymers but also an insightful discussion of potential future prospectives in research. The discovery of novel organosulfur polymers and innovations is highly expected to be stimulated in order to synthesize polymer prototypes with increased functional accuracy, efficiency, and low cost for many industrial applications.

Designing Degradable Polymers from Tricycloalkenes via Complete Cascade Metathesis Polymerization

Cascade metathesis polymerization has been developed as a promising method to synthesize complex but well-defined polymers from monomers containing multiple reactive functional groups. However, this approach has been limited to the monomers involving simple alkene/alkyne moieties or produced mainly non-degradable polymers. In this study, we demonstrate a complete cascade ring-opening/ring-closing metathesis polymerization (RORCMP) using various tricycloalkenes and two strategies for the efficient degradation. Through rational design of tricycloalkene monomers, the structure and reactivity relationship was explored. For example, tricycloalkenes with trans configuration in the central ring enabled faster and better selective cascade RORCMP than the corresponding cis isomers. Also, a 4-substituted cyclopentene moiety in the monomers significantly enhanced the overall cascade RORCMP performance, with the maximum turnover number (TON) reaching almost 10,000 and molecular weight up to 170 kg/mol using an amide-containing monomer. Furthermore, we achieved one-shot cascade multiple olefin metathesis polymerization using tricycloalkenes and a diacrylate, to produce new highly A,B-alternating copolymers with full degradability. Lastly, we successfully designed xylose-based tricycloalkenes to give well-defined polymers that underwent ultra-fast and complete degradation under mild conditions.

Embracing Sustainability: The World of Bio-Based Polymers in a Mini Review

The proliferation of polymer science and technology in recent decades has been remarkable, with synthetic polymers derived predominantly from petroleum-based sources dominating the market. However, concerns about their environmental impacts and the finite nature of fossil resources have sparked interest in sustainable alternatives. Bio-based polymers, derived from renewable sources such as plants and microbes, offer promise in addressing these challenges. This review provides an overview of bio-based polymers, discussing their production methods, properties, and potential applications. Specifically, it explores prominent examples including polylactic acid (PLA), polyhydroxyalkanoates (PHAs), and polyhydroxy polyamides (PHPAs). Despite their current limited market share, the growing awareness of environmental issues and advancements in technology are driving increased demand for bio-based polymers, positioning them as essential components in the transition towards a more sustainable future.

Modulation of Methoxyfenozide Release from Lignin Nanoparticles Made of Lignin Grafted with PCL by ROP and Acylation Grafting Methods

An efficient and sustainable agriculture calls for the development of novel agrochemical delivery systems able to release agrochemicals in a controlled manner. This study investigated the controlled release of the insecticide methoxyfenozide (MFZ) from lignin (LN) nanoparticles (LNPs). LN-grafted poly(ε-caprolactone) (LN-g-PCL) polymers were synthesized using two grafting methods, ring-opening polymerization (ROP)(LN-g-PCLp) and acylation reaction (LN-g-PCLa), creating polymers capable of self-assembling into nanoparticles of different properties, without surfactants. The LN-g-PCLp polymers exhibited a degree of polymerization (DP) from 22 to 101, demonstrating enhanced thermal stability after LN incorporation. LNPs loaded with MFZ exhibited a spherical core-shell structure with a hydrophilic LN outer layer and hydrophobic PCL core, with sizes affected by grafting methods and DP. LNPs controlled MFZ release, displaying variation in release profiles depending on the grafting methodology used, LN-g-PCLp DP, and temperature variations (23 to 30 °C). LNPs formulated with LN-g-PCLa showed a cumulative release of MFZ of 36.78 ± 1.23% over 196 h. Comparatively, increasing the DP of the LN-g-PCLp polymers, a reduction of the LNPs release rate from 92.39 ± 1.46% to 70.59 ± 2.40% was achieved within the same time frame. These findings contribute to identifying ways to modulate the controlled release of agrochemicals by incorporating them in renewable-based LNPs.

Functionalisation of lignin with urethane linkages and their strengthening effect on PLA composites

Lignin was functionalised by crosslinking with hexamethylene diisocyanate (HDI) through the heterogenous reaction in the solvent dimethyl sulfoxide for preferential improvement in the mechanical properties of composites. The successful synthesis of lignin modified with HDI was confirmed by the instrumental analyses, e.g., FTIR, XPS, and FESEM. The incorporation of optimum crosslinked lignin in polylactic acid (PLA) matrix was systematically evaluated on the basis of their thermal stability, mechanical property, glass transition temperature (Tg), water contact angle, water absorption, and water permeability. The results displayed that incorporation of fillers had prominent effects on tensile tear strength, which could improve tensile strength up to 231 % and elongation at break up to 53 % due to the good interface compatibility between PLA and modified lignin. Further, with the inclusion of fillers, PLA composites exhibited higher crystallinity in comparison to neat PLA.

Purification, bioactivity and application of maltobionic acid in active films

The objective of this study was to purify sodium maltobionate using Zymomonas mobilis cells immobilized in situ on flexible polyurethane (PU) and convert it into maltobionic acid for further evaluation of bioactivity (iron chelating ability, antibacterial potential and cytoprotection) and incorporation into films based on cassava starch, chitosan, and cellulose acetate. Sodium maltobionate exhibited a purity of 98.1% and demonstrated an iron chelating ability of approximately 50% at concentrations ranging from 15 to 20 mg mL-1. Maltobionic acid displayed minimal inhibitory concentrations (MIC) of 8.5, 10.5, 8.0, and 8.0 mg mL-1 for Salmonella enterica serovar Choleraesuis, Escherichia coli, Staphylococcus aureus, and Listeria monocytogenes, respectively. Maltobionic acid did not exhibit cytotoxicity in HEK-293 cells at concentrations up to 500 µg mL-1. Films incorporating 7.5% maltobionic acid into cassava starch and chitosan demonstrated inhibition of microbial growth, with halo sizes ranging from 15.67 to 22.33 mm. These films had a thickness of 0.17 and 0.13 mm, water solubility of 62.68% and 78.85%, and oil solubility of 6.23% and 11.91%, respectively. The cellulose acetate film exhibited a non-uniform visual appearance due to the low solubility of maltobionic acid in acetone. Mechanical and optical properties were enhanced with the addition of maltobionic acid to chitosan and cassava films. The chitosan film with 7.5% maltobionic acid demonstrated higher tensile strength (30.3 MPa) and elongation at break (9.0%). In contrast, the cassava starch film exhibited a high elastic modulus (1.7). Overall, maltobionic acid, with its antibacterial activity, holds promise for applications in active films suitable for food packaging.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03879-3.

Assessment of biodegradation of lignocellulosic fiber-based composites - A systematic review

Lignocellulosic fiber-reinforced polymer composites are the most extensively used modern-day materials with low density and better specific strength specifically developed to render better physical, mechanical, and thermal properties. Synthetic fiber-reinforced composites face some serious issues like low biodegradability, non-environmentally friendly, and low disposability. Lignocellulosic or natural fiber-reinforced composites, which are developed from various plant-based fibers and animal-based fibers are considered potential substitutes for synthetic fiber composites because they are characterized by lightweight, better biodegradability, and are available at low cost. It is very much essential to study end-of-life (EoL) conditions like biodegradability for the biocomposites which occur commonly after their service life. During biodegradation, the physicochemical arrangement of the natural fibers, the environmental conditions, and the microbial populations, to which the natural fiber composites are exposed, play the most influential factors. The current review focuses on a comprehensive discussion of the standards and assessment methods of biodegradation in aerobic and anaerobic conditions on a laboratory scale. This review is expected to serve the materialists and technologists who work on the EoL behaviour of various materials, particularly in natural fiber-reinforced polymer composites to apply these standards and test methods to various classes of biocomposites for developing sustainable materials.

A review of cellulose-based derivatives polymers in fabrication of gas separation membranes: Recent developments and challenges

Due to low-cost, sustainability and good mechanical stability, cellulose-based materials are frequently used in fabrication of polymeric gas separation membrane as potential carbohydrate polymers to substitute traditional petrochemical-based materials. In this review, the performance of cellulose-based polymeric membranes i.e. cellulose acetate, cellulose diacetate, cellulose triacetate, ethyl cellulose and carboxymethyl cellulose in the separation of different gases were investigated. This review paper provides the main features and advantages in the fabrication of cellulose-based gas separation membranes. The influence of the functionalization of cellulose on gas separation and permeability performance of related membranes is considered. Influence of different modification procedures such as blending with polymers, nanomaterials and ionic liquids on the gas separation ability of cellulose-based membranes were reviewed. Moreover, a brief inquiry of the potential of cellulose-based gas separation membranes for industrial applications, by examining the performance of different cellulose derivatives and identifying potential strategies for membrane modification and optimization are given, along with the current restrictions and the future perspectives are discussed.

Relationship between the Polymer Blend Using Chitosan, Polyethylene Glycol, Polyvinyl Alcohol, Polyvinylpyrrolidone, and Antimicrobial Activities against Staphylococcus aureus

The findings from Pareto charts, main effect plots, and interaction plots demonstrate the importance of polymer concentration. Increasing concentration improves the inhibition percentage and decreases the MIC50. However, the primary factor that influences these changes is chitosan (CS). Additionally, the interaction between CS and PVP, along with other polymers, plays a crucial role in achieving better antimicrobial effects. These results enhance our understanding of the antimicrobial properties of the studied polymers and offer valuable insights for developing effective antimicrobial formulations. The MIC50 value of M1-M16 was at a polymer percentage of 12.5%. At 12.5% polymer percentage, with the limits of [PVA], [PEG], and [PVP] being 0.002-0.004 g/mL and [CS] being 0.001-0.002 g/mL, using the 2-level full factorial method, the inhibition percentage is equal to 174.1 - 27,812 PVA - 18,561 PVP - 25,960 PEG - 38,752 CS + 9,263,047 PVA*PVP + 10,430,763 PVA*PEG + 15,397,157 PVA*CS + 7,088,313 PVP*PEG + 7,841,221 PVP*CS + 14,228,046 PEG*CS - 3,367,292,860 PVA*PVP*PEG - 5,671,998,721 PVA*PVP*CS - 6,619,041,275 PVA*PEG*CS - 3,917,095,529 PVP*PEG*CS + 2,273,661,969,470 PVA*PVP*PEG*CS. Theoretically, the most economical concentrations of PVA, PVP, PEG, and CS are 0.002, 0.002, 0.002, and 0.001 mg/mL at a concentration of 12.5% to reach an inhibition percentage of 99.162%, which coincides with the MBC value.

Eco Polymeric Materials and Natural Polymer

With the increasing concern regarding the undesirable environmental and socioeconomic consequences of petrochemicals and limited fossil resources, biomass, bio-based polymers, and other renewable natural resources have increasingly become alternatives for the production of functional materials [...].

Study on the Tensile Behavior of Woven Non-Woven PLA/OLA/MgO Electrospun Fibers

The present work deeply studied the mechanical behavior of woven non-woven PLA/OLA/MgO electrospun fibers, efibers, by using Box-Wilson surface response methodology. This work follows up a previous one where both the diameters and the thermal response of such efibers were discussed in terms of both the different amounts of magnesium oxide nanoparticles, MgO, as well as of the oligomer (lactic acid), OLA, used as plasticizer. The results of both works, in term of diameters, degree of crystallinity, and mechanical response, can be strongly correlated to each other, as reported here. In particular, the strain mechanism of PLA/OLA/MgO efibers was studied, showing an orientation of efibers parallel to the applied stress and identifying the mechanically weakest points that yielded the start of the breakage of efibers. Moreover, we identified 1.5 wt% as the critical amount of MgO, above which the plasticizing effect of OLA was weaker as the amount of both components increased. Moreover, the minimum elastic modulus value took place at 15 wt% of OLA, in agreement with the previously reported convergence point in the evolution of the degree of crystallinity. Regarding the yield point, a concentration of OLA between 20 and 30 wt% led to a slight improvement in the yielding capability in terms of tensile strength in comparison with neat PLA efibers. Therefore, the approach presented here permits the design of tailor-made electrospun nanocomposites with specific mechanical requirements.

Cellulose-Based Ionic Conductor: An Emerging Material toward Sustainable Devices

Ionic conductors (ICs) find widespread applications across different fields, such as smart electronic, ionotronic, sensor, biomedical, and energy harvesting/storage devices, and largely determine the function and performance of these devices. In the pursuit of developing ICs required for better performing and sustainable devices, cellulose appears as an attractive and promising building block due to its high abundance, renewability, striking mechanical strength, and other functional features. In this review, we provide a comprehensive summary regarding ICs fabricated from cellulose and cellulose-derived materials in terms of fundamental structural features of cellulose, the materials design and fabrication techniques for engineering, main properties and characterization, and diverse applications. Next, the potential of cellulose-based ICs to relieve the increasing concern about electronic waste within the frame of circularity and environmental sustainability and the future directions to be explored for advancing this field are discussed. Overall, we hope this review can provide a comprehensive summary and unique perspectives on the design and application of advanced cellulose-based ICs and thereby encourage the utilization of cellulosic materials toward sustainable devices.

Biocompatible and Biodegradable 3D Printing from Bioplastics: A Review

There has been a lot of interest in developing and producing biodegradable polymers to address the current environmental problem caused by the continued usage of synthetic polymers derived from petroleum products. Bioplastics have been identified as a possible alternative to the use of conventional plastics since they are biodegradable and/or derived from renewable resources. Additive manufacturing, also referred to as 3D printing, is a field of growing interest and can contribute towards a sustainable and circular economy. The manufacturing technology also provides a wide material selection with design flexibility increasing its usage in the manufacture of parts from bioplastics. With this material flexibility, efforts have been directed towards developing 3D printing filaments from bioplastics such as Poly (lactic acid) to substitute the common fossil- based conventional plastic filaments such as Acrylonitrile butadiene styrene. Plant biomass is now utilized in the development of biocomposite materials. A lot of literature presents work done toward improving the biodegradability of printing filaments. However, additive manufacture of biocomposites from plant biomass is faced with printing challenges such as warping, low agglomeration between layers and poor mechanical properties of the printed parts. The aim of this paper is to review the technology of 3D printing using bioplastics, study the materials that have been utilized in this technology and how challenges of working with biocomposites in additive manufacture have been addressed.

The degradation of single-use plastics and commercially viable bioplastics in the environment: A review

Plastics have become an integral part of human life. Single-use plastics (SUPs) are disposable plastics designed to be used once then promptly discarded or recycled. This SUPs range from packaging and takeaway containers to disposable razors and hotel toiletries. Synthetic plastics, which are made of non-renewable petroleum and natural gas resources, require decades to perpetually disintegrate in nature thus contribute to plastic pollution worldwide, especially in marine environments. In response to these problems, bioplastics or bio-based and biodegradable polymers from renewable sources has been considered as an alternative. Understanding the mechanisms behind the degradation of conventional SUPs and biodegradability of their greener counterpart, bioplastics, is crucial for appropriate material selection in the future. This review aims to provide insights into the degradation or disintegration of conventional single-use plastics and the biodegradability of the different types of greener-counterparts, bioplastics, their mechanisms, and conditions. This review highlights on the biodegradation in the environments including composting systems. Here, the various types of alternative biodegradable polymers, such as bacterially biosynthesised bioplastics, natural fibre-reinforced plastics, starch-, cellulose-, lignin-, and soy-based polymers were explored. Review of past literature revealed that although bioplastics are relatively eco-friendly, their natural compositions and properties are inconsistent. Furthermore, the global plastic market for biodegradable plastics remains relatively small and require further research and commercialization efforts, especially considering the urgency of plastic and microplastic pollution as currently critical global issue. Biodegradable plastics have potential to replace conventional plastics as they show biodegradation ability under real environments, and thus intensive research on the various biodegradable plastics is needed to inform stakeholders and policy makers on the appropriate response to the gradually emerging biodegradable plastics.

Physical, Mechanical, and Structural Properties of the Polylactide and Polybutylene Adipate Terephthalate (PBAT)-Based Biodegradable Polymer during Compost Storage

Today, packaging is an integral part of any food product, preserving its quality and safety. The use of biodegradable packaging as an alternative to conventional polymers reduces the consumption of synthetic polymers and their negative impacts on the environment. The purpose of this study was to analyze the properties of a biodegradable compound based on polylactide (PLA) and polybutylene adipate terephthalate (PBAT). Test samples were made by blown extrusion. The structural, physical, and mechanical properties of the PLA/PBAT material were studied. The property variations during compost storage in the lab were monitored for 365 days. The physical and mechanical properties were measured in accordance with the GOST 14236-2017 (ISO 527-2:2012) standard. We measured the tensile strength and elongation at rupture. We used attenuated total reflectance Fourier transform infrared microscopy (ATR-FTIR) to analyze the changes in the material structure. This paper presents a comparative analysis of the strengths of a biodegradable material and grade H polyethylene film (manufactured to GOST 10354-82). PLA/PBAT's longitudinal and transverse tensile strengths are 14.08% and 32.59% lower than those of LDPE, respectively. Nevertheless, the results indicate that, given its physical and mechanical properties, the PLA/PBAT material can be an alternative to conventional PE film food packaging. The structural study results are in good agreement with the physical and mechanical tests. Micrographs clearly show the surface deformations of the biodegradable material. They increase with the compost storage duration. The scanning microscopy (SEM) surface analysis of the original PLA/PBAT films indicated that the PLA structure is similar to that of a multilayer shell or sponge, which is visible at medium and especially high magnification. We conclude that PLA/PBAT-based biodegradable materials are potential substitutes for conventional PE polymer films.

Approaches in Sustainable, Biobased Multilayer Packaging Solutions

The depletion of fossil resources and the growing demand for plastic waste reduction has put industries and academic researchers under pressure to develop increasingly sustainable packaging solutions that are both functional and circularly designed. In this review, we provide an overview of the fundamentals and recent advances in biobased packaging materials, including new materials and techniques for their modification as well as their end-of-life scenarios. We also discuss the composition and modification of biobased films and multilayer structures, with particular attention to readily available drop-in solutions, as well as coating techniques. Moreover, we discuss end-of-life factors, including sorting systems, detection methods, composting options, and recycling and upcycling possibilities. Finally, regulatory aspects are pointed out for each application scenario and end-of-life option. Moreover, we discuss the human factor in terms of consumer perception and acceptance of upcycling.

Biodegradation of Different Types of Bioplastics through Composting—A Recent Trend in Green Recycling

In recent years, the adoption of sustainable alternatives has become a powerful tool for replacing petroleum-based polymers. As a biodegradable alternative to petroleum-derived plastics, bioplastics are becoming more and more prevalent and have the potential to make a significant contribution to reducing plastic pollution in the environment. Meanwhile, their biodegradation is highly dependent on their environment. The leakage of bioplastics into the environment and their long degradation time frame during waste management processes are becoming major concerns that need further investigation. This review highlights the extent and rate of the biodegradation of bioplastic in composting, soil, and aquatic environments, and examines the biological and environmental factors involved in the process. Furthermore, the review highlights the need for further research on the long-term fate of bioplastics in natural and industrial environments. The roles played by enzymes as biocatalysts and metal compounds as catalysts through composting can help to achieve a sustainable approach to the biodegradation of biopolymers. The knowledge gained in this study will also contribute to the development of policies and assessments for bioplastic waste, as well as provide direction for future bioplastics research and development.

Effects of Bamboo Leaf Fiber Content on Cushion Performance and Biodegradability of Natural Rubber Latex Foam Composites

Bamboo leaf fiber (BLF) was incorporated into an eco-friendly foam cushion made from natural rubber latex (NRL) to enhance the biodegradation rate. The objective of this work was to investigate the effects of BLF content on the foam structure, mechanical properties, cushion performance, and biodegradability. The NRL foam cushion nets with and without BLF were prepared using the Dunlop method along with microwave-assisted vulcanization. BLF (90-106 µm in length) at various loadings (0.00, 2.50, 5.00, 7.50, and 10.00 phr) were introduced to the latex compounds before gelling and vulcanizing steps. Scanning electron microscopy (SEM) showed that the BLF in a NRL foam caused an increase in cell size and a decrease in the number of cells. The changes in the cell structure and number of cells resulted in increases in the bulk density, hardness, compression set, compressive strength, and cushion coefficient. A soil burial test of 24 weeks revealed faster weight loss of 1.8 times when the BLF content was 10.00 phr as compared to the NRL foam without BLF. The findings of this work suggest the possibility of developing an eco-friendly cushion with a faster degradation rate while maintaining cushion performance, which could be a better alternative for sustainable packaging in the future.

Properties of Luffa Cylindrica Mats Reinforced Castor Oil-Based Polyurethane Composite as an Alternative for Oriented Strand Board

The main objective of this work was to produce and characterize a novel ecofriendly castor oil-based polyurethane (COPU) matrix composite reinforced by Luffa cylindrica mats, luffa for short, to be used as panels, as an alternative to oriented strand board (OSB). To do so, the mechanical behavior was evaluated by tree point flexural, perpendicular o surface tensile, screw pullout, and impact tests that were carried on the novel composite along with the neat matrix. Furthermore, the physical characteristics, the thermomechanical behavior, and the functional groups of the materials were observed by water absorption and thickness swelling tests along with dilatometry and Fourier transform infrared spectroscopy (FTIR). A comparison with commercialized OSB was also performed for control. The luffa/COPU composite was prepared by hand lay-up with 48 vol% of luffa mats incorporated as the maximum allowed by the mold under the available resources for manufacturing. The luffa fibers acted as a good reinforcement for the COPU matrix, where the flexural strength and modulus of elasticity were increased by more than 23 and 10 times, respectively, and the other mechanical properties more than doubled for the composites compared to the neat COPU resin. In general, the composite presented a lower performance compared to the commercial OSB, with the impact results being the exception. The water absorption and thickness swallowing results showed an already-expected behavior for the studied materials, where the better performance was found for the hydrophobic neat resin. The FTIR revealed that there was little interaction between luffa and COPU resin, which can be translated to a weak interface between these materials. However, the mechanical behavior, together with the other results presented by the luffa/COPU composite, confirm it is more than enough to be used as civil construction panels such as OSB.

The Impacts of Bio-Based and Synthetic Hydrogels on Soil Hydraulic Properties: A Review

Soil hydraulic properties are important for the movement and distribution of water in agricultural soils. The ability of plants to easily extract water from soil can be limited by the texture and structure of the soil, and types of soil amendments applied to the soil. Superabsorbent polymers (hydrogels) have been researched as potential soil amendments that could help improve soil hydraulic properties and make water more available to crops, especially in their critical growing stages. However, a lack of a comprehensive literature review on the impacts of hydrogels on soil hydraulic properties makes it difficult to recommend specific types of hydrogels that positively impact soil hydraulic properties. In addition, findings from previous research suggest contrasting effects of hydrogels on soil hydraulic properties. This review surveys the published literature from 2000 to 2020 and: (i) synthesizes the impacts of bio-based and synthetic hydrogels on soil hydraulic properties (i.e., water retention, soil hydraulic conductivity, soil water infiltration, and evaporation); (ii) critically discusses the link between the source of the bio-based and synthetic hydrogels and their impacts as soil amendments; and (iii) identifies potential research directions. Both synthetic and bio-based hydrogels increased water retention in soil compared to unamended soil with decreasing soil water pressure head. The application of bio-based and synthetic hydrogels both decreased saturated hydraulic conductivity, reduced infiltration, and decreased soil evaporation. Hybrid hydrogels (i.e., a blend of bio-based and synthetic backbone materials) may be needed to prolong the benefit of repeated water absorption in soil for the duration of the crop growing season.

Bio-Vitrimers for Sustainable Circular Bio-Economy

The aim to achieve sustainable development goals (SDG) and cut CO₂-emission is forcing researchers to develop bio-based materials over conventional polymers. Since most of the established bio-based polymeric materials demonstrate prominent sustainability, however, performance, cost, and durability limit their utilization in real-time applications. Additionally, a sustainable circular bioeconomy (CE) ensures SDGs deliver material production, where it ceases the linear approach from production to waste. Simultaneously, sustainable circular bio-economy promoted materials should exhibit the prominent properties to involve and substitute conventional materials. These interceptions can be resolved through state-of-the-art bio-vitrimeric materials that display durability/mechanical properties such as thermosets and processability/malleability such as thermoplastics. This article emphasizes the current need for vitrimers based on bio-derived chemicals; as well as to summarize the developed bio-based vitrimers (including reprocessing, recycling and self-healing properties) and their requirements for a sustainable circular economy in future prospects.

Cationic Copolymers of Norbornylized Seed Oils for Fiber-Reinforced Composite Applications

Norbornylized seed oils, i.e., norbornylized linseed oil (NLO), norbornylized soybean oil (NSO), and norbornylized high oleic soybean oil (NHOSO), were synthesized via the Diels-Alder reaction of seed oil and dicyclopentadiene (DCPD) at high temperature (∼235 °C) and high pressure (∼80 psi), followed by cationic copolymerization using DCPD with boron trifluoride diethyl etherate catalyst. Norbornylized seed oils were characterized using H1 nuclear magnetic resonance (NMR), attenuated total reflectance-Fourier transform infrared, and gel permeation chromatography (GPC). Copolymers were formulated with four different DCPD contents, and curing was investigated using dynamic differential scanning calorimetry (DSC) measurements. It was found that the curing followed NLO > NSO > NHOSO with NLO having the highest exotherm, lowest activation energy, and lowest onset temperature. Furthermore, the gelation times were the least for NLO-DCPD copolymers. As anticipated, the degree of unsaturation and norbornene moieties strongly influenced the curing of copolymer thermosets. The copolymer products were compression-molded into thermosets and characterized by DSC, Soxhlet extraction, thermogravimetric analysis (TGA), H1 NMR, solid-state C13 NMR, and GPC. NLO-DCPD thermosets demonstrated high cure, higher thermal stability, glass transition temperature, and cross-linking capability compared to the other seed oil-DCPD counterparts. NMR and GPC results further suggested that bis-allylic and norbornene units concomitantly participated very actively during the cationic curing reaction. Moreover, scanning electron microscopy images of glass fiber-reinforced NLO-DCPD copolymer composites demonstrated good interfacial adhesion between the polymer matrix and fiber phases, imparting enhanced thermo-mechanical properties. This research opens a new venue for higher biobased greener polymer constituent for composite applications.

Factors Affecting Mechanical Properties of Reinforced Bioplastics: A Review

The short life cycle and recalcitrant nature of petroleum-based plastics have been associated with plastic waste accumulation due to their composition rather than worldwide overproduction. The drive to replace single-use products has sparked a considerable amount of research work to discover sustainable options for petroleum-based plastics. Bioplastics open up a new horizon in plastics manufacturing operations and industrial sectors because of their low environmental impact, superior biodegradability, and contribution to sustainable goals. Their mechanical properties regarding tensile, flexural, hardness, and impact strength vary substantially. Various attempts have been made to augment their mechanical characteristics and capacities by incorporating reinforcement materials, such as inorganic and lignocellulosic fibres. This review summarizes the research on the properties of bioplastics modified by fibre reinforcement, with a focus on mechanical performance. The mechanical properties of reinforced bioplastics are significantly driven by parameters such as filler type, filler percentage, and aspect ratio. Fibre treatment aims to promote fibre–matrix adhesion by changing their physical, chemical, thermal, and mechanical properties. A general overview of how different filler treatments affect the mechanical properties of the composite is also presented. Lastly, the application of natural fibre-reinforced bioplastics in the automobile, construction, and packaging industries is discussed.

A comprehensive review on recent advancements in biodegradation and sustainable management of biopolymers

Recent years have seen upsurge in plastic manufacturing and its utilization in various fields, such as, packaging, household goods, medical applications, and beauty products. Due to various adverse impacts imposed by synthetic plastics on the health of living well-being and the environment, the biopolymers have been emerged out an alternative. Although, the biopolymers such as polyhydroxyalkanoates (PHA) are entirely degradable. However, the other polymers, such as poly (lactic acid) (PLA) are only partially degradable and often not biosynthesized. Biodegradation of the polymers using microorganisms is considered an effective bioremediation approach. Biodegradation can be performed in aerobic and anaerobic environments. In this context, the present review discusses the biopolymer production, their persistence in the environment, aerobic biodegradation, anaerobic biodegradation, challenges associated with biodegradation and future perspectives. In addition, this review discusses the advancement in the technologies associated with biopolymer production, biodegradation, and their biodegradation standard in different environmental settings. Furthermore, differences in the degradation condition in the laboratory as well as on-site are discussed.

Development and characterization of biodegradable ultraviolet protective and antibacterial polylactic acid-cellulose acetate film modified by phenyl salicylate

The polylactic acid composite films were successfully fabricated via the technique of solvent casting using cellulose acetate (20%, wt) as the reinforcing material and phenyl salicylate as the ultraviolet (UV) absorbent and antibacterial agent. Polylactic acid-cellulose acetate-phenyl salicylate composite films displayed complete absorption effect at the region of UV-C (280-100 nm) and UV-B (315-280 nm), and more than 95% UV absorption effect at the region of UV-A (400-315 nm). These results indicate that the UV shielding performance of the composite films could be significantly improve by addition of phenyl salicylate. Moreover, the addition of 20% phenyl salicylate could improve the steam resistance, mechanical properties and thermal stability of the films, and the composite films had also better antibacterial activity against Escherichia coli. The composite films could reduce the decay rate of fresh lilies and extend their storage time. The degradation characteristics of the films were explored in the natural environment and the laboratory level, which provided application prospect for the development of degradable food packaging materials with anti-ultraviolet and anti-bacteria effect.

Novel Sustainable Castor Oil-Based Polyurethane Biocomposites Reinforced with Piassava Fiber Powder Waste for High-Performance Coating Floor

The search for new greener materials that contribute to a more sustainable world motivated the present study in which novel biocomposites with 10, 20 and 30 vol% of piassava fiber powder waste reinforcing castor oil-based polyurethane (COPU) intended for a high-performance coated floor (HPCF) were developed. The novel biocomposites were characterized by flexural, Izod impact and wear standard tests as well as Fourier transform infrared spectroscopy (FTIR) and fracture analysis using scanning electron microscopy (SEM). Both flexural modulus and strength displayed marked increases reaching more than 800 and 500%, respectively, compared to plain COPU for 30 vol% piassava powder incorporation. FTIR bands indicated the existence of interaction between the piassava constituents and COPU. However, SEM fractographs disclosed the presence of bubbles attributed to retained gases during the COPU curing. Consequently, the Izod impact resistance showed a 50% decrease while the wear was more than three times accentuated for 30 vol% piassava powder biocomposite. These results met the specified values of corresponding standards and revealed a promising new greener material for HPCFs.

Impact of Bis-O-dihydroferuloyl-1,4-butanediol Content on the Chemical, Enzymatic and Fungal Degradation Processes of Poly(3-hydroxybutyrate)

Poly-β-hydroxybutyrate (PHB) is a very common bio-based and biocompatible polymer obtained from the fermentation of soil bacteria. Due to its important crystallinity, PHB is extremely brittle in nature, which results in poor mechanical properties with low extension at the break. To overcome these issues, the crystallinity of PHB can be reduced by blending with plasticizers such as ferulic acid derivatives, e.g., bis-O-dihydroferuloyl-1,4-butanediol (BDF). The degradation potential of polymer blends of PHB containing various percentages (0, 5, 10, 20, and 40 w%) of BDF was investigated through chemical, enzymatic and fungal pathways. Chemical degradation revealed that, in 0.25 M NaOH solution, the presence of BDF in the blend was necessary to carry out the degradation, which increased as the BDF percentage increased. Whereas no enzymatic degradation could be achieved in the tested conditions. Fungal degradation was achieved with a strain isolated from the soil and monitored through imagery processing. Similar to the chemical degradation, higher BDF content resulted in higher degradation by the fungus.

Methodologies to Assess the Biodegradability of Bio-Based Polymers—Current Knowledge and Existing Gaps

Our society lives in a time of transition where traditional petroleum-based polymers/plastics are being replaced by more sustainable alternative materials. To consider these bioproducts as more viable options than the actual ones, it is demanded to ensure that they are fully biodegradable or compostable and that there is no release of hazardous compounds to the environment with their degradation. It is then essential to adapt the legislation to support novel specific guidelines to test the biodegradability of each biopolymer in varied environments, and consequently, establish consistent data to design a coherent labeling system. This review work aims to point out the current standards that can serve as a basis for the characterization of biopolymers’ biodegradation profile in different environments (soil, compost, and aquatic systems) and identify other laboratory methodologies that have been adopted for the same purpose. With the information gathered in this work, it was possible to identify remaining gaps in existing national and international standards to help establish new validation criteria to be introduced in future research and policies related to bioplastics to boost the sustainable progress of this rising industry.

Essential Work of Fracture and Evaluation of the Interfacial Adhesion of Plasticized PLA/PBSA Blends with the Addition of Wheat Bran by-Product

In this work biocomposites based on plasticized poly(lactic acid) (PLA)–poly(butylene succinate-co-adipate) (PBSA) matrix containing wheat bran fiber (a low value by-product of food industry) were investigated. The effect of the bran addition on the mechanical properties is strictly correlated to the fiber-matrix adhesion and several analytical models, based on static and dynamic tests, were applied in order to estimate the interfacial shear strength of the biocomposites. Finally, the essential work of fracture approach was carried out to investigate the effect of the bran addition on composite fracture toughness.

The role of filamentous fungi in advancing the development of a sustainable circular bioeconomy

Human activities generate enormous amounts of organic wastes and residues. Filamentous fungi (FF) are able to grow on a broad range of substrates and survive over a wide spectrum of growth conditions. These characteristics enable FF to be exploited in biorefineries for various waste streams. Valorization of food industry byproducts into biomass and various arrays of value-added products using FF creates promising pathways toward a sustainable circular economy. This approach might also contribute to reaching the sustainable development goals set by the United Nations, particularly for zero hunger as well as affordable and clean energy. This paper presents the application of filamentous fungi in food, feeds, fuels, biochemicals, and biopolymers. The nutritional values, health benefits, and safety of foods derived from byproducts of food industries are also addressed. The technoeconomical feasibilities, sustainability aspects and challenges and future perspectives for biorefineries using filamentous fungi are discussed.

Preparation and Characterization of Chitosan-Alginate Microspheres Loaded with Quercetin

The aim of this paper was to formulate microspheres based on biodegradable polymers (chitosan and sodium alginate), using the complex coacervation technique. Subsequently, the prepared microspheres were loaded with quercetin (QUE), a pharmacological active ingredient insoluble in water and unstable to light, temperature and air. After preparation, the loaded microspheres underwent several studies for physical chemical characterization (performed by scanning electron microscopy-SEM, laser 3D scanning, and thermal analysis-TA). Furthermore, they were analyzed in order to obtain information regarding swelling index, drug entrapment, and in vitro release capacity. The obtained experimental data demonstrated 86.07% entrapment of QUE into the microspheres, in the case of the one with the highest Ch concentration. Additionally, it was proved that such systems allow the controlled release of the active drug over 24 h at the intestinal level. SEM micrographs proved that the prepared microspheres have a wrinkled surface, with compact structures and a large number of folds. On the basis of the TA analysis, it was concluded that the obtained microspheres were thermally stable, facilitating their usage at normal physiological temperatures as drug delivery systems.

Biosynthesis of Poly-(3-hydroxybutyrate) under the Control of an Anaerobically Induced Promoter by Recombinant Escherichia coli from Sucrose

Poly-(3-hydroxybutyrate) (PHB) is a polyester with biodegradable and biocompatible characteristics and has many potential applications. To reduce the raw material costs and microbial energy consumption during PHB production, cheaper carbon sources such as sucrose were evaluated for the synthesis of PHB under anaerobic conditions. In this study, metabolic network analysis was conducted to construct an optimized pathway for PHB production using sucrose as the sole carbon source and to guide the gene knockout to reduce the generation of mixed acid byproducts. The plasmid pMCS-sacC was constructed to utilize sucrose as a sole carbon source, and the cascaded promoter P_3nirB was used to enhance PHB synthesis under anaerobic conditions. The mixed acid fermentation pathway was knocked out in Escherichia coli S17-1 to reduce the synthesis of byproducts. As a result, PHB yield was improved to 80% in 6.21 g/L cell dry weight by the resulted recombinant Escherichia coli in a 5 L bed fermentation, using sucrose as the sole carbon source under anaerobic conditions. As a result, the production costs of PHB will be significantly reduced.

Innovations in applications and prospects of bioplastics and biopolymers: a review

Non-biodegradable plastics are continually amassing landfills and oceans worldwide while creating severe environmental issues and hazards to animal and human health. Plastic pollution has resulted in the death of millions of seabirds and aquatic animals. The worldwide production of plastics in 2020 has increased by 36% since 2010. This has generated significant interest in bioplastics to supplement global plastic demands. Bioplastics have several advantages over conventional plastics in terms of biodegradability, low carbon footprint, energy efficiency, versatility, unique mechanical and thermal characteristics, and societal acceptance. Bioplastics have huge potential to replace petroleum-based plastics in a wide range of industries from automobiles to biomedical applications. Here we review bioplastic polymers such as polyhydroxyalkanoate, polylactic acid, poly-3-hydroxybutyrate, polyamide 11, and polyhydroxyurethanes; and cellulose-based, starch-based, protein-based and lipid-based biopolymers. We discuss economic benefits, market scenarios, chemistry and applications of bioplastic polymers.

A Review of the Applications and Biodegradation of Polyhydroxyalkanoates and Poly(lactic acid) and Its Composites

Overconsumption of plastic goods and improper handling of petroleum-derived plastic waste have brought a plethora of negative impacts to the environment, ecosystem and human health due to its recalcitrance to degradation. These drawbacks become the main driving force behind finding biopolymers with the degradable properties. With the advancement in biopolymer research, polyhydroxyalkanoate (PHA) and poly(lacyic acid) (PLA) and its composites have been alluded to as a potential alternative to replace the petrochemical counterpart. This review highlights the current synthesis process and application of PHAs and PLA and its composites for food packaging materials and coatings. These biopolymers can be further ameliorated to enhance their applicability and are discussed by including the current commercially available packaging products. Factors influencing biodegradation are outlined in the latter part of this review. The main aim of this review article is to organize the scattered available information on various aspects of PHAs and PLA, and its composites for packaging application purposes. It is evident from a literature survey of about 140 recently published papers from the past 15 years that PLA and PHA show excellent physical properties as potential food packaging materials.

Recent Research Progress on Lignin-Derived Resins for Natural Fiber Composite Applications

By increasing the environmental concerns and depletion of petroleum resources, bio-based resins have gained interest. Recently, lignin, vanillin (4-hydroxy-3-methoxybenzaldehyde), and divanillin (6,6'-dihydroxy-5,5'-dimethoxybiphenyl-3,3'-dicarbaldehyde)-based resins have attracted attention due to the low cost, environmental benefits, good thermal stability, excellent mechanical properties, and suitability for high-performance natural fiber composite applications. This review highlights the recent use of lignin, vanillin, and divanillin-based resins with natural fiber composites and their synthesized processes. Finally, discussions are made on the curing kinetics, mechanical properties, flame retardancy, and bio-based resins' adhesion property.

Review on Spinning of Biopolymer Fibers from Starch

Increasing interest in bio-based polymers and fibers has led to the development of several alternatives to conventional plastics and fibers made of these materials. Biopolymer fibers can be made from renewable, environmentally friendly resources and can be fully biodegradable. Biogenic resources with a high content of carbohydrates such as starch-containing plants have huge potentials to substitute conventional synthetic plastics in a number of applications. Much literature is available on the production and modification of starch-based fibers and blends of starch with other polymers. Chemistry and structure–property relationships of starch show that it can be used as an attractive source of raw material which can be exploited for conversion into a number of high-value bio-based products. In this review, possible spinning techniques for the development of virgin starch or starch/polymer blend fibers and their products are discussed. Beneficiation of starch for the development of bio-based fibers can result in the sustainable replacement of oil-based high-value materials with cost-effective, environmentally friendly, and abundant products.

Synthesis of Lignin-Based MMA-co-BA Hybrid Resins from Cornstalk Residue via RAFT Miniemulsion Polymerization and Their Characteristics

The conversion of cornstalk lignin derived from the co-product of bio-refinery into value-added products such as polymeric material has remarkable environmental and economic potential. A novel bio-based methyl methacrylate copolymerized with butyl acrylate (MMA-co-BA) hybrid resin in our research was prepared by the reversible addition-fragmentation chain transfer method using lignin-graft-polyacrylamide (lignin-g-PAM) as a bio-derived macromolecular chain transfer agent. The molecular architecture of lignin-g-PAM and the lignin-based MMA-co-BA hybrid resin was elucidated using 1H nuclear magnetic resonance and attenuated total reflectance-Fourier transform infrared. The thermal behavior and mechanical performance of the resultant lignin-based MMA-co-BA hybrid resins were also investigated through thermogravimetric analysis, differential scanning calorimetry, and a stress-strain test, respectively. The lignin-based acrylate resins system exhibited structure-related thermal and mechanical properties. Compared with pure MMA-co-BA resin, the incorporation of lignin into various lignin-based MMA-co-BA graft copolymers resulted in an improved tensile strength and a higher Young's modulus. This research could provide not only a new avenue to utilize waste biomass for high-value applications, but also a reference for designing new materials for coatings or adhesives.

Potential applications of polycarbohydrates, lignin, proteins, polyacids, and other renewable materials for the formulation of green elastomers

Renewable resources including polycarbohydrates, lignin, proteins, and polyacids are the intrinsically valuable class of materials that are naturally available in great quantities. Their utilization as green additives and reinforcing bio-fillers, in substitution of environmentally perilous petroleum-based fillers, for developing high-performance green rubber blends and composites is presently a highly tempting option. Blending of these renewable materials with elastomers is not straight-forward and research needs to exploit the high functionality of carbohydrates and other natural materials as proper physicochemical interactions are essential. Correlating and understanding the structural properties of lignin, carbohydrates, polyacids, and other biopolymers, before their incorporation in elastomers, is a potential approach towards the development of green elastomers for value-added applications. Promising properties i.e., biodegradability, biocompatibility, morphological characteristics, high mechanical properties, thermal stability, sustainability, and various other characteristics along with recent advancements in the development of green elastomers are reviewed in this paper. Structures, viability, interactions, properties, and use of most common natural polycarbohydrates (chitosan and starch), lignin, and proteins (collagen and gelatin) for elastomer modification are extensively reviewed. Challenges in commercialization, applications, and future perspectives of green elastomers are also discussed. Sustainability analysis of green elastomers is accomplished to elaborate their cost-effectiveness and environmental friendliness.

Porous Sponges from the Mesocarp of Theobroma Cacao L. Pod Shells for Potential Biomaterial Applications

Lignocellulosic materials have garnered significant attention in recent years to generate biomaterials, but nothing has been investigated with cacao residues of significant importance in Ecuador. This study's objective was to generate porous, three-dimensional sponges from cacao pod shell mesocarp with potential use in biomaterial application. Discs from the mesocarp of cacao pod shells were subjected to neutral, acid, and alkaline treatments, at 25oC and 100oC, followed by washing and lyophilization. Sponge composition was evaluated, with the alkaline treatment resulting in the highest cellulose content and the lowest percentage of lignin, with the removal of hemicellulose corroborated by FITR. The sponges presented high water absorption capacities, which increased with the treatment temperature; mainly, the alkaline generated structures had the largest capacity. The sponges' porosity also depended on the treatment, with the acid and alkaline treatments generating larger pores, which significantly grew with treatment temperature. Preliminary in vitro cytotoxicity tests were carried out using Wharton's jelly mesenchymal stem cells, according to ISO 10993.5.2009, with none of the materials being cytotoxic; however, those with greater lignin contents resulted in lower cell viability. In general, it is considered that the alkaline generated sponges presented the more significant potential for biomaterial applications, which could be further tested with In vitro cell proliferation and differentiation studies and possible in vivo assays.

Comparison of the aerobic biodegradation of biopolymers and the corresponding bioplastics: A review

Biodegradable plastics made from biopolymers (made in nature) or from bio-based polymers (made in a factory) are becoming increasingly important in replacing the massive amounts of conventional, non-degradable fossil-based plastics that have been produced and disposed over the past decades. In this review we compare the biodegradation rates and mechanisms of the bioplastics thermoplastic starch, cellulose acetate and lignin based bioplastics with the biodegradation rates and mechanisms of starch, cellulose and lignin, which are the unmodified biopolymers from which these bioplastics are produced. With this comparison we aim to determine to what extent the extensive knowledge on unmodified biopolymer biodegradation can be applied to the biodegradation of bioplastics (modified biopolymers) in the terrestrial environment. This knowledge is important, since it can be of great help in giving direction to the future research and development of bioplastics and for the development of bioplastic waste assessments and policies. We found that the similarities and differences in biodegradation are dependent on the structural changes imposed on a biopolymer during the bioplastic production process. A change in higher level structure, as found in thermoplastic starch, only resulted in a limited number of differences in the biodegradation process. However, when the chemical structure of a polymer is changed, as for cellulose acetate, different microorganisms and enzymes are involved in the biodegradation. Based on the cellulose acetate biodegradation process, a conceptual model was proposed that can be used as a starting point in predicting biodegradation rates of other chemically modified biopolymers used as bioplastics. Future bioplastic biodegradation research should focus on conducting long-term field experiments, since most studies are conducted in a laboratory setting and do not capture all processes occurring in the field situation. This applies even more to lignin based bioplastics, since very little experimental data were available on modified lignin biopolymer biodegradation.

Initiated Chemical Vapor Deposition (iCVD) Functionalized Polylactic Acid-Marine Algae Composite Patch for Bone Tissue Engineering

The current study aimed to describe the fabrication of a composite patch by incorporating marine algae powders (MAPs) into poly-lactic acid (PLA) for bone tissue engineering. The prepared composite patch was functionalized with the co-polymer, poly (2-hydroxyethyl methacrylate-co-ethylene glycol dimethacrylate) (p(HEMA-co-EGDMA)) via initiated chemical vapor deposition (iCVD) to improve its wettability and overall biocompatibility. The iCVD functionalized MAP–PLA composite patch showed superior cell interaction of human osteoblasts. Following the surface functionalization by p(HEMA-co-EGDMA) via the iCVD technique, a highly hydrophilic patch was achieved without tailoring any morphological and structural properties. Moreover, the iCVD modified composite patch exhibited ideal cell adhesion for human osteoblasts, thus making the proposed patch suitable for potential biomedical applications including bone tissue engineering, especially in the fields of dentistry and orthopedy.

Probing β-alkyl elimination and selectivity in polyolefin hydrogenolysis through DFT

A long chain substrate with [(SiO)3ZrH] has been investigated to elucidate selectivity rules in β-alkyl elimination. DFT studies indicate that polypropylene preferentially undergoes β-Me elimination.