Forensic engineering of advanced polymeric materials. Part III - Biodegradation of thermoformed rigid PLA packaging under industrial composting conditions

Degradation and environmental assessment of compostable packaging mixed with biowaste in full-scale industrial composting conditions

The incorporation of representative commercial compostable materials into a full-scale open-air windrow composting process in an industrial site using household-separated biowaste was investigated. Two batches out of the same initial biowaste mixture were studied, one as control and the other containing initially 1.28 wt% of certified compostable plastics. No significant differences in the composting process were revealed. Compostable plastics exhibited a 98 wt% mass loss after 4 months, aligning with industrial composting times. The evolution of the morphology of the materials unveiled polymer specific degradation mechanisms. Both Safety requirements for organic farming were met. Ecotoxicity tests showed no adverse effects, agronomic fertilizing and amending quality was high, the materials compost even enhancing barley growth. The ecological impact assessment demonstrated an advantage for composting over incineration for seven of the eight indicators. In conclusion, this study shows the successful integration of compostable materials into industrial composting, upholding product safety and quality.

An investigation into the stability and degradation of plastics in aquatic environments using a large-scale field-deployment study

The fragmentation of plastic debris is a key pathway to the formation of microplastic pollution. These disintegration processes depend on the materials' physical and chemical characteristics, but insight into these interrelationships is still limited, especially under natural conditions. Five plastics of known polymer/additive compositions and processing histories were deployed in aquatic environments and recovered after six and twelve months. The polymer types used were linear low density polyethylene (LLDPE), oxo-degradable LLDPE (oxoLLDPE), poly(ethylene terephthalate) (PET), polyamide-6 (PA6), and poly(lactic acid) (PLA). Four geographically distinct locations across Aotearoa/New Zealand were chosen: three marine sites and a wastewater treatment plant (WWTP). Accelerated UV-weathering under controlled laboratory conditions was also carried out to evaluate artificial ageing as a model for plastic degradation in the natural environment. The samples' physical characteristics and surface microstructures were studied for each deployment location and exposure time. The strongest effects were found for oxoLLDPE upon artificial ageing, with increased crystallinity, intense surface cracking, and substantial deterioration of its mechanical properties. However, no changes to the same extent were found after recovery of the deployed material. In the deployment environments, the chemical nature of the plastics was the most relevant factor determining their behaviours. Few significant differences between the four aquatic locations were identified, except for PA6, where indications for biological surface degradation were found only in seawater, not the WWTP. In some cases, artificial ageing reasonably mimicked the changes which some plastic properties underwent in aquatic environments, but generally, it was no reliable model for natural degradation processes. The findings from this study have implications for the understanding of the initial phases of plastic degradation in aquatic environments, eventually leading to microplastics formation. They can also guide the interpretation of accelerated laboratory ageing for the fate of aquatic plastic pollution, and for the testing of aged plastic samples.

Photodegradation of polylactic acid: Characterisation of glassy and melt behaviour as a function of molecular weight

During the COVID-19 pandemic, UV-C germicidal lamps became widely available, even for household applications. However, their long-term degradation effects on the mechanical and rheological properties of polylactic acid (PLA) are still not well established. The relationship between degradation and its effects on the molecular structure and macroscale properties are hardly known. In this study, we investigated the effects of long-term exposure to UV-C irradiation on the properties of PLA and interpreted the results at the molecular scale. We performed gel permeation chromatography, Fourier-transform infrared spectroscopy and UV-Vis spectroscopy to analyse changes in chemical structure induced by the UV-irradiation. Then, we carried out thermal, rheological and tensile tests to investigate mechanical and melting properties, and we investigated the applicability of these test results to estimate molecular weight loss. We have created a 3D irradiation map that can facilitate the design of disinfection devices. Based on our results, we propose a maximum number of sterilisation cycles (13 cycles) for the tested PLA films that do not result in significant changes in tensile strength and modulus.

Investigations into the characterization, degradation, and applications of biodegradable polymers by mass spectrometry

Biodegradable polymers have been getting more and more attention because of their contribution to the plastic pollution environmental issues and to move towards a circular economy. Nevertheless, biodegradable materials still exhibit various disadvantages restraining a widespread use in the market. Therefore, additional research efforts are required to improve their performance. Mass spectrometry (MS) affords a relevant contribution to optimize biodegradable polymer synthesis, to confirm macromolecular structures, to examine along the time the progress of degradation processes and highlight advantages and drawbacks in the extensive applications. This review aims to provide an overview of the MS investigations carried out to support the synthesis of biodegradable polymers, with helpful information on undesirable products or polymerization mechanism, to understand deterioration pathways by the structure of degradation products and to follow drug release and pharmacokinetic. Additionally, it summarizes MS studies addressed on environmental and health issues related to the extensive use of plastic materials, that is, potential migration of additives or microplastics identification and quantification. The paper is focused on the most significant studies relating to synthetic and microbial biodegradable polymers published in the last 15 years, not including agro-polymers such as proteins and polysaccharides.

Assessing the Effect of Cellulose Nanocrystal Content on the Biodegradation Kinetics of Multiscale Polylactic Acid Composites under Controlled Thermophilic Composting Conditions

This work studied the effect of cellulose nanocrystal (NCC) content on the biodegradation kinetics of PLA-based multiscale cellulosic biocomposites (PLAMCBs). To facilitate biodegradation, the materials were subjected to thermo-oxidation before composting. Biodegradation was carried out for 180 days under controlled thermophilic composting conditions according to the ASTM D 5338 standard. A first-order model based on Monod's kinetics under limiting substrate conditions was used to study the effect of cellulose nanocrystal (NCC) content on the biodegradation kinetics of multiscale composite materials. It was found that thermo-oxidation at 70 °C for 160 h increased the biodegradability of PLA. Also, it was found that the incorporation of cellulosic fibrous reinforcements increased the biodegradability of PLA by promoting hydrolysis during the first stage of composting. Likewise, it was found that partial substitution of micro cellulose (MFC) by cellulose nanocrystals (NCCs) increased the biodegradability of the biocomposite. This increase was more evident as the NCC content increased, which was attributed to the fact that the incorporation of cellulose nanocrystals facilitated the entry of water into the material and therefore promoted the hydrolytic degradation of the most recalcitrant fraction of PLA from the bulk and not only by surface erosion.

The Role of the Interface of PLA with Thermoplastic Starch in the Nonisothermal Crystallization Behavior of PLA in PLA/Thermoplastic Starch/SiO2 Composites

Corn starch was plasticized by glycerol suspension in a twin-screw extruder, in which the glycerol suspension was the pre-dispersion mixture of glycerol with nano-SiO₂. Polylactide (PLA)/thermoplastic starch/SiO₂ composites were obtained through melt-blending of PLA with thermoplastic starch/SiO₂ in a twin-screw extruder. The nonisothermal crystallization behavior of PLA in the composites was investigated by differential scanning calorimetry. An interface of PLA with thermoplastic starch was proven to exist in the composites, and its interfacial bonding characteristics were analyzed. The interfacial binding energy stemming from PLA with thermoplastic starch exerts a significant influence on the segmental mobility of PLA at the interface. The segmental mobility of PLA is gradually improved by increasing interfacial binding energy, and consequently, the relative crystallinity on the interface exhibits progressive promotion. The Jeziorny model could well describe the primary crystallization of PLA in the composites. The extracted Avrami exponents based on the Jeziorny model indicate that the primary crystallization of PLA follows heterogeneous nucleation and three-dimensional growth. This study has revealed the intrinsic effect of the interfacial segmental mobility on the nonisothermal crystallization behavior of PLA in composites, which is of technological significance for its blow molding.

Efficiency of consumer behaviour and digital ecosystem in the generation of the plastic waste toward the circular economy

A circular economy can help reduce the impact of plastic waste using reaction, resilient, and digital approaches. In addition, it can facilitate reducing plastic consumption. In this regard, consumer behaviour and digitalization are deemed to be two main factors that play major roles in the implementation of a circular economy of plastic waste. The idea of this paper is to understand the relevance of consumer behaviour and digital ecosystem efficiency on plastic waste at the country level. Hence, the efficiency of eight European countries in the generation of plastic waste was analysed using international databases and the statistical method of receiver operation characteristic (ROC). For this purpose, the dependent actual state variables were defined as plastic waste generations, and the independent test variables were defined as digital ecosystem and consumer behaviour factors. ROC plots for the determination of the area under the curve (AUC) indices were produced between the mentioned state and test variables. The results revealed that consumer behaviour increases the higher generation of plastic waste (AUC >0.6), indicating that consumer behaviours have high effectiveness on the generation of plastic waste in European countries. Furthermore, the results indicated that the digital ecosystem has a controlling role in the generation of plastic waste in the study area (AUC <0.5), indicating the digital ecosystem factors associated with the low generation of plastic waste. The overall consumer behaviour in the selected European countries showed an unskilled role regarding the higher generation of plastic waste, while the digital ecosystem context showed a mitigating role in decreasing plastic pollution. The confirmation of the research hypotheses leads to some managerial propositions for the circular economy of plastic waste in the area of consumer behaviour and digitalization. The results propose an elaborated framework, including a reduction in waste generation, recycling in waste circulation, recovery in waste valorization, and efficiency in resource consumption by the digitalization of design technology and education in consumer behaviour for the circular management of plastic waste.

Controlled and Accelerated Hydrolysis of Polylactide (PLA) through Pentaerythritol Phosphites with Acid Scavengers

This study provides insight into the accelerated hydrolysis of polyester PLA through the addition of phosphites based on pentaerythritol. To control hydrolysis and ensure processing stability, different types of phosphites and combinations of phosphites with acid scavengers were studied. Therefore, commercially available PLA was compounded with selected additives on a twin-screw extruder, and hydrolysis experiments were performed at 23 °C, 35 °C and 58 °C in deionized water. Hydrolysis of PLA was evaluated by the melt volume rate (MVR) and size-exclusion chromatography (SEC). For example, after 4 days of water storage at 58 °C, the number average molecular weight of the PLA comparison sample was reduced by 31.3%, whereas PLA compounded with 0.8% phosphite P1 had a 57.7% lower molecular weight. The results are in good agreement with the expected and tested stability against hydrolysis of the investigated phosphite structures. ³¹P-NMR spectroscopy was utilized to elucidate the hydrolysis of phosphites in the presence of lactic acid. With the addition of phosphites based on pentaerythritol, the hydrolysis rate can be enhanced, and faster biodegradation behavior of biodegradable polyesters is expected. Accelerated biodegradation is beneficial for reducing the residence time of polymers in composting facilities or during home composting and as litter or microplastic residues.

Leaching and bioavailability of dissolved organic matter from petrol-based and biodegradable plastics

Petrol-based plastic debris reaching the ocean releases dissolved organic carbon (DOC) and it can also leach fluorescent dissolved organic matter (FDOM). DOC is available to microbial uptake but the FDOM bioavailability has been scarcely studied. Although the most common plastic found in the ocean is petrol-based, the use of biodegradable plastic has increased substantially over the last years. Here we analysed the DOC and FDOM released by three petrol-based (LDPE, PS and EPS) and one biodegradable plastic (PLA) in seawater and examined their bioavailability. We found that the three petro-based plastics released FDOM in the protein-like region while the biodegradable PLA did not. FDOM released by EPS was available to microbial uptake while in the LDPE and PS treatments an increase of FDOM was observed, likely because the FDOM production by bacteria was higher than the consumption in those treatments. Biodegradable PLA leached similar amounts of DOC with comparable microbial bioavailability than petrol-based plastics indicating that, in seawater, it was not degraded faster than petro-based plastics. Especial care should be taken with biodegradable plastic since not all the types degrade in the ocean.

Strategies and progress in synthetic textile fiber biodegradability

Abstract

The serious issue of textile waste accumulation has raised attention on biodegradability as a possible route to support sustainable consumption of textile fibers. However, synthetic textile fibers that dominate the market, especially poly(ethylene terephthalate) (PET), resist biological degradation, creating environmental and waste management challenges. Because pure natural fibers, like cotton, both perform well for consumer textiles and generally meet certain standardized biodegradability criteria, inspiration from the mechanisms involved in natural biodegradability are leading to new discoveries and developments in biologically accelerated textile waste remediation for both natural and synthetic fibers. The objective of this review is to present a multidisciplinary perspective on the essential bio-chemo-physical requirements for textile materials to undergo biodegradation, taking into consideration the impact of environmental or waste management process conditions on biodegradability outcomes. Strategies and recent progress in enhancing synthetic textile fiber biodegradability are reviewed, with emphasis on performance and biodegradability behavior of poly(lactic acid) (PLA) as an alternative biobased, biodegradable apparel textile fiber, and on biological strategies for addressing PET waste, including industrial enzymatic hydrolysis to generate recyclable monomers. Notably, while pure PET fibers do not biodegrade within the timeline of any standardized conditions, recent developments with process intensification and engineered enzymes show that higher enzymatic recycling efficiency for PET polymer has been achieved compared to cellulosic materials. Furthermore, combined with alternative waste management practices, such as composting, anaerobic digestion and biocatalyzed industrial reprocessing, the development of synthetic/natural fiber blends and other strategies are creating opportunities for new biodegradable and recyclable textile fibers.

Article Highlights

Synthetic Biopolymers and Their Composites: Advantages and Limitations-An Overview

Recently, polymer science and engineering research has shifted toward the development of environmentally benign polymers to reduce the impact of plastic leakage on the ecosystems. Stringent regulations and concerns regarding conventional polymers are the main driving forces for the development of renewable, biodegradable, sustainable, and environmentally benign materials. Although biopolymers can alleviate plastic-related pollution, several factors dictate the utilization of biopolymers. Herein, an overview of the potential and limitations of synthetic biopolymers and their composites in the context of environmentally benign materials for a sustainable future are presented. The synthetic biopolymer market, technical advancements for different applications, lifecycle analysis, and biodegradability are covered. The current trends, challenges, and opportunities for bioplastic recycling are also discussed. In summary, this review is expected to provide guidelines for future development related to synthetic biopolymer-based sustainable polymeric materials suitable for various applications.

Effect of Cellulose and Cellulose Nanocrystal Contents on the Biodegradation, under Composting Conditions, of Hierarchical PLA Biocomposites

In this work, the effect of microfibrillated cellulose (MFC) and cellulose nanocrystals (CNCs) on the biodegradation, under composting conditions, of hierarchical PLA biocomposites (HBCs) was studied using a full 2² factorial experimental design. The HBCs were prepared by extrusion processing and were composted for 180 days. At certain time intervals, the specimens were removed from the compost for their chemical, thermal and morphological characterizations. An ANOVA analysis was carried out at different composting times to study MFC and CNCs’ effects on biodegradation. The specimen’s mass loss and molecular weight loss were selected as independent variables. The results show that the presence of MFC enhances the PLA biodegradation, while with CNCs it decreases. However, when both cellulosic fibers are present, a synergistic effect was evident—i.e., in the presence of the MFC, the inclusion of the CNCs accelerates the HBCs biodegradation. Analysis of the ANOVA results confirms the relevance of the synergistic role between both cellulosic fibers over the HBC biodegradation under composting conditions. The results also suggest that during the first 90 days of incubation, the hydrolytic PLA degradation prevails, whereas, beyond that, the enzymatic microbial biodegradation dominates. The SEM results show MFC’s presence enhances the surface biodeterioration to a greater extent than the CNCs and that their simultaneous presence enhances PLA biodegradation. The SEM results also indicate that the biodegradation process begins from hydrophilic cellulosic fibers and promotes PLA biodegradation.

End-of-Life Options for (Bio)degradable Polymers in the Circular Economy

End-of-life options for plastics include recycling and energy recovery (incineration). Taking into account the polymeric waste, recycling is the intentional action that is aimed at reducing the amount of waste deposited in landfills by industrial use of this waste to obtain raw materials and energy. The incineration of waste leads to recovery of the energy only. Recycling methods divide on mechanical (reuse of waste as a full-valuable raw material for further processing), chemical (feedstock recycling), and organic (composting and anaerobic digestion). The type of recycling is selected in terms of the polymeric material, origin of the waste, possible toxicity of the waste, and its flammability. The (bio)degradable polymers show the suitability for every recycling methods. But recycling method should be used in such a form that it is economically justified in a given case. Organic recycling in a circular economy is considered to be the most appropriate technology for the disposal of compostable waste. It is addressed for plastics capable for industrial composting such as cellulose films, starch blends, and polyesters. The biological treatment of organic waste leads also to a decrease of landfills and thereby reducing methane emissions from them. If we add to their biodegradability the absence of toxicity, we have a biotechnological product of great industrial interest. The paper presents the overview on end-of-life options useful for the (bio)degradable polymers. The principles of the circular economy and its today development were also discussed.

Dynamic Mechanical Analysis Investigations of PLA-Based Renewable Materials: How Are They Useful?

Interest in renewable polymers increased exponentially in the last decade and in this context poly(lactic acid) (PLA) became the leader mainly for practical reasons. Nevertheless, it is outstanding also from a scientific point of view, because its thermal and morphological properties are offering challenging new insights. With regard to dynamic mechanical analysis (DMA), PLA does not have the classical behavior of a thermoplastic polymer. Often, overlapping events (enthalpic relaxation, glass transition and crystallization) that occur as the temperature increases make the DMA result of a PLA look inexplicable even for polymer scientists. This review offers a perspective of the main phenomena that can be revealed in a DMA experiment and systematizes the information that can be obtained for every region (glassy, glass transition, rubbery, cold-crystallization and melting). Also, some unusual patterns registered in some cases will be commented upon. The review intends to offer indices that one should pay attention to in the interpretation of a DMA experiment, even if the investigator has only basic skills with DMA investigations.

Forensic Engineering of Advanced Polymeric Materials-Part VII: Degradation of Biopolymer Welded Joints

Welding technology may be considered as a promising processing method for the formation of packaging products from biopolymers. However, the welding processes used can change the properties of the polymer materials, especially in the region of the weld. In this contribution, the impact of the welding process on the structure and properties of biopolymer welds and their ability to undergo hydrolytic degradation will be discussed. Samples for the study were made from polylactide (PLA) and poly(3-hydroxyalkanoate) (PHA) biopolymers which were welded using two methods: ultrasonic and heated tool welding. Differential scanning calorimetry (DSC) analysis showed slight changes in the thermal properties of the samples resulting from the processing and welding method used. The results of hydrolytic degradation indicated that welds of selected biopolymers started to degrade faster than unwelded parts of the samples. The structure of degradation products at the molecular level was confirmed using mass spectrometry. It was found that hydrolysis of the PLA and PHA welds occurs via the random ester bond cleavage and leads to the formation of PLA and PHA oligomers terminated by hydroxyl and carboxyl end groups, similarly to as previously observed for unwelded PLA and PHA-based materials.

(Bio)Degradable Polymeric Materials for Sustainable Future-Part 3: Degradation Studies of the PHA/Wood Flour-Based Composites and Preliminary Tests of Antimicrobial Activity

The need for a cost reduction of the materials derived from (bio)degradable polymers forces research development into the formation of biocomposites with cheaper fillers. As additives can be made using the post-consumer wood, generated during wood products processing, re-use of recycled waste materials in the production of biocomposites can be an environmentally friendly way to minimalize and/or utilize the amount of the solid waste. Also, bioactive materials, which possess small amounts of antimicrobial additives belong to a very attractive packaging industry solution. This paper presents a study into the biodegradation, under laboratory composting conditions, of the composites that consist of poly[(R)-3-hydroxybutyrate-co-4-hydroxybutyrate)] and wood flour as a polymer matrix and natural filler, respectively. Thermogravimetric analysis, differential scanning calorimetry and scanning electron microscopy were used to evaluate the degradation progress of the obtained composites with different amounts of wood flour. The degradation products were characterized by multistage electrospray ionization mass spectrometry. Also, preliminary tests of the antimicrobial activity of selected materials with the addition of nisin were performed. The obtained results suggest that the different amount of filler has a significant influence on the degradation profile.

Biodegradable kinetics and behavior of bio-based polyblends under simulated aerobic composting conditions

The current study evaluates aerobic biodegradation of melt extruded poly(lactic acid) PLA based blends under composting conditions. Samples of neat PLA (NPLA) and bio-based polyblend composites of PLA/LLDPE (linear low-density polyethylene) having different concentration of MCC (microcrystalline cellulose crystal) were analyzed to understand the biodegradation behavior of these blends under simulated composting conditions. Biodegradation kinetics revealed that higher content of MCC and PLA accelerated the biodegradation process of the polymeric blends. Increase in the spherulite growth size and decrease in the spherulite density of the biodegraded samples confirmed the decline in amorphous portion of the test samples due to microbial assimilation, leaving behind the crystalline portion. Surface morphological analysis revealed that the samples of PLA/LLDPE/MCC blends underwent surface erosion prior to bulk biodegradation (50-80%) until the 90th day and the PLA formed fibril-like structures after degradation. This study would help in the design and preparation of biodegradable bio-based commercial blends in the future.

(Bio)degradable Polymeric Materials for Sustainable Future-Part 2: Degradation Studies of P(3HB-co-4HB)/Cork Composites in Different Environments

The degree of degradation of pure poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)] and its composites with cork incubated under industrial and laboratory composting conditions was investigated. The materials were parallelly incubated in distilled water at 70 °C as a reference experiment (abiotic condition). It was demonstrated that addition of the cork into polyester strongly affects the matrix crystallinity. It influences the composite degradation independently on the degradation environment. Moreover, the addition of the cork increases the thermal stability of the obtained composites; this was related to a smaller reduction in molar mass during processing. This phenomenon also had an influence on the composite degradation process. The obtained results suggest that the addition of cork as a natural filler in various mass ratios to the composites enables products with different life expectancies to be obtained.

Prediction studies of environment-friendly biodegradable polymeric packaging based on PLA. Influence of specimens' thickness on the hydrolytic degradation profile

Application of new biodegradable polymer packaging based on polylactide (PLA), susceptible to organic recycling, can help in the waste reduction in landfills. In this paper, the results of the study on abiotic degradation of PLA and its blend containing 15 mol% of poly[(R,S)-3-hydroxybutyrate], as a model for the first step of organic recycling were presented. The samples used for this study have different shapes and thicknesses: rigid films and cuboid-bars. Particular emphasis was placed on determining the pattern of degradation products released into the medium. Originally, the results of present study revealed that the application of electrospray ionization mass spectrometry supported by high performance liquid chromatography allowed envisaging the differences in the degradation products pattern released from the studied PLA-based samples differing in thickness. The significant differences in degradation products pattern were predominately observed in the first steps of incubation process and are caused by an autocatalytic effect, which occurs mainly during degradation of the large size PLA samples. Although, the thickness of PLA-based packaging changes the degradation product patterns, however this does not increase the total amounts of acids released to the medium. Thus, it may be concluded that thickness should not affect significantly organic recycling of the packaging.

(Bio)degradable polymeric materials for a sustainable future - part 1. Organic recycling of PLA/PBAT blends in the form of prototype packages with long shelf-life

Prediction studies of advanced (bio)degradable polymeric materials are crucial when their potential applications as compostable products with long shelf-life is considered for today's market. The aim of this study was to determine the effect of the polylactide (PLA) content in the blends of PLA and poly(butylene adipate-co-terephthalate) (PBAT); specifically how the material's thickness corresponded to changes that occurred in products during the degradation process. Additionally, the influence of talc on the degradation profile of all samples in all environments was investigated. It was found that, differences in the degradation rate of materials tested with a similar content of the PLA component could be caused by differences in their thickness, the presence of commercial additives used during processing or a combination of both. The obtained results indicated that the presence of talc may interfere with materials behavior towards water and consequently alter their degradation profile.

On the Use of PLA-PHB Blends for Sustainable Food Packaging Applications

Poly(lactic acid) (PLA) is the most used biopolymer for food packaging applications. Several strategies have been made to improve PLA properties for extending its applications in the packaging field. Melt blending approaches are gaining considerable interest since they are easy, cost-effective and readily available processing technologies at the industrial level. With a similar melting temperature and high crystallinity, poly(hydroxybutyrate) (PHB) represents a good candidate to blend with PLA. The ability of PHB to act as a nucleating agent for PLA improves its mechanical resistance and barrier performance. With the dual objective to improve PLAPHB processing performance and to obtain stretchable materials, plasticizers are frequently added. Current trends to enhance PLA-PHB miscibility are focused on the development of composite and nanocomposites. PLA-PHB blends are also interesting for the controlled release of active compounds in the development of active packaging systems. This review explains the most relevant processing aspects of PLA-PHB based blends such as the influence of polymers molecular weight, the PLA-PHB composition as well as the thermal stability. It also summarizes the recent developments in PLA-PHB formulations with an emphasis on their performance with interest in the sustainable food packaging field. PLA-PHB blends shows highly promising perspectives for the replacement of traditional petrochemical based polymers currently used for food packaging.

Forensic Engineering of Advanced Polymeric Materials-Part V: Prediction Studies of Aliphatic⁻Aromatic Copolyester and Polylactide Commercial Blends in View of Potential Applications as Compostable Cosmetic Packages

The main aim of the present study was to determine the behavior of the specimens from Ecovio, in the form of dumbbell-shaped samples and films, during degradation in selected cosmetic ingredients such as water and paraffin. The (bio)degradation test of the prototype cosmetic package (sachet) made from a PBAT (poly[(1,4-butylene adipate)–co–(1,4-butylene terephthalate)]) and PLA (polylactide) blend was investigated under industrial composting conditions, and compared with the sample behavior during incubation in cosmetic media at 70 °C. During the degradation tests, the changes of the samples were evaluated using optical microscopy, ¹H NMR (proton nuclear magnetic resonance) and GPC (gel permeation chromatography) techniques. The structures of the degradation products were investigated using ESI-MSⁿ (mass spectrometry with electrospray ionization on positive and negative ions) analysis. The thermal properties of selected materials were determined by DSC (differential scanning calorimetry) and TGA (thermogravimetric analysis) analysis. It was concluded that the PBAT and PLA blend studied had a good stability during aging in cosmetic media, and could be recommended for long-shelf-life compostable packaging of cosmetics, especially with oily ingredients.

Forensic engineering of advanced polymeric materials Part IV: Case study of oxo-biodegradable polyethylene commercial bag - Aging in biotic and abiotic environment

The public awareness of the quality of environment stimulates the endeavor to safe polymeric materials and their degradation products. The aim of the forensic engineering case study presented in this paper is to evaluate the aging process of commercial oxo-degradable polyethylene bag under real industrial composting conditions and in distilled water at 70°C, for comparison. Partial degradation of the investigated material was monitored by changes in molecular weight, thermal properties and Keto Carbonyl Bond Index and Vinyl Bond Index, which were calculated from the FTIR spectra. The results indicate that such an oxo-degradable product offered in markets degrades slowly under industrial composting conditions. Even fragmentation is slow, and it is dubious that biological mineralization of this material would occur within a year under industrial composting conditions. The slow degradation and fragmentation is most likely due to partially crosslinking after long time of degradation, which results in the limitation of low molecular weight residues for assimilation. The work suggests that these materials should not be labeled as biodegradable, and should be further analyzed in order to avoid the spread of persistent artificial materials in nature.