Preparation of degradable chemically cross-linked polylactic acid films and its application on disposable straws

Ultra-high flame retardant starch/wood fiber composites based on the synergistic effect of ammonium polyphosphate and calcium carbonate

The development of bio-based composites and products from natural biomass offers a viable solution to the resource and environmental issues caused by non-renewable petrochemical feedstocks. Nevertheless, the high carbon content inherent in biomass renders bio-based materials highly flammable, thereby increasing their susceptibility to fire hazards and limiting their potential applications. In this study, flame retardant starch/wood fiber composites (SWA) were developed, utilizing starch as the matrix, wood fiber as the reinforcing phase, ammonium polyphosphate (APP) as the flame retardant, and calcium carbonate (CaCO3) as both an inorganic filler and a flame retardant synergist. The SWA composites incorporating 5 % (SWA-5) and 10 % (SWA-10) APP achieved UL-94 V-0 rating, with limiting oxygen index (LOI) of 41.5 % and 57.8 %, respectively. Compared to the control group, SWA-10 exhibited significantly reduced heat release and smoke emission rates, with total heat release (THR) and total smoke production (TSP) reduced by 50.4 % and 72 %, respectively. Additionally, SWA-5 exhibited excellent mechanical properties and outstanding thermal insulation, while SWA-10 showed remarkable biodegradability. Therefore, this work developed ultra-high flame retardant bio-based composites with excellent overall performance, making them suitable for thermal insulation and green building applications.

Improving the performance of polylactic acid/polypropylene/cotton stalk fiber composites with epoxidized soybean oil as a high efficiency plasticizer

Polylactic acid (PLA) can serve as a biodegradable alternative to traditional petroleum-based plastics, but its poor impact resistance and high production costs limit its applications. In this study, different contents of epoxidized epoxy soybean oil (ESO) were added as plasticizer to melt blend with polylactic acid (PLA), polypropylene (PP) and cotton stalk fiber (CSF), examining its impact on the mechanical properties, thermal stability, microstructure, and crystallization behavior of the blends. The results indicated that ESO reacted with PLA and CSF to form branched polymers and microgels. With increasing ESO content, the blends exhibited increased initial thermal decomposition temperature, impact strength, and elongation at break, while stiffness, maximum decomposition rate, and crystallinity decreased. When the mass ratio of CSF to ESO was 2:1, the notch impact strength and elongation at break of PLA/PP/CSF/ESO blends were 1.63 times and 1.98 times higher than those of PLA/PP/CSF blends, respectively. Moreover, a reduction in surface grooves of CSF and formation of a gel layer were observed. Importantly, this study opens an effective new pathway for the utilization of waste natural fibers and the widespread application of biodegradable composite materials, contributing to environmental protection, resource conservation, and cost reduction.

Furan-based renewable elastomers as effective tougheners for PLA: Enhanced mechanical properties and water vapor barrier properties

There is a great need for versatile biomass additives sourced from renewable materials to enhance the performance of polylactic acid (PLA) composites. This study introduces a furan-based polyester elastomer called PNF-PBC that is designed to improve the mechanical and water vapor barrier characteristics of PLA. By incorporating PNF-PBC into PLA, the toughness of the PLA/PNF-PBC biocomposites was considerably enhanced through various intermolecular interactions. A 15 wt% PNF-PBC blend with PLA exhibited a 13.6-fold increase in elongation at break, while having a negligible impact on tensile strength. Furthermore, the water vapor barrier performance of PLA/PNF-PBC biocomposites was greatly boosted by a factor of 10 compared to pure PLA, making them highly suitable for food packaging materials. With its versatile properties, we anticipate that this bio-based PLA/PNF-PBC material will significantly expand the range of applications for PLA composites.

Study of the Preparation and Properties of Chemically Modified Materials Based on Rapeseed Meal

In recent years, there has been increasing interest in developing novel materials based on natural biopolymers as a renewable alternative to petroleum-based plastics. The availability of proteins derived from agricultural by-products, along with their favourable properties, has fostered a renewed interest in protein-based materials, promoting research in innovative technologies. In this study, we propose the use of rapeseed protein-rich meal as the main ingredient for the preparation of novel sustainable materials combining excellent environmental properties such as biodegradability and renewability. The application of sustainable products in the present high-tech society requires the modification of the basic native properties of these natural compounds. The original route proposed in this paper consists of preparation via the compression moulding of flexible biomaterials stabilized by crosslinkers/chain extenders. An investigation of the effects of different denaturing and disulfide bond reducing agents, crosslinkers, and preparation conditions on the material mechanical behaviour demonstrated that the novel materials have appreciable strength and stiffness. The results show the potential of utilizing full meal from vegetable by-products to prepare protein-based materials with guaranteed ecofriendly characteristics and mechanical properties adequate for specific structural applications.

Robust construction of konjac glucomannan/polylactic acid nanofibrous films incorporated with carvacrol via microfluidic blow spinning for food packaging

In recent years, the application of biopolymer-based nanofibers prepared via microfluidic blow spinning (MBS) for food packaging has continuously increased due to their advantages of biocompatibility, biodegradability, and safety. However, the poor spinnability, undesirable water barrier capacity, and loss of antibacterial and antioxidant properties of biopolymer-based nanofibers strictly restrict their real-world applications. In this work, carvacrol (CV) incorporated konjac glucomannan (KGM)/polylactic acid (PLA) nanofibrous films (KP-CV) were produced by MBS. The FTIR spectra and XRD analysis revealed the hydrogen bonding interactions among CV, PLA, and KGM, thus significantly improving the TS of KP-CV nanofibrous films from 0.23 to 1.27 MPa with increased content of CV from 0 % to 5 %. Besides, KP-CV nanofibrous films showed improved thermal stability, excellent hydrophobicity (WCA: 128.19°, WVP: 1.02 g mm/m2 h kPa), and sustained release of CV combined with good antioxidant activities (DPPH radical scavenging activity: 77.51 ± 1.57 %), and antibacterial properties against S. aureus (inhibition zone: 26.33 mm) and E. coli (inhibition zone: 22.67 mm). Therefore, as prepared KP-CV nanofibrous films can be potentially applied as packaging materials for the extended shelf life of cherry tomatoes.