Enhancing the durability of poly(lactic acid) composites by nucleated modification

Abstract

Biodegradable poly(lactic acid) (PLA) composites were prepared using an innovative combination of wood fiber (WF) and 1,3,2,4-bis(3,4-dimethylobenzylideno)sorbitol (DMDBS). DMDBS acted as an effective nucleating agent, which improved the mechanical properties and slowed down the degradation of the WF/PLA composites. The enzymatic degradation of the composites was examined by immersing in proteinase K or cellulase buffer. The presence of DMDBS resulted in a 26.7% increase of the crystallinity compared to the WF/PLA composites. The increase in crystallinity enhanced the thermal stability and tensile strength of the WF/DMDBS/PLA composites by 8.5%. The durability of the WF/DMDBS/PLA composites after nucleated modification was enhanced after enzymolysis. After nucleated modification, the surface of the WF/PLA composites showed clear cracks due to degradation, while these appeared about 2 weeks later in the case of the WF/DMDBS/PLA composites. The results revealed that the introduction of cellulase degraded WF in the composites, which increased hydrolysis or enzymolysis sites. The combination of nucleated modification and enzyme buffer gave an expanded downstream application of WF/PLA composites in packaging and agricultural materials.

Poly(l-Lactic Acid)/Pine Wood Bio-Based Composites

“…Besides its advantages, PLLA has also some drawbacks, mainly brittleness and slow crystallization kinetics that should be overcome to further develop its application possibilities [ 5 , 6 , 7 ]. Several attempts have been made to outbalance these disadvantages, which mainly include the modification of PLLA formulations to develop material with improved plasticization [ 6 , 8 ], impact resistance [ 1 , 9 ], or crystallization rate [ 10 ], often achieved by introduction of particles and fiber-like fillers [ 11 , 12 , 13 ].…”

Supramolecular Interactions in Hybrid Polylactide Blends—The Structures, Mechanisms and Properties

“…The tensile modulus and tensile strength increased slightly with the content of DMBS up to 1.5 wt% but dropped at higher concentrations of the additive. Biodegradable PLA composites were prepared using a combination of wood fiber (WF) and DMBS [ 64 ]. 1,3,2,4-bis(3,4-dimethylobenzylideno)sorbitol acted as an effective nucleating agent for those composites, improved their thermal stability and mechanical properties, and slowed down their enzymatic degradation.…”

Structural biomaterials engineered from lignocellulosic agricultural waste

“…Such materials from agricultural and forestry resources are mostly starch, [9][10][11] cellulose, [12][13][14] lignin, [15][16][17][18][19] and lignocellulose. 9,11,[20][21][22][23][24] In composites and blends, interfacial adhesion is among the most important factors determining their properties, thus the engineering of these materials often involves the modification of interfacial interactions. 25,26 The surface energy of polyolefins and lignocellulosic substances is very low, 27 therefore weak interactions and poor properties are expected in their composites.…”

“…Several papers have been published about the application of natural materials as the component of polymer composites and blends. Such materials from agricultural and forestry resources are mostly starch, 9–11 cellulose, 12–14 lignin, 15–19 and lignocellulose 9,11,20–24 . In composites and blends, interfacial adhesion is among the most important factors determining their properties, thus the engineering of these materials often involves the modification of interfacial interactions 25,26 .…”