The compatible and mechanical properties of biodegradable poly(Lactic Acid)/ethylene glycidyl methacrylate copolymer blends

Abstract

The Fourier transform infrared results suggest that the carboxylic acid groups of poly(lactic acid) (PLA) molecules react with the epoxy groups of molecules of Ethylene Glycidyl Methacrylate Copolymer (EGMC) during the reactive extrusion processes of PLA x EGMC y specimens. The tensile and tear strength values of PLA x-EGMC y blown-film specimens in machine and transverse directions improve significantly, and reach their maximal values as their EGMC contents approach an optimum value of 6 wt.%. The melt shear viscosity values of PLA x EGMC y resins, measured at varying shear rates, are significantly higher than those of the PLA resin, and increase consistently with their EGMC contents. Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) of PLA and PLA x EGMC y specimens reveal that the percentage crystallinity, peak melting temperature, and onset recrystallization temperature values of PLA x EGMC y specimens reduce gradually as their EGMC contents increase. In contrast, the glass transition temperatures of PLA x-EGMC y specimens increase gradually in conjunction with their EGMC contents. Demarcated porous morphology with several connected fungi-decomposed cavities was found on the surfaces of the PLA x EGMC y specimens after being buried for specific amounts of time, in which the sizes of the fungi-decomposed cavities found on the surfaces of buried PLA x EGMC y specimens reduce significantly as their EGMC contents increase. Further DMA and morphological analysis of PLA x EGMC y specimens reveal that the EGMC molecules are compatible with PLA molecules at EGMC contents equal to or less than 2 wt.% because no phaseseparated EGMC droplets and tan δ transitions were found on fracture surfaces and tan δ curves of PLA x-EGMC y specimens, respectively. The possible reasons for these remarkable properties of the PLA/EGMC specimens are proposed in this study.

Biodegradable Plastics Prepared from Poly(lactic acid), Poly(butylene succinate) and Microcrystalline Cellulose Extracted from Waste-Cotton Fabric with a Chain Extender

“…3) showed characteristic peaks at 3,500 cm -1 (OH stretching vibration), 2,995 and 2,945 cm -1 (asymmetric and symmetric stretching vibrations of CH 3 , respectively), 1,755 cm -1 (C=O stretching vibration), 1,455 cm -1 (asymmetric bending vibration of CH 3 ) and those at 1,185, 1,085 and 1,044 cm -1 (C-O-C stretching vibrations) [13,31,32] Pure PBS showed characteristic peaks at 3,450 cm -1 (OH stretching vibration), 2,990 cm -1 (C-H from CH 3 groups), 1,750 cm -1 (C=O stretching vibration) and at 1,155 and 1,045 cm -1 (C-O stretching vibrations) [12,13,33,34]. For the PLA/PBS blend with 30 wt% PBS, the characteristic carbonyl peak at 1,755 cm -1 became broader, indicating that the PLA and PBS were partially miscible.…”

“…7. The pure PLA and PLA component in the blends showed broad and ambiguous diffraction patterns without the two major characteristic peaks at 2h of 16.5°and 19° [ 13,14,32], indicating that the PLA mainly existed in an amorphous state or the amount of crystallites was to low to be traced [13]. This may be attributed to the fact that PLA has a very low crystallization rate, thus the fast cooling rate during processing prevent any significant level of PLA crystallization [31,35].…”

Effect of mixing poly(lactic acid) with glycidyl methacrylate grafted poly(ethylene octene) on optical and mechanical properties of the blown films

“…The inherent brittleness, low deformation at break, low‐melt viscosity, and low‐heat distortion temperature of PLA have restricted its applications . In order to overcome these drawbacks, the processability of film blowing and the mechanical properties of the PLA resin can be improved through copolymerization or blending with other polymers or plasticizers . For example, PLA is blended with other more flexible and biodegradable polymers such as PCL, PBS, poly(3‐hydroxybutyrate) (PHB), and poly(butylene adipate‐ co ‐terephthalate) (PBAT) .…”

Effects of mixing protocols on impact modified poly(lactic acid) layered silicate nanocomposites

“…Polylactic acid (PLA) as one of this class of polymers derived from renewable resources, competes well with many available synthetic polymers owing to its good mechanical and physical properties, biocompatibility, and ease of processability . These attributes make it an outstanding candidate with high potential to substitute for petroleum‐based polymers in various applications such as biomedical, packaging, automotive, and others . However, because of its inherent brittleness and low toughness, this linear thermoplastic polyester needs some modifications to tackle these drawbacks and enlarge its application window.…”