To prepare fully biodegradable materials, variable concentrations of luffa fiber (LF) namely 1, 3, and 5 phr, were incorporated into a poly(lactic acid) (PLA) matrix. To counteract the poor adhesion of the LF to PLA, a compatibilizer which is maleic anhydride‐grafted poly(lactic acid) has been incorporated and the properties of the composites with and without compatibilizer noted, respectively, PLA/LF and PLA/PLA‐g‐maleic anhydride (MA)/LF, were compared. The final torque of PLA/LF was found to decrease with the LF content contrary to that of PLA/PLA‐g‐MA/LF composite which was seen to increase as a result of the interfacial reaction occurring between maleic anhydride groups of the compatibilizer and the hydroxyls of LF. This outcome has been evidenced from the Fourier transform infrared spectroscopy which pointed out the disappearance of the vibration band owing to the anhydride groups of the compatibilizer from the spectra of the PLA/PLA‐g‐MA/LF composite and the better impregnation of LF by the matrix as it has been observed from scanning electron microscopy. Subsequently, the Izod impact strength of the compatibilized composites was seen to increase, especially for 1 phr of LF, whereas the water uptake aptitude was considerably reduced. Also, PLA phase into the composites exhibited lower thermal stability and glass transition temperature compared to pristine PLA.
The potential of ε-caprolactam (CAP) and trimellitic anhydride (TMA) compounds as novel chain extenders for poly(lactic acid) (PLA) has been assessed; the amounts of 0.01, 0.025, and 0.05 wt% each additive have been added. The chain extension was evidenced by the increase in PLA/CAP and PLA/TMA viscosities in mixing torque measurements and by infrared spectroscopy. PLA reaction with CAP and TMA has also been confirmed from contact angle and surface free energy studies, which have shown that the increase in TMA amount decreased the hydrophilicity of PLA due to the decreased concentration of terminal surface hydroxyl groups. However, the addition of CAP accentuated the PLA hydrophilicity as indicated by the increase in the polar component of the surface energy. On the other hand, the glass transition temperature of PLA/TMA and PLA/CAP decreased as a result of a local plasticizing effect, which favored the chain mobility and the crystallization of PLA due to the concomitant nucleating effect of the chain extenders moieties too. Furthermore, the higher molecular weight of PLA/CAP and PLA/TMA was responsible for their increased thermal stability and higher impact strength with respect to PLA. POLYM. ENG. SCI., 60:944-955, 2020.
In this study, physical and electrostatic interactions existing between poly(lactic acid) (PLA) and poly(ethylene terephthalate) (PET) fiber were proved as a promising strategy for preparing novel lightweight PLA/PET fiber composites, without the need of adding compatibilizer or carrying out chemical/physical treatments to the fiber. The impact resistance of the PLA/PET fiber composites increased notably by adding up to 1.5 phr PET fibers thanks to the better dispersion of PET fibers and good polymer-fiber adhesion caused by the creation of hydrogen bonds between the surface hydroxyl and carbonyl groups on both polymers. However, the composites with 2-3 phr PET fibers were brittle due to PET fibers aggregation. The glass transition temperature of PLA increased moderately due to the good matrix/filler interfacial adhesion via hydrogen bond interactions, and its crystallinity showed a trivial variation contrary to the crystallites size, this decreased noticeably because of the fibers inhibiting effect. Finally, an increased thermal stability of the PLA/PET fiber composites was demonstrated.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.