Study On Properties Of Poly(Lactic Acid)/Rice Straw Fiber Composites

As human society’s continual developing, people pay more attention to theenvironmental issues and recognize the necessary of environment protection and theeffective utilization of the environment naturally renewable materials. It is significanceto study biodegradable composites. Rice straw fiber (RSF) and poly(lactic acid)(PLA)was used to prepare a degradable composite in the current study. In order to improvemechanical properties, the modified methods of PLA and RSF were explored, themechanical properties, micro-interface, and thermal properties were characterized bythe universal testing machine scanning electron microscopy (SEM), thermogravimetricanalysis(TGA) and differential scanning calorimetry(DSC). The main conclusions weresummarized as followed:（1）PLA/RSF composites were prepared by using the twin-screw rheometer. TGAresults indicated the thermal stability of RSF/PLA composites decreased with anincreasing RSF content. DSC curves showed RSF played a role as a nucleating agent,glass transition temperature and melting temperature had no significant difference. Thetensile test data showed the tensile strength and the elongation didn’t improve with anincreasing RSF content, SEM studies showed that poor interfacial adhesion betweenRSF and PLA and loosen fracture surface.（2） The effect of plasticizer species on the mechanical properties ofPLA/PCL(polycaprolactone) composites were studied. The tensile test data showed thattensile strength and Elongation of PLA/PCL composites decreased without theplasticizer. The composite sample with a mass ratio of80PLA:20PCL gave the bestmechanical performance, i.e. the highest tensile strength and greatest elongation atbreak. when the component of TPPi was15，the elongation reached243.78%, TPPi wasthe best plasticizer among the PEG1，PEG2and TPPi.（3）The PLA/RSF/PCL composites were studied and the effect of silanecoupling agent species（A171，A-Link35，A1100）were explored. The tensile test datashowed that the effect of RSF that was modified by the alkali treatment and silanecoupling agent A171on the elongation of the composites was the best. TGA resultsshowed the effect of RSF that was modified by the alkali treatment and silane couplingon the stability was the best. DSC curves showed the glass transition temperature and melting temperature had a slight change with an increasing RSF content. Morphologicalstudies by SEM showed that the effect of the A171on the interfacial adhesion betweenRSF and the matrix was the best among the silane coupling agent species.In summary，this work not only brought some directions for the nature plant fibersand PLA composites research，but also gave some references for the engineeringapplication in future.