Mechanical and thermal properties of silk fiber reinforced poly(lactic acid) biocomposites

The purpose of these studies is to add value to the animal fibers and consequently to improve the properties of poly(lactic acid) (PLA)/silk fiber (SF) green composites for the potential use in environmental engineering applications such as food packaging and medicines. PLA/SF biocomposites were prepared by internal melt mixer and compression molding machine. Surface treatment of fiber was investigated in order to improve interfacial adhesion of SF reinforced PLA composites. Fiber was treated with sodium hydroxide (NaOH) 5% w/v for 1 h. The effect of fiber content and length on the mechanical and thermal properties of PLA matrix were studied. Experimentally, it was found that the weight content and fiber length of fillers are key parameters that substantially influence the tensile modulus and impact strength of the composite samples. The surface of the fibers was well bonded with the matrix, as observed by a scanning electron microscope (SEM) image of fractured sample. The thermal stability and crystallinity (Xc) of PLA/SF composites increased with increasing fiber content.