The effect of lignin as a compatibilizer on the physical properties of coconut fiber–polypropylene composites

Lignin has been employed as a compatibilizer in the coconut fiber-polypropylene. The effect of lignin as a compatibilizer on mechanical properties has been studied. The study demonstrates that composites with lignin as a compatibilizer possess higher flexural properties as compared to the control composites. The results also show that tensile properties do not improve as lignin is incorporated. Scanning electron microcopy results (SEM) display some proof of an enhanced compatibility at the interfacial region. In addition to that, the results also exhibit evidence that size irregularities and fiber distribution may play a dominant role on the properties, which may surpass the effect of improved compatibility. Lignin is shown to reduce the water absorption and thickness swelling of the composites. Overall, composites with maleic anhydride-modified polypropylene (Epolene E-43) as a compatibilizer display greater mechanical properties than those with lignin.