Properties of Poplar Fiber Polylactic Acid Composites Comparison of Maleic Anhydride and KH550 Modification

Natural fiber reinforced polylactic acid (PLA), as a kind of biological composite material, has aroused great interest in composites science in recent years. Natural fiber reinforced Polylactic acid composite material has the advantages of natural fiber and polylactic acid. Natural fiber has high strength, stiffness and recyclability, while polylactic acid is biodegradable due to fermentation of its raw materials and renewable agricultural resources such as starch, sugar and cellulose. However, the different polarity of natural fibers and Polylactic acid is the main disadvantage of composite materials. When hydrophilic natural fibers are combined with hydrophobic Polylactic acid, an inefficient interface layer is formed, which leads to uneven aggregation and dispersion of natural fibers. In addition, it has hindered the application of natural fiber-reinforced polylactic acid composites in extended fields such as structural materials.

In order to improve the interfacial adhesion and dispersion of Poplar fibers in polylactic acid (PLA), maleic anhydride (MA) and silane coupling agent (KH550) were used to modify poplar fibers. The mechanical, thermal, rheological and physical properties of the poplar fiber/polylactic acid composite were studied. The effects of different natural fiber modification on the properties of composites were compared. SEM results showed that both MA and KH550 could improve the interfacial adhesion between poplar fiber and PLA, thus improving the mechanical properties of the composites. The tensile strength of 0.5%MA and 2%KH550 was increased by 17% and 23%, respectively. The thermal properties of the composites were improved at 6kh550 (increased by 9% at T90%) and decreased at 0.5%Ma (decreased by 6% at T90%). The wettability of the composites increases by 11.3% at 4kh550 and decreases by 5% at 4mA. Therefore, mechanical properties, economic efficiency, durability and other factors should be carefully considered when selecting modifiers to improve the properties of composites.

DOI:10.3390/polym12030729