Application of Modified Reed Straw in Polylactic Acid Composite Materials

Straw natural fibers can be used as filler or reinforcing material in the field of composite material, but its disadvantages of large number of hydrophilic groups, poor interface compatibility with non-polar polymer materials affects the performance of composite materials, so the chemical modification of plant fiber becomes an effective mean to improve the interface bonding. In this paper, a solid-phase mechanochemical method was used to prepare maleic anhydride esterified modified reed straw (MA-RS). Results of SEM show that the straw is defibrated under the action of maleic anhydride combined with external force, and the fibers have high aspect ratio. FT-IR and XPS tests show that the degree of substitution of maleic anhydride groups on the fiber surface gradually increases with the increase of processing time. The composite materials were prepared by blending modified straw and polylactic acid. Due to the grafting of maleic anhydride, the surface properties of the straw fibers are changed, and the compatibility and interfacial bonding force between the straw fibers and polylactic acid(PLA) are improved. The mechanical test results show that, the tensile strength is increased by about 16%, and the impact strength is increased by about 30%. The SEM observation shows that the modified straw has the better interface compatibility with the PLA matrix than the unmodified straw. © 2021, Editorial Board of Polymer Materials Science & Engineering. All right reserved.