Characteristics of Composite Material of Recycled PLA and Surface Hydrophobization-Modified Cellulose

Polylactic acid (PLA) synthesized using high-purity l-lactide produced through chemical recycling was compounded with cellulose nanofibers (NCF) hydrophobized as a silane coupling agent to produce a composite. PLA was decomposed to Mn = 3,000 ~ 5,000 through hydrolysis, and high purity L-Lactide was obtained through backbiting using Sn/Zn-based organic metal and modified zeolite. The prepared high purity lactide was re-polymerized with PLA after purification and compounded with cellulose. The composite of modified NCF and chemically recycled PLA (NCF-re-PLA) exhibited better mechanical properties than novel PLA. As for mechanical properties, tensile strength and Young's modulus were measured through universal testing machine, and properties tended to increase as the cellulose content increased. In addition, the physical properties were evaluated according to the hydroxyl group substitution rate of cellulose, and the cellulose was analyzed through fourier-transform infrared spectroscopy and x-ray diffraction. Additionally, the compatibility of PLA and cellulose composite was confirmed through scanning electron microscopy. In this study, PLA was prepared using high purity lactide obtained through chemical recycling, and modified NCF was synthesized according to the modification silane coupling rate and type. Overall, the NCF-re-PLA upcycling series manufactured using eco-friendly materials will have promising applications in the bio-compatible and plastics industries.