Biopolymer composites based on ultrasound/plasma-modified fiber waste and polybutylene adipate terephthalate (PBAT): Physicochemical and functional performance

A strategy for a circular economy is to reuse and modify agricultural wastes through green methodologies, which can be employed as high-value raw materials to produce sustainable materials. Thus, polybutylene adipate terephthalate (PBAT) composites containing plasma (P) and ultrasound/plasma (UP) modified Agave fibers (AF) were prepared by the melt mixing process. The effect of content (10% and 20%) and type of fiber on the processing, structural, mechanical, and water barrier performance of PBAT composites was assessed. FTIR analysis exhibited the presence of O-Si-O groups in all composites containing modified AF, indicating the presence of nanometric hexamethyldisiloxane (HMDSO) coating on the fiber surface. The addition of modified AF into PBAT polymer promoted higher torque levels and specific energy during the composites processing, indicating higher matrix-fiber interactions that hindered the free flow of the polymeric chains. Nevertheless, SEM, DSC, and crystallinity results revealed that PBAT-AFUP composites exhibited more homogeneous surfaces and ordered structures that promoted higher entanglement between modified fibers and the PBAT matrix and restricted the binding sites for water interaction as changes in tensile modulus (from 90 to 163 MPa) and water contact angle (from 63 to 77(degrees)) indicated. These findings show that modified Agave fibers are a sustainable raw material that can be easily processed to produce soft and hydrophobic PBAT-based composites. Highlights center dot The fiber type determined the functional performance of the PBAT composites center dot The modified fibers increased the entanglement of composite chains center dot UP-modified fibers improved the water barrier performance of the PBAT matrix