Recycling Waste Polyester via Modification with a Renewable FattyAcid for Enhanced Processability

摘要

Polyethylene terephthalate (PET) waste oftencontains a large amount of thermally unstable contaminantsand additives that negatively impacts processing. A reducedprocessing temperature is desired. In this work, we reportusing a renewably sourced tall oil fatty acid (TOFA) as amodifier for recycled PET. To that end, PET wascompounded with TOFA at different concentrations andextruded at 240 °C. Phase transition behaviors characterizedby thermal and dynamic mechanical analyses exhibit shifts inthe melting and recrystallization temperatures of PET to lowertemperatures and depression of glass transition temperature from 91 to 65 °C. Addition of TOFA also creates crystal-phaseimperfection that slows recrystallization, an important processing parameter. Changes in the morphology of plasticized PETreduces and stabilizes the melt viscosity at 240 and 250 °C. Melt-spun, undrawn continuous filaments of diameter 36?46 μmmade from these low-melting PET exhibit 29?38 MPa tensile strength, 2.7?2.8 GPa tensile modulus, and 20?36% elongation.These results suggest a potential path for reusing waste PET as high-performance polymeric fibers.