Synthesis of a secondary plasticizer for poly(vinyl chloride) by recycling of poly(ethylene terephthalate) bottle waste through aminolytic depolymerization

This study focuses on the synthesis and application of didecanoate of bis(3‐hydroxypropyl) terephthalamide (DD‐BHPTA) as a secondary plasticizer in poly(vinyl chloride) (PVC) compounding. DD‐BHPTA was synthesized from poly(ethylene terephthalate) bottle waste through aminolysis followed by condensation reaction with decanoic acid. Synthesized DD‐BHPTA was characterized by Fourier‐transform infrared spectroscopy, differential scanning calorimetry, and nuclear magnetic resonance. Plasticized PVC was prepared by compounding PVC in different ratios with DD‐BHPTA and dioctyl phthalate (DOP) using a two‐roll mill. This newly synthesized plasticizer completely fused with PVC. The mechanical, thermal, and rheological properties like glass transition temperature, tensile strength, % elongation, dynamic mechanical analysis, solvent resistance, accelerated ultraviolet weathering test for color stability, differential scanning calorimetry, and thermal gravimetric analysis of plasticized PVC were investigated. DD‐BHPTA along with DOP plasticizer demonstrated plasticization efficiency similar to that of DOP alone, with the same plasticizer loading. DD‐BHPTA was found to be the more efficient plasticizer when used in combination with DOP. Thus, DD‐BHPTA can be used as a secondary plasticizer for DOP and can substitute DOP up to 50% of plasticizer loading. J. VINYL ADDIT. TECHNOL., 23:152–160, 2017. © 2015 Society of Plastics Engineers