Effect of Processing Conditions on Chain Extension of Virgin and Recycled Poly(ethylene terephthalate)
Duarte Izarelle da Silva (1), Andrade Daniela de Lourdes Anjos Coutinho Simões (2), Canedo Eduardo Luís (3), Silva Suédina Maria de Lima (2)*
(1) Program of Post Graduation on Science and Materials Engineering.UFCG - Campina Grande Paraiba - Brazil, (2) Department of Materials Engineering, Federal University of Campina Grande - Campina Grande Paraiba - Brazil, (3) Pernambuco Institute of Technology, ITEP - Campina Grande Paraiba - Brazil
In the present work, poly(ethylene terephthalate) virgin (PET-V) and post-consumer (PET-PC) were additivated with a multifunctional styrenic-acrylic-epoxi oligomer (Joncryl Polyad PR 002), sold as a chain extender for condensation polymer such as PET, in order to compensate the decrease of molar mass of these polymer during processing. PET-V and PET-PC as received and additivated with 1.5% of chain extender were compounded in a laboratory internal mixer (Haake Rheomix 3000) with high intensity rotors for 20 min at different rotor speeds (30, 60 and 120 rpm) The effect of rotor speed on the viscosity and molar mass of the polymers during the melt processing stage was estimated based on the torque-temperature-time supplied by the equipment. Incorporation of additive resulted in the increase of melt viscosity and preservation or increase of the molar mass of the resins. Best results were obtained at 60 rpm. These findings, confirmed by intrinsic viscosity measurements on the products, indicate that the chain extender was effective. The real-time determination of molar mass variations during processing was found to be a fast and precise tool to estimate polymer degradation and chain extension additives effectiveness.
Keywords: PET, chain extender, processing conditions