Comparison of crystallization kinetics of polyethylene terephthalate (PET) and reorganized PET

摘要

Structural and thermal studies of Polyethylene terephthalate (PET) and reorganized PET (RPET) are done using XRD and DSC. XRD results show that there is more crystallinity in RPET than PET suggesting overall more freedom to chain movement in RPET than in PET, which is due to less chain entanglement in RPET. Nonisothermal Crystallization kinetics of PET and RPET was studied using the Avrami model and Lauritzen Hoffman Theory. Avrami showed strong secondary crystallization for PET and RPET. The Lauritzen Hoffman parameters (K-g & U*) were estimated using Vyazovkin-Sbirrazzuoli's isoconversional approach and Lauritzen-Hoffman method using G = 1/t(0.5). The isoconversional method regime transition (I-II) at 197 degrees C and 190 degrees C for PET and RPET, respectively. The U* values calculated for PET and RPET are 5151 J/mol and 1981 J/mol respectively in regime II. sigma(e) and q values are lower for RPET which confirms less entanglement in RPET. Overall, PET & RPET are structurally different & show different thermal behavior.