Correlation between Polymerization of Cyclic Butylene Terephthalate(CBT) and Crystallization of Polymerized CBT

摘要

The correlation between ring-opening polymerization(ROP) of cyclic butylene terephthalate(CBT) and crystallization of polymerized CBT(p CBT) strongly affected the final properties of p CBT and its composites.The major objective of this contribution is to pinpoint the threshold temperature between them and the interrelation is successfully disclosed.That is,crystallization during polymerization occurs below 204 °C and the crystallization properties of p CBT are determined by this isothermal ROP stage; polymerization and crystallization are gradually separated with the increase of temperature of ROP(TP) from 204 °C,and the crystallization properties of p CBT are dominated by cooling stage; only polymerization is performed above 212 °C.Moreover,quantitative analysis suggests that uniform crystal size distributions and thicker lamellar crystals derive from the stage of crystallization during polymerization.On the contrary,the crystal size distributions become wider above 204 °C of TP and lead to obvious double melting peaks during heating scan.These efforts provide a very useful guide for the related investigation and application of CBT.