Real‐time X‐ray scattering study of thermal expansion of poly(butylene terephthalate)

Abstract

AbstractReal‐time x‐ray scattering at elevated temperatures has been used to investigate the thermal expansion characteristics of poly(butylene terephthalate), PBT. Changes in the six lattice parameters of the α‐form of PBT were obtained from wide‐angle x‐ray scattering over the temperature range from 35 to 215°C. The linear thermal expansion coefficients relating the unit cell parameters at temperature T to their values at 0°C are found to be The temperature dependence of both the long period and the lamellar thickness of semicrystalline PBT were determined from real‐time small‐angle x‐ray scattering analysis of the one‐dimensional electron density correlation function. The long period, lamellar thickness, and degree of crystallinity increase as the temperature increases. We find an average linear thermal expansion coefficient of the bulk material to be αave = 5.0 × 10−4°C−1. © 1992 John Wiley & Sons, Inc.