Journal of Polymer Science Part B: Polymer Physics, Vol.32, No.3, 573-577, 1994
Preparation of Small Poly(Butylene Terephthalate) Spheres by Crystallization from Solution
The crystallization of poly (butylene terephthalate) (PBT) from moderately dilute solutions of PBT in a diglycidyl ether of bisphenol-A epoxy has been investigated. PBT dissolves in this epoxy approximately 35-degrees-C below its usual melting temperature of 227-degrees-C to form a one-phase solution. Cooling this solution below 165-degrees-C leads to rapid crystallization of the PBT. The resulting mixture of liquid epoxy and crystalline PBT has a low viscosity and contains highly birefringent, individual PBT spherulites. The PBT spherulites have a narrow size distribution and a high surface-to-volume ratio. These particles are suggested to arise from a rapid crystallization that follows liquid-liquid phase separation.
Keywords:INDUCED PHASE-SEPARATION;POLYMER DILUENT SYSTEMS;POLYSTYRENE LATEX-PARTICLES;THERMODYNAMICS