The influence of fibers on the crystallization of poly(ethylene terephthalate) as related to processing of composites

Abstract The effect of fiber reinforcement on the isothermal crystallization of poly(ethylene terephthalate) (PET) was investigated using differential scanning calorimetry (DSC). Unidirectional fiber composites were prepared using glass and aramid fibers in PET. The rate of crystallization, as reflected by crystallization half‐time, and the degree of crystallinity of PET are seen to depend on the type of reinforcing fiber as well as on crystallization temperature. Crystallization kinetics are also analyzed using an Avrami model for the volume of polymer crystallized as a function of time. The crystalline morphology of PET in fiber‐reinforced systems was studied using polarized light microscopy. Results concerning nucleation densities and growth morphologies are used in explaining differences seen in crystallization kinetics in fiber‐reinforced systems.