Effect of water on the kinetics of polyethylene terephthalate

Solid‐State Polymerization of Poly(ethylene terephthalate): The Effect of Water Vapor in the Carrier Gas

“…As pointed out by Whitehead, [26] the hydrolytic degradation of PET causes loss of intrinsic viscosity (IV), increase of the carboxyl content, change of color, etc., even during post-reaction stages, such as granulation, spinning, drying, and storage. PET studies performed at humid environments also reported the plasticizing role of water, [27,29,30] which leads to reduction of the glass transition temperature, [30] decrease of the mechanical performance, [29] swelling of the resin, [26] and modification of the resin morphology. [27] The chemicrystallization effect induced by water (scissions of entangled chains of the amorphous phase, leading to formation of shorter segments with sufficient mobility to crystallize and to increase the rate of crystallization) has also been considered.…”

“…[27] The chemicrystallization effect induced by water (scissions of entangled chains of the amorphous phase, leading to formation of shorter segments with sufficient mobility to crystallize and to increase the rate of crystallization) has also been considered. [30,31] This can be regarded as a deleterious effect, as high crystallinity is not desired in most SSP processes. All the previous studies show the importance of maintaining the gas humidity ratio at acceptable limits in different stages of SSP processes.…”