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首页> 外文期刊>Journal of Applied Polymer Science >Effects of crystallinity on solid-state polymerization of poly(ethylene terephthalate)
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Effects of crystallinity on solid-state polymerization of poly(ethylene terephthalate)

机译：结晶度对聚对苯二甲酸乙二醇酯固相聚合的影响

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摘要

There has been a widely held assumption that the solid-state polymerization (SSP) rate of poly(ethylene terephthalate) (PET) decreases with increasing crystallinity. Several published articles that purported to prove this assumption were based on faulty experiments. Therefore, a proper experimental procedure has been used to study the true effects of crystallinity on the SSP of PET. The results show that, for PET in pellet and powder forms, the SSP rate increases with increasing crystallinity. This is because an increase in the crystallinity results in increased end-group concentration in the amorphous phase, where SSP reactions take place, and decreased concentrations of inactive end groups trapped inside the crystals, thereby increasing the rates of end-group collision and reactions. These positive effects outweigh the negative effect of the increased byproduct-diffusion resistance because of the increase in crystallinity. As the particle size of PET is increased beyond a critical value of about 7 mm, the SSP rate actually decreases with increasing crystallinity because of the excessively increased byproduct-diffusion resistance within the PET particles. However, this critical particle size is far greater than the pellet sizes of commercial PET resins. (c) 2006 Wiley Periodicals, Inc.
机译：人们普遍认为，聚对苯二甲酸乙二酯（PET）的固态聚合（SSP）速率会随着结晶度的增加而降低。几篇声称证明这一假设的文章均基于错误的实验。因此，已经使用适当的实验程序来研究结晶度对PET SSP的真实影响。结果表明，对于粒状和粉末形式的PET，SSP速率随结晶度的增加而增加。这是因为结晶度的增加导致发生SSP反应的非晶相中端基浓度的增加，以及捕获在晶体内部的非活性端基浓度的降低，从而增加了端基碰撞和反应的速率。由于结晶度的增加，这些积极的作用超过了增加的副产物扩散阻力的负面作用。当PET的粒径增加到超过约7 mm的临界值时，SSP速率实际上会随着结晶度的增加而降低，这是因为PET颗粒内的副产物扩散阻力过分增加。但是，该临界粒度远大于市售PET树脂的粒料粒度。 （c）2006年Wiley Periodicals，Inc.

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