PBT和PET聚酯的差别.docVIP

PBT and PET Polyester: The Difference Crystallinity Makes By Michael Sepe from Michael P. Sepe LLC 聚酯PBT和PET：结晶造成差异 上海北京顺德（翻译和评述） （来自于塑料产业论坛） （上海北京顺德email：jiazhiliao@263.net，手 To properly understand the differences in performance between PET and PBT we need to compare apples to apples—the semi-crystalline forms of each polymer. 为了正确理解PET和PBT性能之间的差异，我们需要按照一个合理的标准来比较每个聚合物的结晶形式。 （1） （2） （1）The differences between PBT and PET are best understood by examining the chemical structure of the repeating unit that makes up the polymer chains. The essential feature that makes the materials distinctive is the terephthalate ester group that lends its name to this family of materials. 理解PBT和PET差异的最好方式就是检查构成聚合物分子链的重复单元的化学结构。造成PBT和PET区别于别的材料的基本特征是对苯二甲酸酯基团，这类材料的名字就来源于这里。 （2）If PET preforms get too hot in the preheat cycle, they turn cloudy and brittle with crystallization. The trick is to keep the material above its glass-transition temperature, but below its crystallization temperature. This graph shows that the temperature window may not be very wide.如果PET在预结晶阶段变得太热，它们就会因为结晶变得模糊不透明，并且发脆。办法是保持PET材料的预热温度在玻璃化温度以上和结晶温度以下。图（2）显示PET的温度窗口也许并不宽。 Last month we profiled similarities and differences between different chemistries in the acetal polymer family. This month we will begin making a similar comparison between different commercially available polyesters known as PBT and PET. Many years ago, while working for a custom injection molder, I worked closely with one of our customers to convert a series of parts from 30% glass-fiber reinforced PBT to a PET with the same level of filler. It served as a practical application of the differences between the materials on both processing and performance levels. 上个月，我们曾经归纳了POM家族的不同化学结构的相似性和差别。这个月，我们将开始对不同化学结构的聚酯，如PBT何PET进行比较。许多年前，在一个注塑模塑公司那里工作时，我与我的一个客户一起工作，加工一系列部件，材料包括30%玻纤增强PBT到具有同样填料含量的的PET。它们用于不同的应用，因此加工和性能也有所不同。 Fundamentally, the chemistry of PET and PBT is very similar. Polyesters are synthesized by reacting an organic acid,