In our chemical, rubber and plastic industries, polyester is one of our commonly used rubber and plastic materials; And no matter what aspect of use, the functional requirements for rubber and plastic materials are very high. Compared with general materials, rubber and plastic engineering materials are also called high-function materials; However, most of the functional polyesters (PBT) have a problem of poor heat resistance and hydrolysis, which limits its use by more users.

From the chemical point of view, the main factor affecting the heat-resistant hydrolysis of polyester (PBT) is the concentration of carboxyl end group in the chemical composition of polyester, and there is ester bond in the carboxyl end group. When the polyester (PBT) is placed in water at a temperature higher than its glass transition temperature, the ester bond will break. The acid environment formed by hydrolysis will accelerate the hydrolysis reaction of polyester (PBT) and sharply reduce its function. The following engineering plastics online give us two ways to deal with the poor heat-resistant hydrolysis of polyester (PBT):

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At the top of the list, adding hydrolysis stabilizers such as carbodiimide in water with polyester (PBT) will consume the carboxyl group generated by hydrolysis, slow down the acid hydrolysis rate of polyester (PBT) and improve the hydrolysis resistance of polyester (PBT) resin.

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Second, the hydrolysis resistance of polyester (PBT) is improved by increasing the carboxyl group at the end of PBT to reduce the carboxyl group concentration. For example, additives with epoxide functional groups (such as sag Series) are added, and the functional group GMA reacts with the carboxyl group at the end of PBT to block the end, and then the hydrolysis resistance of PBT is improved.

Article source: PBT engineering plastics http://www.wywantong.com/