Definitions PCT, PCTG, PCTA and PETG

The following definitions have been traditionally used in the trade to describe the range of CHDM-based polyester compositions  

Structure represents PETG when xis the major glycol component Structure represents PCTG when yis the major glycol component 

PCTA likewise refers to an acid-modified PCT copolyester. Isophtlialic acid (IPA), or alternatively tire dimethyl ester of IPA, is tire most commonly used modifying dibasic acid to prepare PCTA copolyesters. PCTA tlius refers to PCT compositions modified witli up to 50 mol% IPA. The PCTA structure is as follows  

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