High-barrier poly(hydroxy amide ethers): Effect of polymer structure on oxygen transmission rates. 2

The synthesis of a series of new high-barrier poly(hydroxy amide ethers) is described. The polymers are formed by the reactions of Bisphenol A diglycidyl ether, OCH2CHCH2OC6H4C(CH3)(2)C6H4- OCH2CHCH2O, with a series of N,N'-alkylenebis(4-hydroxybenzamides) of general formula HOC6H4-CONHRNHCOC6H4OH [R = -(CH2)(2-6)-, -CH2CH(OH)CH2-, -CH2C6H4CH2-, or -C6H4-] at 140-160 degrees C in propylene glycol monophenyl ether solvent using ethyltriphenylphosphonium acetate as initiator. Poly(hydroxy amide ethers) of general structure [-CH2CH(OH)CH2OC6H4C(CH3)(2)C6OCH2CH-(OH)-CH2OC6H4CONHRNHCOC6H4O-](n) are readily prepared in high molecular weight. These amorphous thermoplastics have glass transition temperatures (T-g) of 110-152 degrees C and oxygen transmission rates (O2TR) which range from 1.0 to 2.8 cc.mil/(100 in.(2).atm.day) (barrier units or BU) at 23 degrees C and 58-86% relative humidity. The effect that polymer structure has on O2TR and T-g is discussed. Of special interest is the poly(hydroxy amide ether) in which R = m-C6H4-. This polymer combines a good oxygen barrier (1.5 BU) with T-g of an engineering thermoplastic (152 degrees C).