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 with a series of N, N ‘-alkylenebis(4-hydroxybenzamides) of general formula HOC 6 H 4 CONHRNHCOC 6 H 4 OH [R = −(CH 2 ) 2 - 6 −, −CH 2 CH(OH)CH 2 −, −CH 2 C 6 H 4 CH 2 −, or −C 6 H 4 −] at 140−160 °C in propylene glycol monophenyl ether solvent using ethyltriphenylphosphonium acetate as initiator. Poly(hydroxy amide ethers) of general structure [−CH 2 CH(OH)CH 2 OC 6 H 4 C(CH 3 ) 2 C 6 H 4 OCH 2 CH(OH)CH 2 OC 6 H 4 CONHRNHCOC 6 H 4 O−] n are readily prepared in high molecular weight. These amorphous thermoplastics have glass transition temperatures ( T g ) of 110−152 °C and oxygen transmission rates (O 2 TR) which range from 1.0 to 2.8 cc·mil/(100 in. 2 ·atm·day) (barrier units or BU) at 23 °C and 58−86% relative humidity. The effect that polymer structure has on O 2 TR and T g is discussed. Of special interest is the poly(hydroxy amide ether) in which R = m -C 6 H 4 −. This polymer combines a good oxygen barrier (1.5 BU) with the T g of an engineering thermoplastic (152 °C).