HIGH-BARRIER POLY(HYDROXY AMIDE ETHERS) - EFFECT OF POLYMER STRUCTUREON OXYGEN TRANSMISSION RATES - 3

The synthesis of a series of new high-barrier poly(hydroxy amide ether s) is described. The polymers are formed by the reactions of aromatic diglycidyl ethers, OCH2CHCH2OArOCH2CHCH2O, with N,N'-bis(3-hydroxyphen yl)adipamide, HOC6H4NHCO(CH2)(4)CONHC6H4OH, at 140-160 degrees C in pr opylene glycol monophenyl ether solvent using ethyltriphenylphosphoniu m acetate as initiator. Poly(hydroxy amide ethers) of general structur e H)CH2OArOCH2CH(OH)CH2OC6H4NH(CH2)(4)CONHC6H4O-](n) are readily prepa red in high molecular weight. The mainly amorphous thermoplastics have glass transition temperatures (T-g) of 78-146 degrees C and oxygen tr ansmission rates (O2TR) that range from 0.2 to 1.8 cc.mil/(100 in.(2). atm.day) (barrier units or BU) at 23 degrees C and 45-90% relative hum idity. It was determined that barrier properties improve (i.e., O2TR d ecreases) as the aromatic core unit, Ar, becomes less bulky or more po lar. For example, the poly(hydroxy amide ether) in which Ar is the aro matic unit based on bis(4-hydroxyphenyl)-1,1,1,3,3,3-hexafluoropropane has an O2TR of 1.8 BU, while the poly(hydroxy amide ethers) in which Ar is based on the more compact 2,6-dihydroxynaphthylene or more polar 1,1-bis(4-hydroxyphenyl)acetamide units have lower O2TR of 0.2 BU. In one instance, an amorphous poly(hydroxy amide ether) was induced to c rystallize, yielding a semicrystalline polymer with significantly lowe r O2TR. The derivative in which Ar is the 4,4'-biphenylene unit (O2TR = 0.3 BU, T-g = 110 degrees C) was annealed at 160 degrees C to yield a crystalline material with significant improvement in oxygen barrier (O2TR = 0.06 BU, T-g = 117 degrees C, T-m = 195 degrees C). Other effe cts that polymer structure has on O2TR and T-g are discussed.