Synthesis and properties of polyether nitrile copolymers with pendant methyl groups

Polyether nitrile and polyether nitrile copolymers with pendant methyl groups were prepared by the nucleophilic substitution reaction of 2,6^′-dichlorobenzonitrile with hydroquinone (HQ) and with varying mole proportions of HQ and methyl hydroquinone (MeHQ) using N-methyl pyrrolidone solvent in the presence of anhydrous K₂CO₃. The polymers were characterised by different physico-chemical techniques. The crystallinity of the polymers was found to decrease with increase in concentration of the MeHQ units in the polymer. Thermogravimetric studies showed that all the polymers were stable up to 450 °C with a char yield above 50% at 900 °C in N₂ atmosphere. The glass transition temperature and activation energy of the polymers was found to increase with increase in concentration of the MeHQ units in the polymer.