CATALYTIC ACTIVITY OF 4-VINYLPYRIDINE-GRAFTED POLYETHYLENE PREPARED BY PHOTOGRAFTING - EFFECT OF GRAFTING CONDITIONS

Relationships between the catalytic activity of 4-vinylpyridine (4VP)-grafted low-density polyethylene film and the photografting conditions [such as polymerization system (vapour- and liquid-phase processes), monomer concentration, polymerization temperature and film thickness] were investigated. Hydrolysis of p-nitrophenylacetate with the 4VP-grafted sample was carried out at 40-degrees in water/ethanol (1/4 v/v) at pH 6.3. Higher catalytic activity was observed for the 4VP-grafted samples prepared by using the liquid-phase process, a lower monomer concentration, lower polymerization temperature and a film thickness of 70 mum. It is supposed that the 4VP-grafted chains are situated on the film surface, resulting in the higher activity.