PREPARATION OF PYRIDYL-TERMINATED OLIGODIMETHYLSILOXANE AND SILOXANE-GRAFTED COPOLYMERS CONTAINING PYRIDYL GROUPS AT THE SIDE-CHAIN ENDS

The preparation of hetero difunctional oligodimethylsiloxanes (ODMSs) was carried out. The ODMSs contained 2-(4-pyridyl)ethyl (Py) or 2-(2,6-di-t-butyl-4-pyridtl)ethyl (DBPy) at one end and a reactive group, such as 3-methacryloxypropyl (MP) or hydrosilyl (H), at the other end. These oligosiloxanes were prepared by anionic ring-opening polymerization of hexamethylcyclotrisiloxane (D3) initiated with silanolate anions containing pyridyl groups. To obtain the initiators, novel silanol compounds containing Py or DBPy groups were prepared from 4-methylpyridine and 2,6-di-t-butyl-4-methylpyridine, respectively. The average degree of polymerization could be controlled by changing the ratio of D3 and the initiator. Py-ODMS-MP and DBPy-ODMS-MP were copolymerized with methyl methacrylate or butyl methacrylate hydrosilylation of DBPy-ODMS-H with vinyldimethylsilated polysulphone (PSF) was carried out to afford PSF/DBPy-ODMS graft copolymer. The gas permeability coefficients of nitrogen, oxygen and carbon dioxide for the copolymer membranes were evaluated.