the toluene layer is separated and the residual toluene in the aqueous phase is removed by distillation the aqueous solution is further purified by ultrafiltration using a 0 2 u03bcm hydrophilic polyethersulfone filter and then freeze dried to obtain the dry polymer this gives a polymer containing 53 mole styrene 3 8 mole n 3 triethoxysilyl propyl half amide from maleic anhydride 3 8 mole n tallow half amide of maleic anhydride and 39 4 mole n n diethyl half amide of maleic anhydride preparation of n 3 triethoxysilyl propylacrylamide tespa is as follows 197 4 g of 3 aminopropyl triethoxysilane and 89 9 g of triethylamine are dissolved in 330 g thf purged with nitrogen and cooled to 0 u00b0 c with mixing 83 9 g of acryloyl chloride is added dropwise and after the addition the mixture is heated to 40 u00b0 c for 2 hr the mixture is cooled to room temperature and the salt filtered out the resulting solution of tespa 42 in thf is used as is without further purification preparation of the tetrapolymer of n tert octylacrylamide acrylic acid 1 vinyl 2 pyrrolidinone and tespa to give a polymer containing 5 mole silane containing monomer units polymer vii is as follows 1 89 g of 1 vinyl 2 pyrrolidinone 0 66 g acrylic.