含磺酸甜菜碱两性离子共聚物P(AM-co-VPPS)的合成及盐溶液性质

4-乙烯基吡啶(4-VP)与1,3-丙烷磺内酯在80℃下反应20h,合成了4-乙烯基-1-(3-磺丙基)吡啶内嗡盐(4-VPPS);并在水溶液中与丙烯酰胺(AM)单体进行自由基共聚合,获得了同时含正负离子基团的磺酸甜菜碱两性离子共聚物P((AM-co-VPPS));采用红外光谱和1H-NMR对共聚物结构和组成进行了表征;进而考察了单体组成、引发剂用量、单体总浓度及反应温度对两性离子共聚物特性黏数的影响.通过考察单体投料比与共聚物组成的关系,利用Finemann-Ross和Kelen-Tudos方法,获得AM和4-VPPS单体对的竞聚率分别为2.01、8.71和1.99、8.44.共聚物溶液性质研究结果表明,P(AM-co-VPPS)在含NaCl和CaCl2的水溶液中的特性黏数都比纯水中的大,表现出明显的反聚电解质行为.特性黏数增加的程度随共聚物中4-VPPS单元的含量和水中盐浓度增加而增大;当共聚物中4-VPPS摩尔含量为10.2%时,其在1mol/LNaCl、2mol/LNaCl和2mol/LCaCl2水溶液中特性黏数与在纯水中相比,分别增加47.3%、56.7%和56.8%.

SYNTHESIS AND SALT SOLUTION PROPERTIES OF ZWITTERIONIC COPOLYMER P(AM-co-VPPS) CONTAINING SULFOBETAINE GROUPS

A zwitterionic monomer of 4-vinylpyridine propylsulfobetaine(4-VPPS) was prepared by the ring opening reaction of 1,3-cyclopropanesultone(PS) with 4-vinylpyridine(4-VP) at 80℃ for 20 h.Zwitterionic copolymers P(AM-co-VPPS) containing sulfobetaine groups were synthesized by copolymerization of acrylamide(AM) and 4-VPPS in aqueous solutions.The effects of 4-VPPS mole fraction in total monomer,the amount of initiator,total monomer concentration and reaction temperature on intrinsic viscosity of copolymers were investigated.The structure and composition of the copolymers were characterized by FTIR spectroscopy and 1H-NMR.The reactivity ratios of r_l(AM)and r_2(4-VPPS) had been determined to be 2.01,8.71 and 1.99,8.44 according to Finemann-Ross equation and Kelen-Tudos equation,respectively.The experimental results showed that the intrinsic viscosity of copolymers reached the maximum value 656.4 mL/g when the reaction took 12 h at 20℃,with 0.03 wt% initiator concentration,2% 4-VPPS mole fraction in total monomer and 30 wt% total monomer concentration.The experimental results from viscometry indicated that copolymers P(AM-co-VPPS) exhibited typical anti-polyelectrolyte behavior,i.e.,the intrinsic viscosity of the zwitterionic copolymer increased with increasing the amount of low molecular weight electrolytes added regardless of NaCl or CaCl_2.The increase of the intrinsic viscosity of copolymers P(AM-co-VPPS) in brine compared to that in the deionized water was strongly influenced by species and concentration of salts and the 4-VPPS mole fraction percentage in the copolymer P(AM-co-VPPS).As for copolymer P(AM-co-VPPS) containing 10.2 mol% 4-VPPS,the intrinsic viscosity increased by 47.3%,56.7% and 56.8% respectively in 1 mol/L NaCl,2 mol/L NaCl and 2 mol/L CaCl_2 compared to that in deionized water.The zwitterionic copolymers with brine induced viscosifying effect could be used in enhanced oil recovery.