丙烯酰胺/丁基苯乙烯疏水缔合共聚物的合成与表征

以丁基苯乙烯(BS)为疏水单体,采用自由基胶束聚合法合成了丙烯酰胺(AM)/丁基苯乙烯(BS)疏水缔合水溶性共聚物(PSAM),来解决该类聚合物热稳定性较差的难题。研究得到了适宜的反应条件:n(K2S2O8)∶n(Na2SO3)=3∶1,引发剂和BS相对于单体总量的摩尔分数分别为0.06%和1.45%,总单体在水里的质量分数为20%,SDS在水里的质量分数为5.5%,pH=6~7,反应温度50℃。采用该反应条件得到PSAM的临界缔合质量浓度为1 g/L,对应的水溶液表观黏度为21 mPa.s;质量浓度为2 g/L时,对应的水溶液表观黏度为78 mPa.s;质量浓度为1 g/L和2 g/L的PSAM在浓度为0.137 mol/L的NaC l水溶液中,于80℃老化120 d后的表观黏度分别为11.8 mPa.s和49.3 mPa.s,黏度保留率分别为42.1%和45.1%。通过元素分析、UV、FTIR表征了PSAM的分子结构;DSC分析表明PSAM为嵌段共聚物,两个玻璃化转变温度分别为BS链段的106℃和丙烯酰胺链段的203℃。

Synthesis and Characterization on Hydrophobically Associating Acrylamide-based Copolymer with Butyl Styrene

The copolymers(PSAM) of acrylamide(AM) with butylstyrene(BS) were synthesized by the micellar free radical copolymerization technique to improve the poor thermal stability of hydrophobically associating water-soluble copolymers.The suitable reaction parameters were found that mole ratio of potassium persulphate to sodium sulfite,mole percent of initiator and mole percent of BS relative to total monomer,mass percent of total monomer in water,mass percent of surfactant in water,reaction temperature,pH value and reaction time are 3∶1,0.06%,1.45%,20%,5.5%,50 ℃,6~7 and 12 h,respectively.Under above reaction conditions,the polymer was synthesized,which critical association mass concentration is about 1 g/L,and with the increase of polymer concentration from 1 g/L to 2 g/L,the apparent viscosity increases from 21 mPa·s to 78 mPa·s.After ageing for 120 d at 80 ℃,the apparent viscosities of 1 g/L and 2 g/L PSAM in 0.137 mol/L NaCl solution were 11.8 mPa·s and 49.3 mPa·s,respectively,and the retention ratios of apparent viscosity were 42.1% and 45.1%,respectively,showing excellent anti-ageing property of the polymer.The polymer was characterized by elementary analysis,UV and FTIR.DSC measurement shows that the glass transition temperatures of PSAM are 106 ℃ of BS segments and 203 ℃of AM segments,indicating that BS is distributed in the copolymer molecules in the form of block-structure,which is favourable to the intermolecular hydrophobic association.