耐温热敏聚合物冻胶的制备及性能评价

Preparation and performance evaluation of heat-resistant thermosensitive polymer gel

以丙烯酰胺/丙烯酰吗啉/N-乙烯基吡咯烷酮共聚物(AAN)为成胶剂、对苯二酚和乌洛托品为交联剂、硫脲为除氧剂、纳米SiO_(2)为高温稳定剂制备了冻胶,研究了聚合物、交联剂、除氧剂和高温稳定剂用量对冻胶成胶性能和热稳定性的影响。实验结果表明,聚合物链上伯酰胺基的水解是冻胶在高温下热稳定性差的主要原因,加入纳米SiO_(2)可有效抑制水解从而提高冻胶的强度和热稳定性。优化的冻胶组成为1.0%(w)热敏聚合物AAN、0.4%(w)对苯二酚、0.4%(w)乌洛托品、0.2%(w)硫脲、2.0%(w)纳米SiO2,该冻胶在165℃下的成胶时间为3 h,成胶后弹性模量为93.2 Pa,可在90 d内保持冻胶强度级别为H,脱水率小于5%;该冻胶对高渗通道有良好的封堵能力,封堵率在99.5%以上。

The gel was prepared using acrylamide-acryloyl morpholine-N-vinylpyrrolidone copolymer(AAN)as gelling agent,hydroquinone and urotropine as crosslinking agent,thiourea as deoxidant and nano SiO2 as high-temperature stabilizer.The effects of amount of polymer,crosslinking agent,deoxidant and high temperature stabilizer on the gelling properties and thermal stability of the gel were studied.The experimental results show that the hydrolysis of primary amide group on the polymer chain is the main reason for the poor thermal stability of the gel at high temperature.The addition of nano SiO_(2) can effectively inhibit the hydrolysis and improve the strength and thermal stability of the gel.The optimal composition of gel is 1.0%(w)AAN,0.4%(w)hydroquinone,0.4%(w)urotropine,0.2%(w)thiourea,2.0%(w)nano SiO_(2).The gelation time of the system at 165℃ is 3 h,the elastic modulus after gelation is 93.2 Pa,the strength level can be maintained at H within 90 d,and the dehydration rate is less than 5%.The gel has good plugging capacity for high permeability channels with plugging rate above 99.5%.