新型聚合硼酸酯表面活性剂PBE的合成及其性能

Synthesis and Properties of a Novel Borate Ester Polymer Surfactant

以偶氮二异丁腈为引发剂,用N-羟甲基丙烯酰胺、硼酸三乙酯和N,N-二羟乙基十二烷基胺直接聚合合成了新型聚合硼酸酯表面活性剂PBE。采用红外光谱、核磁共振和凝胶色谱测试技术对其进行了结构表征;考察了PBE及其硼酸酯单体MBE的抗水解性、热稳定性、乳化力等性能,并由表面张力测定研究了PBE在不同溶液pH值下的表面性质。结果表明,由直接聚合合成反应,经提纯后可得白色或淡黄色固体粉末PBE,反应收率为77.2%,产物重均分子量可达Mw=28400g/mol。PBE抗水解性能强,热分解温度可达320℃,稳定性相比单体MBE有所提高。PBE的HLB值在10~13,其对石蜡油、松节油、甲苯和石油醚的乳化力明显优于单体MBE和乳化剂Tween-85。在25℃时,随溶液pH值的增大,PBE临界胶束浓度CMC明显降低,pH值在6-7时,CMC降低幅度最大,但溶液pH对γCMC影响较小;其中pH=7时,PBE临界胶束浓度CMC达到0.12g/L,γCMC为31.2mN/m,其表面活性与常规低分子量表面活性剂的应用水平相似,而优于聚乙烯醇、聚氧化乙烯-氧化丙烯嵌段共聚物Pluronic104等常规高分子表面活性剂。

With azobisisobutyronitrile（AIBN） as the initiator, a novel borate ester polymer surfactant （PBE） was prepared via the direct polymerization of N-hydroxymethyl acrylamide, triethyl borate and N, N-dihydroxyethyl dodecylamine. The structure of the compound was characterized by FHR, 1H NMR and GPC. Antihydrolysis ability, thermal stability（TG）, emulsifying power of PBE and its borate ester monomer MBE were measured, and its surface properties at different pH values were studied by the surface tension method. The result shows by the direct polymerization synthesis process, white or light yellow powders PBE can be obtained with a yield of 77.2% after purification, and the product molecular weight Mw is about 28 400 g/mol. PBE possesses a good ability of anti-hydrolysis, and its thermolysis temperature may reach 320℃, the heat stability of which is better than that of MBE. The HLB value of PBE is in a range of 10 - 13, it has apparently better emulsifying power to paraffin oil, turpentine, toluene and benzine compared with MBE and commercial emulsification agent Tween-85. At 25 ℃, the critical micell concentration （CMC） of PBE in aqueous solution significantly decreased with pH increasing, when pH varied from 6 to 7, the CMC decrease extent was the greatest. However, the pH has little influence on the corresponding γCMC of PBE. At pH = 7, 25 ℃, the CMC of PBE is 0. 12 g/L, TCMC is 31.2 mN/m; surface activity of PBE is similar to those of regular low molecular weight surfactants, and is superior to those of certain polymeric surfactants, such as PVA and Pluronic104.