羧基聚醚共改性三硅氧烷的合成及其性能研究

SYNTHESIS AND PROPERTIES OF CARBOXYL AND POLYETHER CO-MODIFIED TRISILOXANE

实验以1,1,1,3,5,5,5-七甲基三硅氧烷(MD^HM)和端烯丙基聚氧乙烯聚氧丙烯醚(APPE)为原料,在氯铂酸催化下,经硅氢加成反应先制得聚醚三硅氧烷(PETS),再将PETS与氯乙酸(CA)进行缩合反应合成一种羧基聚醚共改性三硅氧烷(CPETS)。以IR对CPETS的结构进行了表征,并对CPETS的界面性能及在农药中的应用性能进行了测定。实验结果表明:氯铂酸用量(以铂计)占总单体质量分数4×10^(-5)、MD^HM和APPE按n(Si-H):n(C=C)=1.0:1.1、反应温度80～90℃、反应时间2～4 h,得浅褐色透明液体PETS;再按n(PETS):n(CA)=1.0:1.05、反应温度65～80℃、反应时间3～4 h,减压脱低沸物30 min后,得无色至微黄色透明液体CPETS。CPETS具有优良的表面活性,其临界胶束浓度(cmc)为1.6 g/L,临界胶束浓度时的表面张力(γ_(cmc))为25.2 mN/m。在41%草甘膦异丙胺盐水剂1 000倍稀释液中添加质量分数为0.10%的CPETS后,可使该农药稀释液的γ_(cmc)由55.20 mN/m降至26.96 mN/m;接触野菠菜的瞬间接触角由68.0°降低至46.5°,30 s时的接触角由56.0°降低至32.0°。

A new kind of carboxyl and polyether co-modified trisiloxane（CPETS） was synthesized bythe condensation reaction of polyether substituted trisiloxane（PETS） with chloroacetic acid（CA）. PETS was prepared by hydrosilylation from 1,1,1,3,5,5,5-heptamethyltrisiloxane （MDH M） and allyl polyoxyethylenepolyoxypropylene ether（APPE） in the presence of chloroplatinic acid catalyst. The chemical structure of CPETS was characterized by IR. The interfacial properties of CPETS were measured, and its application was investigated in pesticide. The results show that when chloroplatinic acid （calculated according to platinum） dosage （relative to monomer mass fraction） is 4 × 10^-5, reaction temperature 80 - 90 ℃, reaction time 2 - 4 h, and MD^HM to APPE is n（Si-H） ： n（C=C） = 1.0： 1.1, PETS with a light shade of brown and limpidity was obtained. Afterwards, CPETS with a light yellow and limpidity was synthesized under the conditions：n（PETS） ： n（CA）= 1.0 ：1.05, reaction temperature 65 -80℃, reaction time 3 -4 h, and then low-boiling materials are removed for 30 rain under vacuum. CPETS exhibits excellent surface activity. The critical micelle concentration （cmc） of CPETS solution is 1.6 g/L. The surface tension （γcmc） of CPETS solution in cmc is 25.2 mN/m. When CPETS was added with 0.1% into glyphosate isopropylamin 41% AS diluted to 1 000 times with water, the surface tension of glyphosate isopropylamin solution decreased from 55.20 mN/ m to 26.96 mN/m. Its contact angles reduced from 68.0° to 46.5° at split second and from 56.0° to32.0° at 30 s on potherb spinach leaf.