室温硫化硅橡胶乳液的制备与性能

通过乳液转相点法,制备了稳定性好的嵌段甲基硅橡胶纳米乳液。研究了表面活性剂的化学结构、亲水亲油平衡值对硅橡胶乳液稳定性的影响;确定了非离子乳化剂和阴离子乳化剂的复配体系;研究了复合乳化剂的复配比例和添加量对硅橡胶乳液稳定性的影响;分析了乳液转相点法的相转变机理。对硅橡胶乳液交联固化得到的弹性体的性能进行了表征。结果表明:当非离子乳化剂聚氧乙烯月桂醚和阴离子乳化剂十二烷基苯磺酸钠以物质的量比1∶1进行复配,复合乳化剂添加量10%时,硅橡胶乳液的粒径为57 nm,以3 000 r/min的速度离心30 min仍能保持稳定;固化得到的弹性体密度0.98 g/cm ³,邵A硬度43,拉伸强度1.69 MPa,断裂伸长率178.68%,各项指标均与溶剂型硅橡胶弹性体较为接近。

Preparation and Properties of Room Temperature Vulcanized Silicone Rubber Emulsion

The nano-emulsions consisting of water, block methyl silicone rubber and composite surfactants were prepared by emulsion inversion point (EIP) method. The effect of the chemical structure and hydrophilic-lipophilic balance value on the stability of the silicone rubber emulsions was examined and then the composite system of nonionic surfactant and anionic surfactant was determined. The influence of the surfactant type and the ratio of the composite surfactants and concentration on the stability of the silicone rubber nano-emulsion properties was also investigated. The mechanism of EIP was analyzed. The properties of the elastomer obtained by vulcanizing the silicone rubber emulsion were tested. The results showed that the particle size of the silicone rubber nano-emulsion characterized by dynamic light scattering was about 57 nm, meanwhile, the emulsion kept stable after centrifuged for 30 min with 3 000 r/min when the polyethylene glycol mono-dodecyl ether was mixed with sodium dodecyl benzene sulfonate at a mole ratio of 1∶1 and the composite surfactants concentration was 10%. The density, hardness, tensile strength and elongation at break of the waterborne elastomer was 0.98 g/cm ³, 43 HA, 1.69 MPa and 178.68% respectively, which were similar with that of the solvent-based silicone rubber elastomer.