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采用粒子设计、聚合物形态的概念,以St为核单体、BA为壳单体,十二烷基苯磺酸钠(DSB)和烷基酚聚氧乙烯醚(OP-10)的混合乳化剂为乳化体系,K2S2O(8KPS)为引发剂,引入甲基丙烯酸(MAA)功能性单体,采用壳单体预乳化的核壳乳液聚合工艺。制备出的核壳苯丙乳液具有高Tg、低最低成膜温度和良好的稳定性。当St的用量为55.0%~57.5%、BA的用量为42.5%~45.0%时,混合乳化剂的用量占单体量的2.5%~3.0%,且m(OP-10)∶m(DSB)=2∶1,引发剂用量占单体量的0.55%~0.60%,pH缓冲剂的用量占单体量的0.55%~0.60%,当预乳化温度为45℃、反应温度为80℃,可以制备出具有核壳结构的苯丙乳液。该乳液在配制内墙涂料时可以不加成膜助剂、增塑剂和抗冻融剂,可以有效降低建筑内墙涂料的VOC。 相似文献
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The time-dependent liquid film thickness and pressure drop are measured by using parallel-wire conductance probes and capacitance differential-pressure transducer. A mathematical model with iterative procedure to calculate holdup and pressure drop in horizontal and inclined gas-liquid stratified flow is developed. The predictions agree well with over a hundred experimental data in 0.024 and 0.04 m diameter pipelines. 相似文献
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Using butyl acrylate(BA),methyl methacrylate(MMA),methacrylic acid(MAA) and mixed emulsifier as raw materials,the self-crosslinked emulsion was prepared via pre-emulsified and semi-continuous seeded emulsion polymerization technology in the presence of N-hydroxymethyl acrylamide and poly solidum maleate. The influence of mass ratio of BA to MMA,amount of N-hydroxymethyl acrylamide and poly solidum maleate on the rheological properties of the self-crosslinked emulsion was studied. Possible cross-linked mechanism of self-crosslinked monomer was investigated. And the relationship between emulsion viscosity and shear rate was investigated. The results show that the self-crosslinked acrylate emulsion with high elasticity can be synthesized when the mass fractions of BA is 60%,MMA is 40%,and added amount of N-hydroxymethyl acrylamide is 2.5%-3.0% and added amount of poly solidum maleate is 0.3%-0.4%. The self-crosslinkage process of N-hydroxymethyl acrylamide involves two steps. One is copolymerization of N-hydroxymethyl acrylamide and acrylate,the other is cross-linkage among polymer molecules via condensation reaction of methylol. The emulsion is of rheological properties of pseudo-plastic fluid and belongs to non-Newtonian fluid. 相似文献
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