交联型丙烯酸酯乳液聚合稳定性的研究

采用半连续种子乳液聚合技术和预乳化工艺制备改性丙烯酸酯乳液。重点讨论了乳化体系、加料方式、聚合温度、电解质以及交联单体等因素对聚合稳定性的影响,并简要介绍了其控制方法。     

有机硅改性丙烯酸聚氨酯杂合水分散体的合成研究

采用侧链含活性双键的自乳化水性聚氨酯作为乳化剂和反应物,利用分子复合技术,合成了聚氨酯、丙烯酸酯和有机硅互穿网络的杂合水分散体。通过研究得出合成工艺参数为采用DMPA(二羟甲基丙酸)初始阶段与聚合物多元醇同时加入工艺制备聚氨酯并控制NCO／OH为1．5～1．6及引入交联单体TMPMEE(三羟甲基丙烷单烯丙基醚)使双键含量为0．2mmol／g左右,选择聚氨酯与共聚单体质量比为(2～1)：1,其中共聚单体中有机硅氧烷Coatosil 1706含量为4％～6％。     

湿化学法制备铋掺杂二氧化锡纳米粉体的硬团聚控制

Bismuth-doped tin dioxide （BTO） nanometer powders were prepared by the wet chemical method using tin tetrachloride （SnCl4）, bismuth nitrate EBi（NO3）3] and ammonia as raw materials. Nonbridge hydroxides and capillary force between particles were found to be key factors causing hard aggregation of BTO through analyzing the formation mechanism of hard aggregation. The hard aggregation of BTO was eliminated effectively when the Bi-Sn precursor （BSP） was treated with post processing including dispersing with ultrasonic wave, refluxing and distilling with addition of n-butanol and benzene （DRD） and drying by microwave. Characterized with X-ray diffraction （XRD） and transmission electron microscopy （TEM）, BTO spherical particles with tetragonal phase structure are well crystallized, dispersed easily and the average size was less than 10 nm.     

Preparation of aqueous dispersion of epoxy curing agent with specially synthesized phase inversion emulsifier

Generally, the curing agents for aqueous ambient-temperature-cured epoxy resin systems are epoxy-polyamine adduct, which are rendered water-soluble by salting with organic acids, while these acids have adverse influence on film property. It is a trend to develop aqueous dispersion of epoxy curing agent free of organic acids. The conventional surfactants are not suited to act as phase inversion emulsifiers to prepare aqueous dispersion of epoxy-polyamine adduct. So a special phase inversion emulsifier TETADGEPG-EPON834 was synthesized in two steps. Firstly, diglycidyl ether of polyglycol （DGEPG） was used as the chain extender to react with triethylenete tramine （TETA） in propylene glycol methyl ether （PM） at 70℃ for about 4 h. Secondly, epoxy resin （EPON834） was used as the chain extender to react with the adduct of TETA-DGEPG in PM at 65℃ for about 3 h. Then the special phase inversion emulsifier was used to prepare aqueous dispersion of EPON828-TETA adduct terminated by E10. In circumstances of low emulsifier concentration （5%）, phase inversion was not completed at phase inversion point （PIP） （0.35）. While the phase inversion has completely finished at PIP （0.45） in the circumstances of high emulsifier concentration （10%）. A stable aqueous dispersion of EPON828-TETA adduct terminated by E10 was prepared in circumstances of high emulsifier concentration （10%）.