Synthesis and characterization of polyfunctional aziridine/polyester microcapsules by multiple emulsion-solvent evaporation method

Polyfunctional aziridine/polyester microcapsules as control-release waterborne cross-linker were synthesized by multiple emulsion-solvent evaporation method. The results show that, a lower surface free energy with shell polyester is more favourable for the formation of microcapsules. Full encapsulating microcapsules are synthesized with the polyester with a surface free energy of 34.5 mJ/m². Shell-to-core feeding mass ratio has a significant influence on the morphology and core content of the resulting microcapsules. Well defined spherical microcapsules with uniform shell thickness and core content at around 22% are produced at a shell-to-core mass ratio of 1:1. When 2.5% of colloid stabilizer is used, hollow spherical microcapsules are obtained. A high solvent evaporation rate results in wrinkling and porosity of the microcapsules, and an evaporation rate equivalent to solvent elimination in about 2 h provides a uniform rate of surface hardening. The characterization of the microcapsules by SEM and FTIR demonstrates that polyfunctional aziridine is encapsulated at the centre of the microcapsule. The microcapsules synthesized can be broken at a high shear rate.     

双环戊二烯马来酸单酯的合成及工艺条件优化

双环戊二烯马来酸单酯(DHCM)是一种新型的功能性单体,用于改性不饱和聚酯树脂不仅具有优异的气干性和低收缩率,而且产品色泽较浅,无胶凝颗粒、贮存稳定性好。该文研究了以顺丁烯二酸酐(MA)、双环戊二烯(DCPD)和水为原料合成DHCM的工艺,探讨了原料配比、催化剂种类、反应温度和反应时间等因素对DHCM收率及产品中w(DHCM)的影响,并通过正交实验及红外、GC-MS等进行了表征,确定了优化的工艺条件:原料摩尔比n(MA)∶n(H2O)∶n(DCPD)=1.0∶1.0∶1.0,反应温度125℃,催化剂为醋酸钠,反应时间2.5 h。在该条件下,DHCM的收率为90%,产品中w(DHCM)>85%。     

形状记忆聚氨酯材料的研究进展

形状记忆聚氨酯是一种可以响应外界刺激,并通过特定的热力学过程回复到初始形态的新型智能高分子材料。基于不同的应用,提供形状展开功能、形状固定及回复功能、形状回复率及回复力可控等性能。形状记忆聚氨酯可以通过热、电、光、磁等方式直接或者间接地激发材料的形状记忆性能,在智能纺织、航空航天、生物医用等领域具有广阔的应用前景。首先介绍了形状记忆聚氨酯的结构、记忆机理和分类;然后讨论了影响其形状记忆性能的因素,主要包括硬段种类和含量的影响、软段的种类和相对分子质量的影响、交联剂的影响、掺杂填料的影响等。在此基础上总结了形状记忆聚氨酯在不同领域的应用进展,最后展望了形状记忆聚氨酯网络结构化设计思路和未来的发展方向。     

水性裱书胶玻璃化温度对儿童卡书性能的影响研究

通过调节软硬单体的比例合成不同玻璃化温度(Tg)的聚合物乳液水性裱书胶,研究Tg对儿童卡书性能的影响,结果表明:随着聚合物Tg的降低,卡书弯曲度变小,含水率增大,卡书耐低温性能优秀,但高温容易出现开胶。     

高固低黏羟基丙烯酸树脂水分散体研究进展

介绍了羟基丙烯酸树脂的水分散规律及原理、溶液聚合的溶剂及水分散的助溶剂的选用方法。综述了制备高固体分低黏度羟基丙烯酸树脂水分散体的研究进展,主要包括提高聚合温度、选用过氧化二叔戊基等引发剂合成低分子量低交联度聚合物;合成核壳结构或以叔碳酸缩水甘油酯、叔碳酸乙烯酯、甲基丙烯酸苄酯、(甲基)丙烯酸异冰片酯、甲基丙烯酸环己酯、甲基丙烯酸叔丁基环己酯等功能单体合成枝化结构羟基丙烯酸树脂;采用多步聚合工艺制备具有特殊结构或较低分子量的共聚物,并对其原理进行了简要分析。最后总结了羟基丙烯酸树脂水分散体目前存在的一些问题,主要包括耐水耐溶剂性、稳定性、成膜性等;并对解决上述一系列问题的研究方向进行了展望,主要包括树脂结构、成膜机理、涂料配方等。     

新型结晶聚酯树脂的合成研究及表征

以对笨二甲酸、己二酸、偏苯三酸酐、新戊二醇为主要原料,通过两步法合成了一种新型结晶聚酯树脂.介绍了合成工艺及原材料的选择,通过红外光谱分析、差热分析、宽角X射线衍射分析、热重分析、扫描电镜分析等测试了其结构、形态和热性能.结果表明,合成的新型结晶聚酯树脂热稳定性很高,物理性质突出.     

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%）.     

聚酰胺胺树形大分子的应用研究进展

介绍了聚酰胺胺树形大分子作为表面活性剂在生物医药、石油开采等领域中的应用,聚酰胺胺树形大分子在制备LB单层膜、自组装单层膜中的应用,以及在制备纳米材料模板、催化剂载体、污水处理絮凝剂、药物载体等方面的应用研究进展。     

涂料体系中纳米粉体的表面改性及分散研究进展

介绍了纳米材料由于其特殊的结构层次使它具有与块状材料所不同的光、电、磁和力学性能,将无机的纳米粒子应用于涂料中能显著地提升涂料的功能性。综述了纳米涂料的表面改性、纳米粒子在涂料体系中的分散及纳米粒子改性及分散性的表征方法。     

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.