PROGRESS IN PHASE INVERSION EMULSIFICATION FOR EPOXY RESIN WATERBORNE DISPERSIONS

In this review, our recent work in phase inversion emulsification （PIE） for polymer （especially epoxy resin） waterborne dispersions is summarized. Based on experimental results about PIE process, the physical model is proposed which can guide the synthesis of the waterborne dispersions such as polymer/nanoparticle composite dispersion. In the presence of a latent curing catalyst, PIE can give a crosslinkable epoxy resin waterborne dispersion. The dispersions can form cured transparent coatings with some unique properties such as UV shielding. They are promising in functional coatings, waterborne resin matrices for composites, and sizing for high performance fibers.

PREPARATION OF BISPHENOL A EPOXY RESIN WATERBORNE DISPERSIONS BY THE PHASE INVERSION EMULSIFICATION TECHNIQUE

The phase inversion emulsification technique (PIET) is an effective physical method for preparing waterborne dispersions of polymer resins. Some results concerning the preparation of bisphenol A epoxy resin waterborne dispersions by PIET in our laboratory were summarized. Electrical properties, rheological behavior and morphological evolution during phase inversion progress were systematically characterized. The effects of the emulsifier concentration and emulsification temperature on phase inversion progress and the structural features of the waterborne particles were studied as well. The deformation and break up of water drops in a shear field were analyzed in terms of micro-theology, while the interaction and coalescence dynamics of water drops were discussed in terms of DLVO theory and Smoluchowski effective collision theory, respectively. Based on the experimental results and theoretical analysis, a physical model of phase inversion progress was suggested, by which the effects of the parameters on phase inversion progress and the structural features of the waterborne particles were interpreted and predicted.

HYDRODYNAMIC AND THERMODYNAMIC EFFECTS IN PHASE INVERSION EMULSIFICATION PROCESS OF EPOXY RESIN IN WATER

The mechanism of phase inversion emulsification process （PIE） was studied for waterborne dispersion of highly viscous epoxy resin using non-ionic polymeric surfactants. Drop deformation and breakup, rheological properties, conductivity, and particle size measurements reveal the micro-structural transition amid emulsification. It is revealed that strong flow causes water drop to burst with the formation of droplets and huge interface. Phase inversion corresponds to an abrupt rheological transition from a type of viscous melt with weak elasticity to a highly elastic type of aqueous gel. This implies that the phase inversion equivalent to a curvature inversion. Based on this, a geometric model is postulated to correlate process variables to the particle size. The coverage and conformation of the surfactant plays key role for the particle size of the final emulsion. The interactions of thermodynamic and hydrodynamic effects are also discussed. It is concluded that the thermodynamics control the PIE while the hydrodynamics drives the creation of interface and involves every step of PIE.

离聚体水基微乳液化的研究──聚苯醚离聚体微乳化过程的相反转

以乙酰磺酸为磺化剂制备了磺化度为３～１７ｍｏｌ％的磺化聚苯醚（ＳＰＰＯ）并中和成盐，在一定的温度和搅拌速度下，加水将ＳＰＰＯ乳化成水包油的稳定水基微乳液．用乳化过程中的体系的电导率、粘度和表面张力的变化表征了乳化相反转过程．另外还研究了溶剂的极性和离子含量对ＳＰＰＯ溶液可乳化性和乳化过程的影响．

聚苯醚离聚体水基微乳液粒径及稳定性的研究

以乙酰磺酸为磺化剂制备了磺化度为３ ～１７ ｍｏｌ％ 的磺化聚苯醚（ＳＰＰＯ） ，并中和成盐，在一定的温度和搅拌速度下，加水将ＳＰＰＯ 离聚体溶液乳化成水包油的稳定水基微乳液。用光散射法及透射电镜法（ＴＥＭ） 测定了ＳＰＰＯ 离聚体水基微乳液的粒径及粒径分布，研究了磺化度、溶剂的极性、固含量等因素对微乳液粒径及稳定性的影响。

磺化聚苯醚离聚体微乳化过程相反转的研究

以乙酰磺酸为磺化剂制备了磺化度为 3%～ 1 7%mol的磺化聚苯醚 (SPPO)并中和成盐 ,在一定的温度和搅拌速度下 ,加水将SPPO乳化成水包油的稳定水基微乳液。用乳化过程中的体系的电导率、粘度和表面张力的变化表征了乳化相反转过程。

溶剂极性对磺化聚苯醚微乳液相反转的影响

以乙酰磺酸为磺化剂制备了磺化度摩尔分数为３％～１７％的磺化聚苯醚（ＳＰＰＯ），在一定的温度和搅拌速度下，加水将ＳＰＰＯ离聚体溶液乳化成水包油的稳定水基微乳液．用电导率、粘度、表面张力等表征了ＳＰＰＯ离聚体溶液在微乳化过程中的相反转，研究了溶剂的极性对相反转的影响．

环氧树脂水基分散体系的相反转乳化

以聚乙二醇 -邻苯二甲酸酐 -环氧树脂E -4 4多元嵌段共聚体为乳化剂 ,将环氧树脂E -4 4乳化成水包油的稳定水基乳液。用乳液体系电导率和粘度的变化表征了相反转乳化过程。研究了乳化剂浓度、三元多嵌段共聚体中亲水嵌段分子量和乳化温度对相反转乳化过程的影响。实验结果表明 ,体系在较高乳化剂浓度 (9.1 % )下为完全相反转 ,在低乳化剂浓度 (4.1 % )下为不完全相反转。相反转时水与环氧树脂E -4 4的重量比值随乳化剂浓度、乳化温度的增加以及亲水嵌段分子量的减小而增加。环氧树脂E -4 4水基乳液的平均乳液粒径随乳化温度的降低而减小。

离聚体水基微乳液化的研究——聚苯乙烯离聚体微乳化过程相反转的表征

以乙酰磺酸为磺化剂制备磺化度为３～１５ｍｏｌ％的磺化聚苯乙烯（ＳＰＳ）并中和成盐．在一定的温度和搅拌速率下，加水将ＳＰＳ乳化成水包油的稳定水基微乳液．用乳化过程中体系电导率和粘度的变化表征了乳化相反转过程．研究了溶剂的极性和离子含量对聚苯乙烯离聚体溶液可乳化性和乳化过程及乳液稳定性的影响．

漆酚甲醛缩聚物水基分散体系的相反转乳化

用复合表面活性剂将漆酚缩甲醛聚合物乳化为水包油型的稳定水基乳液。系统研究了乳化剂种类、乳化剂用量、H LB值和乳化温度等对相反转乳化过程的影响,并用乳液体系电导率变化和黏度变化表征了相反转乳化过程。实验结果表明,复合乳化剂吐温-20/司班-20乳化效果最好;高乳化剂用量和低乳化温度有利于水包油乳液的形成;当水和油的质量比(R)为1.05时,体系开始发生相反转,至R=1.4时,体系由油包水型转化为水包油型。相反转乳液粒径小,分布均匀。

乳化剂分子亲水组分含量对相反转乳化过程的影响

The effects of emulsifier molecular architecture on phase inversion process including the critical water content at phase inversion point as well as the particle size are investigated. It is found that the water content at phase inversion point reaches a maximum when the molar ratio of the hydrophilic component PEG10000 to the hydrophobic component bisphenol A epoxy resin E20 is equal to 1∶1, meanwhile, the particle size reaches a minimum (about 100 nm). From the experimental results, it can be seen that to alter the molecular architecture of the emulsifier is an effective method to control the size of the waterborne particles prepared by phase inversion emulsification technique.

非离子型水性环氧-聚氨酯乳液的制备及性能研究

以异佛尔酮二异氰酸酯(IPDI)、聚乙二醇(PEG)、环氧树脂E-51为主要原料,合成了聚氨酯预聚体接枝改性的环氧树脂,并以改性环氧树脂作为乳化剂,乳化环氧树脂E-51,通过相反转法制备了纳米级的非离子型水性环氧-聚氨酯乳液。采用红外光谱(FT-IR)对改性环氧树脂进行结构表征,通过纳米粒度分析仪和透射电镜(TEM)研究了乳液的粒径和形貌,同时研究了PEG相对分子质量和聚氨酯预聚体用量对乳液稳定性、粒径的影响。结果表明:当PEG相对分子质量为6 000,聚氨酯预聚体含量为20%时,制备的水性环氧-聚氨酯乳液的综合性能最佳,此时所制备乳液稳定性好,粒径小于150 nm。

Span-OP乳化体系下丙烯酰胺反相微乳液的制备

使用 Span80-OP7、Span80-OP10、Span80-OP15乳化体系制备了以柴油为连续相的丙烯酰胺反相微乳液,确定形成微乳的最佳 HLB 值为7.0。通过电导率法与目测法相结合绘制出体系的拟三元相图,表明以Span80-OP10作为复合乳化剂形成的反相微乳区面积较大,油相与乳化剂的最佳质量比为3:1。同时发现,在体系中添加质量分数为2%的乙酸钠可以提高丙烯酰胺单体溶液的增溶量,此时体系组成(质量分数)为:水相39.52%,油相45.36%,乳化剂相15.12%。

非离子型水性环氧树脂乳液的研制及性能研究

采用环氧树脂E-51与不同分子质量的聚乙二醇(PEG)反应合成一系列高分子非离子型环氧树脂乳化剂,并采用相反转法制备水性环氧树脂乳液,考查了PEG分子质量、E-51与PEG摩尔比、反应时间、乳化剂用量及乳化条件对水性环氧树脂乳液的黏度、稳定性、粒径的影响。结果表明:以过硫酸钾为引发剂,n(E-51)∶n(PEG-2000)=1∶1,在180℃下反应4h合成的乳化剂具有较好的乳化效果;乳化剂用量为20%,乳化温度60℃,分散机转速为3000r/min时,乳液粒径可达1.026μm且分布较窄,乳液黏度适中,具有较好的离心稳定性和储存稳定性。

相反转乳化技术制备环氧树脂交联多孔微球

This work provides a new method to prepare crosslinkable multi\|hollow micro\|spheres of epoxy resin dispersible in water by incomplete phase inversion emulsification in the presence of a catalytic curing agent.The key is to add the curing agent in the vicinity of the phase inversion point at low temperature so as to control the emulsifier capability of the pre\|curing oligomers at a low level,which ensures the achievement of incomplete phase inversion emulsification.Scanning electron micrographs of the spheres reveal that the particles size is mainly in the range of 1～10 μm with sub\|micron cavities within the spheres.DSC is used to measure the curing behavior of the spheres.Two broad exothermic peaks around 120 and 162℃ are found in the as\|prepared particles,while the first peak shifts to higher temperature 135℃ and the onset temperature exceeds 100℃ in the thermally treated sample at 95℃ for 1 5?h.This indicates that the initial step curing process under the post\|treatment conditions is nearly completed.After further treated at high temperature for example 200℃,a glass transition temperature about 130℃ is found,and the two peaks disappear due to a full achievement of the curing process.Extraction results show that after treated at 95℃ for 1 5?h in water,the micro\|sized spheres become insoluble.It is concluded that the entitled waterborne microspheres are crosslinkable and multiporous.A preliminary result demonstrates a potential application of the entitled multi\|hollow spheres as opacifiers due to their intensive light scattering within the hollows.

无皂相反转乳化法制备高分子水基分散体系

Based on the insight into the mechanism of phase inversion emulsification in the presence of curing agents, a new method called surfactant free phase inversion emulsification was proposed to prepare epoxy resin waterborne dispersions. The waterborne particles are in sub micron range with narrow size distribution. Transparent cured films could be formed from the dispersions even at ambient temperature. The stability of the dispersions could be enhanced by post polymerization at a high temperature for some time. The knowledge about the phase inversion and the stability of the waterborne dispersions might provide a new way to enhance oil recovery.

乳化工艺对水性聚氨酯乳液及性能的影响

以异佛尔酮二异氰酸酯(IPDI)、聚醚二元醇(N220)为主要原料合成了脂肪族水性聚氨酯乳液,研究了乳化温度、中和方式、分散方法、叶轮转速及降粘方法对水性聚氨酯乳液及涂膜性能的影响。结果表明,温度在25~30℃左右,采取直接分散和后中和工艺能得到综合性能优异的水性聚氨酯乳液;如以水和丙酮降粘,水温20℃,水与丙酮的质量比应低于3∶1。

转相乳化法制备零VOC水性醇酸乳液的实验研究

采用转相乳化法制备了零VOC水性醇酸乳液.探讨了乳化剂配比、用量及乳化时间等对乳液性能的影响.结果表明:乳化剂的质量比为1∶1,乳化剂用量4%时,乳化时间为3 h^4 h时,乳液稳定性最好,平均粒径为170 nm.

自乳化水性环氧防腐涂料乳液的探索研究

通过相转化法,用磷酸和丙烯酸及其酯类单体对环氧树脂进行改性,得到了一种性能优良的自乳化水性环氧防腐涂料乳液,主要用于容器内壁的防护装饰。

溶剂极性对聚苯醚离聚体微乳液相反转影响的研究

以乙酰磺酸为磺化剂制备了磺化度为 3%～ 1 7% (摩尔比 )的磺化聚苯醚 (SPPO)。在一定的温度和搅拌速度下 ,加水将SPPO离聚体溶液乳化成水包油的稳定水基微乳液。用电导率、粘度、表面张力等表征了SPPO离聚体溶液在微乳化过程中的相反转 ,研究了溶剂的极性对SPPO微乳化过程相反转的影响。