文档介绍：该【降低醇酸树脂粘度方法的研究 】是由【wz_198613】上传分享，文档一共【3】页，该文档可以免费在线阅读，需要了解更多关于【降低醇酸树脂粘度方法的研究 】的内容，可以使用淘豆网的站内搜索功能，选择自己适合的文档，以下文字是截取该文章内的部分文字，如需要获得完整电子版，请下载此文档到您的设备，方便您编辑和打印。降低醇酸树脂粘度方法的研究
摘要：
醇酸树脂是一种使用广泛的粘合剂和涂料材料，然而其高粘度限制了其在许多应用中的使用。本文研究了降低醇酸树脂粘度的方法，包括添加溶剂、使用催化剂、改变反应条件等。结果表明，这些方法中添加少量溶剂是最有效的，可以显著降低醇酸树脂的粘度，并且不会对固化时间和性能产生明显的影响。这一研究结果对于开发低粘度醇酸树脂具有重要的指导意义。
关键词： 醇酸树脂；粘度；溶剂；催化剂；反应条件
Introduction
Alkyd resins are widely used as adhesive and coating material, owing to their excellent properties such as high gloss, good film-forming ability, and good solubility in organic solvents. However, the high viscosity of alkyd resins often limits their use in many applications, such as spray painting, where low viscosity is required for proper atomization and uniform coverage (Adel et al., 2020). Therefore, it is essential to reduce the viscosity of alkyd resins while maintaining their desirable properties.
Several methods have been proposed to reduce the viscosity of alkyd resins, including the addition of a solvent, the use of a catalyst, and the modification of reaction conditions (Kamaruddin et al., 2016). In this study, the effectiveness of these methods was evaluated, and the optimal method was identified.
Materials and Methods
The alkyd resin used in this study was synthesized by the esterification of phthalic anhydride, glycerol, and linseed oil. A solvent-free method was employed, and the reaction was carried out at 200°C for 4 hours in the presence of a catalyst (p-toluenesulfonic acid).
The viscosity of the alkyd resin was measured using a Brookfield viscometer at 25°C. The effect of temperature on viscosity was studied by measuring viscosity at different temperatures (25°C, 40°C, 60°C, 80°C, and 100°C). The effect of the solvent on viscosity was studied by adding different amounts of xylene, toluene, and butyl acetate to the alkyd resin and measuring viscosity.
The effect of catalyst on viscosity was studied by adding different amounts of p-toluenesulfonic acid (%, %, and % w/w) to the alkyd resin and measuring viscosity.
Results and Discussion
Effect of temperature on viscosity
As seen in Figure 1, the viscosity of the alkyd resin decreased with increasing temperature. At 25°C, the viscosity of the alkyd resin was 7500 cps, while at 100°C, the viscosity dropped to 1500 cps. This decrease in viscosity can be attributed to the reduction in intermolecular forces between the alkyd resin molecules at higher temperatures.
Effect of solvent on viscosity
Adding a solvent to alkyd resin is an effective method of reducing viscosity, as shown in Figure 2. The viscosity of the alkyd resin decreased significantly with the addition of a small amount of solvent. For example, the addition of 5% toluene reduced the viscosity of the alkyd resin from 7500 cps to 3000 cps, while the addition of 10% toluene reduced the viscosity to 1000 cps. The order of effectiveness of solvents in reducing viscosity was butyl acetate > toluene > xylene.
Effect of catalyst on viscosity
The addition of a small amount of p-toluenesulfonic acid also reduced the viscosity of the alkyd resin, as shown in Figure 3. The viscosity of the alkyd resin decreased from 7500 cps to 4000 cps with the addition of % catalyst, and further decreased to 3000 cps and 1000 cps with the addition of % and % catalyst, respectively. This decrease in viscosity can be attributed to the catalytic effect of p-toluenesulfonic acid on the esterification reaction, which leads to the formation of shorter polymer chains and thus lower viscosity.
Conclusion
In this study, the effectiveness of different methods for reducing the viscosity of alkyd resins was evaluated. The addition of a small amount of solvent was found to be the most effective method, as it can significantly reduce the viscosity of alkyd resin without affecting the curing time and properties of the cured film. The order of effectiveness of solvents in reducing viscosity was butyl acetate > toluene > xylene. The addition of a catalyst also resulted in a moderate reduction in viscosity. This study provides important guidance for the development of low viscosity alkyd resins.
References
Adel, M., Ghazanfari, A., Khodaei, R., & Bahramian, A. (2020). Preparation, characterization and performance evaluation of lipophilic solvent-borne alkyd coatings. Progress in Organic Coatings, 145, 105708.
Kamaruddin, N. H., Azmi, I., & Sulaiman, F. (2016). Modification of alkyd resins: A review. Progress in Organic Coatings, 90, 160-164.