Experiment § Epoxy and nylon
Polymer textbooks tell you that crystalline thermoplastic polymers have Tm (melting point) and Tg (glass transition temperature), while non-crystalline thermoplastic polymers and thermosetting polymers have only Tg. This statement is correct, but the picture on the left is the result of a DSC heating scan after a certain epoxy resin is cured. From the picture, you can find the Tg (100℃) of the epoxy resin after curing and the endothermic peak above 180°C. The appearance of the former Tg is easy to understand, but how can there be a signal of the latter Tm? In fact, there is a special nylon powder with a particle size of only a few millimeters (5-20um), which can be dispersed in liquid epoxy resin. When the epoxy resin is cured, the nylon powder is evenly dispersed in the solid epoxy resin, which can improve the toughness of the resin. Since this kind of nylon is a crystalline thermoplastic polymer, the endothermic curve of crystal melting appears at high temperatures. In other words, this DSC spectrum is the result of thermosetting epoxy resin blended with thermoplastic nylon powder. Textbooks only talk about principles. Many practical situations require more experimentation, reading more books, and more thinking before they become effective knowledge.
- Author: Dr. Ming-Xu, Li Everwide Chemical
Activity § Everwide Chemistry-Dale Carnegie Training
In order to let everyone learn about interpersonal communication and teamwork, Everwide Chemical has cooperated with Carnegie Training this year to launch two Dell Carnegie training courses with a total of 64 people. www.carnegie.com.tw/index.php?FC=CD The first batch will officially start on February 23. During the class, the students interacted enthusiastically with the lecturers and teaching assistants. During the discussion, the laughter continued, and everyone didn't want to end the class until they stepped out of the classroom. Everyone looked forward to the next week's class. I believe that after 12 weeks of training, every colleague can enjoy the joy of work more and face life with enthusiasm and optimism.
Knowledge § Matters needing attention in soft epoxy resin
(1) In terms of mechanical properties, soft epoxy resin can reduce internal stress and improve thermal shock capability. However, soft epoxy resins have poor performance in repeated flexing, so it is necessary to avoid the application in this case. (2) In terms of application temperature, the application temperature of soft epoxy resin made of non-reactive plasticizer is lower, and the phenomenon of plasticizer volatilization must be prevented, so it is generally suitable for use at room temperature. The application temperature of the soft epoxy resin made by the reactive plasticizer is relatively high, and long-term use below 100°C is mostly no problem. However, temperatures above 150°C may cause aging reactions, which will make the colloid hard, brittle, and darker in color. (3) In terms of formulation compatibility, attention must be paid to the long-term compatibility between non-reactive plasticizers and resins. If the compatibility is not good enough, the non-reactive plasticizer may migrate to the surface of the cured product, causing sweating and pollution. (4) In terms of hardness stability, soft epoxy resins generally have a tendency to gradually increase in hardness. In addition to the above-mentioned increase in hardness due to high application temperature, volatilization of plasticizer, or structural aging, many cases are affected by changes in the reaction rate of the resin. Since the reaction rate of soft epoxy resins is generally slow, often after measuring the hardness of the cured product, the reaction rate slowly increases, which causes problems in evaluating the hardness. Regarding this situation, we can use a slightly higher temperature to accelerate the curing reaction and obtain a more accurate final hardness. We must also let customers understand the reason why the hardness of the soft epoxy resin changes greatly. (5) In terms of material cost, due to the difference between reactive and non-reactive plasticizers, the quality and price of soft epoxy resin on the market are also very different, so in the research and development stage, we should clearly understand the needs of customers and decide the reasonable price.
Living § Have you got a master's degree?
Recently, I was looking for R&D talents from the job hunting website, and the final discovery surprised me. The current master's degree may be similar to the previous junior high school graduation. My interview question is: "20g of sugar added to 80g of water will become 100g of sugar water with a concentration of 20%. How much more water must be added to this 100g of sugar water to become 5% sugar water?" There may be more than half of the master's students who can't answer. Both of the two masters of chemical engineering I interviewed this year gave wrong answers, which shows that their foundation is very fragile since they were young. At my age, high schools had to take the joint exams, and universities also had to take the joint exams. If you don’t pass the high school entrance exam, you will go to the higher vocational exams and prepare for employment. The college acceptance rate is less than 50%, and you will feel embarrassed if you pass the exam. Since I was a child, I was worried that I could not keep up and fail to get a good school. I have lived in my thirties, and I have dreamed of taking an exam several times, but the fear of not being prepared for it shows how stressful I was when I was studying in the past. Now it is advocating exemption from examinations to study, happily learning, and opening the door to universities. The university is afraid that if it fails to recruit people, it will close down and accept all kinds of students. Many people graduated from the master's class, but even the university spells it wrong, and it is written as university; .major is spelled as majeor. This is the current master's level! Our education system allows many people who shouldn't go to university or graduate school to obtain academic qualifications, but their abilities will never have a corresponding output value. I don't know who should be responsible for this phenomenon? It can pass once by accident but it is impossible to pass it all the time. If the future generation only has the bubble value of kuso online auctions, can everyone accept Taiwan's change? If your values are still in the age of the entrance exam, you must pay close attention to your children, because school education has begun to be irregular now.
─Author: Mrs. Hui-Xu, Li R&D Engineer, Everwide Chemical
Thriving 是奮發向上的意思，是永寬的電子報 內文編輯: 李姮蓉 版面設計: 曾文政 電子郵件：service@everwide.com.tw
