Experiment § Simple evaluation method for reaction exotherm
When the epoxy resin reacts, it will release heat, causing the temperature of the resin to rise. Using thermocouples and timers to record the relationship between temperature and time is a simple evaluation method.
Figure 1: Two resins with different reaction speeds have different temperature rises. The resin with a faster reaction rate rose to 86°C after 13 minutes. Under the same conditions, the resin with a slower reaction rate, the highest temperature reached in 15 minutes, is only 48°C.
Figure 2: The same resin, different quality, the range of temperature rise is also different. The reaction exotherm is easily balanced with the surrounding environment in a system with a small mixing weight, so the temperature change is relatively gentle. In a system with a large mixing weight, the reaction exotherm is less likely to dissipate, so it will cause its temperature to rise sharply.
Figure 3: The same resin, the same quality, different heat dissipation areas, and temperature changes are also different. The exact weight of AB was mixed and placed in a cylindrical container with a diameter of 6.5 cm and 11 cm. The former heat dissipation area is small, and the temperature rises quickly, and the temperature reaches the highest peak of 167°C in just 8 minutes. The latter has a larger heat dissipation area, and the rate of temperature rise is relatively slow. The maximum temperature at 13 minutes is 86°C.
─Author: Dr. Ming-xu, Li, R&D Engineer, Everwide Chemical
Activity § Information integration platform-e-resources
Thriving! This is the slogan of the Everwide Chemical Electronic Newsletter, which means: Prosperity and Prosperity.
Our e-newsletter is published in the form of a bi-weekly report. In addition to introducing software and hardware facilities, it also provides a lot of chemical information and experimental experience to let everyone know more about Everwide Chemical. Every half month, many readers write e-mails to tell us the advantages and disadvantages of the current newsletter. "Your newsletter in this issue is wonderful!" Every time we receive encouragement of this kind, we are pleased, and we can't wait to edit the following newsletter right away. The content of many newsletters is extracted from our intranet "Everwide e-School." This intranet has information such as knowledge exchange, work experience, project research and development, and easy sketches, etc. At present, there are more than 2,500 articles, which shows that the company's colleagues love this communication platform. Enter "Everwide e-Academy" to see what's new, and it has become a hobby shared by many colleagues every day. From "electronic newspaper" to "Everwide e-school," we eagerly demonstrate the liveliness and innovation of the word world and also inject rich and diverse elements into the company.
Knowledge § What is the catalyst for the reaction of epoxy resin and fatty amine?
The answer is alcohol and phenols.
Alcohols are weaker in acidity and have a poor catalytic effect. The more commonly used alcohol is benzyl alcohol. Phenols are slightly more acidic and have better catalytic effects. The most widely used alcohol is nonylphenol. Because phenols are toxic and are considered environmental hormones, their use will gradually be restricted. Many Japanese raw material manufacturers have discontinued the production of products containing phenols, which is the direction to be paid attention to in research and development. Substances with greater acidity than phenols are not suitable for catalyzing the reaction between epoxy resins and fatty amines. Excessive acidity may cause fatty acids and catalysts to react to form fatty ammonium salts.
Living § Globe making (2)
To get to know the earth, first, find out the north and south poles of the earth, further find out the equator, further distinguish the color position of the ocean and land, and point out the Taiwan where I live. Finally, I asked the children to tell where they wanted to go most. Explain why? They will start to tell where they want to go. Some children say he wants to go to Antarctica because he can ski. Another kid said that the Antarctic ozone layer has broken holes, and the skin is harmed if you go to Antarctica.
It may be difficult for a 7 to 8-year-old child to remember the names of the oceans, land, and countries on the earth, but it is easier for them to observe and find out by themselves. How to let children draw the continents of the earth? I first put a rubber band around the middle of the earth and then used a black oil pen to draw the equator and divide it into the upper and lower hemispheres. The left and right molds initially shot this plastic ball, so there is a bonding line, and that bonding line can just be used as an international date line. In this way, a sphere is divided into four equal parts; I took out the breathable medical tape and pasted a circle so that it is perpendicular to the international date line and the equator at the same time, so that the sphere is just divided into eight equal parts, and an eight-part sphere needs The positioning will be much more accurate. My child and I spent an hour or two drawing each continent's land. Although it was not easy, I was very moved to see A Xin, who was suspected of being hyperactive by the school teacher, carefully drawing the map. When we were drawing the globe, apart from everyone knowing that Italy kicked rock-like boots, we also accidentally discovered that the island of New Guinea * looks like a dinosaur; and a particular terrain in northeastern Canada looks like a fox. These are all exciting things discovered in the process of painting the earth.
* The attached picture shows the island of New Guinea, shaped like a dinosaur, and is the second-largest island in the world. The land located east of 141 degrees east longitude belongs to Papua New Guinea; the land located west of 141 degrees east longitude belongs to Papua and West Papua provinces in Indonesia.
─Author: Ms. Miao-ling, Lin, R&D Engineer, Everwide Chemical
