Experiment § TGA experiment predicts material life
Thermogravimetric analysis is often used to evaluate the life of materials (Figure 1). Figure 2 represents the process of pyrolysis and weight loss of materials at high temperatures. Cracking begins at point A, and point B represents the reaction's end (the cracking reaction rate is 100%). The blue line indicates the position of the different cracking reaction rates. Using various heating rate experiments to obtain the temperature at which different cracking reaction rates occur, the kinetic parameters of cracking can be calculated. The data in the upper right corner of Figure 3: E is the activation energy of the reaction, Z is the collision factor, and Conversion refers to the cleavage reaction rate from which the parameter is calculated. Figure 3 shows that the pyrolysis of the tested material at 150°C is very slow and that at 180°C is much faster. The same data is presented in Figure 4: At 180℃, it will crack 5% in 2 years, and it will crack 10% in 4.5 years. Kinetics Cracking Study can help us calculate the data. The hard part is: Which conditions are used to calculate the parameters? How much cracking is serious? What is the correlation between material cracking and actual performance? These involve selection, judgment, and the design of other related experiments. Sometimes the correlation between the data and the real situation cannot be obtained, and another way of evaluation is needed. Sometimes the service life of material has nothing to do with high-temperature cracking, such as stress cycling, color change, toughness to brittleness, adhesion strength, etc., which TGA experiments cannot answer.
─ Author: Dr. Ming-Xu, Li
Activity § Year-end shipping matters
At the end of the year's busy hour, the manufacturing department, in addition to working hard to manufacture, has to put forward many improvement plans, work diligently, and eliminate unnecessary waste. The researchers are also so stressed. During the new DMA instrument teaching, they listened carefully to the operation details and copied notes frequently because the times are changing so fast that it is difficult to catch up. Remind everyone: Our last production and shipping date this year is 2/2 (Tue). 2/3~2/5 is a series of the annual event for plant reorganization and Everwide Chemical: the year-end meeting. 2/6~2/14 is the 9-day Spring Festival holiday. We will officially go to work on February 15th (Mon) and continue to serve everyone! With this article, I would like to bless the Biweekly News readers: The Jade Monkey is prosperous. The Year of the Monkey is auspicious, and many wishes!
Knowledge § Why are mercaptan hardeners prone to surface formation?
The reaction between Mercaptan and epoxy resin is not fast; still, adding alkaline catalyst will become faster, ranging from tens of seconds to several minutes, depending on the strength of the alkalinity. Commonly used alkaline substances are tertiary amines. Mercaptans and tertiary amines make up the hardener of epoxy resin; this formula will be affected by oxygen to produce polysulfide, so skinning occurs. This phenomenon mostly occurs on the surface of a liquid in contact with air; and the ingredients under the crust surface are not affected. Then again, measures to isolate oxygen, such as: changing the form of packaging so that there is no room for remaining air; introducing nitrogen to isolate the air, etc., can all solve this problem.
Living § Hehuan east peak special training
On December 5th last year, Ming-Xu invited Ji-Shiung and me to go to Hehuan East Peak, adapt to the environment where the mountain air is rarefied, and prepare for the end of December to climb the Yushan North Peak. It was about 5 a.m. when the car went to Wuling, and the temperature was about 3 degrees, wearing a feather coat could barely resist the cold wind. At the mountain pass next to the Songsyue Lodge, today's special training will begin. Walking on the wooden path in the dark, let the heart slowly adapt to the mountain's height. Although Hehuan East Peak is right next to the highway, the mountain is very steep, so when you reached some part of the stairs, you have to stop and take a big breath. The sky is misty, and the temperature is low, I have been waiting for the sky to light up quickly. Unexpectedly, it started to rain halfway, and there was no sign of stopping, so we had to put on raincoats and up until we reached the peak at 7 o'clock. Except for the yellow and green arrow bamboo short forest, the others are all white, and there is no view at all. I told myself that the mountain god wanted me to come again. We happily shelter behind the small bush next to the top of the mountain, ate a piece of bread, and drank a sip of cold water. When I took out the only two tissues from my pocket to wipe my glasses, I found that the toilet paper had soaked up the rain in my pocket and was unusable. In a very embarrassing situation, I suddenly remembered what Hughes had said: "Money is not comparable to tissue by the bed." Everyone was pleased when we went down the mountain because we completed the mountain guide's pre-school assignments and took a big step to Yushan.
─ Author: Ms. Su-Hui, Chen
