Experiment § Stepwise temperature Scan
Thermogravimetric analysis (TGA) can be used to observe the thermal cracking phenomenon of polymers, as well as the content of inorganic powders. This article attempts to use it to analyze the ratio of solvent to water. The sample is sealed in the sample tray and a small hole is pierced in the center of the disk surface (Figure 1, 2) to allow water and solvent to evaporate through the small hole. Through the appropriate program setting, the solvent is switched from heating mode to constant temperature mode when it volatilizes significantly. When the evaporation of the solvent slows, switch from the constant temperature mode back to the heating mode (Figure 3). This type of programming and graphics is commonly known as a " Stepwise temperature Scan " and is used to describe a step-by-step, step-like phenomenon. It can be used to analyze samples with different proportions of water and solvents to estimate the true proportion of the sample through the consistency of the curve. Taking the unknown: H2O+BCS=98+2H2O+BCS=95+5 as an example (Figure 4), it can be observed from the curve that the unknown is quite consistent with the H2O+BCS=98+2 curve, and far from the H2O+BCS=95+5 curve, so the true proportion of the unknown is inferred to be similar to the former. Although the real proportion cannot be directly measured, it can still be analyzed indirectly through the adjustment and comparison of different proportions, isn't it amazing?
─Author: Mr. Jing-Jie, Shen
Activity § Year-end meeting in 2022
Two years later, we came to Pomegranate Country Middle School for the year-end meeting. The site is upgraded and prepared in advance to avoid oversights (Figure 1). This time a large-scale challenge was held in the auditorium, and the game brought the body movements closer together and helped to unite the team. From discussing strategies to complementing each other, to the use of hands and feet, and finally successfully (Figure 2, 3). The award ceremony announced the winners (Figures 4, 5) and shared the company's annual philanthropic deeds. We also watched the movie " Listen Before You Sing" together and still felt the inspired energy across the screen. We congratulated each other and welcomed a wonderful year.
Knowledge § EU REACH restrictions on isocyanates
PU is made up of polyols and isocyanates. Isocyanates have great reactivity, easily react with amines, alcohols, and water, and have been concerned about their use. There have been reports that exposure to isocyanates affects breathing, including reduced lung function. In some individuals who are particularly sensitive to toxicity, symptoms of wheezing and shortness of breath are observed. Isocyanates can react with polyols into prepolymers, and then vacuum to remove excess isocyanate monomers, which can greatly reduce their toxicity. At present, the European Union stipulates that the concentration of isocyanate should not exceed 0.1% (weight ratio) when used alone or in combination, unless the company can complete the use safety training before use.
Living § Earthquake Education Park
We woke up early on the weekend holidays, and on this family day, we went to the earthquake education park together. I recalled that in the early morning of September 21, 1999, a strong earthquake occurred in Nantou County, which destroyed many buildings and homes, causing serious damage and casualties. Located in the Fuxing Middle School in Wufeng, Taichung, the ground is at the crack of the earthquake, the entire school collapsed, and the occurrence of the reverse fault caused the playground of the Fuxing Middle School to split into multiple pieces, and the height of the playground ruins was nearly the height of an adult. Later, the government also built the 921 earthquake education park on the original site. In addition to the movement of the education section and earthquake prevention, the campus also restored the appearance of the middle school classrooms at that time, and even the handwashing station next to it can be used. There is also a space that simulates the intensity of the earthquake, and after entering, you can experience different seismic degrees and shaking degrees, the seismic degree is in order from the smallest to the largest, and you can stand firmly at the beginning, and then the seismic level 7 is simply shaking and unstable, and even you will be dizzy. Taiwan is located at the junction of the Eurasian plate and the Philippine Sea plate, when the plates squeeze each other, earthquakes will occur, so Taiwan belongs to the high-frequency seismic zone, dare not imagine if such a large earthquake occurs again in our lives, how much psychological and material damage will be. It is recommended to have an earthquake bag at home in case you need it!
─Author: Ms. Ying-Zhu, Huang
