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Everwide Newsletter No.214

Updated: Jul 30, 2021


Experiment § Viscosity change of two-component type

The two-component epoxy resin will start to react after mixing. The method of measuring the viscosity in the laboratory is as follows: control 5g of a homogeneously mixed resin in an environment of 25°C and measure the change in viscosity (Figure 1). The data obtained by this method has nothing to do with the resin's weight and is not affected by the exothermic heat of chemical reactions and changes in ambient temperature, so the accuracy and reproducibility are better. (Figure 2) shows that the viscosity of epoxy resin increases slowly. When the client measures the viscosity change, the results obtained are almost the same. Except that the customer did not control the temperature and was affected by the ambient temperature, the most important thing was that the customer directly measured the viscosity based on the actual mixing weight (Figure 3, resin 150g). The resin will increase in temperature due to chemical reaction, resulting in a decrease in the initial viscosity (Figure 4, the initial temperature is 21°C, and the viscosity is 0.6 Pa.s; after 45 minutes, the temperature rises to 44°C, and the viscosity drops to 0.4 Pa.s). An increase in temperature will cause the chemical reaction to become faster, and the heat released will further increase the temperature, causing the reaction to become faster and faster; finally, the viscosity rises sharply and colloidizes in 75 minutes (the laboratory-measured usable time for more than 180 minutes). This viscosity change is affected by the mixing quality: the higher the mixing quality, the initial viscosity decrease, and then the sharp increase is more obvious. This experiment shows that the definition of a laboratory may not be the same as the actual application; if you can evaluate it yourself before application, you will have a better understanding.

─ Author: Miss Su-Huan, Li

 

Activity § Cleaning the exterior wall project

In recent years, air pollution has become more and more serious, not only affecting our health, but buildings are also covered with thick dust. We have a small wall-washer that can only clean the walls on the lower floors. We especially request the merchant to help clean the exterior wall during the New Year's Day holiday for thorough cleaning. The cleaning staff stood in the cage of the large crane and used high-pressure water jets to clean the exterior wall in two days. After the cleaning, the building was completely renewed, and everyone couldn't believe their eyes: the tiles and cement showed the original color and stand in front of us as wearing new clothes. As the new year is approaching, the factory plans a series of cleaning activities to sort out the dead spots in the factory area, such as the top floor, water ditches, etc., to bring us a new look in the new year.

 

Knowledge § How to reduce the odor in the resin formulation?

Certain resin formulations can have an unpleasant odor. In fact, the strange smell has nothing to do with the level of toxicity, and it has nothing to do with the concentration of volatilization.

For example, mercaptan hardeners have a strange gas smell, but they are not toxic and generally have a very low concentration; it is just that the human sense of smell is particularly sensitive to such substances. For products with a peculiar smell, the following methods are used to improve the formula: 1. Choose low-volatility raw materials, but may be limited by the raw material manufacturer's production capacity; 2. Research on odor absorber, but there are not many successful cases; 3. Add a mask to cover the original peculiar smell with a stronger smell, but it will increase the entire system's smell. Odor masking agents are currently more commonly used and effective methods, but the best choice is to use them in a ventilated place or wear a gas mask to isolate the odor.

 

Living § Challenge Yushan north peak

Dad has climbed Yushan many times, but he always feels sorry that he didn't see Yushan with his own eyes: because Yushan was at the foot when he reached the top. The best angle to see Yushan is to see the main peak from the north peak. Almost all compositions that look like majestic screens are taken from this angle. Now that we passed the test of Hehuan East Peak, of course, we immediately formed a group to march towards Yushan North Peak. In the past few years, Yushan has snowed in December, except this year; it must be waiting for us to go. Climb to Paiyun Lodge on the first day of climbing. The young colleagues in the company did not take a break and took an extra 3.5 hours to go back and forth to Yushan West Peak (3518m). Figure 1,2 is halfway to the West Peak, taking photos of the North Peak and the main peak. Everyone was excited to see the angle of the main peak from the top of the North Peak the next day. Departure is at 4 am in the next morning. After passing Fengkou, there was a trembling undercut section, and the strong wind was like a typhoon, and everyone feels like to almost die. After passing several ups and downs hillsides, we arrived at the North Peak weather station at 9:30 and then took photos of the summit at the triangle point (Figure 3, 4). There was a thick fog at that time and no clear view of Yushan but everyone is still very happy, witnessing the success of Dad and Mom at the age of 76 and 71 years old, and they all said they want to follow them. It is often said that two-thirds of Taiwan's area is high mountains, so flat land is narrow and densely populated. From another perspective, the mountains are few inhabitants, with a vast view and beautiful scenery; they are the most beautiful places in Taiwan (pictures 5~7)!

─ Author: Dr. Ming-Xu, Li


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