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Everwide Newsletter No.160

Updated: Aug 10, 2021


Experiment § Density detection method of lightweight materials

In order to meet the "lightweight" requirements of composite materials, we have developed many foam materials and lightweight soils. Customers are always curious to ask: "What is the proportion (or density) of the product?" At present, the most commonly used method is to make a calculation based on the physical properties of water (density = 1 g/cm3) and Archimedes' principle. The steps are as follows: 1. Measure the weight of the object to be tested (Figure 1, 2.473g). 2. Put the test object into the water. Since the density of the foamed material is less than 1, it means it will float on the water. The object to be measured is pushed into the water through the mechanism of the density meter, so the scale shows a negative value. This value represents: the weight of the test object in the air minus the buoyancy of the test object in the water is equal to the volume of the test object in the water multiplied by the water density (Figure 2, -3.207g). 3. The weight of the test object in the air minus the buoyancy of the test object in the water and then divided by the density of the water is equal to the volume of the test object. 4. Use the formula of "Density = Weight / Volume" to calculate the density of the object to be measured. The above figure is an example [2.473g-(-3.207g)] ÷ 1g/cm3 = 5.68cm3, so the density of the object to be measured is 2.473g ÷ 5.68cm3 = 0.435g/cm3. This method of measurement seems more complicated, but the data is quite accurate. Please refer to Figure 3 for related organizations.

——Author: Mr. Jing-Rong, Li

 

Activity § Tensile test pieces piled into hills

Adhesive strength is important data for customers to judge the quality of the adhesive. We Everwide have many types of equipment to measure this characteristic. From kilogram-level push-pull force gauges to 1 ton and 30-ton tensile machines, the experimental temperature ranges from -40 to 180°C. The experimental design includes the execution of various processing conditions and environmental testing conditions. The permutation and combination of these test requirements are quite amazing, so we make a large number of tensile test pieces to do experiments. When these test pieces were pulled apart, they could not be reused because of deformation and rust, so we collected them in the bucket, accumulated a considerable amount, and sent them to the resource recycling field. In the past five years, we have used about 90,000 pieces of aluminum, weighing 600 kilograms, and they will pile up into a hill when placed on a truck. These test films record our arduous process of developing high-strength adhesives. I can’t believe we have done so many experiments! May this article wish everyone full of energy in 2014.

 

Knowledge § Why do some one-component epoxy resins have bubbles after baking?

There are several reasons for the formation of bubbles after heating and curing of one-component resin: 1. The reaction exotherm is too violent, and when cracking occurs, the volume of the resin will greatly expand, which looks like foam. The above-mentioned problems can be solved by lowering the reaction temperature and prolonging the reaction time. 2. This phenomenon occurs when certain components in the resin formula have smaller molecular weights and higher volatility. For example, there are some diluents, catalysts, one-liquid hardeners, and so on. This phenomenon can only be eliminated by changing the formula. 3. Air bubbles in the glue itself. Putting the glue on the glass and inspecting it, we can see whether there are bubbles in the glue before curing or bubbles that escape from the glue after curing. If no bubbles occur on the glass sheet, then it can be judged that the bubbles are caused by the influence of the substrate. 4. The substrate absorbs moisture and is damp, and releases bubbles caused by water vapor at high temperatures. The most common example is PC or Nylon. The solution can be to heat the substrate above the processing temperature (preferably above 100°C) for a period of time to eliminate this phenomenon.

 

Living § Japan Travel

Our biggest breakthrough last year was the two trips to Japan. Both of these trips included visits to exhibitions and visits to raw materials vendors. The feeling of visiting the exhibition in Japan this time is very different from previous experience: on the one hand, there is a language barrier, and both parties must communicate in poor English and Japanese. But as long as we have the courage, we can all understand each other. On the other hand, the content of the exhibition itself exposes many of the latest technologies, which makes us eager to watch, eager to take photos, take notes, and obtain data, and also eager to go back to China and try it out. The visit to the raw material factory gave us a great shock. When we discuss issues, we are often surrounded by five or six R&D personnel asking for details. When we visited the site, the employees at each station would stop their work and bow to us. We found that the supervisor and the employees of the factory had a good interaction, and they always had polite conversations. A factory may be a special case, but when the factories we visit all have these characteristics, we can't help but guess: this is the ideal state of the integration of work, life, and culture. We went to Tokyo Tower, Meiji Jingu, and other scenic spots. We also visited the University of Tokyo to see what the world’s top universities look like (ranked 21 in the world, 1st in Asia, 8 Nobel Prize winners, the photos are famous landmarks Yasuda lecture hall). Finally, with his head full of memories, he returned to his warm home.

─Author: Miss, Miao-Ling, Lin and Mr. Jing-Lie, Chen


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