Interactive Platform § What is prepreg?
Prepreg is composed of a series of fiber bundles (carbon, glass fiber) impregnated with resin. When making fiber prepreg, two types of resin are used. One is to heat the resin to reduce its viscosity and spread it evenly between the fibers, which is called hot melt adhesive type. The other is to dissolve the resin in the solvent, and then volatilize the solvent after the resin is impregnated with the fiber, which is called solvent type. In the process of hot melt adhesive method, the resin content is easy to control, the drying step can be omitted, and there is no residual flux, but the resin viscosity is high, and the fiber is easily deformed when the fiber braid is impregnated. The solvent method has low investment cost and a simple process, but the use of solvent is easy to remain in the prepreg, which affects the strength of the final composite material and causes environmental pollution. The types of fiber prepreg include unidirectional fiber prepreg and woven fiber prepreg. Unidirectional fiber prepreg has the greatest strength in the fiber direction and is usually used for laminates with different combinations of directions, while woven fiber prepreg has the greatest strength in the fiber direction. The impregnated cloth has different weaving methods, its strength is approximately equal in both directions, and can be applied to different structures. The resin of the fiber prepreg is in the stage of partial reaction and will continue to react and cure at room temperature. Usually need to be stored in a low-temperature environment. Generally, if there is no low-temperature storage equipment, the production amount of prepreg must be controlled within the principle of being able to be used up within the storage period. Fiber prepreg applications: high-performance products such as sports equipment such as golf clubs and fishing rods with high bending resistance, high toughness, and low stiffness products. Industrial use is the most developing field in the future, and various corresponding prepregs have been developed for civil engineering, energy-related, pressure vessels, transportation equipment, oil exploration, electronic equipment, industrial equipment, and other uses. Since the relevant prepreg materials are required to have certain heat resistance, impact resistance, moisture resistance, etc., the supporting resins generally use epoxy resins with medium temperature curing (130°C) ~ high-temperature curing (180°C). To improve its heat resistance requirements, Everwide Chemical is actively researching and developing prepreg materials using bismalamide resin and polyamide resin.
Experiment § How to obtain a high-resolution TGA map?
The spectrum of TGA sometimes has a gentle curve change, and the temperature of the instrument may rise again when the test piece is about to decompose. Therefore, due to the change of weight, it is easy to have errors in temperature judgment. As long as the program is rewritten in the current TGA, the resolution can be greatly improved.
The procedure is as follows: 1. Abort next segment if %/min > 5.0. 2. Ramp 10°C/min to 1000°C. 3. Abort next segment if %/min < 0.5. 4. Isothermal 1000 min. 5. Repeat 1 until 1000°C.
The five steps are: Raise 10°C ~1000°C per minute (step 2). When the weight starts to change slightly (step 1). Keep the fixed temperature and stop heating (step 4). When there is no change in weight fixation (step 3). Increase the temperature further (step 5).
Knowledge § External and internal plastination
External plasticization means that the plasticizer added to the resin will not react with the resin and will not become part of the resin structure. This type of plasticizer may migrate to the surface of the object and cause contamination in the future, or it may cause the plastic to gradually harden due to the reduction of the plasticizer content. Internal plasticization means that the plasticizer added to the resin will react with the resin and become part of the resin structure. Plastics using this type of plasticizer have relatively stable properties because the plasticizer will not migrate.
Living § Drinking
One day, a customer of our company invited all the suppliers to have a meal. When the wine was in full swing, a client asked all the people: "Have you made a lot of money from their company?" The people who were named to answer all answered politely. Some answered that it was difficult to make money because of rising raw materials. There were many reasons, but none of them admitted to making money. When it was my turn, I said, "Thank you for your cultivation, Mr. Wu, our company has made a lot of money from your company." Everyone was startled when they heard it, and thought to themselves, "This kid makes too much money, isn't he afraid of being bargained for?" Then I went on to say, "But all the money we make from your company is spent on your company.” "In the past, we used an oven to heat samples before shipping, and those products that would be cured were deemed to have passed the quality inspection." "Now every batch of shipments, we use infrared spectrometers to ensure the quality of the details of the products for you. " "In the past, our materials were applied to your parts, and the long-term applicability and reliability could not be evaluated." "Now you can send your products to our company for environmental experiments such as high temperature, high humidity, and thermal shock." "In the past, we only knew the adhesive strength of your products at 25°C, but we couldn't understand the effects of high temperature or low temperature. ." "Now it can provide adhesion strength at -40~180℃ temperature, allowing you to evaluate the reliability of products in harsh environments." "You asked me in the past: "Can resins that take five days to cure at room temperature be shipped at 80℃/1 hour? "I answer you:" It should be possible. "It can't be 100% sure." "Now we have a differential scanning card meter that will give you the correct answer within 2 hours, so you can rest assured." "All the money we make from your company is used to improve products and provide you with better service." At this point, I asked the customer: "Have we sold you such a great product, has it helped you make a lot of money? " Mr. Wu listened and said with a smile: "Yes! Just make money for this cup of soju." The guests at a table all burst into laughter. Although this is an interesting thing, it is also the belief of Everwide Chemical. "Every revenue that a customer gives us can be regarded as an encouragement and affirmation from the customer." "Behind each revenue, we should also use it with caution and pay attention to whether the customer can satisfy himself or not. Customers also expect us to improve the quality and service of our products.” I hope that all colleagues and our distribution partners will reflect on the latter all the time 364 days, and strive to improve in all aspects.
─Author: Dr. Ming-Xu, Li Everwide Chemical
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