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Casting is the mother of the machinery industry, certainly not a sunset industry. As long as there is machinery industry, casting is needed. For example, automobiles, high-speed railways, and subways all have many mechanical parts. Most of these parts need to be cast to obtain a general shape, and further processing can be used to obtain the parts. There are also more castings directly applied. It can be said that casting is by our side. Maybe you can't think of it. We deal with casting every day. For example, computers, air conditioners, cars, high-speed rail, washing machines, and buses. Big to power stations, rockets, airplanes. All have the shadow of casting. Put it this way, casting is one of the three major forming methods. The problem with casting is that it is too old and the simplest forming method. But it is also the cheapest and easiest method. But it is also the most complex, deepest, and most difficult science to overcome. Every place it involves can be a top-notch subject. As mentioned earlier, it is the most cost-effective molding and the most complex industry. This contradiction causes the top talents to have no better income. No one is willing to engage in casting, and casting talents are not available. Take a look at foreign aircraft engines. Its depth lies in the materials. Casting is actually the most important process among them. Such as single crystal casting, composite materials.

1.Biodegradable plastics are not easy to handle. They need centralized processing to be truly degradable, and it is difficult to distinguish whether the products are degradable. I personally think that biodegradability is only a concept, and it is necessary that all plastic products are biodegradable and people in society classify plastics in order to truly make biodegradable materials useful.
At present, people’s awareness of garbage classification is still too weak, and we should use plastics that can be recycled and processed twice. Recycling companies should collect and process plastics in order to better deal with plastics in an environmentally friendly manner.
2.There are many differences in degradable plastics from the literal meaning. Incompletely degradable plastics such as photo-oxidation degradation and starch-based degradation have been banned in Europe because they are incompletely degraded after use. The chain scission occurs under the action of photooxygen, etc., and the relatively small polymer chain is still generated, which is still a pollution to the ecological environment. Then there is the microplastic pollution that people are arguing about, which is also the main cause. Domestic regions such as Yunnan Province are still vigorously promoting such degradable plastics.
Completely degradable plastics generally mean that they will be completely degraded under certain conditions such as composting, and decomposed into environmentally harmless substances. At present, there are mainly two categories. One is petroleum-based PBS and PBAT and other completely degradable plastics, and the other One type is bio-based fully degradable plastics represented by polylactic acid. The common feature of these plastics is that they cannot be used alone, and most of them require a variety of completely degradable materials to be modified before they can be satisfactorily used. The other is that they cannot undergo environmental degradation, which means that the degradation time is very long, just like ordinary plastics in ordinary environments. In addition, the investment and production costs of these completely degradable plastics are huge. At present, the domestic planned polylactic acid production plan, due to huge investment and technical obstacles, 80% of the projects will fail. Capital prefers products such as PBAT on oil-based routes.
3.The use and characteristics of PLA and PBAT are similar to PP and PE in ordinary plastics, and they need to be added to each other for modification. At present, the main market is still abroad, and the domestic market will not develop too fast under the current policy. If you want to enter this industry, it is recommended to focus on processing and modification