PA (Polyamide, Polyamide) is an engineering plastic widely used in chemical, automotive, electronics, aerospace and other fields. In the field of raw materials for chemical production, there are two main manufacturing methods for PA: polycondensation and ring-opening polymerization. This article will introduce these two manufacturing methods in detail.
I. Polycondensation
Polycondensation method is to generate polyamide salt through the reaction of dibasic acid and dibasic amine, and then through the steps of high temperature melting, dehydration, cyclization, etc., and finally get PA. The specific steps are as follows:
1. batching: according to a certain proportion of dibasic acid and dibasic amine added to the batching tank, add an appropriate amount of water for mixing, so that it fully reacted to generate polyamide salt.
2. Melting: Add the polyamide salt into the high temperature melter and heat it to a certain temperature to make it melt into a fluid.
3. Dewatering: In the high temperature molten state, the polyamide salt is dehydrated by vacuum pumping out the water.
4. Cyclization: The dehydrated polyamide salt undergoes a cyclization reaction at high temperature to produce PA.
PA made by the polycondensation method has a compact molecular structure, excellent mechanical properties, and high heat resistance, abrasion resistance, and corrosion resistance. However, the production process of this method is more complex, requires high temperature and vacuum conditions, energy consumption.
II, ring-opening polymerization method
ring-opening polymerization method is through the ring-opening polymerization of cyclic monomers to generate PA. specific steps are as follows:
1. Preparation of cyclic monomers: through the diamine and dibasic acid lactone reaction to generate cyclic monomers.
2. Ring-opening polymerization: Under the action of catalyst, the cyclic monomer is heated to a certain temperature, so that its ring-opening polymerization to generate PA.
PA made by ring-opening polymerization has higher molecular weight, regular molecular structure, and better processing performance and mechanical properties. At the same time, the production process of this method is relatively simple, and energy consumption is low.
Overall, both the polycondensation method and the open ring polymerization method have their advantages and disadvantages, and the choice of which method to use depends on the specific product requirements and production process. In the actual production process, the most suitable manufacturing method needs to be selected based on comprehensive consideration of factors such as product performance requirements, production costs, and environmental requirements.
Regardless of which method is used, the manufacture of PA requires strict control of the quality of raw materials, reaction temperature and time, processing and other factors to ensure the quality and performance of the product. At the same time, it is also necessary to pay attention to environmental protection and safe production and other aspects to ensure that the production process complies with relevant laws, regulations and standard requirements.
Future, with the continuous progress of science and technology and environmental protection awareness, PA manufacturing methods will be optimized and improved to increase production efficiency, reduce energy consumption and environmental pollution, contributing to the promotion of sustainable development of the chemical industry.
