Spinning method of polyimide fiber
Release time:
2023-05-31
The spinning methods of polyimide fiber can be divided into wet spinning and dry spinning. According to whether the spinning slurry is polyimide or polyamide acid, there are one-step spinning and two-step spinning.
The first step is to obtain polyamide acid fiber by wet or dry spinning of concentrated solution of polyamide acid, and the second step is to obtain polyimide fiber by chemical or thermal cyclization of polyamide acid fiber spun in one step, so it is called two-step method.
Two step spinning of polyimide fiber has been widely used since the development of polyimide fiber.
The fiber stretching process can be carried out in one step, or in the process of two-step imide, or in each step.
Information
2019-05-05
What are polymer materials included?
It mainly includes three categories: plastic, chemical fibers, and rubber. There are many types of synthetic materials among them, which are made from monomers produced by petrochemical industry through polymerization reactions. Some have special properties that natural materials cannot achieve and are widely used in industrial and agricultural production and daily life, so they have developed rapidly. In the 1930s, the world's production of polymer materials did not exceed 100kt, but by the 1980s it had reached about 80Mt, with plastics accounting for 3/4. Due to the fact that plastic is lighter than metal, its production by volume has already surpassed that of metal materials.
Classification of curing agents by purpose
2019-04-29
Curing agents can be divided into room temperature curing agents and heating curing agents according to their use. Epoxy resin generally has excellent performance during high-temperature curing, but coatings and adhesives used in civil construction require room temperature curing due to heating difficulties; So most of them use fatty amines, alicyclic enantiomers, and polyamides, especially in winter when coatings and adhesives have to be used in combination with polyisocyanates, or when using odorous polyols.
What is the fine chemical industry?
2019-05-05
Fine chemical industry is a general term for the production of fine chemicals, abbreviated as "fine chemical industry". The meaning of fine chemicals is still under discussion abroad. Chemical products with the following characteristics are commonly referred to as fine chemicals, namely:
How should curing agents be selected?
2019-05-05
(1) Consider the variety and performance of curing agents. The variety of curing agents has a significant impact on the mechanical properties, heat resistance, water resistance, corrosion resistance, etc. of the cured product. For example, curing agents such as aromatic polyamines, imidazole, and anhydride have a higher heat resistance than curing agents such as aliphatic polyamines and low molecular weight polyamides in curing epoxy resins; The water resistance of aromatic anhydride cured epoxy resin is better than that of aromatic diamine and aliphatic polyamine curing agents; Triethylenetetramine curing agent has good alkali resistance, but poor acid resistance and formaldehyde solution resistance. The resistance of epoxy resin cured with alicyclic polyamines (such as isophorone diamine) is excellent. The alkali resistance of epoxy resin cured with anhydride curing agent is superior to acid resistance. Appropriate curing agents should be selected based on different applications and performance requirements.
Structural characteristics of curing agents
2023-05-29
The curing temperature of the curing agent is closely related to the heat resistance of the cured product. Similarly, in the same type of curing agent, although it has the same functional group, its properties and cured product characteristics also differ due to different chemical structures. Therefore, a comprehensive understanding of the properties and characteristics of polyamine curing agents with the same functional group but different chemical structures is crucial for selecting curing agents.
The main properties of plasticizers
2023-05-29
Plasticizers are usually structurally polar or partially polar, and are liquids or low melting point solids with high boiling points, high volatility, and good miscibility with polymers. Plasticizers are distributed between macromolecular chains, which can reduce intermolecular forces, reduce polymer viscosity, and enhance flexibility. Plasticizers are divided into two categories: main plasticizer and secondary plasticizer. The main plasticizer has a good compatibility with resins, with low permeability and volatility, which can improve plasticization efficiency.
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