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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.

What is the fine chemical industry?


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?


(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


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


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.

Spinning method of polyimide fiber


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.

How to use epoxy resin curing agent?


1. Replace high toxicity curing agents with low toxicity ones. 2. Improve the operating environment, consciously separate the operating area from the non operating area, automate and seal it as much as possible, install ventilation facilities, and so on.

The role of curing agents


The physical and chemical properties of the curing agent have a significant impact on toxicity. For example, whether a curing agent is liquid or solid, its toxic effects vary. Solid state can easily adhere to the skin, while liquid state has vapor pressure. Generally speaking, if the chemical activity of the curing agent is high, its biomass activity is also strong, which is prone to toxicity, and it seems to be a rule. The toxicity of curing agents is manifested in the following aspects.

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