1. Aramid fiber

The full name of aramid fiber is aromatic polyamide fiber. It is a linear polymer composed of aromatic groups and amide groups. It has excellent mechanical properties. Stable chemical structure. Desirable mechanical properties. It has ultra-high strength, high modulus, high temperature resistance, acid and alkali resistance, and light weight. Wear resistance and other excellent properties.

Compared with ordinary flexible polymer molecular chains. The main chain structure of aramid fiber is mainly composed of a rod-shaped molecular structure formed by paraposition of benzene rings. Due to the presence of large conjugated benzene rings. It is difficult for molecular segments to undergo internal rotation. This results in a linear rigid structure. This rigid molecular chain easily forms a liquid crystal form. Achieve high modulus. during the spinning process. This structure also enables high-density multi-layer stacking along the fiber orientation within a limited space. Gives the polymer higher strength.

2. Classification of aramid fiber

depending on the chemical structure. Aramid fibers are divided into para-aramid, meta-aramid and heterocyclic aramid. Among them, para-aramid and meta-aramid have a wider application range.

1. Para-aramid 1414

Para-aramid is also known as polyparaphenylene terephthalamide fiber (PPTA) and polyparabenzamide fiber (PBA). It uses p-phenylenediamine and terephthaloyl chloride as monomer raw materials. In N-methylpyrrolidone (NMP)-calcium chloride. Obtained by low temperature solution condensation polymerization.

The main chain structure is mainly composed of a rod-shaped molecular structure formed by benzene rings in paraposition. Due to the presence of large conjugated benzene rings. It is difficult for molecular segments to undergo internal rotation. This results in a linear rigid structure.

2. Meta-aramid 1313

Meta-aramid is also known as poly-m-phenylene isophthalamide (PMTA) fiber. It uses m-phenylenediamine and isophthaloyl chloride as raw materials. It is produced through process steps such as polymerization reaction, neutralization reaction and spinning.

Compared to para-aramid. The covalent bonds of the molecular chain of meta-aramid have no conjugation effect, and the rotation potential within the molecular chain is lower than that of para-aramid. The flexibility of the macromolecular chain is stronger than that of para-aramid. The fiber crystallinity is smaller than that of para-aramid.