UHMWPE

Ultra-High-Molecular-Weight Polyethylene(UHMWPE) fiber, also known as ultra-high modulus polyethylene (UHMPE) fiber or extended chain polyethylene (ECPE) fiber, emerged in the early 1990s as the third generation of high-strength, high-modulus fibers. It has a molecular weight ranging from 1 to 6 million and a linear, straight-chain structure with nearly 100% orientation, making it the strongest fiber available with excellent mechanical properties.

As one of the world's three leading high-tech fibers (alongside the carbon fiber and then aramid fiber), UHMWPE fiber boasts resistance to ultraviolet radiation, chemical corrosion, high energy absorption, low dielectric constant, high electromagnetic wave transmission, low friction coefficient, and outstanding impact and cut resistance.

The main method for producing UHMWPE fiber is the "gel spinning-hot drawing method," based on the Tip-Contact method.

This technique uses a dilute solution of UHMWPE powder with a molecular mass over 1 million and solvents like decalin, paraffin oil, or kerosene, with added antioxidants. Manufacturers extrude the solution through a spinneret, rapidly cool it to form gel precursor filaments, and then extract and dry these filaments before super drawing to produce UHMWPE fibers.

The process unravels large molecules and maintains their state for further stretching during super drawing. This step increases the fibers' crystallinity, orientation, and transforms their structure, greatly improving their strength and modulus. The "gel spinning-hot drawing method" has become a popular technology in the industrial production of UHMWPE fibers, and it is used to make commercial fibers like Spectra and Dyneema.

Depending on the solvent, the process divides into dry spinning, using volatile substances like decalin (represented by companies like DSM and TOYOBO), and wet spinning, using solvents like mineral oil or white oil (represented by companies like HONEYWELL and Mitsui Chemicals).