Nanocomposites and High-Modulus Fibers Based on Ultrahigh-Molecular-Weight Polyethylene and Silicates: Synthesis, Structure, and Properties

摘要

Nanocomposites based on ultrahigh-molecular-weight polyethylene and inorganic fillers—such as organomodified layered aluminosilicates, aerosil, and diatomite—are prepared via polymerization filling. The polymerization of ethylene was conducted in the suspension mode with the use of a conventional Zie-gler-Natta catalyst, TiCl4 + Al(i-Bu)3, under mild conditions (a temperature of 30°C and a pressure of 0.1 MPa). The structure and properties of the composites are studied via X-ray diffraction analysis and DSC. The polyethylene matrix features a high enthalpy, a high melting temperature (up to 143°C), a crystallinity of 70-80%, a content of the monoclinic phase of 12-15%, and a bulk density of 0.05-0.15 g/cm3; the molecular mass is (1.5-1.6) x 106. High-modulus, high-strength fibers with an elastic modulus of 25-28 GPa and a strength of 0.65-0.70 GPa are prepared via direct solvent-free molding of nascent reactor powders based on ultrahigh-molecular-weight polyethylene filled (7 wt %) with aerosol or montmorillonite modified with vinyltrimethoxysilane.