Polymerization compounding of HDPE/Kevlar composites. I. Morphology and mechanical properties

Abstract

The aim of this work is to perform the polymerization compounding to improve the properties of Kevlar/PE composites. The approach consists in involving the surface of a reinforcement in a polymerization process of a polymer to be used either as a matrix in the final composite or as a special surface treatment to enhance solid/polymer interface properties in the composite. The polymerization compounding process is illustrated here with the polyaramid fibers as reinforcements and polyethylene as a matrix. The number of active sites on the fiber surface, initially insufficient to anchor the catalyst, were increased by a hydrolysis reaction prior to the polymerization. The anchored catalyst was subsequently used to conduct the Ziegler-Natta polymerization reaction of ethylene. The modified fibers were incorporated into the polyethylene resin to produce composites at fiber concentrations as high as 15 wt%. The morphology of the fibers and the composites was tested using electron microscopy. Finally, the mechanical properties of the composites (in impact and tensile tests) were measured to characterize the properties of model composites. POLYM. COMPOS., 27: 129 -137, 2006.

Encapsulation of nanoparticles by polymerization compounding in a gas/solid fluidized bed reactor

“…An evident alternative to eliminate all the aforementioned negative aspects is to perform the nanoparticle encapsulation as a gas–solid reaction, where the gaseous phase contains the monomer of interest. The polymerization of ethylene via Ziegler–Natta catalyst for nanoparticle encapsulation and composite preparation has been reported by several researchers,8, 15, 16 using a liquid suspension where the ethylene gas is dissolved. We also have successfully used this procedure to encapsulate zirconia nanoparticles in hexane 11.…”

Effect of surface modification on the interface quality between hemp and linear medium‐density polyethylene

“…The mechanical properties of composite materials depend on three main factors: the strength and elasticity of the reinforcing agent, the strength and stability of the matrix, and the quality of the interface between both elements to ensure optimum stress transfer . But highly polar and hydrophilic natural fibers are incompatible with most thermoplastic matrices (nonpolar and hydrophobic) . Nevertheless, this incompatibility can be improved by modifying the topology of the fibers via surface modification .…”

Improving aramid pulp dispersion in epoxy resin via the in situ preparation of SiO2 on an aramid pulp surface

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