These oxygen-containing chemical functionalities cause the treated particles to have high surface energy. This in turn means that the treated particles are readily wetted and dispersed in polar polymers, such as polyols. The effectiveness of treatment on wettability and dispersion is dramatically illustrated by comparing the dispersion of treated and non-treated UHMW PE particles in water.

Non-treated UHMW PE (left)

Surface-modified UHMW PE (right)

Non-treated UHMW PE (left) and surface-modified UHMW PE (right) in water. Note the enhanced wetting and excellent dispersion of the surface-modified UHMW PE

Excellent dispersion is essential if composite materials are to have good physical properties. If polymer particles are not well wetted and dispersed, clumps of dry particles result in the cured material. These areas function as voids and result in poor physical properties such as tensile strength.

The surface modification is also very important because it results in much stronger bonding between the particles (or fibers) and the matrix resin. The enhanced adhesion is a result of chemical bonding with surface functionalities and hydrogen. The improved bonding of treated particles is illustrated via scanning electron photomicrographs; (sem) comparing the failure surfaces of tensile samples made with non-treated or surface-modified polyethylene particles in a polyurethane matrix. With non-treated polyethylene particles, adhesion is so weak that the particles readily disbond at the particle/polyurethane interface. In contrast, surface-modified polyurethane particles adhere so strongly that the particles tear in half rather than disbond from the urethane.

	Non-treated polyethylene   particles in polyurethane   no adhesion
Surface-modified polyethylene  particles in polyurethane excellent adhesion

Titanium Carbide Polymer Alloys

Titanium Carbide (TiC) is one of the hardest and most abrasion-resistant materials known. Unlike other super-hard carbides and nitrides, TiC grains are not cutting or abrasive because they have rounded shapes. Since TiC has a relatively low density, its incorporation into polymers increases the density only slightly. In comparison, other metal carbides and nitrides are much denser.

INHANCE^® TiC is produced by reacting 2micron particles of TiC, coupling agents and 18 to 63 microns polyethylene.

INHANCE^® TiC products can be combined with an extremely broad array of types of polymers, ranging from polar polyurethane's to non-polar fluoropolymers. Incorporation of INHANCE® TiC, products in various polymers gives a significant increase in abrasion resistance. In highly abrasive applications, parts molded in it last much longer.

One type of plastic (UHMW PE) with 30% INHANCE^® Ti-9113 has sliding abrasion resistance that is fifty eight times (58X) greater than steel. That means that in an abrasive application, approximately 58 parts made in steel would be worn out and replaced in the lifetime of one part made in that hard phase polymer composite!

Incorporation of INHANCE^® TiC products in various polymers generally maintains or improves other physical properties such as tensile strength, flexural modulus, temperature stability, and creep resistance. These qualities are noteworthy since materials generally must have several physical attributes to be acceptable for specific applications.