(183s) Evaluation of the Influence of Fine Particle Surface Modification with Thehansen Solubility Parameters

Achieving desired functionalities with only one kind of polymeric material is challenging and composite materials are used more frequently than mono materials. To develop multiple functionalities, materials must be combined. Common processing methods include adding inorganic materials, reinforcing with fibers and laminating. Among these approaches, techniques to add inorganic materials such as copper or TiO₂, are widely used industrially to improve thermal conductivity and strength. To maximize the desired functionality, it is necessary to ensure that the additive is well dispersed in the matrix . However, there are many surface treatment agents with differing characteristics, making it difficult to select optimum silane coupling agents. The HSP is a physical property value expressed as the square root of the cohesive energy density. Hansen reported HSP values for more than 1200 organic compounds and 500 polymers.

there have been few reports comparing surfaces before and after treatment by with fatty acids. There also have been few HSP studies on the effects of silane coupling treatments. Among these reports, Su et al. prepared nanosilica treated by silane coupling agents to prepare polydimethylsiloxane composite crosslinked membranes and evaluated their mechanical properties. In that report, the authors studied the improvement in the tensile strength of the membranes though the use of HSP theory. However, existing reports of fatty acid and silane coupling agent treatments, have yet to consider the effects on the HSP values of fine particle surfaces after the surface treatments. Thus, surface treatment agents have yet to be treated by HSP theory. In this study, we report some examples of these material systems and pay particular attention to copper particles, which are important for optimizing the strength and electrical properties of rubber. Copper particles were dispersed in an organic solvent and their particle diameter was measured. The affinity of the particles for each solvent was evaluated based on the results of particle size measurements. From our affinity evaluation results, we obtained the HSP values of the copper particle surface based on the Hansen solubility sphere method. Furthermore, we performed a silane coupling agents treatment on the surface of the copper fine particles. The HSP values of the copper fine particle surface after the silane coupling treatment were determined by the Hansen solubility sphere method for the dispersibility evaluation. We investigated changes in the HSP values induced by silane coupling agent treatments. A hydrophobic silane coupling agent was selected assuming that the silane coupling agent would improve dispersibility of the particles in nonpolar substances, such as polymers. Our results show that the HSP concept can be used to select silane coupling agents to treat the surfaces of fine particle.