HYDROPHILIC-HYDROPHOBIC POLYMER COMPOSITES

Polymer composites are of practical importance because their two phase structure often allows for a synergistic behavior regarding their mechanical properties and also for selective permeability to organic liquids. A method of preparing a new type of composite, which the authors call a hydrophilic-hydrophobic composite, is suggested in the present paper. This composite is synthesized starting from a concentrated emulsion (gel) of a hydrophobic (hydrophilic) monomer dispersed in a continuous phase of a hydrophilic (hydrophobic) monomer. In order to increase the hydrophobicity and hydrophilicity of the phases involved, and hence to ensure the stability of the gel, solutions of the corresponding monomers in decane (for the hydrophobic monomer) and water (for the hydrophilic monomer) have been employed. The gel is stabilized by an appropriate surfactant dissolved in the continuous phase. Initiators are added to each of the phases before the preparation of the gel. After the preparation of the gel at room temperature, the system is heated to 40°C for polymerization to occur. This method can be contrasted to the interpenetrating network method in which a crosslinked polymer is swelled with a second monomer and with crosslinking and activating agents, and finally subjected to a second polymerization.