Synthesis of hydrophobic crosslinkable resins

After reviewing the literature relating to the synthesis and properties of hydrophobic materials, and then considering potential methods for their synthesis, a route for the preparation of novel materials was chosen. A reaction scheme involving the condensation of an excess of 1,4-bis (chloromethyl) benzene with bisphenolic compounds, and conversion of the resultant chloromethyl products to their vinyl analogues is described. A variety of methods were used to accomplish the initial etherification. The use of dimethyl acetamide and potassium carbonate was found to reduce the incidence of side reactions. The vinylation stage, using the Wittig reaction was also studied. The products were characterised by NMR and IR spectroscopy and by gel permeation and high perfonnance liquid chromatography. The curing reaction of the vinyl terminated material was studied using differential scanning calorimetry. The reaction product derived from bisphenol A was cured into various specimens, and the physical properties of the material examined. The polymer combines reasonable mechanical properties with one of the lowest water absorption maximov reported in the literature for non-fluorinated thennosets. On immersion in water at 700 C. the absorption maximov was 0.28% by weight. The thermooxidative degradation of the base material was also examined