Glass fibre reinforced cement - treated with gaseous silicon tetra:fluoride to give improved retention of mechanical properties

摘要

Glass fibre reinforced cement composites with improved durability are made by treating the material with gaseous SiF4. The treatment is pref. carried out in an autoclave, until the Ca(OH)2 in teh inter filamentary spaced has been converted into CaF2. The treatment reduces the level of alkalinity of the prod. so that long term degradation of the glass fibres by the alkaline cement is reduced and the prod. retains its high initial mechanical strength for long periods. Conversion of the inter filamentary crystalline Ca(OH)2 into CaF2 reduces the physical pressure on the glass fibres and thus reduces mechanical damage to the fibres. The SiF4 penetrates deep into the interior of the body, in contrast to CO2 previously used. Treated prods. have improved resistance to household chemicals.