Poly(dimethylsiloxane) sealant with improved properties by blending with vinyl polymers

Novel adhesive sealants with markedly improved mechanical and durability properties have been prepared by blending poly(dimethylsiloxane) with PVC or (VAc-VC) copolymer. The effect of blending with the vinyl-type polymer, the influence of three types of substrates (California redwood, aluminum, or Portland cement mortar), and the effect of weathering on the properties of the PDS or the resulting products were assessed by stress-strain testing and toughness determinations. The morphology of unblended PDS and the PDS-based blends was studied by SEM observation in conjunction with EDXA and DSC measurements. Results have indicated considerable improvement in mechanical properties and enhanced weathering resistance in some of the blends used in conjunction with either wood or aluminum substrates.