Chemistry of elastomeric finishes

The mesh stracture responsible for elasticity is achieved by the condensation of a mixture of silicone prepolymers on the fabric surface. This mixture may often consist of a terminal silanol (a, co-dihydroxy polydimethylsiloxane), methyl hydrogen silane and a metal salt catalyst (Fig. 12.1). The crosslinking reaction that forms the elastic structure in shown in Fig. 12.2. Some hydrosilane groups can be oxidised by air to silanol groups. Condensation of the silanol groups of neighbouring molecules generates crosslinked structures that are necessary for elasticity. 

The incorporation of a small content of tri- or tetra-functional silanols, hydroxysilanes, acyloxy or ester derivatives is another approach that yields wide- 

2 Reaction of a silane and a silanol to form an elastomeric finish. 

ASTM D 4964 Standard Test Method for Tension and Elongation of Elastic Fabrics (Constant-Rate-of-Extension Type Tensile Testing Machine) 

ASTM D 2594a Standard Test Method for Stretch Properties of Knitted Fabrics Having Low Power 

---