Stabilizers for polymer foams based on recycling of polydimethylsiloxane

A process for producing polyether polydimethylsiloxanes, comprising:

• (a) submitting a recycled-polydimethylsiloxane-containing composition, comprising a recycled linear polydimethylsiloxane to an equilibration reaction with at least one poly(methylhydrogen)siloxane in the presence of at least one equilibration catalyst to form a poly(methylhydrogen)-polydimethylsiloxane copolymer;
• and
• (b) submitting the poly(methylhydrogen)-poly dimethylsiloxane copolymer obtained in (a) to a hydrosilylation reaction with at least one polyether, comprising at least one carbon-carbon double bond reactive to Si—H bonds to obtain a polyether poly dimethylsiloxane,
• wherein the recycled linear poly dimethylsiloxane is obtained from recycling of at least one linear polydimethylsiloxane or copolymer thereof,
• wherein recycling of the least one linear polydimethylsiloxane or copolymer thereof, comprises:
• (c) submitting a polydimethylsiloxane-containing composition, comprising at least one linear polydimethylsiloxane or copolymer thereof to catalytic depolymerization in the presence of at least one depolymerization catalyst to form at least one cyclic polydimethylsiloxane in a depolymerization reaction mixture;
• (d) distilling the depolymerization reaction mixture to obtain a cyclic-polydimethylsiloxane-containing composition, comprising at least one cyclic polydimethylsiloxane;
• (e) optionally submitting the cyclic-polydimethylsiloxane-containing composition to a fractional distillative purification;
• (f) submitting the cyclic-polydimethylsiloxane-containing composition, comprising the at least one cyclic polydimethylsiloxane to a polymerization reaction in the presence of a polymerization catalyst to obtain the recycled linear poly dimethylsiloxane in the recycled-polydimethylsiloxane-containing composition;
• and
• (g) optionally purifying the recycled-polydimethylsiloxane-containing composition.