Abstract: Multi-block copolymers of recurring structural units of polysiloxanes and recurring structural units of aliphatic polyesters, polyethers or polyetheresters with rubber properties, the individual polymeric blocks constituting rubber-type products with glass transition temperatures below practical usefulness and a process for their production.

Abstract: Thermoplastic moulding materials consisting of(1) 70 to 99.9% by weight of a cellulose ester or cellulose mixed ester(2) 0.1 to 30% by weight of a rubber polymer built up in the form of blocks from recurring structural units (I) with molecular weights of 10,000 to 1,000,000--A--B-- IwhereinA denotes bifunctional polysiloxane segements of the formula--(R.sup.1)(R.sup.2)SiO--.sub.x IIin whichR.sup.1 and R.sup.2 =aryl (in particular phenyl) or alkyl (in particular methyl) andx is a number such that the molecular weight is .gtoreq.500, andB denotes bifunctional aliphatic polyester and/or aliphatic polyester segments with molecular weights of .gtoreq.800,and the glass transition temperatures of the polymeric blocks A and B are less than 20.degree. C., which contains additionally(3) 0 to 30% by weight based on the mixture of (1) and (2) of a plasticizer.

Abstract: The invention relates to new block copolymers consisting of recurring polysiloxane blocks and recurring conjugated diene homo-or copolymer blocks with particularly good rubber properties, in particular at low temperatures.

Abstract: Process for the polymerization of cyclic aliphatic carbonates in the presence of aprotic organic solvents with exclusion of atmospheric oxygen and atmospheric moisture, wherein organometallic compounds of elements of main group 1 of the periodic table are used as initiators, the monomer/solvent ratio is in the range from 1 part by weight to 50 parts by weight of monomer per 100 parts by weight of solvent and the polymerization temperature is between -100.degree. C. and +20.degree. C.

Abstract: Block copolymers of recurring structural units of the series of polysiloxanes and recurring structural units of the series of aliphatic polyesters, polyethers or polyetheresters with rubber properties, the polymeric block-forming polymers in each case producing rubber-type products with glass transition temperatures below practical temperatures of use and a process for the production thereof.