Thermoplastic, crystalline block copolymers are disclosed, each comprising a plurality of recurring units selected from the group consisting of those of the structural formulae F1 and F'1, and combinations thereof: F1: -A [SiR2 (GSiR2)aASiR2G'SiR2A]pSiR2(GSiR2)aASiR2(OSiR2)n] and F'1: -A [SiR2G'SiR2ASiR2(GSiR2)aA]pSiR2G'SiR2ASiR2(OSiR2)n] in which the symbols A, which are identical, represent linear or branched chain alkylene radicals having from 2 to 6 carbon atoms, or cyclohexylene radicals; the symbols R, which are identical or different, represent alkyl and halogenoalkyl radicals having from 1 to 5 carbon atoms, cycloalkyl and halogenocycloalkyl radicals having from 3 to 8 carbon atoms, aryl and halogenoaryl radicals having from 6 to 8 carbon atoms or cyanoalkyl radicals having from 3 to 4 carbon atoms; the symbols G, which are identical, represent linear or branched chain alkylene radicals having from 1 to 8 carbon atoms, divalent organic radicals corresponding to the formula F2: -CH2)xQTQ(CH2-x, in which the symbols Q, which are identical, represent one of the groups -O- and -OCO-, the -OCO- being bonded to T by the -CO- radical, the symbol T represents a monocyclic, divalent hydrocarbon radical having from 6 to 8 carbon atoms, or a divalent organic radical which has from 10 to 22 carbon atoms and consists of 2 hydrocarbon rings which are fused to one another or bonded together by a valence bond or by one of the groups of the formulae -O-, -CH2-, -C(CH3)2- and -Si(R'-2, wherein R' is an alkyl radical having from 1 to 3 carbon atoms, and the symbols x, which are identical represent 1, 2 or 3, or divalent hydrocarbon radicals corresponding to the formula F3: -CH2)bT(CH2)b, in which the symbol T has the measuring given for the formula F2 and the symbols b, which are identical, represent 0 or 1; s the symbols G', which are identical, have the meaning given above for G, except that they do not correspond to the formula F2; the symbols a, which are identical, represent 0 or 1; the symbols p represents any number ranging from 1 to 120; and the symbol n represents any number ranging from 1 to 1,500.
Elastomeric organopolysiloxane block copolymers and non-elastomeric organosilicic copolymer blocks therefor