Abstract: A fast crystallizing polyester composition comprising a block copolyester containing the repeating polymeric segments A and B wherein A is a polymeric segment of ethylene terephthalate units and B is a polymeric segment having a glass-transition temperature of less than 0.degree. C. and preferably less than -20.degree. C., the concentration of the segments of B being between 0.05 and 10 mole % of the block copolyester, and a crystallization nucleant which is an at least partially neutralized salt, preferably an alkali metal salt, of a polymer containing pendant neutralizable groups.

Abstract: Fast crystallizing polyester compositions obtained by reacting a polyester having an intrinsic viscosity of greater than 0.3 which polyester comprises aromatic or cycloaliphatic residues obtained from diacids and/or hydroxyacids and aliphatic, aromatic or cycloaliphatic residues of diols with an ionizable metal salt of a compound containing a group of the formula >NH, preferably selected from compounds of the formula: ##STR1## and acid amides, lactams, polyamides and sulphonamides.

Abstract: A polyamide masterbatch composition containing at least 10% by weight of a polyamide with a melting point of 230.degree. C. or below and at least 60% by weight of fire-retardant materials comprising halogenated organic compounds and optionally a synergist for the halogenated compounds.

Abstract: A graft copolymer comprises a substrate of a diene rubber, and a homogeneous superstrate containing units of acrylonitrile and at least one aromatic olefin having a molar ratio of acrylonitrile to olefin between 2 and 9. The superstrate may also contain a minor amount (preferably less than 10 mole %) of at least one other comonomer selected from acenaphthylene, vinyl carbazole and its derivatives, maleimide and its N-substituted derivatives and norbornene and its derivatives.

Abstract: A fire retardant polyamide composition containing at least 10% by weight of a polyamide containing a major proportion of nylon 66 or nylon 6 units and from 1 to 90%, preferably 5 to 25% by weight of a salt derived from melamine or a melamine derivative containing at least one --NH.sub.2 group, the salt being chosen from at least one of the borate, halide, sulphamate and demi-sulphate.

Abstract: A graft copolymer comprises a substrate of a diene rubber, and a homogeneous superstrate containing units of acrylonitrile and at least one aromatic olefin having a molar ratio of acrylonitrile to olefin between 2 and 9. The superstrate may also contain a minor amount (preferably less than 10 mole %) of at least one other comonomer selected from acenaphthylene, vinyl carbazole and its derivatives, maleimide and its N-substituted derivatives and norbornene and its derivatives.

Abstract: A laminate for packaging formed from at least two different thermoplastic polymers, one of which comprises a homogeneous copolymer of acrylonitrile and at least one aromatic olefine (the molar concentration of units of acrylonitrile to units of aromatic olefine being within the range 86% to 93%.

Abstract: A graft copolymer having a diene rubber substrate and a superstrate which is a homogeneous copolymer comprising acrylonitrile and aromatic olefin, the diene rubber substrate and the superstrate having refractive indices differing by less than 0.008 from each other and from that of a homogeneous acrylonitrile/aromatic olefin resin with which the graft copolymer may be subsequently blended, the resin containing units of acrylonitrile within the range 86 to 93 percent molar.

Abstract: A process for the preparation of aromatic sulphone copolymers in which a polyaryl sulphone containing repeat units --Ar--SO.sub.2 -- (where Ar is a bivalent aromatic residue which may vary from unit to unit in the polymer chain and at least some of the Ar units have an aromatic ether or thioether group in the polymer chain ortho or para to at least one --SO.sub.2 -- group) is caused to react with an alkali metal salt of at least one halophenol or halothiophenol or with essentially equimolar quantities of an alkali metal salt of at least one dihydric phenol or thiophenol and at least one dihalobenzenoid compound, in which the halogen atoms are activated by an electron-attracting group.