Abstract: A thermoplastic resin composition can be obtained by adding about 0.1 to 20 parts by weight of a diene-series block copolymer (2) to 100 parts by weight of a resin composition containing a polycarbonate-series resin (1) as a basic component of which the proportion of terminal hydroxy groups relative to the whole of the terminals is 1 mole % or above (about 5 to 40 mole %). The polycarbonate-series resin base may further comprise a thermoplastic resin composition (3) such as a rubber-modified styrenic resin. The block copolymer component (2) includes an epoxy-modified block copolymer, etc. When added an organophosphorus compound as a flame retardant (4), or a fluorine-containing resin as a flame-retartant auxiliary (5), a halogen-free flame-retardant thermoplastic resin composition can be obtained. A thermoplastic resin with an improved flowability and impact strength can be obtained by modifying a polymer blend of the polycarbonate-series resin and the styrenic-series resin in quality.

Abstract: An aromatic polysulfone ether/polythioether sulfone copolymer having the formula: ##STR1## wherein each of R.sup.1 and R.sup.2 which may be the same or different, is hydrogen, halogen or a hydrocarbon group having from 1 to 8 carbon atoms, each of a and b which may be the same or different, is an integer of from 0 to 4, Ar is a bivalent aromatic residue selected from the group consisting of: ##STR2## wherein each of R.sup.3, R.sup.4 and R.sup.5 which may be the same or different, is hydrogen, or a hydrocarbon group having from 1 to 8 carbon atoms, each of c to e which may be the same of different, is an integer of from 0 to 4, Y is a single bond, --O--, --S--, --SO--, --SO.sub.2 --, ##STR3## wherein R is hydrogen or a hydrocarbon group having from 1 to 6 carbon atoms, and each of m and n is an integer indicating the degree of polymerization and m:n is from 1:20 to 20:1, said copolymer having an inherent viscosity .eta..sub.inh of from 0.1 to 1.5 as measured at 30.degree. C.