Abstract: A polyethylene, having 1 to 60 methyl branches and 1 to 60 hexyl or higher branches per 1000 carbon atoms, a g-value of 0.5 to 0.8, and a limiting viscosity [.eta.] of 0.005 to 20.0 dl/g as measured at 140.degree. C. in o-dichlorobenzene, and a method for producing the same by polymerizing ethylene using a catalyst system comprising a coordination nickel compound of zero- or two-valent nickel and an aminobis(imino)phosphorane represented by a general formula (I): ##STR1## where R.sub.1, R.sub.2, R.sub.3 and R.sub.4 may be the same as or different from each other and are respectively n-alkyl, isoalkyl, aryl or trialkylsilyl, in the presence of .alpha.-olefin.

Abstract: A poly(phenylene sulfide) material containing predominantly para-phenylene sulfide structural units and having a melt viscosity of at least 5 poises (at 300.degree. C.) may be treated or reacted with an alkali metal sulfide and/or hydrosulfide in a polar aprotic solvent at a relatively low temperature in the range of 150.degree.-230.degree. C. so as to introduce an increased amount of reactive thiolate or thiol end groups to the polymer molecule and hence to enhance the reactivity of the polymer material. The thus modified and highly reactive poly(phenylene sulfide) material exhibits an improved compatibility with other polymers and is expected to be useful in preparation of polymer alloys of improved or modified physical and chemical properties.

Abstract: There are disclosed a class of halogen-ended polyalkylene glycols and halogen-ended polyolefins (II) which are copolymerizable with polyarylene sulfides or sulfone-based polymers. These halogen-ended polymers may be readily copolymerized with polyarylene sulfides or sulfone-based polymers to provide polyphenylene sulfide copolymers (I) exhibiting increased crystallization speeds. These high crystallization speeds enable the copolymers to be molded in a low-temperature mold, for example, at 100.degree. C. or less, while providing fully crystallized moldings having excellent heat resistance properties.