Abstract: Styrene homo-or-co- polymers, the stereoregularity of which is mainly syndiotactic are disclosed, having repeating unit or two or more different repeating units defined by a general formula (I): ##STR1## wherein each R may be the same or different. And a method of preparation of syndiotactic copolymers wherein there are two different repeating units represented by formula (I); wherein the polymerization is carried out with a catalyst comprising (a) a titanium compound and (b) a contact product of an organoaluminum compound and a condensing agent such as water.

Abstract: Styrene homo-or-co- polymers, the stereoregularity of which is mainly syndiotactic are disclosed, having repeating unit or two or more different repeating units defined by a general formula (I): ##STR1## wherein each R may be the same or different. And a method of preparation of syndiotactic copolymers wherein there are two different repeating units represented by formula (I); wherein the polymerization is carried out with a catalyst comprising (a) a titanium compound and (b) a contact product of a organoaluminum compound and a condensing agent such as water.

Abstract: Styrene copolymers having a repeating unit (I) represented by the general formula: ##STR1## and a repeating unit (II) represented by the general formula: ##STR2## (wherein all the symbols are as defined in the appended claims), and having the stereoregularity that is mainly syndiotactic, and cross-linked styrene copolymers obtained by cross-linking the above styrene copolymers. The styrene copolymers are reactive resins (heat-sensitive resins and radiation-sensitive resins) and are excellent in heat resistance and chemical resistance. The cross-linked styrene copolymers are excellent in heat resistance, chemical resistance and mechanical strength.

Abstract: Styrene homo-or-co- polymers, the stereoregularity of which is mainly syndiotactic are disclosed, having repeating unit or two or more different repeating units defined by a general formula (I): ##STR1## wherein each R may be the same or different. And a method of preparation of syndiotactic copolymers wherein there are two different repeating units represented by formula (I); wherein the polymerization is carried out with a catalyst comprising (a) a titanium compound and (b) a contact product of an organoaluminum compound and a condensing agent such as water.

Abstract: A process for production of styrene polymers is disclosed, comprising polymerizing styrene monomers by the use of a catalyst comprising (a) a titanium compound and (b) a contact product of an organoaluminum compound and a condensing agent, and further in the presence of hydrogen. The styrene polymers produced by the present process have a stereo structure that substituent groups are mainly in the syndiotactic configuration. Thus the styrene polymers have high heat resistance and high solvent resistance as compared with atactic polystyrene commonly used and are useful as materials for production of articles for which high heat resistance and high solvent resistance are required.

Abstract: A new ethylene copolymer comprising:a repeating unit (A) represented by the formula: --CH.sub.2 --CH.sub.2 --;a repeating unit (B) represented by the formula: ##STR1## (wherein R.sup.1 is defined as hereinbefore), and a repeating unit (C) represented by the formula: ##STR2## (wherein R.sup.2 and R.sup.3 are defined as hereinbefore), said repeating units (A), (B) and (C) being orientated in a random and straight chain arrangement, said repeating unit (B) content being 0 to 45 mol %, said repeating unit (C) content being 0.001 to 45 mol %, and said copolymer having a weight average molecular weight of at least 5,000.A process for producing said ethylene copolymer by using a catalyst containing a specific chromium compound.

Abstract: A new ethylene copolymer comprising: a repeating unit (A) represented by the formula:--CH.sub.2 --CH.sub.2 --;a repeating unit (B) represented by the formula: ##STR1## (wherein R.sup.1 is defined as hereinbefore), and a repeating unit (C) represented by the formula: ##STR2## (wherein R.sup.2 and R.sup.3 are defined as hereinbefore), said repeating units (A), (B) and (C) being orientated in a random and straight chain arrangement, said repeating unit (B) content being 0 to 45 mol %, said repeating unit (C) content being 0.001 to 45 mol %, and said copolymer having a weight average molecular weight of at least 5,000.A process for producing said ethylene copolymer by using a catalyst containing a specific chromium compound.

Abstract: A process for production of styrene polymers of high syndiotactic configuration is disclosed, comprising polymerizing styrene or styrene derivatives by the use of a catalyst comprising: (A) a titanium compound, e.g., at least one compound selected from those represented by the formulae: TiR.sup.1.sub.a R.sup.2.sub.b R.sup.3.sub.c X.sup.1.sub.4 -(a+b+c) and TiR.sup.1.sub.d R.sup.2.sub.e X.sup.1.sub.3-(d+e) (all the symbols are as defined in the appended claims); and (B) a contact product of an organoaluminum compound and a condensation agent, e.g., a product resulting from modification of trimethylaluminum with water. Because of such high syndiotactic configuration, the styrene polymers are greater in thermal resistance and solvent resistance than conventional atactic polystyrene.

Abstract: A process for producing a polyethylene composition which comprises polymerizing ethylene in the presence of a catalyst comprising (A) a contact treatment product of (a) a high activity catalyst component and (b) a filler, and (B) an organoaluminum compound.This process has no need for a deashing step, i.e., a step to remove the catalyst after polymerization, since the catalyst has a remarkably high activity.In the polyethylene composition produced, the filler is dispersed uniformly and the separation of the filler from the polyethylene is scarcely observed.

Abstract: A process for production of styrene polymers of high syndiotactic configuration is disclosed, comprising polymerizing styrene or styrene derivatives by the use of a catalyst comprising: (A) a titanium compound, e.g., at least one compound selected from those represented by the formulae: TiR.sup.1.sub.a R.sup.2.sub.b R.sup.3.sub.c X.sup.1.sub.4 -(a+b+c) and TiR.sup.1.sub.d R.sup.2.sub.e X.sup.1.sub.3-(d+e) (all the symbols are as defined in the appended claims); and (B) a contact product of an organoaluminum compound and a condensation agent, e.g., a product resulting from modification of trimethylaluminum with water. Because of such high syndiotactic configuration, the styrene polymers are greater in thermal resistance and solvent resistance than conventional atactic polystyrene.