摘要:
Amorphous propylene polymers are disclosed having the following characteristics:(a) intrinsic viscosity [.eta.]>1 d1/g;(b) %(r)-%(m)>0, wherein % (r) is the % of syndiotactic diads and %(m) is the % of isotactic diads;(c) less than 2% of the CH.sub.2 groups contained in sequences (CH.sub.2).sub.n, with n.gtoreq.2;(d) Bernoullianity index (B)=1.+-.0.2.These propylene polymers, which are in addition endowed with a narrow molecular weight distribution, can be obtained directly from the polymerization reaction of propylene as sole product and, therefore, do not require to be separated.
摘要:
Supported catalysts for the polymerization of olefins comprise the following components: (A) a porous organic support functionalised with groups having active hydrogen atoms; (B) an organo-metallic compound of aluminium containing heteroatoms selected from oxygen, nitrogen and sulphur; and (C) a compound of a transition metal selected from those of groups IVb, Vb or VIb of the Periodic Table of the Elements, containing ligands of the cyclopentadienyl type. These supported catalysts, obtainable in the form of spherical particles, can be used in the polymerization reaction of olefins either in liquid or in gas phase, thus producing polymers endowed with a controlled morphology and with a high bulk density.
摘要:
Novel crystalline copolymers of propylene with minor proportions of ethylene and/or alpha-olefins, endowed with very good mechanical properties, a low melting point and a limited solubility in xylene at 25.degree. C., and the process for preparing them by means of the polymerization of mixtures of propylene with ethylene and/or alpha-olefins of suitable composition, by using catalysts obtained from stereorigid and chiral compounds of zirconium, and methylalumoxanic compounds.
摘要:
Novel crystalline copolymers of propylene with minor proportions of ethylene and/or alpha-olefins, endowed with very good mechanical properties, a low melting point and a limited solubility in xylene at 25° C., and the process for preparing them by means of the polymerization of mixtures of propylene with ethylene and/or alpha-olefins of suitable composition, by using catalysts obtained from stereorigid and chiral compounds of zirconium, and methylalumoxanic compounds.
摘要:
Syndiotactic polymers of alpha-olefins selected from the group consisting of 1-butene, 4-methyl-1-pentene and 4-methyl-1-hexene and a method of preparation thereof by polymerizing said olefins with catalysts obtained from specific Zr or Hf cyclopentadienyl compounds and aluminoxane compounds.
摘要:
A process for the production of primarily syndiotactic vinyl aromatic polymers by polymerizing or copolymerizing vinyl aromatic monomers such as styrene or styrene derivatives in the presence of a catalyst system comprising the product of the reaction between:a) a compound of a transition metal (M) different from titanium and containing at least a bond M-O, M-C, M-N, M-P, M-S or M-halogen, andb) an organoaluminum compound containing at least an oxygen atom bound to the aluminum atom or bound between two aluminum atoms.Compound a) can be used as such or may be supported on a suitable carrier.
摘要:
Catalysts for the polymerization of olefins, comprising the product of the reaction between:A) a cyclopentadienyl compound of Ti, Zr or Hf;B) an alumoxane compound of formula: ##STR1## in which R.sup.1, R.sup.2, R.sup.3, R.sup.4, the same or different from each other, are alkyl, alkenyl or alkylaryl radicals having 2 to 20 carbon atoms.
摘要:
Supported catalysts for the polymerization of olefins comprise the following components: (A) a porous organic support functionalised with groups having active hydrogen atoms; (B) an organo-metallic compound of aluminium containing heteroatoms selected from oxygen, nitrogen and sulphur; and (C) a compound of a transition metal selected from those of groups IVb, Vb or VIb of the Periodic Table of the Elements, containing ligands of the cyclopentadienyl type. These supported catalysts, obtainable in the form of spherical particles, can be used in the polymerization reaction of olefins either in liquid or in gas phase, thus producing polymers endowed with a controlled morphology and with a high bulk density.
摘要:
Ethylene copolymers are prepared with comonomers selected from:(a) .alpha.-olefins,(b) cycloolefins and(c) polyenes,with a content of ethylene units of between 80 and 99 mol %, a content of units derived from .alpha.-olefin, cycloolefin and/or polyene comonomers of between 1 and 20 mol %, characterized in that:(a) in TREF (Temperature Rising Elution Fractionation) analysis, a quantity equal to at least 90% by weight of the copolymer is eluted within a temperature interval of less than 50.degree. C., and(b) M.sub.w /M.sub.n >3, where M.sub.w is the weight-average molecular weight and M.sub.n is the number-average molecular weight, both determined by means of GPC.