摘要:
The present invention belongs to the field of polyolefin alloy preparation, and particularly relates to a polyolefin composite material in good form with adjustable composition and performances, produced by controlling a composite catalyst composed of Zieglar-Natta catalyst and metallocene catalyst to be catalytic by stage in the olefin polymerization reaction. This material is composed of propylene polymer and ethylene copolymer which is obtained by copolymerizing ethylene with alpha olefin or diolefin, wherein: the molar content of alpha olefin or diolefin in the ethylene copolymer is 0%˜60%, and the ethylene copolymer is 3˜80% by weight of the polyolefin composite material; the polyolefin composite material is in particle form, and the ethylene copolymer has a molecular weight distribution of 1˜6 and a glass transition temperature of −80˜0° C.; and the ethylene copolymer produced in the reaction is dispersed homogeneously in the propylene polymer particles to form the polyolefin composite material.
摘要:
The invention relates to a process for preparing polyolefin graft copolymers (II) from linear and well defined polyolefin copolymers (I) containing divinylbenzene comonomer units, wherein R, in formulas I and II, is a C1 to C10 linear or branched alkyl group or a C6 to C10 substituted or unsubstituted aromatic group; and wherein G and G′, independantly, are selected from —H, —OH, epoxy, —NH2, —COOH, anhydride, —Cl, —Br, —M, —COOM (M=metal, e.g., Li, Na, K and Ca) or a polymer chain having the molecular weight of at least about 500, which can be derived from both step and chain polymerization reactions. G and G′ can be selected singly or in a combination of two or more thereof. In the graft copolymer composition, the combined alpha-olefin mole .% (x+y) is from about 50 to 99.9 mole %. Preferably, x+y is from 85 to 99.9 mole %, and most preferably x+y is from 95 to 99.9 mole %. The sum of x, y, m and n is 100%, and n is at least 0.05%. The molecular weight of backbone polymer chain has a number average molecular weight (Mn) of at least about 1,000, and preferably at least about 10,000.
摘要:
The invention relates to linear copolymers containing alpha-olefin and divinylbenzene comonomer units and to a process for preparing the copolymers, the copolymers having a mole ratio of unsaturation/divinylbenzene (TUS/DOU) between 0.8 and 1.1, a molecular weight distribution of less than 4, and a homogeneous composition distribution, and having the structural formula ##STR1## in which R is a linear or branched C.sub.1 to C.sub.10 alkyl group or a phenyl or alkyl-substituted phenyl group, x+y is the mole % of alpha-olefin units in the copolymer, z is the mole % of divinylbenzene units in the copolymer, the sum of x+y is from 50 to 99.9, and the sum of x+y+z is 100. The copolymers are prepared in the presence of a bridged metallocene catalyst having a spacial opening at the metal active site of between 135 and 105.degree. for reacting with only one of the two vinyl groups in the divinylbenzene comonomer, which assures the formation of linear copolymers without detectable branching structure.
摘要:
A process for preparing polypropylene compositions having high impact strength at low temperatures is disclosed in which the reaction is catalyzed by Ziegler-Natta/metallocene hybrid catalysts by the in-situ polymerization of one or more olefins of the formula CH2═CHR, in which R is hydrogen or an alkyl, cycloalkyl or aryl group having from 1 to 10 carbon atoms, and more specifically comprises preparing an olefin polymer by Ziegler-Natta catalyst components of the titanium or vanadium/metallocene hybrid catalysts while the metallocene components are inactivated beforehand by catalyst inactivators; and polymerizing one or more olefins in the presence of the above olefin polymer, followed by a reactivation of the metallocene components.