Ethylene-propylene copolymers were synthesized using a TiCl4/MgCl2/SiO2/diester type supported Ziegler-Natta catalyst with or without the presence of hydrogen in a slurry polymerization process.The copolymer was inhom...Ethylene-propylene copolymers were synthesized using a TiCl4/MgCl2/SiO2/diester type supported Ziegler-Natta catalyst with or without the presence of hydrogen in a slurry polymerization process.The copolymer was inhomogeneous in composition and can be fractionated into two parts, fractions soluble and insoluble in n-octane at room temperature, respectively.The soluble part is a nearly random copolymer,while the insoluble part is a kind of segmented copolymer,as revealed by 13 C-NMR and DSC analyses.Adding H2 in the reaction system caused an increase of copolymer yield and a decrease of the insoluble part,but the propylene content and average length of propylene segments of the insoluble part were markedly increased,meanwhile the average length of ethylene segments of the insoluble part was markedly decreased.Copolymer sequence distribution of the soluble part was only slightly changed by H2. The segmented copolymer fraction present in this ethylene-propylene copolymer has the similar structure as the segmented copolymer fractions found in polypropylene/poly（ethylene-co-propylene） reactor alloy.Mechanism of the hydrogen effect on copolymer structure is discussed.展开更多
Spherical MgCl 2 supported metallocene catalyst was prepared by supporting MAO on carrier which was prepared from MgCl 2 ·n EtOH.Ethylene polymerization was carried out by addition of MAO/MgCl 2,different metallo...Spherical MgCl 2 supported metallocene catalyst was prepared by supporting MAO on carrier which was prepared from MgCl 2 ·n EtOH.Ethylene polymerization was carried out by addition of MAO/MgCl 2,different metallocenes and alkylaluminum,in the absence of soluble MAO.It shows high activity for ethylene polymerization at lower Al/Zr(Al/Zr=45).The effect of concentration of Al( i Bu) 3 on polymerization activities and activation of Et(Ind) 2ZrCl 2 were studied.Kinetic behavior of ethylene polymerization on spherical MgCl 2 supported metallocene catalyst was investigated,which indicated the polymers obtained by reaction could affect the diffusion of ethylene in hexane under the experiment condidtion.Different aluminium alkyls have great impact on the whole polymerization behavior,and the relative reactivity decreases in the following order:Al( i Bu) 3>AlEt 3>AlMe 3>AlEt 2Cl,in which Al( i Bu) 3 shows the highest catalytic activity (5 78×10 7 g PE/mol\|Zr·h).展开更多
文摘Ethylene-propylene copolymers were synthesized using a TiCl4/MgCl2/SiO2/diester type supported Ziegler-Natta catalyst with or without the presence of hydrogen in a slurry polymerization process.The copolymer was inhomogeneous in composition and can be fractionated into two parts, fractions soluble and insoluble in n-octane at room temperature, respectively.The soluble part is a nearly random copolymer,while the insoluble part is a kind of segmented copolymer,as revealed by 13 C-NMR and DSC analyses.Adding H2 in the reaction system caused an increase of copolymer yield and a decrease of the insoluble part,but the propylene content and average length of propylene segments of the insoluble part were markedly increased,meanwhile the average length of ethylene segments of the insoluble part was markedly decreased.Copolymer sequence distribution of the soluble part was only slightly changed by H2. The segmented copolymer fraction present in this ethylene-propylene copolymer has the similar structure as the segmented copolymer fractions found in polypropylene/poly（ethylene-co-propylene） reactor alloy.Mechanism of the hydrogen effect on copolymer structure is discussed.
文摘Spherical MgCl 2 supported metallocene catalyst was prepared by supporting MAO on carrier which was prepared from MgCl 2 ·n EtOH.Ethylene polymerization was carried out by addition of MAO/MgCl 2,different metallocenes and alkylaluminum,in the absence of soluble MAO.It shows high activity for ethylene polymerization at lower Al/Zr(Al/Zr=45).The effect of concentration of Al( i Bu) 3 on polymerization activities and activation of Et(Ind) 2ZrCl 2 were studied.Kinetic behavior of ethylene polymerization on spherical MgCl 2 supported metallocene catalyst was investigated,which indicated the polymers obtained by reaction could affect the diffusion of ethylene in hexane under the experiment condidtion.Different aluminium alkyls have great impact on the whole polymerization behavior,and the relative reactivity decreases in the following order:Al( i Bu) 3>AlEt 3>AlMe 3>AlEt 2Cl,in which Al( i Bu) 3 shows the highest catalytic activity (5 78×10 7 g PE/mol\|Zr·h).
