A new polymer-supported metallocene catalyst has been prepared, The polymer-supported metallocene displayed considerably high activity in ethylene polymerization, the highest being 3.62x10(7) gPE/molZr.h, the molecula...A new polymer-supported metallocene catalyst has been prepared, The polymer-supported metallocene displayed considerably high activity in ethylene polymerization, the highest being 3.62x10(7) gPE/molZr.h, the molecular weight of the polyethylene produced was Mn = 1.29x10(5). about 3-4 times those of corresponding homogeneous zirconocenes. The polymer-supported metallocene keeps the characteristics of homogeneous metallocene catalysts, and offers some features, such as adaptable to gas phase and slurry processes: easy to prepare in low cost: relatively high activity and lower MAO/Zr ratio; lower inorganic residues in the polyolefins as compared to cases of SiO2, Al2O3 or MgCl2; unitary active structure, no complex surface as with SiO2; good control of morphology of the resulting polymer.展开更多
Mesoporous silica （MS）, 3-aminopropyltriethoxysilane （APTES） modified mesoporous silica （AMS）, bis（3- trimethoxysilylpropyl）amine modified mesoporous silica （BAMS） and APTES modified solid spherical silica ...Mesoporous silica （MS）, 3-aminopropyltriethoxysilane （APTES） modified mesoporous silica （AMS）, bis（3- trimethoxysilylpropyl）amine modified mesoporous silica （BAMS） and APTES modified solid spherical silica （AS） were prepared and used to immobilize metallocene catalysts for ethylene polymerization. Gel permeation chromatography results showed that polyethylenes （PEs） catalyzed by AMS （or BAMS） supported metallocene catalysts at the molar ratios of Al/Zr = 100, 300 and 500 were of bimodal molecular weight distribution （BMWD）; while PEs catalyzed by the above catalysts at the molar ratios of Al/Zr 〉 800 were of monomodal molecular weight distribution （MMWD）. However, MS （or AS） supported metallocene catalysts could only produce PEs with MMWD in spite of the molar ratio of Al/Zr. It was because that AMS （or BAMS） supported catalysts possessed two active sites for ethylene polymerization at low molar ratios of Al/Zr due to the combination effects of mesopore geometrical constraint and amino groups of the supports, which was confirmed by X-ray photoelectron spectroscopy. This brings forward a novel and easy method for the synthesis of polyolefin with BMWD.展开更多
Polymerization of propylene was carried out under bulk process at 70 degrees C using the supported metallocene catalyst with four kinds of SiO2 as carrier with triethylaluminum used as cocatalyst. The morphology of th...Polymerization of propylene was carried out under bulk process at 70 degrees C using the supported metallocene catalyst with four kinds of SiO2 as carrier with triethylaluminum used as cocatalyst. The morphology of the products was studied by SEM. It was found the property of the carriers gave great effect on the fine structure of the products as well as the apperance.展开更多
The possibility of mesoporous acid solid as a carder for metallocene catalyst in ethylene polymerization and catalyst for polyethylene （PE） catalytic degradation was investigated. Here, HMCM-41 and AIMCM-41, and mes...The possibility of mesoporous acid solid as a carder for metallocene catalyst in ethylene polymerization and catalyst for polyethylene （PE） catalytic degradation was investigated. Here, HMCM-41 and AIMCM-41, and mesoporous silicoaluminophosphate molecular sieves （SAPO1 and SAPO2） were synthesized and used as acid solid. Much more gases were produced during catalytic degradation in PE/acid solid mixtures via in situ polymerization than those via physical mixing. The particle size distribution results exhibited that the particle size of SAPO1 in the PE/SAPOI mixture via in situ polymerization was about 1/14 times of that of the original SAPO1 or SAPO1-supported metallocene catalyst. This work shows a novel technology for chemical recycling of polyolefin.展开更多
SiO2/rac-Me2Si[2-Me-4-Naph-Ind]2ZrCl2 was prepared and different co-catalysts were used in bulk polymerization of propene. The morphology of polypropene could be controlled by altering the co-catalysts. The isotactic ...SiO2/rac-Me2Si[2-Me-4-Naph-Ind]2ZrCl2 was prepared and different co-catalysts were used in bulk polymerization of propene. The morphology of polypropene could be controlled by altering the co-catalysts. The isotactic polypropene with good morphology and high bulk density were prepared. The formation mechanism of active centers was proposed, by which the effect of co-catalysts on the morphology of polypeopene was analyzed.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
A novel polymer-supported metallocene catalyst has been prepared. The polymer-support-ed metallocene displayed considerably high activity in ethylene polymerization, the highest being 3.62× 107 g/(mol · h), ...A novel polymer-supported metallocene catalyst has been prepared. The polymer-support-ed metallocene displayed considerably high activity in ethylene polymerization, the highest being 3.62× 107 g/(mol · h), the molecular weight of the polyethylene produced was Mn = 1.29 × 105 , about 3～4 times those prepared by corresponding homogeneous zirconocenes. The polymer-supported metallocene poly(styrene-acrylamide)supported zirconocene]keeps thecharacteristics of homogeneous metallocene catalysts, and offers some features, such as adaptable togas phase and slurry processes; easy to prepare in low cost; relatively high activity and lowerMAO/Zr ratio ; lower inorganic residues in the polyolefins as compared to those using SiO2, Al2O3 orMgCl2; unitary active structure, no complex surface as with SiO2; good control of morphology of theresulting polymer.展开更多
文摘A new polymer-supported metallocene catalyst has been prepared, The polymer-supported metallocene displayed considerably high activity in ethylene polymerization, the highest being 3.62x10(7) gPE/molZr.h, the molecular weight of the polyethylene produced was Mn = 1.29x10(5). about 3-4 times those of corresponding homogeneous zirconocenes. The polymer-supported metallocene keeps the characteristics of homogeneous metallocene catalysts, and offers some features, such as adaptable to gas phase and slurry processes: easy to prepare in low cost: relatively high activity and lower MAO/Zr ratio; lower inorganic residues in the polyolefins as compared to cases of SiO2, Al2O3 or MgCl2; unitary active structure, no complex surface as with SiO2; good control of morphology of the resulting polymer.
基金supported by the National Natural Science Foundation of China(Nos.50525311,20734006 and 50621302)
文摘Mesoporous silica （MS）, 3-aminopropyltriethoxysilane （APTES） modified mesoporous silica （AMS）, bis（3- trimethoxysilylpropyl）amine modified mesoporous silica （BAMS） and APTES modified solid spherical silica （AS） were prepared and used to immobilize metallocene catalysts for ethylene polymerization. Gel permeation chromatography results showed that polyethylenes （PEs） catalyzed by AMS （or BAMS） supported metallocene catalysts at the molar ratios of Al/Zr = 100, 300 and 500 were of bimodal molecular weight distribution （BMWD）; while PEs catalyzed by the above catalysts at the molar ratios of Al/Zr 〉 800 were of monomodal molecular weight distribution （MMWD）. However, MS （or AS） supported metallocene catalysts could only produce PEs with MMWD in spite of the molar ratio of Al/Zr. It was because that AMS （or BAMS） supported catalysts possessed two active sites for ethylene polymerization at low molar ratios of Al/Zr due to the combination effects of mesopore geometrical constraint and amino groups of the supports, which was confirmed by X-ray photoelectron spectroscopy. This brings forward a novel and easy method for the synthesis of polyolefin with BMWD.
文摘Polymerization of propylene was carried out under bulk process at 70 degrees C using the supported metallocene catalyst with four kinds of SiO2 as carrier with triethylaluminum used as cocatalyst. The morphology of the products was studied by SEM. It was found the property of the carriers gave great effect on the fine structure of the products as well as the apperance.
基金the support of the National Natural Science Foundation of China （No. 20174039） the Ministry of Science and Technology of China （No. 2005CB623800）.
文摘The possibility of mesoporous acid solid as a carder for metallocene catalyst in ethylene polymerization and catalyst for polyethylene （PE） catalytic degradation was investigated. Here, HMCM-41 and AIMCM-41, and mesoporous silicoaluminophosphate molecular sieves （SAPO1 and SAPO2） were synthesized and used as acid solid. Much more gases were produced during catalytic degradation in PE/acid solid mixtures via in situ polymerization than those via physical mixing. The particle size distribution results exhibited that the particle size of SAPO1 in the PE/SAPOI mixture via in situ polymerization was about 1/14 times of that of the original SAPO1 or SAPO1-supported metallocene catalyst. This work shows a novel technology for chemical recycling of polyolefin.
基金This work was supported by the National NaturalScience Foundation of China (Grant No. 29734141).
文摘SiO2/rac-Me2Si[2-Me-4-Naph-Ind]2ZrCl2 was prepared and different co-catalysts were used in bulk polymerization of propene. The morphology of polypropene could be controlled by altering the co-catalysts. The isotactic polypropene with good morphology and high bulk density were prepared. The formation mechanism of active centers was proposed, by which the effect of co-catalysts on the morphology of polypeopene was analyzed.
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).
文摘A novel polymer-supported metallocene catalyst has been prepared. The polymer-support-ed metallocene displayed considerably high activity in ethylene polymerization, the highest being 3.62× 107 g/(mol · h), the molecular weight of the polyethylene produced was Mn = 1.29 × 105 , about 3～4 times those prepared by corresponding homogeneous zirconocenes. The polymer-supported metallocene poly(styrene-acrylamide)supported zirconocene]keeps thecharacteristics of homogeneous metallocene catalysts, and offers some features, such as adaptable togas phase and slurry processes; easy to prepare in low cost; relatively high activity and lowerMAO/Zr ratio ; lower inorganic residues in the polyolefins as compared to those using SiO2, Al2O3 orMgCl2; unitary active structure, no complex surface as with SiO2; good control of morphology of theresulting polymer.
