Polypropene （PP） plastics can be effectively degraded by natural volatile con- stituents from Ledum palustre catalyzed by atmospheric air dielectric barrier （DBD） plasma. The electron spin resonance （ESR） result...Polypropene （PP） plastics can be effectively degraded by natural volatile con- stituents from Ledum palustre catalyzed by atmospheric air dielectric barrier （DBD） plasma. The electron spin resonance （ESR） result indicates that the volatile constituents produce radicals in aerobic condition energized by power sources such as light, UV, plasma and so on. The degradation is a novel chemically oxidative way and it is initiated by a series of radical reactions. Lots of active cud oxidative species, radicals, products cud high euergy electromagnetic field in plasma aggravate the degradation process. The results about PP maximum tensile strength （Crbmax） confirm this conclusion. PP plastic heavily loses its extensibility, mechanical integrity and strength in a short time after suffering a synergetic treatment of the herb extract and air DBD plasma with no toxic residues left. The components of herb extract keep almost unchanged and may be reused. This study offers a new approach to manage and recycle typical plastics.展开更多
Some highly active η~5-pentamethylcyclopentadienyltribenzyloxy titanium complexes [Cp Ti(OBz)_3] activated by modified methylaluminoxane (mMAO) were prepared and used as the catalyst for styrene syndiospecific polyme...Some highly active η~5-pentamethylcyclopentadienyltribenzyloxy titanium complexes [Cp Ti(OBz)_3] activated by modified methylaluminoxane (mMAO) were prepared and used as the catalyst for styrene syndiospecific polymerization and propene atactic polymerization. Styrene could be copolymerized with propene when the propene was prepolymerized for a period, to which styrene and tri-isobutylaluminum (TIBA) were then added. The titled block copolymer together with the related homopolymers was obtained. The copolymerization porducts can be divided into the homopolymers and the copolymer by successive solvent extraction with boiling butanone, heptane and tetrahydrofuran (THF), and each fraction was characterized by ~13C NMR, DSC and WAXD. It was found that aPS and aPP were soluble in boiling butanone and heptane respectively. The block copolymer (sPS-b-aPP) composed of syndiottactic polystyrene segment was soluble in boiling THF and the residue was chiefly sPS.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
基金supported by National Natural Science Foundation of China (No.20706060)Specialized Research Fund for the Doctoral Program of Higher Education of China (No.20070425515)+1 种基金Natural Science Foundation of Shandong Province,China (No.Q2007B06)PetroChina Innovation Foundation (No.07E1022)
文摘Polypropene （PP） plastics can be effectively degraded by natural volatile con- stituents from Ledum palustre catalyzed by atmospheric air dielectric barrier （DBD） plasma. The electron spin resonance （ESR） result indicates that the volatile constituents produce radicals in aerobic condition energized by power sources such as light, UV, plasma and so on. The degradation is a novel chemically oxidative way and it is initiated by a series of radical reactions. Lots of active cud oxidative species, radicals, products cud high euergy electromagnetic field in plasma aggravate the degradation process. The results about PP maximum tensile strength （Crbmax） confirm this conclusion. PP plastic heavily loses its extensibility, mechanical integrity and strength in a short time after suffering a synergetic treatment of the herb extract and air DBD plasma with no toxic residues left. The components of herb extract keep almost unchanged and may be reused. This study offers a new approach to manage and recycle typical plastics.
文摘Some highly active η~5-pentamethylcyclopentadienyltribenzyloxy titanium complexes [Cp Ti(OBz)_3] activated by modified methylaluminoxane (mMAO) were prepared and used as the catalyst for styrene syndiospecific polymerization and propene atactic polymerization. Styrene could be copolymerized with propene when the propene was prepolymerized for a period, to which styrene and tri-isobutylaluminum (TIBA) were then added. The titled block copolymer together with the related homopolymers was obtained. The copolymerization porducts can be divided into the homopolymers and the copolymer by successive solvent extraction with boiling butanone, heptane and tetrahydrofuran (THF), and each fraction was characterized by ~13C NMR, DSC and WAXD. It was found that aPS and aPP were soluble in boiling butanone and heptane respectively. The block copolymer (sPS-b-aPP) composed of syndiottactic polystyrene segment was soluble in boiling THF and the residue was chiefly sPS.
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.
