The structural analysis of two PP/PE copolymer samples,1 and 2,was conducted by using^(13)C-NMR,GPC and crystallization segregation DSC(CSDSC)techniques.A pure polypropylene sample was also used for comparison.It was ...The structural analysis of two PP/PE copolymer samples,1 and 2,was conducted by using^(13)C-NMR,GPC and crystallization segregation DSC(CSDSC)techniques.A pure polypropylene sample was also used for comparison.It was found that the two copolymer samples are very close in composition(the ethylene mol content is 4.3%and 4.5%,respectively),stereoregularity(96%and 97%)and molecular weight(M_(w)=7.0 x 10^(4)and 7.3 x 10^(4);M-(w)/M_(n)=5.0 and 6.1,respectively).While the CSDSC thermograms of the two samples are quite different from each other.Sample 1 shows a higher average melting temperature and a broader distribution of its thermogram These phenomena were explained as an indication of a less uniform distribution of ethylene units along the PP chains for sample 1.It was noted that CSDSC is a very sensitive and convenient technique for structural studies of copolymers.展开更多
The monomer methacrylamido propyl trimethy ammonium chloride( MAPTAC) was copolymerized onto the fiber surface of polypropylene( PP) nonwoven fabric under ultroviole radiation. The weak acid red GN dye adsorption and ...The monomer methacrylamido propyl trimethy ammonium chloride( MAPTAC) was copolymerized onto the fiber surface of polypropylene( PP) nonwoven fabric under ultroviole radiation. The weak acid red GN dye adsorption and adsorptive filtration performance of the resulted PP fabrics were investigated.The results showed that the grafting copolymerization preferred to happen in the inner layer of the fabrics. The water flux of the grafted fabrics decreases with the increase of grafting yield. The collapse of the grafted polymer chains causes the flux increase in acidic condition,or vice versa at alkaline version. The coiling of the polyelectrolyte chains upon the dye adsorption seems to violate the routine assumption of the rigid substrate, and this gets the adsorption energy constant negative. The static adsorption process follows the Lagergren's pseudo-second order kinetic equation. The removals of circa( ca.) 100% of the total permeation volume3 500 mL simulated dye wastewater was reached during permeation.The dye adsorbed fabrics were regenerated by the mixed media of the cationic surfactant / ethanol /water. The grafted fabric assumes stable fabric integrity and stability during permeation,and presents excellent dye adsorption capacity,easy desorption, and repeatable utilization.展开更多
The melting behavior of polypropylene (PP) and low ethylene content polypropylenecopolymer with and without nucleating agent samples crystallized under both isothermal and non-isothermal conditions were studied by Dif...The melting behavior of polypropylene (PP) and low ethylene content polypropylenecopolymer with and without nucleating agent samples crystallized under both isothermal and non-isothermal conditions were studied by Differential Scanning Calorimeter (DSC) and X-raydiffraction. Multiple melting behavior were observed depending on the existence of nucleatingagent and crystallization conditions. The observed phenomena have been discussed by the effect ofnucleating agent on perfection of crystal and the melting and recrystallization of imperfect crystalto a more perfect crystal during the heating process of samples.展开更多
文摘The structural analysis of two PP/PE copolymer samples,1 and 2,was conducted by using^(13)C-NMR,GPC and crystallization segregation DSC(CSDSC)techniques.A pure polypropylene sample was also used for comparison.It was found that the two copolymer samples are very close in composition(the ethylene mol content is 4.3%and 4.5%,respectively),stereoregularity(96%and 97%)and molecular weight(M_(w)=7.0 x 10^(4)and 7.3 x 10^(4);M-(w)/M_(n)=5.0 and 6.1,respectively).While the CSDSC thermograms of the two samples are quite different from each other.Sample 1 shows a higher average melting temperature and a broader distribution of its thermogram These phenomena were explained as an indication of a less uniform distribution of ethylene units along the PP chains for sample 1.It was noted that CSDSC is a very sensitive and convenient technique for structural studies of copolymers.
基金the Priority Academic Development Program for Textile Science and Textile Engineering of Jiangsu Higher Education Institutions,Chinathe Environmental Protection Department of Jiangsu Province,China(No.2012009)Suzhou Municipal Government,China(No.SYG201202)
文摘The monomer methacrylamido propyl trimethy ammonium chloride( MAPTAC) was copolymerized onto the fiber surface of polypropylene( PP) nonwoven fabric under ultroviole radiation. The weak acid red GN dye adsorption and adsorptive filtration performance of the resulted PP fabrics were investigated.The results showed that the grafting copolymerization preferred to happen in the inner layer of the fabrics. The water flux of the grafted fabrics decreases with the increase of grafting yield. The collapse of the grafted polymer chains causes the flux increase in acidic condition,or vice versa at alkaline version. The coiling of the polyelectrolyte chains upon the dye adsorption seems to violate the routine assumption of the rigid substrate, and this gets the adsorption energy constant negative. The static adsorption process follows the Lagergren's pseudo-second order kinetic equation. The removals of circa( ca.) 100% of the total permeation volume3 500 mL simulated dye wastewater was reached during permeation.The dye adsorbed fabrics were regenerated by the mixed media of the cationic surfactant / ethanol /water. The grafted fabric assumes stable fabric integrity and stability during permeation,and presents excellent dye adsorption capacity,easy desorption, and repeatable utilization.
文摘The melting behavior of polypropylene (PP) and low ethylene content polypropylenecopolymer with and without nucleating agent samples crystallized under both isothermal and non-isothermal conditions were studied by Differential Scanning Calorimeter (DSC) and X-raydiffraction. Multiple melting behavior were observed depending on the existence of nucleatingagent and crystallization conditions. The observed phenomena have been discussed by the effect ofnucleating agent on perfection of crystal and the melting and recrystallization of imperfect crystalto a more perfect crystal during the heating process of samples.
