Grafting polymer glycols onto nano-silica surface through one-step procedure was investigated.The major characteristic of this procedure is that all the materials and reagents(silica,PEG,TDI,DBTDL,solvent)required for...Grafting polymer glycols onto nano-silica surface through one-step procedure was investigated.The major characteristic of this procedure is that all the materials and reagents(silica,PEG,TDI,DBTDL,solvent)required for grafting were added simultaneously into the reaction vessel.TDI and DBTDL were used as coupling agent and catalyst,respectively. The products were characterized by FTIR,TGA,elemental analyses and TEM,giving evidence for successful grafting of PEG.Possible mechanism of this grafting was studied and two grafting processes were proposed.The process through which the grafting proceeds depends on the reaction temperature.Effect of molecular weight of PEG on grafting was also investigated.展开更多
The effect of cationic surfactant cetyltrimethylammonium bromide (CTAB) on the gelation of partially hydrolyzed polyacrylamide (HPAM) by Cr (III) was investigated by using rheological measurements. The results indi...The effect of cationic surfactant cetyltrimethylammonium bromide (CTAB) on the gelation of partially hydrolyzed polyacrylamide (HPAM) by Cr (III) was investigated by using rheological measurements. The results indicated that the CTAB concentration has a pronounced effect on the viscoelastic properties of the gelling system.展开更多
文摘Grafting polymer glycols onto nano-silica surface through one-step procedure was investigated.The major characteristic of this procedure is that all the materials and reagents(silica,PEG,TDI,DBTDL,solvent)required for grafting were added simultaneously into the reaction vessel.TDI and DBTDL were used as coupling agent and catalyst,respectively. The products were characterized by FTIR,TGA,elemental analyses and TEM,giving evidence for successful grafting of PEG.Possible mechanism of this grafting was studied and two grafting processes were proposed.The process through which the grafting proceeds depends on the reaction temperature.Effect of molecular weight of PEG on grafting was also investigated.
基金This work was subsidized by the Special Funds for Major State Basic Research Projects(G 1999064800)the National Natural Science Foundation (2973414150103012) and SKLEP (0062).
文摘Two novel iron-based catalysts have been synthesized with high catalytic activity (about 108g oligomers/molFe穐) for ethylene oligomerization.
文摘The effect of cationic surfactant cetyltrimethylammonium bromide (CTAB) on the gelation of partially hydrolyzed polyacrylamide (HPAM) by Cr (III) was investigated by using rheological measurements. The results indicated that the CTAB concentration has a pronounced effect on the viscoelastic properties of the gelling system.
