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Effects of polyethylenimine on the dispersibility of hollow silica nanoparticles

WEN Lixiong, WANG Qing, ZHENG Tianyuan, CHEN Jianfeng

《化学科学与工程前沿（英文）》 2007年第1卷第3期页码 277-282 doi: 10.1007/s11705-007-0050-4

摘要： In this study, two different methods were applied to disperse hollow silica nanoparticles (HSNP); one employed polyethylenimine (PEI) as the dispersant during the synthesis processes for preparing HSNP, while the other added PEI into suspensions of the prepared HSNP and used milling treatment to achieve the desired dispersion. It was found that adding PEI during the synthesis process of HSNP had no noticeable improvement in the dispersion, while adding PEI into suspensions of the prepared HSNP and utilizing milling treatment resulted in remarkable dispersion improvement. Therefore, the latter was chosen as the method in dispersing HSNP suspensions. The adsorption of PEI on the surface of HSNP and the stability of the aqueous suspensions was investigated. The results indicated that the adsorption of PEI on the surface of HSNP would increase the repulsive energy among particles, hence reducing the agglomeration of HSNP and improving the stability of the aqueous suspensions. The change of HSNP’s ζ potential after adding PEI and the relationship between the adsorbed amount of PEI and pH were also investigated.

关键词： dispersion improvement different prepared HSNP relationship agglomeration

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Synthesis of vinylferrocene and the ligand-exchange reaction between its copolymer and carbon nanotubes

Ran SHI,Hai WANG,Ping TANG,Yuezhen BIN

《化学科学与工程前沿（英文）》 2014年第8卷第2期页码 171-178 doi: 10.1007/s11705-014-1428-8

摘要： To improve the dispersibility of carbon nanotubes (CNTs), poly(vinylferrocene- -styrene) (poly(Vf- -St)), was grafted onto the surface of CNTs by a ligand-exchange reaction. Poly(Vf- -St) was obtained by a radical copolymerization reaction using styrene and vinylferrocene as the monomers. The vinylferrocene was synthesized from ferrocene via a Friedel-Crafts acylation. The molecular weight, molecular weight distribution, and amount of Vf in the poly(Vf- -St) were 1.32 × 10 , 1.69 and 17.6% respectively. The degree of grafting of the copolymer onto the CNTs surface was calculated from thermogravimetric analysis and varied from 27.1% to 79.7%. The addition of the poly(Vf- -St) greatly promoted the dispersibility of the modified CNTs in anhydrous alcohol. The electrical conductivity of composites prepared from the polymer-grafted CNTs and copolymer (acrylonitrile, 1,3-butadiene and styrene, ABS) strongly depended on the degree of grafting. These results show that the amount of polymer grafted onto the surface of CNTs can be controlled and that the electrical properties of composites prepared with these grafted polymers can be tuned.

关键词： vinylferrocene poly (Vf-co-St) CNTs dispersibility