A new monomer,vinyltriallylsilane（CB3）,having functionnal groups with different hydrosilylation reactivity was designed and synthesized by allylation reaction from vinyltrichlorosilane.Then,photocrosslinkable hyperb...A new monomer,vinyltriallylsilane（CB3）,having functionnal groups with different hydrosilylation reactivity was designed and synthesized by allylation reaction from vinyltrichlorosilane.Then,photocrosslinkable hyperbranched（poly（siloxysilane）） with terminal allyl groups was prepared via hydrosilylation reaction of vinyltriallylsilane（CB3） and dimethylbis（dimethylsiloxy）silane（A2） monomers at the presence of Karstedt catalyst,and characterized by means of FTIR,（）1H-NMR,（）29Si-NMR,and SEC/RI/MALLS technology.The polymerization process of A2 and CB3 monomers was studied in situ by using FTIR.It was found that silicon hydride would preferentially react with vinyl groups during the reaction. This can cause to the generation of an intermediate with one Si—H and three allyl groups.By using it to conduct further self-polymerization,hyperbranched polymer can be obtained.The degree of branching of the resulting hyperbranched poly（siloxysilane） was calculated to be 0.44 by quantitative（）29Si-NMR spectroscopy,and the weight average molecular weight was 12.1 kg/mol with its polydispersity of 2.52.Finally,the UV curing behavior of the resulting polymer initiated with different photoinitors was also investigated.展开更多
Polydimethylsiloxane （PDMS）, tetraethoxysilane （TEOS）, ethyl alcohol （EtOH） and deionized water were main raw materials to prepare silicone-modified hybrid thin films using sol-gel method. The effect of the cont...Polydimethylsiloxane （PDMS）, tetraethoxysilane （TEOS）, ethyl alcohol （EtOH） and deionized water were main raw materials to prepare silicone-modified hybrid thin films using sol-gel method. The effect of the contents of H2O and PDMS on thin films was studied. When the volume ratio of H20 to TEOS is 0.5, the optimum quality of thin films is obtained. And the gelation time is affected slightly by H20 content. Uniform thin films are obtained when the volume ratio of PDMS to TEOS is 0.2. Yet, the sol would be inactive in 6 d. Various properties of thin films were studied, including hardness, adhesive quality, hydrophobic property, corrosion protection property, and abrasion resistance. Test results show that the pencil hardness is generally 3-6 H, and adhesive quality achieves the highest standard of 0. When the sintering temperature is below 400℃, the contact angle is about 95° and hydrophobic films are obtained. The abrasion resistance of thin films is better than that of aluminum alloy when the sintering temperature is higher than 300℃. And the excellent corrosion protective effect is obtained by single-layer coating when the sintering temperature is higher than 400℃.展开更多
文摘A new monomer,vinyltriallylsilane（CB3）,having functionnal groups with different hydrosilylation reactivity was designed and synthesized by allylation reaction from vinyltrichlorosilane.Then,photocrosslinkable hyperbranched（poly（siloxysilane）） with terminal allyl groups was prepared via hydrosilylation reaction of vinyltriallylsilane（CB3） and dimethylbis（dimethylsiloxy）silane（A2） monomers at the presence of Karstedt catalyst,and characterized by means of FTIR,（）1H-NMR,（）29Si-NMR,and SEC/RI/MALLS technology.The polymerization process of A2 and CB3 monomers was studied in situ by using FTIR.It was found that silicon hydride would preferentially react with vinyl groups during the reaction. This can cause to the generation of an intermediate with one Si—H and three allyl groups.By using it to conduct further self-polymerization,hyperbranched polymer can be obtained.The degree of branching of the resulting hyperbranched poly（siloxysilane） was calculated to be 0.44 by quantitative（）29Si-NMR spectroscopy,and the weight average molecular weight was 12.1 kg/mol with its polydispersity of 2.52.Finally,the UV curing behavior of the resulting polymer initiated with different photoinitors was also investigated.
基金supported partly by the School of Mechanical,Electronic and Control Engineering,Beijing Jiaotong university,China
文摘Polydimethylsiloxane （PDMS）, tetraethoxysilane （TEOS）, ethyl alcohol （EtOH） and deionized water were main raw materials to prepare silicone-modified hybrid thin films using sol-gel method. The effect of the contents of H2O and PDMS on thin films was studied. When the volume ratio of H20 to TEOS is 0.5, the optimum quality of thin films is obtained. And the gelation time is affected slightly by H20 content. Uniform thin films are obtained when the volume ratio of PDMS to TEOS is 0.2. Yet, the sol would be inactive in 6 d. Various properties of thin films were studied, including hardness, adhesive quality, hydrophobic property, corrosion protection property, and abrasion resistance. Test results show that the pencil hardness is generally 3-6 H, and adhesive quality achieves the highest standard of 0. When the sintering temperature is below 400℃, the contact angle is about 95° and hydrophobic films are obtained. The abrasion resistance of thin films is better than that of aluminum alloy when the sintering temperature is higher than 300℃. And the excellent corrosion protective effect is obtained by single-layer coating when the sintering temperature is higher than 400℃.
