In this article,a series of high refractive indices(1.50-1.53)thiol phenyl polysiloxane(TPS)were synthesized via hydrolytic sol-gel reaction.The Fourier transform infrared spectra(FT-IR)and nuclear magnetic resonance ...In this article,a series of high refractive indices(1.50-1.53)thiol phenyl polysiloxane(TPS)were synthesized via hydrolytic sol-gel reaction.The Fourier transform infrared spectra(FT-IR)and nuclear magnetic resonance spectra(NMR)results showed that TPS conformed to the predicted structures.Natural terpene linalool was exploited as photocrosslinker to fabricate UV-curing linalool-polysiloxane hybrid films(LPH)with TPS via photoinitiated thiol-ene reaction.LPH rapidly cured under UV irradiation at the intensity of 80 mW/cm^(2) in 30 s,exhibiting good UV-curing properties.The optical transmittance of LPH in the wavelength of 300-800 nm was over 90%,exhibiting good optical transparency.The water contact angle and water vapor permeability results showed that the introduction of phenyl groups enhance the hydrophobicity and water vapor barrier properties of LPH.The results indicated the potential of LPHs in the applications of optical functional coatings.展开更多
Side chain liquid crystalline golysiloxanes conta ing biphenyl and benzyl ether mesogen were synthesized by the hydrosilation of poly(methylhydrcsiloxane) with 4-(4-allyloxybenzytoxy)-4'- methoxybiphenyl(M_1),4-(4...Side chain liquid crystalline golysiloxanes conta ing biphenyl and benzyl ether mesogen were synthesized by the hydrosilation of poly(methylhydrcsiloxane) with 4-(4-allyloxybenzytoxy)-4'- methoxybiphenyl(M_1),4-(4-allyloxybenzyloxy)-4'-ethoxybiphenyl(M_2),4-(4-allyloxybenzyloxy)-4'- propoxybiphenyl(M_3),4-(4-allyloxybenzyloxy)-4'-butoxybiphenyl(M_4),4-(4-allyloxybenzyloxy)-4'- pentyloxybiphenyl(M_5).The phase behavior of monomeric and polymeric liquid crystals was chararcterized by differential scanning calorimetry and optical polarization microscopy.Both the monomeric and polymeric liquid crystals exhibit liquid crystal behaviors.展开更多
A new capillary gas chromatography stationary phase, monokis (2,6 di O benzyl 3 O propyl (3’)) hexakis(2,6 di O benzyl 3 O methyl) β CD bonded polysiloxane, was synthesized. It ex...A new capillary gas chromatography stationary phase, monokis (2,6 di O benzyl 3 O propyl (3’)) hexakis(2,6 di O benzyl 3 O methyl) β CD bonded polysiloxane, was synthesized. It exhibited separation abilities to disubstituted benzene isomers and some chiral solutes. It was also found that the polarity of CD derivatives can be lowered both by chemically bonding it to polysiloxane and by diluting it in polysiloxane. The separation abilities of the polysiloxane anchored CDs (SP CD) are higher than that of the unbonded CDs (S CD) and the diluted S CD at lower column temperature. Hydrosilylation reaction is one of the best methods to lower the operating temperature of CDs.展开更多
A series of stable waterborne polysiloxaneurethane (WPSUR) dispersions were prepared using amino-terminated polydimethylsiloxane (NS), dimethylolpropionic acid (DMPA), castor oil, polypropylene glycol and toluen...A series of stable waterborne polysiloxaneurethane (WPSUR) dispersions were prepared using amino-terminated polydimethylsiloxane (NS), dimethylolpropionic acid (DMPA), castor oil, polypropylene glycol and toluene diisocyanate. Meanwhile, NS with different molecular weights was synthesized and used as the soft co-segment. Effects of types and contents of soft co-segments as well as chain extenders on the thermal degradation and stability for WPSUR films were examined. Results reveal that WPSUR films exhibit excellent water resistance and mechanical properties as compared with pure polyurethane (PU) films, and the NS soft co-segment possesses a remarkable effect on the second stage (stage Ⅱ), while the content of the hard segment is propitious to the initial stage (stage Ⅰ). Moreover, the highest temperature of stage Ⅱ (T2m) for WPSUR films using NS as soft co-segment is 413℃, approximately being 30℃ higher than that of those typical PUs using HDA and APDMS as the chain extenders, respectively.展开更多
The film morphology of dodecyl/carboxyl modified polysiloxane(RCAS) on cotton fabric or the silicon wafer was investigated and characterized by field emission scanning electron microscopy(FESEM),atomic force microscop...The film morphology of dodecyl/carboxyl modified polysiloxane(RCAS) on cotton fabric or the silicon wafer was investigated and characterized by field emission scanning electron microscopy(FESEM),atomic force microscope(AFM),and Fourier transform infrared spectrometer(FTIR).Experimental results indicate that RCAS is a good film forming material on different substrates.Relatively smooth film was formed on cotton fabric surface,on which the grooves disappeared.In addition,RCAS formed a micromorphology inhomogeneous and unsmooth film on the silicon wafer.Many high or low bright peaks distributed randomly on the film surface,especially as the field was 2μm×2 μm and the date scale was 5 nm in AFM observation.Then RCAS was emulsified with nonionic surfactant alkyl polyoxyethylene ether in order to achieve a transparent organosilicon emulsion-RCAS emulsion(RCSE),which possessed good stability.The properties of RCSE and its application performance on cotton fabrics were investigated and characterized by transmission electron microscope(TEM),particle size analysis,and voltage test instrument.The results show that the average particle size of RCAS emulsion is 28.32 nm,while the ζ voltage is-37.88 mV.Compared with untreatd cotton fabric,the softness of treated fabric can be improved with RCSE to a certain extent.At the same time,the fabric treated with RCSE acquires unique fluffy and soft handle.展开更多
In this paper, a new polymer of polysiloxane modified polyurethane was synthesized by using H-containing silicone oil, toluene diisocyanate(TDI), 1,4-butanediol and unsaturated polyether.
We put forward a large-area and cost-effective method to fabricate superhydrophobic coating by introducing in-situ functionalized nano-SiO2 into side-amino modified hydroxy-terminated polydimethylsiloxane (SA-HTPDMS...We put forward a large-area and cost-effective method to fabricate superhydrophobic coating by introducing in-situ functionalized nano-SiO2 into side-amino modified hydroxy-terminated polydimethylsiloxane (SA-HTPDMS) curing system. With the characterization using water contact angle (WCA) tester, Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), atomic force microscopy (AFM) and simultaneous thermal analysis, the as-prepared coating displayed a tremendous WCA of 154.8±1°, sliding angle (SA) about 3.5° and stable self-cleaning property range from -10 to 80 ℃. It was also found that the synergistic effect of surface micro-nano hierarchical structure and chemical hydrophobicity, stability from matrix had made contributions to the superhydrophobicity and excellent heat resistance up to 300 ℃.展开更多
Polydimethylsiloxane/ polymethylacrylate ( PDMS/ PMA ) interpenetratrating polymer networks (IPNs) was fabricated by simultaneous synthesis and characterized by thermogravimetry ( TG ). The kinetics of the therm...Polydimethylsiloxane/ polymethylacrylate ( PDMS/ PMA ) interpenetratrating polymer networks (IPNs) was fabricated by simultaneous synthesis and characterized by thermogravimetry ( TG ). The kinetics of the thermal decomposition of polysiloxane/ polymethylacrylate IPNs in N2 and air was studied at different heating rates. It was observed that there were two decomposition peaks both in N2 and air, which showed that thermal decomposition process obeyed two-step pyrolysis mechanism and accorded with the two compositions of IPN. Kinetic parameters were determined during simultaneous integration of the Doyle equation and the IPN/ s kinetics equation was one-order equation in N2 and Air. The decomposition activation energy in N2 and air were 147. 405 kJ· monl^-1 and 192.656 kJ·monl^-1 respectively.展开更多
A series of novel polysiloxane polyurea-urethane blockcopolymers based on methylene bis(p-phenylisocyanate (MDI), sodium-s-1,2-dihydroxy propyl sulphonate (SDPS) and aminopropyl-terminated polydimethylsiloxane (ATPS) ...A series of novel polysiloxane polyurea-urethane blockcopolymers based on methylene bis(p-phenylisocyanate (MDI), sodium-s-1,2-dihydroxy propyl sulphonate (SDPS) and aminopropyl-terminated polydimethylsiloxane (ATPS) was synthesized with varying length of soft segments and neutralizing cation. The effect of the chemical composition and the cation on the morphology and mechanical properties of the samples were studied. It was found that the SDPS chain extender based samples have definite chemical structure (-MDI-SDPS-MDI-ATPS-). As the length of the soft segment increases, an improvement of phase separation was observed. In addition, when SO3Na was translated into SO3H or the sulphonic acid groups were neutralized with different charge cations (Na+, Zn2+ and Al3+), the morphology and mechanical properties changed greatly.展开更多
A new ionic liquids grafted polysiloxane used as stationary phase for capillary gas chromatography (CGC) is described. The stationary phase of 1-vinyl-3-hexylimidazolium hexafluorophosphate anchored to polysiloxane ...A new ionic liquids grafted polysiloxane used as stationary phase for capillary gas chromatography (CGC) is described. The stationary phase of 1-vinyl-3-hexylimidazolium hexafluorophosphate anchored to polysiloxane (PMHS-[VHIm][PF6]) was synthe- sized, characterized and coated onto capillary columns by static coating. The results show that the present stationary phase exhibits a very good chromatographic resolution and selectivity for Grob test mixture and alcohols with baseline resolution and symmetry peaks. The present work suggests that novel stationary phase has a great potential for further development and application. 2009 Mei Ling Qi. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.展开更多
A series of side chain liquid crystalline polysiloxanes containing either cholesteryl or cyanobiphenyl mesogenic groups were synthesized by the hydrosilylation reaction of a polysiloxane containing Si H group with a v...A series of side chain liquid crystalline polysiloxanes containing either cholesteryl or cyanobiphenyl mesogenic groups were synthesized by the hydrosilylation reaction of a polysiloxane containing Si H group with a vinyl terminated compound containing the mesogenic group. Their chemical structures were confirmed by IR, 1H NMR, and elemental analysis, Their phase behaviors were investigated by differential scanning calorimetry, optical polarizing microscope, and X ray diffraction techniques. The results show that all these polysiloxanes except PⅤ display smectic or nematic mesonorphism or both. The dependence of phase transition temperature on the rigidity of mesogenic unit. the length of spacer group, and the flexibility of Si(CH 3) 2O chain is also described.展开更多
Two kinds of side chain liquid crystalline polysiloxanes containing crown ether and benzyl ether were synthesized and characterized by optical polarization microscopy. Both the monomeric liquid crystals and polymeric ...Two kinds of side chain liquid crystalline polysiloxanes containing crown ether and benzyl ether were synthesized and characterized by optical polarization microscopy. Both the monomeric liquid crystals and polymeric liquid crystals show smectic phases.展开更多
Phenolic hydroxyl-terminated polysiloxanes were incorporated into epoxy resins to reduce the internal stress owing to the mismatch in coefficient of thermal expansion (CTE). Polysiloxane-epoxy resin block copolymers w...Phenolic hydroxyl-terminated polysiloxanes were incorporated into epoxy resins to reduce the internal stress owing to the mismatch in coefficient of thermal expansion (CTE). Polysiloxane-epoxy resin block copolymers were made by a pre-reaction step prior to the curing. In the cured resin, the domain size of the polysiloxane phase depended on the structure of the phenolic hydroxyl-terminated polysiloxane. It was found that the modulus of the cured resin depended largely on the level of the modifier, while the CTE was affected greatly by the structure of the polysiloxane. By means of incorporating a few percent of methylphenylsiloxane unit into the polydimethylsiloxane chain, or by introducing; more compatible end-capping groups, the compounds of more effective low stress modifiers were synthesized.展开更多
A new serial chiral side-chain liquid crystal polysiloxanes containing L-Tyr structures were synthesized at room temperature. Both of them exhibited Sc phase at room temperature.
A modified Stober method has been developed which permits the controlled growth of spherical hollow spheres with diameters between 197 and 208 nanometers by consecutively cocondensed methyltrimethoxysilane and dimethy...A modified Stober method has been developed which permits the controlled growth of spherical hollow spheres with diameters between 197 and 208 nanometers by consecutively cocondensed methyltrimethoxysilane and dimethyldimethoxysilane monomers onto microemulsion of polydimethylsiloxane and subsequently removing the templated polydimethylsiloxane by exposure to solvents. Ammonia was used as a morphological catalyst. The morphology of the polymer spheres was demonstrated by transmission electron micrographs (TEM) and atomic force microscopy (AFM).展开更多
The present paper represents the syntheses of polypropyloxymethyldithia 15-crown-5 and 18-crown-6 supported on silica and their platinum complexes. The platinum complexes are effective catalysts for the hydrosilylatio...The present paper represents the syntheses of polypropyloxymethyldithia 15-crown-5 and 18-crown-6 supported on silica and their platinum complexes. The platinum complexes are effective catalysts for the hydrosilylation of olefins with triethoxysilane. The influences of temperature, amount of platinum complexes used and the nature of olefins used on the catalytic activity of the complexes are also investigated in this paper.展开更多
A novel soluble, reactive ladder-like polysilsesquioxane (L) with lateral bromophenyl groups was synthesized successfully by stepwise coupling polymerization (SCP) method including preaminolysis, hydrolysis and polyco...A novel soluble, reactive ladder-like polysilsesquioxane (L) with lateral bromophenyl groups was synthesized successfully by stepwise coupling polymerization (SCP) method including preaminolysis, hydrolysis and polycondensation steps. The monomer 3-trichlorosilylpropoxy-4-bromobenzene (M) was first prepared via hydrosilylation reaction catalyzed by dicyclopentadienylplatinum dichloride (Cp2PtCl2). The title polymer (L) was characterized by 1H-NMR, 29Si-NMR, FTIR, X-ray diffraction (XRD), DSC and vapor pressure osmometry (VPO). The experimental results indicate that the polymer (L) possesses a typical ladder-like structure.展开更多
Excellent mechanical properties are the prerequisite for the application of superhydrophobic polymer coatings.However,significantly improving the mechanical properties without affecting other properties such as hydrop...Excellent mechanical properties are the prerequisite for the application of superhydrophobic polymer coatings.However,significantly improving the mechanical properties without affecting other properties such as hydrophobicity is a huge challenge.In this study,a superhydrophobic coating with excellent mechanical properties was prepared by spraying a mixture of polysiloxane resins based on three siloxane monomers,hexadecyltrimethoxysilane(HDTMS) modified nano-SiO_(2)particles(SiO_(2)-HDTMS) and polystyrene-grafted halloysite nanotubes(HNTs-PS).SiO_(2)-HDTMS dispersed homogeneously in polysiloxane coatings and the water contact angle of corresponding coating exceeding 150°,achieving superhydrophobicity.The SiO_(2)-HDTMS/HNTs-PS/polysiloxane composite coatings showed excellent abrasion resistance with the water coating contact angle remaining above 150°after 90 abrasion cycles,indicating that HNTs-PS can significantly improve the mechanical properties of the coating without affecting the hydrophobic properties of the coating.The achieved coating also exhibited excellent antifouling and acid and alkali corrosion resistance.This work provides a convenient and ecologically friendly method to prepare superhydrophobic polysiloxane composite coating with excellent mechanical properties,which is promising in the application of anti-fouling,anti-corrosion,and oil-water separation etc.展开更多
基金the financial funding of the Guangdong Province Applied Science and Technology R&D Special Fund Project:Key Technologies for Industrialization of Sulfur-Resistant and High Refractive-Index LED Packaging Silicone Materials(2016B090930010).
文摘In this article,a series of high refractive indices(1.50-1.53)thiol phenyl polysiloxane(TPS)were synthesized via hydrolytic sol-gel reaction.The Fourier transform infrared spectra(FT-IR)and nuclear magnetic resonance spectra(NMR)results showed that TPS conformed to the predicted structures.Natural terpene linalool was exploited as photocrosslinker to fabricate UV-curing linalool-polysiloxane hybrid films(LPH)with TPS via photoinitiated thiol-ene reaction.LPH rapidly cured under UV irradiation at the intensity of 80 mW/cm^(2) in 30 s,exhibiting good UV-curing properties.The optical transmittance of LPH in the wavelength of 300-800 nm was over 90%,exhibiting good optical transparency.The water contact angle and water vapor permeability results showed that the introduction of phenyl groups enhance the hydrophobicity and water vapor barrier properties of LPH.The results indicated the potential of LPHs in the applications of optical functional coatings.
基金The project supported by the National Natural Science Foundationthe Doctoral Programme Foundation of Institution of Higher Education of China
文摘Side chain liquid crystalline golysiloxanes conta ing biphenyl and benzyl ether mesogen were synthesized by the hydrosilation of poly(methylhydrcsiloxane) with 4-(4-allyloxybenzytoxy)-4'- methoxybiphenyl(M_1),4-(4-allyloxybenzyloxy)-4'-ethoxybiphenyl(M_2),4-(4-allyloxybenzyloxy)-4'- propoxybiphenyl(M_3),4-(4-allyloxybenzyloxy)-4'-butoxybiphenyl(M_4),4-(4-allyloxybenzyloxy)-4'- pentyloxybiphenyl(M_5).The phase behavior of monomeric and polymeric liquid crystals was chararcterized by differential scanning calorimetry and optical polarization microscopy.Both the monomeric and polymeric liquid crystals exhibit liquid crystal behaviors.
文摘A new capillary gas chromatography stationary phase, monokis (2,6 di O benzyl 3 O propyl (3’)) hexakis(2,6 di O benzyl 3 O methyl) β CD bonded polysiloxane, was synthesized. It exhibited separation abilities to disubstituted benzene isomers and some chiral solutes. It was also found that the polarity of CD derivatives can be lowered both by chemically bonding it to polysiloxane and by diluting it in polysiloxane. The separation abilities of the polysiloxane anchored CDs (SP CD) are higher than that of the unbonded CDs (S CD) and the diluted S CD at lower column temperature. Hydrosilylation reaction is one of the best methods to lower the operating temperature of CDs.
基金supported by the Science and Technology Department of Zhejiang Province(No.2006C11050)
文摘A series of stable waterborne polysiloxaneurethane (WPSUR) dispersions were prepared using amino-terminated polydimethylsiloxane (NS), dimethylolpropionic acid (DMPA), castor oil, polypropylene glycol and toluene diisocyanate. Meanwhile, NS with different molecular weights was synthesized and used as the soft co-segment. Effects of types and contents of soft co-segments as well as chain extenders on the thermal degradation and stability for WPSUR films were examined. Results reveal that WPSUR films exhibit excellent water resistance and mechanical properties as compared with pure polyurethane (PU) films, and the NS soft co-segment possesses a remarkable effect on the second stage (stage Ⅱ), while the content of the hard segment is propitious to the initial stage (stage Ⅰ). Moreover, the highest temperature of stage Ⅱ (T2m) for WPSUR films using NS as soft co-segment is 413℃, approximately being 30℃ higher than that of those typical PUs using HDA and APDMS as the chain extenders, respectively.
基金National Natural Science Foundation of China (No. 50373025)Doctoral Fund of the Ministry of Education of China (No.200807080002)Postgraduate Innovation Foundation of Shaanxi University of Science & Technology,China
文摘The film morphology of dodecyl/carboxyl modified polysiloxane(RCAS) on cotton fabric or the silicon wafer was investigated and characterized by field emission scanning electron microscopy(FESEM),atomic force microscope(AFM),and Fourier transform infrared spectrometer(FTIR).Experimental results indicate that RCAS is a good film forming material on different substrates.Relatively smooth film was formed on cotton fabric surface,on which the grooves disappeared.In addition,RCAS formed a micromorphology inhomogeneous and unsmooth film on the silicon wafer.Many high or low bright peaks distributed randomly on the film surface,especially as the field was 2μm×2 μm and the date scale was 5 nm in AFM observation.Then RCAS was emulsified with nonionic surfactant alkyl polyoxyethylene ether in order to achieve a transparent organosilicon emulsion-RCAS emulsion(RCSE),which possessed good stability.The properties of RCSE and its application performance on cotton fabrics were investigated and characterized by transmission electron microscope(TEM),particle size analysis,and voltage test instrument.The results show that the average particle size of RCAS emulsion is 28.32 nm,while the ζ voltage is-37.88 mV.Compared with untreatd cotton fabric,the softness of treated fabric can be improved with RCSE to a certain extent.At the same time,the fabric treated with RCSE acquires unique fluffy and soft handle.
文摘In this paper, a new polymer of polysiloxane modified polyurethane was synthesized by using H-containing silicone oil, toluene diisocyanate(TDI), 1,4-butanediol and unsaturated polyether.
基金Supported by National High Technology Research and Development ProgramofChina(863Program)(No.2003AA305920)
文摘We put forward a large-area and cost-effective method to fabricate superhydrophobic coating by introducing in-situ functionalized nano-SiO2 into side-amino modified hydroxy-terminated polydimethylsiloxane (SA-HTPDMS) curing system. With the characterization using water contact angle (WCA) tester, Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), atomic force microscopy (AFM) and simultaneous thermal analysis, the as-prepared coating displayed a tremendous WCA of 154.8±1°, sliding angle (SA) about 3.5° and stable self-cleaning property range from -10 to 80 ℃. It was also found that the synergistic effect of surface micro-nano hierarchical structure and chemical hydrophobicity, stability from matrix had made contributions to the superhydrophobicity and excellent heat resistance up to 300 ℃.
文摘Polydimethylsiloxane/ polymethylacrylate ( PDMS/ PMA ) interpenetratrating polymer networks (IPNs) was fabricated by simultaneous synthesis and characterized by thermogravimetry ( TG ). The kinetics of the thermal decomposition of polysiloxane/ polymethylacrylate IPNs in N2 and air was studied at different heating rates. It was observed that there were two decomposition peaks both in N2 and air, which showed that thermal decomposition process obeyed two-step pyrolysis mechanism and accorded with the two compositions of IPN. Kinetic parameters were determined during simultaneous integration of the Doyle equation and the IPN/ s kinetics equation was one-order equation in N2 and Air. The decomposition activation energy in N2 and air were 147. 405 kJ· monl^-1 and 192.656 kJ·monl^-1 respectively.
文摘A series of novel polysiloxane polyurea-urethane blockcopolymers based on methylene bis(p-phenylisocyanate (MDI), sodium-s-1,2-dihydroxy propyl sulphonate (SDPS) and aminopropyl-terminated polydimethylsiloxane (ATPS) was synthesized with varying length of soft segments and neutralizing cation. The effect of the chemical composition and the cation on the morphology and mechanical properties of the samples were studied. It was found that the SDPS chain extender based samples have definite chemical structure (-MDI-SDPS-MDI-ATPS-). As the length of the soft segment increases, an improvement of phase separation was observed. In addition, when SO3Na was translated into SO3H or the sulphonic acid groups were neutralized with different charge cations (Na+, Zn2+ and Al3+), the morphology and mechanical properties changed greatly.
基金the National Natural Science Foundation of China for the funding(No.20675007)
文摘A new ionic liquids grafted polysiloxane used as stationary phase for capillary gas chromatography (CGC) is described. The stationary phase of 1-vinyl-3-hexylimidazolium hexafluorophosphate anchored to polysiloxane (PMHS-[VHIm][PF6]) was synthe- sized, characterized and coated onto capillary columns by static coating. The results show that the present stationary phase exhibits a very good chromatographic resolution and selectivity for Grob test mixture and alcohols with baseline resolution and symmetry peaks. The present work suggests that novel stationary phase has a great potential for further development and application. 2009 Mei Ling Qi. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
文摘A series of side chain liquid crystalline polysiloxanes containing either cholesteryl or cyanobiphenyl mesogenic groups were synthesized by the hydrosilylation reaction of a polysiloxane containing Si H group with a vinyl terminated compound containing the mesogenic group. Their chemical structures were confirmed by IR, 1H NMR, and elemental analysis, Their phase behaviors were investigated by differential scanning calorimetry, optical polarizing microscope, and X ray diffraction techniques. The results show that all these polysiloxanes except PⅤ display smectic or nematic mesonorphism or both. The dependence of phase transition temperature on the rigidity of mesogenic unit. the length of spacer group, and the flexibility of Si(CH 3) 2O chain is also described.
基金This project was financially supported by the National Natural Science Foundation of China(Approved No.29775006)
文摘Two kinds of side chain liquid crystalline polysiloxanes containing crown ether and benzyl ether were synthesized and characterized by optical polarization microscopy. Both the monomeric liquid crystals and polymeric liquid crystals show smectic phases.
文摘Phenolic hydroxyl-terminated polysiloxanes were incorporated into epoxy resins to reduce the internal stress owing to the mismatch in coefficient of thermal expansion (CTE). Polysiloxane-epoxy resin block copolymers were made by a pre-reaction step prior to the curing. In the cured resin, the domain size of the polysiloxane phase depended on the structure of the phenolic hydroxyl-terminated polysiloxane. It was found that the modulus of the cured resin depended largely on the level of the modifier, while the CTE was affected greatly by the structure of the polysiloxane. By means of incorporating a few percent of methylphenylsiloxane unit into the polydimethylsiloxane chain, or by introducing; more compatible end-capping groups, the compounds of more effective low stress modifiers were synthesized.
文摘A new serial chiral side-chain liquid crystal polysiloxanes containing L-Tyr structures were synthesized at room temperature. Both of them exhibited Sc phase at room temperature.
基金support of the Key Laboratory of Advanced Textile Materials and Manufacturing Technology(Zhejiang Sci-Tech University),Ministry of Education(No.2005QN04)the National Natural Science Foundation of China(No.20573095)is gratefully acknowledged.
文摘A modified Stober method has been developed which permits the controlled growth of spherical hollow spheres with diameters between 197 and 208 nanometers by consecutively cocondensed methyltrimethoxysilane and dimethyldimethoxysilane monomers onto microemulsion of polydimethylsiloxane and subsequently removing the templated polydimethylsiloxane by exposure to solvents. Ammonia was used as a morphological catalyst. The morphology of the polymer spheres was demonstrated by transmission electron micrographs (TEM) and atomic force microscopy (AFM).
基金Supported by the Fund for Ph.D. programme from State Education Commission
文摘The present paper represents the syntheses of polypropyloxymethyldithia 15-crown-5 and 18-crown-6 supported on silica and their platinum complexes. The platinum complexes are effective catalysts for the hydrosilylation of olefins with triethoxysilane. The influences of temperature, amount of platinum complexes used and the nature of olefins used on the catalytic activity of the complexes are also investigated in this paper.
基金This work was supported by the National Natural Science Foundation of China (No. 20174047, 20204016, 50273043) andDow Corning Corporation, USA.
文摘A novel soluble, reactive ladder-like polysilsesquioxane (L) with lateral bromophenyl groups was synthesized successfully by stepwise coupling polymerization (SCP) method including preaminolysis, hydrolysis and polycondensation steps. The monomer 3-trichlorosilylpropoxy-4-bromobenzene (M) was first prepared via hydrosilylation reaction catalyzed by dicyclopentadienylplatinum dichloride (Cp2PtCl2). The title polymer (L) was characterized by 1H-NMR, 29Si-NMR, FTIR, X-ray diffraction (XRD), DSC and vapor pressure osmometry (VPO). The experimental results indicate that the polymer (L) possesses a typical ladder-like structure.
基金supported by the National Natural Science Foundation of China(21878092,21838003,91834301 and 51621002)the Shanghai Scientific and Technological Innovation Project(19JC1410400)+2 种基金Program of Shanghai Academic Research Leader(19XD1401400)the Innovation Program of Shanghai Municipal Education Commissionthe Fundamental Research Funds for the Central Universities(222201718002)。
文摘Excellent mechanical properties are the prerequisite for the application of superhydrophobic polymer coatings.However,significantly improving the mechanical properties without affecting other properties such as hydrophobicity is a huge challenge.In this study,a superhydrophobic coating with excellent mechanical properties was prepared by spraying a mixture of polysiloxane resins based on three siloxane monomers,hexadecyltrimethoxysilane(HDTMS) modified nano-SiO_(2)particles(SiO_(2)-HDTMS) and polystyrene-grafted halloysite nanotubes(HNTs-PS).SiO_(2)-HDTMS dispersed homogeneously in polysiloxane coatings and the water contact angle of corresponding coating exceeding 150°,achieving superhydrophobicity.The SiO_(2)-HDTMS/HNTs-PS/polysiloxane composite coatings showed excellent abrasion resistance with the water coating contact angle remaining above 150°after 90 abrasion cycles,indicating that HNTs-PS can significantly improve the mechanical properties of the coating without affecting the hydrophobic properties of the coating.The achieved coating also exhibited excellent antifouling and acid and alkali corrosion resistance.This work provides a convenient and ecologically friendly method to prepare superhydrophobic polysiloxane composite coating with excellent mechanical properties,which is promising in the application of anti-fouling,anti-corrosion,and oil-water separation etc.