UV-curable hyperbranched polyurethane acrylate-polyurethane diacrylate/SiO2 dispersion （HBPUA-PUDA/SiO2） was prepared with isophorone diisocyanate （IPDI）, hyperbranched polyester Boltorn H20 （H20）, hydroxy-ethyl...UV-curable hyperbranched polyurethane acrylate-polyurethane diacrylate/SiO2 dispersion （HBPUA-PUDA/SiO2） was prepared with isophorone diisocyanate （IPDI）, hyperbranched polyester Boltorn H20 （H20）, hydroxy-ethyl acrylate （HEA）, polyethyleneglycol （PEG-200）and nano-SiO2. The UV curing kinetics of the films was investigated by FTIR. The results show that the curing speed of the films increases with the adding of nano-SiO2 and decreases with the adding of PUDA due to the slower chain movement. The thermal stability of the HBPUA-PUDA/SiO2 films was studied by using thermogravimetric analysis coupled with Fourier transform infrared spectroscopy （TGA/FTIR）. The results show that all films exhibit two degradation stages located at about 320 and 440℃ corresponding to the degradation for hard segments of urethane-acrylate and the degradation for soft segment and polyester core. In addition, the results from the analysis of TGA/FTIR also indicate that the decomposition temperature of HBPUA-PUDA/SiO2 film is 15℃ higher than that obtained for pure polymer. The degradation mechanism was proposed according to TGA/FTIR results.展开更多
A new solid acid catalyst,SO4^2-/TiO2 modified with tin,was prepared using a sol-gel method and its physicochemical properties were revealed by nitrogen adsorption-desorption,X-ray powder diffraction,scanning electron...A new solid acid catalyst,SO4^2-/TiO2 modified with tin,was prepared using a sol-gel method and its physicochemical properties were revealed by nitrogen adsorption-desorption,X-ray powder diffraction,scanning electron microscopy,Fourier transform infrared spectroscopy,infrared spectroscopy of adsorbed pyridine,temperature-programmed desorption of ammonia and thermal gravimetric analysis.The structure,acidity and thermal stability of the SO4^2-/TiO2-SnO2 catalyst were studied.Incorporating tin enlarged the specific surface area and decreased crystallite size of the SO4^2-/TiO2 catalyst.The total acid sites of the modified catalyst increased and Bronsted acid strength remarkably increased with increasing tin content.The decomposition temperature of sulfate radical in the modified catalyst was 100 ℃ greater and its mass loss was more than twice that of the SO4^2-/TiO2 catalyst.The SO4^2-/TiO2-SnO2 catalyst was designed to synthesize 1,6-hexanediol diacrylate by esterification of 1,6-hexanediol with crylic acid.The yield of 1,6-hexanediol diacrylate exceeded 87% under the optimal reaction conditions：crylic acid to 1,6-hexanediol molar ratio = 3.5,catalyst loading = 7%,reaction temperature = 130 ℃ and reaction time = 3 h.The modified catalyst exhibited excellent reusability and after 10 cycles the conversion of 1,6-hexanediol was above 81%.展开更多
A novel UV-curable prepolymer polypropyleneglycol diglycidyl ether diacrylate （PPGGEA） was synthesized by utilizing polypropyleneglycol diglycidyl ether （PPGGE） and acrylic acid （AA） as starting materials, N, N-...A novel UV-curable prepolymer polypropyleneglycol diglycidyl ether diacrylate （PPGGEA） was synthesized by utilizing polypropyleneglycol diglycidyl ether （PPGGE） and acrylic acid （AA） as starting materials, N, N-dimethylbenzylamine as catalyst and p-hydroxyanisole as inhibitor. The optimum synthetic conditions were in the following： the concentration of N, N-dimethylbenzylamine was 0.80 wt% of reactants, the concentration of p-hydroxyanisole was 0.3 wt% of reactants, the reaction temperature was 90-110 ~C, and the molar ratio of PPGGE to AA was 1：2.2. Meanwhile, 1-hydroxycyclohexyl phenyl ketone of a UV-cured initiator was added to the synthesized PPGGEA to prepare a kind of UV-cured coating. The mechanical properties of the UV-cured films were determined, giving 29.99 MPa of tensile strength, 834.27 MPa of the Young＇s modulus and 5.66% of elongation at tear.展开更多
A novel UV-curable prepolymer hexanediol diglycidyl ether diacrylate （HDGEA） was synthesized by utilizing hexanediol diglycidyl ether （HDGE） and acrylic acid （AA） as starting materials, N, N-dimethylbenzylamine ...A novel UV-curable prepolymer hexanediol diglycidyl ether diacrylate （HDGEA） was synthesized by utilizing hexanediol diglycidyl ether （HDGE） and acrylic acid （AA） as starting materials, N, N-dimethylbenzylamine as catalyst and p-hydroxyanisole as inhibitor. The optimal synthetic conditions were that the concentration of N, N-dimethylbenzylamine was 0.80 wt% of reactants, the concentration of p-hydroxyanisole was 0.3 wt% of reactants, the reaction temperature was 90-110 ℃, and the molar ratio of HDGE to AA was 1︰2.2. Meanwhile, 1-hydroxycyclohexyl phenyl ketone of a UV-curing initiator was added to the synthesized HDGEA to prepare a kind of UV-curing coating. The mechanical properties of the UV-cured films were determined, giving 31.87 MPa of tensile strength, 871.88 MPa of Young＇s modulus and 6.77% of elongation at tear.展开更多
Using polyethylene glycol（PEG） or glycerol as the plasticizer, we synthesized the hydrogels from poly（ethylene glycol） diacrylate（PEGDA）, polyvinylpyrrolidone（PVP） and poly（vinyl alcohol）（PVA） under UV rad...Using polyethylene glycol（PEG） or glycerol as the plasticizer, we synthesized the hydrogels from poly（ethylene glycol） diacrylate（PEGDA）, polyvinylpyrrolidone（PVP） and poly（vinyl alcohol）（PVA） under UV radiation. The effects of different plasticizers on the mechanical properties and adhesion properties of the hydrogels were investigated. The results show that the plasticizer can improve the elongation and peeling force. The most pronotmced changes in the tensile property of the hydrogels are due to the addition of glycerol followed by PEG, the lower the plasticizer＇s molecular weight, the greater its effect. The maximum peeling force is 0.317 or 0.257 N with PEG or glycerol as plasticizer, respectively, and their adhesion properties are due to the formation of hydrogen bonds.展开更多
To investigate the effects of polyethylene glycol cross-linking on the mechanical properties, 80 porcine aortic valves were harvested, decellularized, and introduced with sulflaydryl. Then the valves were randomly ass...To investigate the effects of polyethylene glycol cross-linking on the mechanical properties, 80 porcine aortic valves were harvested, decellularized, and introduced with sulflaydryl. Then the valves were randomly assigned into 5 experimental groups and 1 control group （n=16）. For the valves in those experimental groups, branched polyethylene glycol diacrylate （PEG） of 5 different molecular weights （3.4, 8, 12, 20, 40 kDa） were synthesized and cross-linked with them respectively. The efficiency of the cross-linking was determined by measuring the amount of residual thiol group and the mechanical properties of the cross-linked valve leaflets were assessed by uni-axial planar tensile testing. The efficiency of the PEG 20 kDa group was 70.72±2.33%, obviously superior to that of the other groups （p〈0.05）. Tensile test proved that branched PEG cross-linking can significantly enhance the mechanical behaviors of the deeellularized valve leaflet and the Young＇s modulus of each group was positively correlated with the molecular weight of PEG. It was concluded that branched PEG with the molecular weight of 20 kDa can effectively cross-link the decellularized porcine aortic valves and improve their mechanical properties, which makes it a promising cross-linker that can be used in the modification of decellularized tissue engineering valves.展开更多
A novel UV-curable prepolymer neopentyl glycol diglycidyl ether diacrylate (NPGGEA) was synthesized by using neopentyl glycol diglycidyl ether (NPGGE) and acrylic acid (AA) as starting materials, N, N-dimethylbenzylam...A novel UV-curable prepolymer neopentyl glycol diglycidyl ether diacrylate (NPGGEA) was synthesized by using neopentyl glycol diglycidyl ether (NPGGE) and acrylic acid (AA) as starting materials, N, N-dimethylbenzylamine as catalyst and p-hydroxyanisole as inhibitor. The optimum synthetic conditions were taken as follows: The concentration of N,N-dimethylbenzylamine, 0.80% of reactants; the concentration of p-hydroxyanisole, 0.3% of reactants; the reaction temperature, 90-110 ; the molar ratio of NPGGE to AA, 1:2.2. Meanwhile, 1-hydroxycyclohexyl phenyl ketone of a UV-cured initiator was added to the synthesized NPGGEA to prepare a kind of UV-cured coating. Mechanical properties of the UV-cured films were determined, giving 28.75 MPa of tensile strength, 923.82 MPa of Young’s modulus and 5.51% of elongation at tear.展开更多
Poly（ethylene glycol） diacrylate/polyvinyl alcohoI（PEGDA/PVA） hydrogels were prepared from PEGDA and PVA as precurors by means of single UV radiation（UV ra.）, UV radiation followed by high energy electron beam i...Poly（ethylene glycol） diacrylate/polyvinyl alcohoI（PEGDA/PVA） hydrogels were prepared from PEGDA and PVA as precurors by means of single UV radiation（UV ra.）, UV radiation followed by high energy electron beam irradiation（Irra.）, UV radiation followed by freeze-thawing（FT） or UV ra. and Irra. followed by FT, respectively. 2-Hydroxy-l-[4-（hydroxyethoxy）phenyl]-2-methyl-l-propanone（Irgacure 2959） was used as a photoinitiator. The effects of the various methods on the swelling and mechanical properties of the hydrogels were investigated. The results show that hydrogels made by UV ra. plus high energy electron beam irradiation followed by FT showed a higher crosslinking density and a larger tensile strength than those made by the other methods.展开更多
Organic-inorganic hybrid</span><b> </b><span style="font-family:Verdana;">network polymers have been synthesized by addition reaction of a thiol-functionalized random type silsesquiox...Organic-inorganic hybrid</span><b> </b><span style="font-family:Verdana;">network polymers have been synthesized by addition reaction of a thiol-functionalized random type silsesquioxane (SQ109) and alkyl diacrylate or diisocyanate compounds. Thiol-ene reaction of SQ109 and 1,4-butanediol diacrylate (BDA) successfully yield porous polymer in toluene initiated by azobis</span></span><span style="font-family:Verdana;">(</span><span style="font-family:Verdana;">isobutyronitrile</span><span style="font-family:Verdana;">)</span><span style="font-family:Verdana;"> (AIBN) at 60</span><span style="font-family:Verdana;">°</span><span style="font-family:Verdana;">C. Morphology of the porous polymers was composed by connected globules, and the diameter of the globules decreased with increasing in the monomer concentration </span><span style="font-family:Verdana;">of</span><span style="font-family:Verdana;"> the reaction </span><span style="font-family:Verdana;">system</span><span style="font-family:""><span style="font-family:Verdana;">. By contrast, the reaction with 1,6-hexanediol diacrylate or </span><span style="font-family:Verdana;">1,5-hexadiene yielded homogeneous clear gels. Thermal analyses of SQ109-BDA</span><span style="font-family:Verdana;"> porous polymers indicated that thermal degradation of ester groups of BDA in the polymer network occurred at around 300</span></span><span style="font-family:Verdana;">°</span><span style="font-family:Verdana;">C. The porous polymer was also obtained </span><span style="font-family:Verdana;">by</span><span style="font-family:Verdana;"> the reaction </span><span style="font-family:Verdana;">using</span><span style="font-family:""><span style="font-family:Verdana;"> a photo-initiator (Irugacure184) at room temperature, and showed higher Young’s modulus than the corresponding porous polymer obtained with the reaction with AIBN due to the small size of </span><span style="font-family:Verdana;">the globules. Young’s modulus of SQ109-BDA porous polymer increased</span>展开更多
文摘UV-curable hyperbranched polyurethane acrylate-polyurethane diacrylate/SiO2 dispersion （HBPUA-PUDA/SiO2） was prepared with isophorone diisocyanate （IPDI）, hyperbranched polyester Boltorn H20 （H20）, hydroxy-ethyl acrylate （HEA）, polyethyleneglycol （PEG-200）and nano-SiO2. The UV curing kinetics of the films was investigated by FTIR. The results show that the curing speed of the films increases with the adding of nano-SiO2 and decreases with the adding of PUDA due to the slower chain movement. The thermal stability of the HBPUA-PUDA/SiO2 films was studied by using thermogravimetric analysis coupled with Fourier transform infrared spectroscopy （TGA/FTIR）. The results show that all films exhibit two degradation stages located at about 320 and 440℃ corresponding to the degradation for hard segments of urethane-acrylate and the degradation for soft segment and polyester core. In addition, the results from the analysis of TGA/FTIR also indicate that the decomposition temperature of HBPUA-PUDA/SiO2 film is 15℃ higher than that obtained for pure polymer. The degradation mechanism was proposed according to TGA/FTIR results.
文摘A new solid acid catalyst,SO4^2-/TiO2 modified with tin,was prepared using a sol-gel method and its physicochemical properties were revealed by nitrogen adsorption-desorption,X-ray powder diffraction,scanning electron microscopy,Fourier transform infrared spectroscopy,infrared spectroscopy of adsorbed pyridine,temperature-programmed desorption of ammonia and thermal gravimetric analysis.The structure,acidity and thermal stability of the SO4^2-/TiO2-SnO2 catalyst were studied.Incorporating tin enlarged the specific surface area and decreased crystallite size of the SO4^2-/TiO2 catalyst.The total acid sites of the modified catalyst increased and Bronsted acid strength remarkably increased with increasing tin content.The decomposition temperature of sulfate radical in the modified catalyst was 100 ℃ greater and its mass loss was more than twice that of the SO4^2-/TiO2 catalyst.The SO4^2-/TiO2-SnO2 catalyst was designed to synthesize 1,6-hexanediol diacrylate by esterification of 1,6-hexanediol with crylic acid.The yield of 1,6-hexanediol diacrylate exceeded 87% under the optimal reaction conditions：crylic acid to 1,6-hexanediol molar ratio = 3.5,catalyst loading = 7%,reaction temperature = 130 ℃ and reaction time = 3 h.The modified catalyst exhibited excellent reusability and after 10 cycles the conversion of 1,6-hexanediol was above 81%.
基金the Innovatory Group Program of the Natural Science Foundation of Hubei Province(No.2004ABC001)the National"863"Hi-tech Foundation of China(No.2002AA6Z3083)
文摘A novel UV-curable prepolymer polypropyleneglycol diglycidyl ether diacrylate （PPGGEA） was synthesized by utilizing polypropyleneglycol diglycidyl ether （PPGGE） and acrylic acid （AA） as starting materials, N, N-dimethylbenzylamine as catalyst and p-hydroxyanisole as inhibitor. The optimum synthetic conditions were in the following： the concentration of N, N-dimethylbenzylamine was 0.80 wt% of reactants, the concentration of p-hydroxyanisole was 0.3 wt% of reactants, the reaction temperature was 90-110 ~C, and the molar ratio of PPGGE to AA was 1：2.2. Meanwhile, 1-hydroxycyclohexyl phenyl ketone of a UV-cured initiator was added to the synthesized PPGGEA to prepare a kind of UV-cured coating. The mechanical properties of the UV-cured films were determined, giving 29.99 MPa of tensile strength, 834.27 MPa of the Young＇s modulus and 5.66% of elongation at tear.
基金Funded by the Natural Science Foundation of Jiangxi Province (No.2008GZC0021)the National "863" Hi-tech Foundation of China (No.2002AA6Z3083)
文摘A novel UV-curable prepolymer hexanediol diglycidyl ether diacrylate （HDGEA） was synthesized by utilizing hexanediol diglycidyl ether （HDGE） and acrylic acid （AA） as starting materials, N, N-dimethylbenzylamine as catalyst and p-hydroxyanisole as inhibitor. The optimal synthetic conditions were that the concentration of N, N-dimethylbenzylamine was 0.80 wt% of reactants, the concentration of p-hydroxyanisole was 0.3 wt% of reactants, the reaction temperature was 90-110 ℃, and the molar ratio of HDGE to AA was 1︰2.2. Meanwhile, 1-hydroxycyclohexyl phenyl ketone of a UV-curing initiator was added to the synthesized HDGEA to prepare a kind of UV-curing coating. The mechanical properties of the UV-cured films were determined, giving 31.87 MPa of tensile strength, 871.88 MPa of Young＇s modulus and 6.77% of elongation at tear.
文摘Using polyethylene glycol（PEG） or glycerol as the plasticizer, we synthesized the hydrogels from poly（ethylene glycol） diacrylate（PEGDA）, polyvinylpyrrolidone（PVP） and poly（vinyl alcohol）（PVA） under UV radiation. The effects of different plasticizers on the mechanical properties and adhesion properties of the hydrogels were investigated. The results show that the plasticizer can improve the elongation and peeling force. The most pronotmced changes in the tensile property of the hydrogels are due to the addition of glycerol followed by PEG, the lower the plasticizer＇s molecular weight, the greater its effect. The maximum peeling force is 0.317 or 0.257 N with PEG or glycerol as plasticizer, respectively, and their adhesion properties are due to the formation of hydrogen bonds.
基金funded by the National High-Technology Research and Development Program of China(863 Program)(No.2009AA03Z420)the National Natural Science Foundation of China(Nos.30872540,81400290)
文摘To investigate the effects of polyethylene glycol cross-linking on the mechanical properties, 80 porcine aortic valves were harvested, decellularized, and introduced with sulflaydryl. Then the valves were randomly assigned into 5 experimental groups and 1 control group （n=16）. For the valves in those experimental groups, branched polyethylene glycol diacrylate （PEG） of 5 different molecular weights （3.4, 8, 12, 20, 40 kDa） were synthesized and cross-linked with them respectively. The efficiency of the cross-linking was determined by measuring the amount of residual thiol group and the mechanical properties of the cross-linked valve leaflets were assessed by uni-axial planar tensile testing. The efficiency of the PEG 20 kDa group was 70.72±2.33%, obviously superior to that of the other groups （p〈0.05）. Tensile test proved that branched PEG cross-linking can significantly enhance the mechanical behaviors of the deeellularized valve leaflet and the Young＇s modulus of each group was positively correlated with the molecular weight of PEG. It was concluded that branched PEG with the molecular weight of 20 kDa can effectively cross-link the decellularized porcine aortic valves and improve their mechanical properties, which makes it a promising cross-linker that can be used in the modification of decellularized tissue engineering valves.
基金supported by the National High-Technology Research and Development Program of China (Grant No.2002AA6Z3083)
文摘A novel UV-curable prepolymer neopentyl glycol diglycidyl ether diacrylate (NPGGEA) was synthesized by using neopentyl glycol diglycidyl ether (NPGGE) and acrylic acid (AA) as starting materials, N, N-dimethylbenzylamine as catalyst and p-hydroxyanisole as inhibitor. The optimum synthetic conditions were taken as follows: The concentration of N,N-dimethylbenzylamine, 0.80% of reactants; the concentration of p-hydroxyanisole, 0.3% of reactants; the reaction temperature, 90-110 ; the molar ratio of NPGGE to AA, 1:2.2. Meanwhile, 1-hydroxycyclohexyl phenyl ketone of a UV-cured initiator was added to the synthesized NPGGEA to prepare a kind of UV-cured coating. Mechanical properties of the UV-cured films were determined, giving 28.75 MPa of tensile strength, 923.82 MPa of Young’s modulus and 5.51% of elongation at tear.
文摘Poly（ethylene glycol） diacrylate/polyvinyl alcohoI（PEGDA/PVA） hydrogels were prepared from PEGDA and PVA as precurors by means of single UV radiation（UV ra.）, UV radiation followed by high energy electron beam irradiation（Irra.）, UV radiation followed by freeze-thawing（FT） or UV ra. and Irra. followed by FT, respectively. 2-Hydroxy-l-[4-（hydroxyethoxy）phenyl]-2-methyl-l-propanone（Irgacure 2959） was used as a photoinitiator. The effects of the various methods on the swelling and mechanical properties of the hydrogels were investigated. The results show that hydrogels made by UV ra. plus high energy electron beam irradiation followed by FT showed a higher crosslinking density and a larger tensile strength than those made by the other methods.
文摘Organic-inorganic hybrid</span><b> </b><span style="font-family:Verdana;">network polymers have been synthesized by addition reaction of a thiol-functionalized random type silsesquioxane (SQ109) and alkyl diacrylate or diisocyanate compounds. Thiol-ene reaction of SQ109 and 1,4-butanediol diacrylate (BDA) successfully yield porous polymer in toluene initiated by azobis</span></span><span style="font-family:Verdana;">(</span><span style="font-family:Verdana;">isobutyronitrile</span><span style="font-family:Verdana;">)</span><span style="font-family:Verdana;"> (AIBN) at 60</span><span style="font-family:Verdana;">°</span><span style="font-family:Verdana;">C. Morphology of the porous polymers was composed by connected globules, and the diameter of the globules decreased with increasing in the monomer concentration </span><span style="font-family:Verdana;">of</span><span style="font-family:Verdana;"> the reaction </span><span style="font-family:Verdana;">system</span><span style="font-family:""><span style="font-family:Verdana;">. By contrast, the reaction with 1,6-hexanediol diacrylate or </span><span style="font-family:Verdana;">1,5-hexadiene yielded homogeneous clear gels. Thermal analyses of SQ109-BDA</span><span style="font-family:Verdana;"> porous polymers indicated that thermal degradation of ester groups of BDA in the polymer network occurred at around 300</span></span><span style="font-family:Verdana;">°</span><span style="font-family:Verdana;">C. The porous polymer was also obtained </span><span style="font-family:Verdana;">by</span><span style="font-family:Verdana;"> the reaction </span><span style="font-family:Verdana;">using</span><span style="font-family:""><span style="font-family:Verdana;"> a photo-initiator (Irugacure184) at room temperature, and showed higher Young’s modulus than the corresponding porous polymer obtained with the reaction with AIBN due to the small size of </span><span style="font-family:Verdana;">the globules. Young’s modulus of SQ109-BDA porous polymer increased</span>
