A Aeries of hydroxylic hyperbranched polymers were derived from 2,2-bis(methylol) propionic acid and tris(methylol) propane reacted with acrylic acid to various extents. The obtained acrylated hyperbranched polymers a...A Aeries of hydroxylic hyperbranched polymers were derived from 2,2-bis(methylol) propionic acid and tris(methylol) propane reacted with acrylic acid to various extents. The obtained acrylated hyperbranched polymers alone or with a monofunctional diluent, isobornylene acrylate(IBOA) were further cured by UV radiation. The cured films based on the modified polymers alone all demonstrated poor mechanical properties due to their high network densities and low moving ability of polymer chains. For the composite systems, the cured films demonstrated improved mechanical properties due to the low network densities and high chain moving ability. With more IBOA included in the systems, acrylate groups can react to a higher extent during the curing process.展开更多
In this paper, we combined high-end cationic UV-curable material with fluorinated chain obtaining a series of new fluorine-containing aromatic oxetane monomers via a mild nucleophilic substitution reaction. The struct...In this paper, we combined high-end cationic UV-curable material with fluorinated chain obtaining a series of new fluorine-containing aromatic oxetane monomers via a mild nucleophilic substitution reaction. The structures and properties of monomers were characterized using ~1 H-NMR, ^（19） F-NMR, dynamic viscosity tests and differential scanning calorimetry（DSC）. It was determined that all of the fluorinated monomers obtained had much lower viscosity and higher thermostability after the introduction of hexafluorobenzene. Then, UV-curable coatings were prepared using four fluorine-containing aromatic oxetane monomers（FOX1-4）; the UV-curing kinetics, with three kinds of initiators, and properties of the cured films were evaluated using real-time Fourier transform infrared（FTIR） spectroscopy, water and diiodomethane contact angle tests, surface energy calculations and scanning electron microscopy（SEM）. The FTIR spectroscopy results showed that the coatings possessed excellent conversion rate（〉 99% with liquid initiator PAG-201 in 150 s）, and as the fluorine content increased, the monomers exhibited decreased mobility with the increasing viscosity and worse solubility with fluorinated monomers, resulting in a lower conversion rate. Moreover, the coatings possessed favorable hydrophobic and oleophobic properties and low surface energies owing to the fluoride chains floating to the membrane-air interface, which was also confirmed by discrete concave structures in SEM images. These new kinds of monomers can replace traditional fluorinated cationic monomers applied to the fingerprint resistant, fouling resistant, scratch resistant and anti-aging coatings, adhesives or printing ink materials.展开更多
By using diphenyliodonium salts with different counterions as photo acid generators (PAGs), the effect of acidity on ring-opening polymerization of epoxy monomers and polycondensation of polyol with hexamethoxymethyl ...By using diphenyliodonium salts with different counterions as photo acid generators (PAGs), the effect of acidity on ring-opening polymerization of epoxy monomers and polycondensation of polyol with hexamethoxymethyl melamine (HMMM) was studied. The result shows that the rate of ring-opening polymerization is evidently dependent on the acidity of the acid and strong photo-generated acid is required. However, there is a leveling effect in the polycondensation system; if the photo-generated acid is stronger than protonated HMMM, the acidity does not obviously affect the polycondensation rate.展开更多
The reactive diluent prepared by siloxane modified Trimethylene oxide can improve the performance of the UV curing system.Therefore,1,7-bis[(3-ethyl-3-methoxyoxacylobutane)propyl]octadecylosiloxane(BEMOPOMTS)was synth...The reactive diluent prepared by siloxane modified Trimethylene oxide can improve the performance of the UV curing system.Therefore,1,7-bis[(3-ethyl-3-methoxyoxacylobutane)propyl]octadecylosiloxane(BEMOPOMTS)was synthesized from diethyl carbonate,trimethylopropanes,allyl bromide,and 1,1,3,3,5,5,7,7-octadecylosiloxane as the main raw materials.BEMOPOMTS can be used as reactive diluents in the field of cationic UV curing.It has good thermal stability,and the addition of BEMOPOMTS significantly improves the tensile strength and elongation at break of epoxy resin.Compared with the pure epoxy resin,adding 20%BEMOPOMTS increased the elastic modulus by 25%to 677 MPa.展开更多
In this study,a series of hindered urea bond(HUB)containing polyurethane-urea methacrylate prepolymers and a none HUB containing polyurethane methacrylate prepolymer were prepared using isobornyl methacrylate as the r...In this study,a series of hindered urea bond(HUB)containing polyurethane-urea methacrylate prepolymers and a none HUB containing polyurethane methacrylate prepolymer were prepared using isobornyl methacrylate as the reactive diluent via one-pot procedure.The prepolymers were characterized fully by various techniques.Then,their thermosets were fabricated via UV curing in presence of a photo initiator,and their mechanical property and thermal behavior were investigated and compared.Different from the none HUB containing thermoset,the HUB containing thermosets(defined as PUT)could be recycled and reprocessed by hot press under relatively mild conditions with high recovery ratio of mechanical property.Furthermore,zinc oxide(ZnO)nanoparticles were modified with 3-(trimethoxysilyl)propyl methacrylate and the modified ZnO(defined as ZnO-TPM)was dispersed and polymerized into PUT matrix to prepare their nanocomposites.The influence of ZnO-TPM on the mechanical performance of the composites was evaluated,which indicated that the Young’s modulus and tensile strength increased gradually to the maximum values at ZnO-TPM content of 1 wt%and then decreased.The composites also displayed good reprocessability with improved recovery ratio compared to the pure PUT sample.In addition,the composite materials exhibited strong UV absorption capacity,implying their potential application in the circumstance where UV-shielding was required.展开更多
Recently, the application of ultraviolet (UV) curable monomers to human nails, (also known as UV gel nails) has become a popular decoration technique for women’s nails. However, the unreacted layer, the depletion of ...Recently, the application of ultraviolet (UV) curable monomers to human nails, (also known as UV gel nails) has become a popular decoration technique for women’s nails. However, the unreacted layer, the depletion of residual monomers from the cured UV gel nails, which can cause allergy and asthma, and the increase in temperature during curing process, are major concerns. In this study, the thickness of the unreacted layer, the increase in temperature, and the residual contents in cured film of UV gel nail treatment were measured for the first time. The results of this study indicated that the thickness of unreacted layer was not affected by the cast thickness;however, the intensity of UV light and the photoinitiator concentration had significant effect on the thickness of the unreacted layer. To reduce the thickness of the unreacted layer, the intensity of the UV light and the photoinitiator concentration should be increased. However, the maximum temperature observed during the curing of UV gel nails increases with an increase in the intensity of the UV light and the photoinitiator concentration. A suitable cast thickness range (21 ~ 150 μm), which resulted in the formation of a cured film and without producing temperatures that exceed that of the human body, was identified. The mass fraction of the residuals in the cured layer decreased with an increase in the exposure time, the UV intensity, and the photoinitiator concentration.展开更多
基金Supported by the National Natural Science Foundation of China(No.2 0 2 0 4 0 0 5 ,5 0 2 330 30 ) and Basic Research Fund ofTsinghua University(No.JC2 0 0 2 0 30 )
文摘A Aeries of hydroxylic hyperbranched polymers were derived from 2,2-bis(methylol) propionic acid and tris(methylol) propane reacted with acrylic acid to various extents. The obtained acrylated hyperbranched polymers alone or with a monofunctional diluent, isobornylene acrylate(IBOA) were further cured by UV radiation. The cured films based on the modified polymers alone all demonstrated poor mechanical properties due to their high network densities and low moving ability of polymer chains. For the composite systems, the cured films demonstrated improved mechanical properties due to the low network densities and high chain moving ability. With more IBOA included in the systems, acrylate groups can react to a higher extent during the curing process.
基金financially supported by the National Natural Science Foundation of China (No. 21574014)
文摘In this paper, we combined high-end cationic UV-curable material with fluorinated chain obtaining a series of new fluorine-containing aromatic oxetane monomers via a mild nucleophilic substitution reaction. The structures and properties of monomers were characterized using ~1 H-NMR, ^（19） F-NMR, dynamic viscosity tests and differential scanning calorimetry（DSC）. It was determined that all of the fluorinated monomers obtained had much lower viscosity and higher thermostability after the introduction of hexafluorobenzene. Then, UV-curable coatings were prepared using four fluorine-containing aromatic oxetane monomers（FOX1-4）; the UV-curing kinetics, with three kinds of initiators, and properties of the cured films were evaluated using real-time Fourier transform infrared（FTIR） spectroscopy, water and diiodomethane contact angle tests, surface energy calculations and scanning electron microscopy（SEM）. The FTIR spectroscopy results showed that the coatings possessed excellent conversion rate（〉 99% with liquid initiator PAG-201 in 150 s）, and as the fluorine content increased, the monomers exhibited decreased mobility with the increasing viscosity and worse solubility with fluorinated monomers, resulting in a lower conversion rate. Moreover, the coatings possessed favorable hydrophobic and oleophobic properties and low surface energies owing to the fluoride chains floating to the membrane-air interface, which was also confirmed by discrete concave structures in SEM images. These new kinds of monomers can replace traditional fluorinated cationic monomers applied to the fingerprint resistant, fouling resistant, scratch resistant and anti-aging coatings, adhesives or printing ink materials.
基金This project was supported by the National Natural Science Foundation of China(59633110 and 59773007)
文摘By using diphenyliodonium salts with different counterions as photo acid generators (PAGs), the effect of acidity on ring-opening polymerization of epoxy monomers and polycondensation of polyol with hexamethoxymethyl melamine (HMMM) was studied. The result shows that the rate of ring-opening polymerization is evidently dependent on the acidity of the acid and strong photo-generated acid is required. However, there is a leveling effect in the polycondensation system; if the photo-generated acid is stronger than protonated HMMM, the acidity does not obviously affect the polycondensation rate.
基金Funded by the National Natural Science Foundation of China(No.21865017)。
文摘The reactive diluent prepared by siloxane modified Trimethylene oxide can improve the performance of the UV curing system.Therefore,1,7-bis[(3-ethyl-3-methoxyoxacylobutane)propyl]octadecylosiloxane(BEMOPOMTS)was synthesized from diethyl carbonate,trimethylopropanes,allyl bromide,and 1,1,3,3,5,5,7,7-octadecylosiloxane as the main raw materials.BEMOPOMTS can be used as reactive diluents in the field of cationic UV curing.It has good thermal stability,and the addition of BEMOPOMTS significantly improves the tensile strength and elongation at break of epoxy resin.Compared with the pure epoxy resin,adding 20%BEMOPOMTS increased the elastic modulus by 25%to 677 MPa.
文摘In this study,a series of hindered urea bond(HUB)containing polyurethane-urea methacrylate prepolymers and a none HUB containing polyurethane methacrylate prepolymer were prepared using isobornyl methacrylate as the reactive diluent via one-pot procedure.The prepolymers were characterized fully by various techniques.Then,their thermosets were fabricated via UV curing in presence of a photo initiator,and their mechanical property and thermal behavior were investigated and compared.Different from the none HUB containing thermoset,the HUB containing thermosets(defined as PUT)could be recycled and reprocessed by hot press under relatively mild conditions with high recovery ratio of mechanical property.Furthermore,zinc oxide(ZnO)nanoparticles were modified with 3-(trimethoxysilyl)propyl methacrylate and the modified ZnO(defined as ZnO-TPM)was dispersed and polymerized into PUT matrix to prepare their nanocomposites.The influence of ZnO-TPM on the mechanical performance of the composites was evaluated,which indicated that the Young’s modulus and tensile strength increased gradually to the maximum values at ZnO-TPM content of 1 wt%and then decreased.The composites also displayed good reprocessability with improved recovery ratio compared to the pure PUT sample.In addition,the composite materials exhibited strong UV absorption capacity,implying their potential application in the circumstance where UV-shielding was required.
文摘Recently, the application of ultraviolet (UV) curable monomers to human nails, (also known as UV gel nails) has become a popular decoration technique for women’s nails. However, the unreacted layer, the depletion of residual monomers from the cured UV gel nails, which can cause allergy and asthma, and the increase in temperature during curing process, are major concerns. In this study, the thickness of the unreacted layer, the increase in temperature, and the residual contents in cured film of UV gel nail treatment were measured for the first time. The results of this study indicated that the thickness of unreacted layer was not affected by the cast thickness;however, the intensity of UV light and the photoinitiator concentration had significant effect on the thickness of the unreacted layer. To reduce the thickness of the unreacted layer, the intensity of the UV light and the photoinitiator concentration should be increased. However, the maximum temperature observed during the curing of UV gel nails increases with an increase in the intensity of the UV light and the photoinitiator concentration. A suitable cast thickness range (21 ~ 150 μm), which resulted in the formation of a cured film and without producing temperatures that exceed that of the human body, was identified. The mass fraction of the residuals in the cured layer decreased with an increase in the exposure time, the UV intensity, and the photoinitiator concentration.
