The radiative curable dendritic acrylated aromatic/aliphatic polyesters based on pentaerythritol, 1,2,4 benzenetricaboxylic anhydride and epoxy propane modified with acryloyl chloride were synthesized via a diver...The radiative curable dendritic acrylated aromatic/aliphatic polyesters based on pentaerythritol, 1,2,4 benzenetricaboxylic anhydride and epoxy propane modified with acryloyl chloride were synthesized via a divergent procedure, and their photopolymerization kinetics was studied by photo differential scanning calorimetry. The mechanical properties and the morphology of the fracture surface of the cured dendritic polyester films were investigated by means of dynamic mechanical thermal analysis and scanning electron microscopy, respectively.展开更多
The photoinduced bulk polymerization of a reactive-hindered amine light stabilizers (r-HALS), 4-acryloyl-2, 2, 6,6-tetramethylpiperidinyl (ATMP), was performed at 80 C by using a DPC technique. An unique periodic expo...The photoinduced bulk polymerization of a reactive-hindered amine light stabilizers (r-HALS), 4-acryloyl-2, 2, 6,6-tetramethylpiperidinyl (ATMP), was performed at 80 C by using a DPC technique. An unique periodic exponential attenuation-type oscillating curve was found when the polymerization was carried out in air, but this phenomenon was not found in nitrogen. It is supposed that this unique kinetic performance may be attributed to nitroxyl radicals that are produced in situ from the oxidation of ATMP. ATMP polymer with narrow polydispersity (d = 1.03) can be obtained by photoinduced solution polymerization of ATMP. The signal detected in ESR may be assigned to the nitroxyl radicals in the matrix of ATMP polymer. Since this kind of recycling of nitroxyl radicals is well documented for the photostabilizing mechanism of HALS, the present results may serve as a kinetic evidence for this mechanism.展开更多
The diversity of biomedical applications makes stereolithographic(SL)three-dimensional(3D)printing process complex.A strategy was developed to simulate the layer-by-layer fabrication of 3D printed products combining p...The diversity of biomedical applications makes stereolithographic(SL)three-dimensional(3D)printing process complex.A strategy was developed to simulate the layer-by-layer fabrication of 3D printed products combining polymerization kinetic with reaction conditions to realize print preview.As a representative example,the typical UV-curable dental materials based on epoxy acrylate and photoinitiator with different molar ratios was exposed under varying intensity of UV light to verify the simulation results.A theoretical kinetics model containing oxygen inhibition was established.In-situ FTIR was employed to measure propagation and termination constants while coupled UV/vis was performed to examine the law of light attenuation during cure reaction,even with various colours and additives.Simulation results showed that the correlation coefficient square between the experiments and simulations of epoxy acrylate with 1%,2%and 3%initiator upon 20 mW/cm2 UV light are 0.8959,0.9324 and 0.9337,respectively.Consequently,our simulation of photopolymerization for SL 3D printing successfully realized visualization of printing quality before practically printing the targeted biomedical objects with complex topology structures.展开更多
基金Supported by the National Natural Science Foundation of China(No. 2 0 0 74 0 34)
文摘The radiative curable dendritic acrylated aromatic/aliphatic polyesters based on pentaerythritol, 1,2,4 benzenetricaboxylic anhydride and epoxy propane modified with acryloyl chloride were synthesized via a divergent procedure, and their photopolymerization kinetics was studied by photo differential scanning calorimetry. The mechanical properties and the morphology of the fracture surface of the cured dendritic polyester films were investigated by means of dynamic mechanical thermal analysis and scanning electron microscopy, respectively.
基金the National Natural Science Foundation of China(No.20274023)key project foundation of National Ministry of Education(No.02114)Guangdong Province Natural Science Foundation of China(No.021241)for supporting this work.
文摘The photoinduced bulk polymerization of a reactive-hindered amine light stabilizers (r-HALS), 4-acryloyl-2, 2, 6,6-tetramethylpiperidinyl (ATMP), was performed at 80 C by using a DPC technique. An unique periodic exponential attenuation-type oscillating curve was found when the polymerization was carried out in air, but this phenomenon was not found in nitrogen. It is supposed that this unique kinetic performance may be attributed to nitroxyl radicals that are produced in situ from the oxidation of ATMP. ATMP polymer with narrow polydispersity (d = 1.03) can be obtained by photoinduced solution polymerization of ATMP. The signal detected in ESR may be assigned to the nitroxyl radicals in the matrix of ATMP polymer. Since this kind of recycling of nitroxyl radicals is well documented for the photostabilizing mechanism of HALS, the present results may serve as a kinetic evidence for this mechanism.
基金supported by the National Natural Science Foundation of China(51703148,21574019),ChinaChina Postdoctoral Science Foundation(2017M611901),China+3 种基金Fundamental Research Funds for the Central Universities(2232019D3-07),ChinaShanghai Belt and Road Joint Laboratory of Advanced Fiber and Low-dimension Materials(18520750400),ChinaKey Laboratory of High-Performance Fibers&Products,Ministry of Education,Center for Civil Aviation Composites,Donghua University and Key Laboratory of Shanghai City for Lightweight Composites(X12811901/018),ChinaInitial Research Funds for Young Teachers of Donghua University,China.
文摘The diversity of biomedical applications makes stereolithographic(SL)three-dimensional(3D)printing process complex.A strategy was developed to simulate the layer-by-layer fabrication of 3D printed products combining polymerization kinetic with reaction conditions to realize print preview.As a representative example,the typical UV-curable dental materials based on epoxy acrylate and photoinitiator with different molar ratios was exposed under varying intensity of UV light to verify the simulation results.A theoretical kinetics model containing oxygen inhibition was established.In-situ FTIR was employed to measure propagation and termination constants while coupled UV/vis was performed to examine the law of light attenuation during cure reaction,even with various colours and additives.Simulation results showed that the correlation coefficient square between the experiments and simulations of epoxy acrylate with 1%,2%and 3%initiator upon 20 mW/cm2 UV light are 0.8959,0.9324 and 0.9337,respectively.Consequently,our simulation of photopolymerization for SL 3D printing successfully realized visualization of printing quality before practically printing the targeted biomedical objects with complex topology structures.
