Following deformation, thermally induced shape memory polymers(SMPs) have the ability to recover their original shape with a change in temperature. In this work, the thermomechanical properties and shape memory behavi...Following deformation, thermally induced shape memory polymers(SMPs) have the ability to recover their original shape with a change in temperature. In this work, the thermomechanical properties and shape memory behaviors of three types of epoxy SMPs with varying curing agent contents were investigated using a molecular dynamics(MD) method. The mechanical properties under uniaxial tension at different temperatures were obtained, and the simulation results compared reasonably with experimental data. In addition, in a thermomechanical cycle, ideal shape memory effects for the three types of SMPs were revealed through the shape frozen and shape recovery responses at low and high temperatures, respectively, indicating that the recovery time is strongly influenced by the ratio of E-51 to 4,4'-Methylenedianiline.展开更多
It was investigated that the reaction of 4,4′-diphenylmethanediamine(MDA)with CO2 and bromoethane to synthesize diethyl 4,4′-diphenylmethanedicarbamate(MDC)under the catalysis of Cs2CO3 cooperating with DBU in super...It was investigated that the reaction of 4,4′-diphenylmethanediamine(MDA)with CO2 and bromoethane to synthesize diethyl 4,4′-diphenylmethanedicarbamate(MDC)under the catalysis of Cs2CO3 cooperating with DBU in supercritical carbon dioixide.The optimum reaction conditions were MDA(10mmol),EtBr(30mmol),Cs2CO3(6mmol)as catalyst cooperating with DBU(30mmol),a temperature of 60 °C,a pressure of 8 MPa,and a reaction time of 4 hours.MDC was obtained in the yield of 88% under the optimum reaction condtions.展开更多
基金the National Natural Science Foundation of China(Grant Nos.11272044 and 11023001)
文摘Following deformation, thermally induced shape memory polymers(SMPs) have the ability to recover their original shape with a change in temperature. In this work, the thermomechanical properties and shape memory behaviors of three types of epoxy SMPs with varying curing agent contents were investigated using a molecular dynamics(MD) method. The mechanical properties under uniaxial tension at different temperatures were obtained, and the simulation results compared reasonably with experimental data. In addition, in a thermomechanical cycle, ideal shape memory effects for the three types of SMPs were revealed through the shape frozen and shape recovery responses at low and high temperatures, respectively, indicating that the recovery time is strongly influenced by the ratio of E-51 to 4,4'-Methylenedianiline.
文摘It was investigated that the reaction of 4,4′-diphenylmethanediamine(MDA)with CO2 and bromoethane to synthesize diethyl 4,4′-diphenylmethanedicarbamate(MDC)under the catalysis of Cs2CO3 cooperating with DBU in supercritical carbon dioixide.The optimum reaction conditions were MDA(10mmol),EtBr(30mmol),Cs2CO3(6mmol)as catalyst cooperating with DBU(30mmol),a temperature of 60 °C,a pressure of 8 MPa,and a reaction time of 4 hours.MDC was obtained in the yield of 88% under the optimum reaction condtions.
