In order to study the relationship between the main process parameters and the cell size, the mathematical model of cell growth of microcellular foaming injection process is built. Then numeric simulation is employed ...In order to study the relationship between the main process parameters and the cell size, the mathematical model of cell growth of microcellular foaming injection process is built. Then numeric simulation is employed as experimental method, and the Taguchi method is used to analyze significance of effect of process parameters on the cell size. At last the process parameters are focused on melt temperature, injection time, mold temperature and pretidied volume. The significance order from big to small of the effect of each process parameters on cell size is melt temperature, pre-filled volume, injection time, and mold temperature. On the basis of above research, the effect of each process parameter on cell size is further researched. Appropriate reduction of the melt temperature and increase of the pre-filled volume can optimize the cell size effectively, while the effects of injection time and mold temperature on cell size are less significant.展开更多
Novel microcellular foams using thin plasticized PC sheet were prepared by compression molding. The measurement results showed that T of plasticized PC was decreased and the molecular chain mobility was increased. Dec...Novel microcellular foams using thin plasticized PC sheet were prepared by compression molding. The measurement results showed that T of plasticized PC was decreased and the molecular chain mobility was increased. Decrease in T and increase in chains mobility were contributed to the widen of foaming temperature window. Effects of processing conditions on cell size, cell density and relative density were also investigated. The experimental results show that the temperature, tributyl citrate and foaming agent content have more effects on the structures and morphology of the plasticized PC microcellular foam. Effects of experimental conditions on cell size distribution have also been discussed.展开更多
The effect of carbon black(CB),carbon nanotube(CNT),and graphene(G)on foaming,electrical conductivity(EC),and electromagnetic interference(EMI)shielding of polystyrene(PS)foam that has been produced via microwave heat...The effect of carbon black(CB),carbon nanotube(CNT),and graphene(G)on foaming,electrical conductivity(EC),and electromagnetic interference(EMI)shielding of polystyrene(PS)foam that has been produced via microwave heating operation and supercritical carbon dioxide(CO_(2))was studied.Foams containing 1 wt%,CNT,and G reached over 90%porosity after 30 s and 3 min radiation time,respectively;however,PS/CB foam did not expand properly even after 3.5 min.In addition,the expansion ratio of PS/CB and PS/G was one-sixth and one-half of PS/CNT,respectively-due to the great CNT’s ability to convert microwave radiation to heat.EC of solid and porous nanocomposites has been increased via raising filler content;however,PS/CNT displayed the highest value at the same volume fractions.This ascending trend could not endure during foaming,so a remarkable optimum-point has been observed for nanocomposite foams.Eventually,EMI-shielding properties of solid and foam nanocomposites were discussed.展开更多
文摘In order to study the relationship between the main process parameters and the cell size, the mathematical model of cell growth of microcellular foaming injection process is built. Then numeric simulation is employed as experimental method, and the Taguchi method is used to analyze significance of effect of process parameters on the cell size. At last the process parameters are focused on melt temperature, injection time, mold temperature and pretidied volume. The significance order from big to small of the effect of each process parameters on cell size is melt temperature, pre-filled volume, injection time, and mold temperature. On the basis of above research, the effect of each process parameter on cell size is further researched. Appropriate reduction of the melt temperature and increase of the pre-filled volume can optimize the cell size effectively, while the effects of injection time and mold temperature on cell size are less significant.
基金Funded by the Natural Science Foundation of Hubei Provincial Science&Technologies Department(2010CDB04604)
文摘Novel microcellular foams using thin plasticized PC sheet were prepared by compression molding. The measurement results showed that T of plasticized PC was decreased and the molecular chain mobility was increased. Decrease in T and increase in chains mobility were contributed to the widen of foaming temperature window. Effects of processing conditions on cell size, cell density and relative density were also investigated. The experimental results show that the temperature, tributyl citrate and foaming agent content have more effects on the structures and morphology of the plasticized PC microcellular foam. Effects of experimental conditions on cell size distribution have also been discussed.
基金This work was financially supported by the National Natural Science Foundation of China(Grant No.51703083).
文摘The effect of carbon black(CB),carbon nanotube(CNT),and graphene(G)on foaming,electrical conductivity(EC),and electromagnetic interference(EMI)shielding of polystyrene(PS)foam that has been produced via microwave heating operation and supercritical carbon dioxide(CO_(2))was studied.Foams containing 1 wt%,CNT,and G reached over 90%porosity after 30 s and 3 min radiation time,respectively;however,PS/CB foam did not expand properly even after 3.5 min.In addition,the expansion ratio of PS/CB and PS/G was one-sixth and one-half of PS/CNT,respectively-due to the great CNT’s ability to convert microwave radiation to heat.EC of solid and porous nanocomposites has been increased via raising filler content;however,PS/CNT displayed the highest value at the same volume fractions.This ascending trend could not endure during foaming,so a remarkable optimum-point has been observed for nanocomposite foams.Eventually,EMI-shielding properties of solid and foam nanocomposites were discussed.
