In this paper, acrylonitrile-butadiene-styrene （ABS） nanocomposite foams are produced using carbon dioxide through the solid-state batch process. Microcellular closed-cell foams are produced with the relative densit...In this paper, acrylonitrile-butadiene-styrene （ABS） nanocomposite foams are produced using carbon dioxide through the solid-state batch process. Microcellular closed-cell foams are produced with the relative density ranging from 0.38 to 0.97. The effects of the processing conditions on the density, morphology, and flexural properties of ABS and its nanocomposite foams are studied. It is found that nanoclay particles, as nucleating sites, play an important role in reducing the size of cells and increasing their number in the unit volume of foamed polymer, as well as increasing the flexural modulus of foam through reinforcing its matrix.展开更多
A progressive micromechanical method is presented in order to predict the elastic constants of polydispersed composites including multi-directional or randomly ori- ented reinforcement particles. Heterogeneities of va...A progressive micromechanical method is presented in order to predict the elastic constants of polydispersed composites including multi-directional or randomly ori- ented reinforcement particles. Heterogeneities of various types are introduced into the matrices in a gradual manner. At each step, the Mori-Tanaka method is used to ob- tain the stiffness tensor of the intermediate medium used as a matrix of the following step. The proposed method is capable of introducing any kind of heterogeneities based on their dimensions, orientations, mechanical properties, and volume fractions to the ma- trix. Furthermore, suitable probability density functions can be defined for physical and structural parameters of the composite, including the level of the filler-matrix interfacial bonding, the aspect ratio, and the orientation of reinforcement particles. The efficiency of the iterative approach and the convergence of the solution are studied by computing the stiffness tensors of unidirectional and bidirectional particulate composites. The results of the present study are also compared with the literature data for a randomly oriented particulate composite.展开更多
文摘In this paper, acrylonitrile-butadiene-styrene （ABS） nanocomposite foams are produced using carbon dioxide through the solid-state batch process. Microcellular closed-cell foams are produced with the relative density ranging from 0.38 to 0.97. The effects of the processing conditions on the density, morphology, and flexural properties of ABS and its nanocomposite foams are studied. It is found that nanoclay particles, as nucleating sites, play an important role in reducing the size of cells and increasing their number in the unit volume of foamed polymer, as well as increasing the flexural modulus of foam through reinforcing its matrix.
文摘A progressive micromechanical method is presented in order to predict the elastic constants of polydispersed composites including multi-directional or randomly ori- ented reinforcement particles. Heterogeneities of various types are introduced into the matrices in a gradual manner. At each step, the Mori-Tanaka method is used to ob- tain the stiffness tensor of the intermediate medium used as a matrix of the following step. The proposed method is capable of introducing any kind of heterogeneities based on their dimensions, orientations, mechanical properties, and volume fractions to the ma- trix. Furthermore, suitable probability density functions can be defined for physical and structural parameters of the composite, including the level of the filler-matrix interfacial bonding, the aspect ratio, and the orientation of reinforcement particles. The efficiency of the iterative approach and the convergence of the solution are studied by computing the stiffness tensors of unidirectional and bidirectional particulate composites. The results of the present study are also compared with the literature data for a randomly oriented particulate composite.
