Fabrication And Mechanics Behavior Of Polystyrene Shape Memory Polymer Foam

Shape Memory Polymer is a new and important branch of the Smart Material.SMP’s main characteristic is the function of shape memory. SMP can change theshape proactively and finish the cyclic process of shape memory “Originalshape�'Temporary shape�'Original shape”.As much cellular exist in the traditional foam material, comparison with othermaterial, the foam material has the characteristics of high specific strength, highspecific modulus and light. It is very significant to combine the advantages of foamand SMP to fabricate the polystyrene shape memory polymer foam.(1) The fabrication of polystyrene shape memory polymer foam: doexperiments to confirm the program of fabricating the polystyrene shape memorypolymer foam. They are both methods of physical foaming with liquid physicalfoaming agent and solid pore-foaming agent respectively. Observe the cellular ofthe foams by using Scanning Electron Microscope (SEM). Calculate the relativedensity and porosity of the foam by doing some experiments. Use relative densityand porosity to evaluate quality of the foam.(2) The test of polystyrene shape memory polymer foam’s mechanicalproperties: there are three parts of the test: a. compression tests at normaltemperature. b. compression tests at different temperatures. c. tests of thepolystyrene shape memory polymer foam’s recoverability. Use the data ofcompression tests at normal temperature to represent the relation between stress andstrain, the effective elastic modulus of the foam. Use the data of compression testsat different temperatures to represent the relation between temperature and effectiveelastic modulus. Use the data of tests of the polystyrene shape memory polymerfoam’s recoverability to represent the recovery ratio and shape retention ratio of thefoam. (3) Analysis of polystyrene shape memory polymer foam’s mechanicalproperties: there are two parts: a. calculate the effective elastic modulus of the foam.b. simulate the foam’s mechanical properties of compression. The method ofcalculating the effective elastic modulus of the foam is method of differentiation.Suppose the cellular of the foam’s bulk modulus and Poisson ratio are zero. Use theGibson-Ashby’s model to simulate the relation between stress and strain.