Mechanical properties pure shear

The polyphenylenes were brittle and did not form self-standing films when cast from solution. Therefore, they were considered poor materials. The use of these polymers was instead investigated as additives in polystyrene to improve processing and mechanical properties. A mixture of polystyrene and hyperbranched polyphenylene (5%) was studied and the results showed that the melt viscosity, especially at high temperatures and shear rates, was reduced by up to 80% as compared to pure polystyrene. Also, the thermal stability of polystyrene... 

Theimotropic liquid crystalline polymers can be formulated with high concentration of glass fiber to withstand working temperatures in excess of 300°C. In processing LCP, one problem arises. LCP orients itself in the direction of shear or flow - the process which benefits many materials but makes products from pure LCP excessively anisotropic. To balance mechanical properties it has been suggested that some quantities of short glass or mineral fibers be added to LCP. 

Good results are obtained with the Kawabata approach, which measures several different mechanical properties of the fabric at the same time. The Kawabata evaluation system for fabrics uses four devices measuring the tensile and shearing, pure bending, and compressional properties, and surface characteristics of fabrics. Key parameters are the applied force, the rate of deformation, and the tension on the sample. By comparison with subjectively evaluated standards, statistical correlations can be drawn, leading to the objective quantification of fabric softness. The method, however, is too complex for routine work [26], Some other methods are reviewed by Mooney [52] ... 

Rheology is the science that deals with the deformation and flow of matter under various conditions an example is plastic melt flow. The rheology of plastics, particularly TPs, is complex but manageable. These materials combine the properties of an ideal viscous liquid (pure shear deformations) with those of an ideal elastic solid (pure elastic deformation). Plastics are therefore said to be viscoelastic (Figure 17). The mechanical behavior of plastics is dominated by the viscoelastic phenomena such as tensile... 

Terminology used in discussing the mechanical and thermal properties of laminates is similar to that of metals, except for shear properties. Intralaminar, in-plane, or longitudinal shear reflects pure shear resolved onto a 45° shear plane. A property called interlaminar or horizontal shear is unique to laminates and is the shear between adjacent layers of a laminate. Intralaminar shear is a basic material property, which is strongly influenced by manufacturing techniques. 

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