Relation with mechanical properties

The phase morphology of the blends determines the mechanical properties. These correlations, which will be described in the following sections, have been investigated in different ways. 

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It has also been suggested that steady state low shear dynamic measurements in the melt could be a convenient method for the study of particle dispersion in relation to flller properties, which might also correlate with mechanical properties of the composite [48,49]. 

A clearer understanding of the relationship between foam structure and mechanical properties of solid foams has been developed by Gibson and Ashby (1988). They related the mechanical properties (e.g., strength, modulus, yield stress, fracture toughness) of idealised cellular solids to their relative density. This work considered the cell walls of solid foams as a three-dimensional network of beams (Figure 20.18) and treated their deformation in terms of classical solid mechanics, with strength and modulus related to beam thickness and length by the equations ... 

This paper is devoted to the study of a part of the complex phenomena of reinforcement, namely the behavior of the host elastomer in the presence of filler particles. The results of solid state NMR experiments and some other methods for filled PDMS are reviewed. The short-range dynamic phenomena that occur near the filler surface are discussed for PDMS samples filled with hydrophilic and hydrophobic Aerosils. This information is used for the characterization of adsorption interactions between siloxane chains and the Aerosil surface. Possible relations between mechanical properties of filled silicon rubbers on the one hand and the network structure and molecular motions at flie PDMS-Aerosil interface on the other hand are discussed as well. 

The most important development in lyotropic liquid crystalline polymers after Kevlar is probably the synthesis of poly [benzo(l,2-d 4,5-d ) bisthiazole-2,6-diyl]-l,4-phenylene, or for short, poly(p-phenylene benzo-bisthiazole) ( PBT Wolfe and Loo, 1980 Wolfe et al., 1981), and the closely related poly [benzo(l,2-d 5,4-d )bisoxazole-2,6-diyl]-l,4-phenylene or poly(p-phenylene benzobisoxazole) ( PBO Helminiak and Arnold, 1977 Wolfe and Arnold, 1981). Both PBT and PBO are lyotropic liquid crystalline and can be spun into fibers with mechanical properties even superior to that of Kevlar fibers. The molecular structures of these polymers are shown in Figure 5.2. 

An attempt is made in Chapter 6 to relate the mechanical property of the rubber under dynamic conditions to the state of cure. The mechanical properties of the unvulcanized rubber are also evaluated, with plasticity versus temperature and the scorch. The mechanical properties of the vulcanized rubber are then considered, in static and dynamic modes. 

Because some mechanical properties depend on how the material was tested, it is important and necessary to establish specified test methods. Standard test methods have been adopted for ceramics. In the United States ASTM International (originally the American Society for Testing and Materials, ASTM) is the primary organization developing standards for materials testing. ASTM Committee C-28 on Advanced Ceramics has completed several standards and ones related to mechanical properties and testing are listed in Table 16.1. Specialized subcommittees work on specific areas within the field of advanced ceramics. Coimnittee C28.01 is involved with standards related to mechanical properties and performance of monolithic ceramics. Committee C28.02 deals with reliability issues. The National Institute of Standards and Technology (NIST) has established several free databases that list mechanical properties of ceramics. 

Gel Content. Gel content is a measure of extent of cure, and has implications in terms of crosslink density. The measure gel content is also can be related to mechanical properties. Gelling occurs when the substrate has affinity for the solvent, but the crosslinks present in the substrate prevent dissolution. However, when the gel content is high, swelling is decreased due to entropic limitations. The gel content data is presented in Figures 12a and 12b. The gel content corrletes well with the mechanical properties. An increase in tensile strength and modulus is reflected in the increasing gel content. 

Aspects of texture related to mechanical properties of food are called consistency. Auditorial sensations are associated with a range of textural characteristics (such as crispiness). 

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