Fibre reinforced polymer composites constituent materials, material properties

Composites are made up of individual materials these are referred to as constituent materials. The purpose of a composite is to create a material that combines its constituent parts in some beneficial way. The two main categories of constituent materials are the matrix and the reinforcement. The synthetic matrix materials are either thermoplastic or thermosetting resins. These polymers bind the reinforcement together and determine the physical in-service properties of the composite material. Polymers can also act as reinforcing material in composites Kevlar for instance, is a synthetic polymer fibre that is very strong and imparts toughness to a composite. 

The mechanical properties of FRP composites are dependent upon the ratio of fibre and matrix material, the mechanical properties of the constituent materials, the fibre orientation in the matrix, and ultimately the processing and methods of fabrication, which are the subject of Part II. Chapters discuss prepreg processing, liquid composite moulding (LCM), filament winding processes and pultrusion of advanced fibre-reinforced polymer (FRP) composites. 

This chapter has focused on the elastic qualities of advanced fibre-reinforced composites, in terms of characterization, measurement and prediction from the basic constituents, i.e. the fibre and matrix. Unidirectional fibre-reinforced polymers were the material selected for these brief elastic analyses. These comprised the micromechanics approaches which were applied to predicting the lamina elastic properties from the basic constituents and the classical lamination theory which was used to predict the elastic properties of composites materials composed of several laminae stacked at different orientations. The theoretical predictions were compared against available experimental data, illustrating the predictive capability of the theoretical analysis. Finally, a brief overview was delivered on the identification methods for elastic properties based on full-field measurements. This approach proved to be suitable for anisotropic and heterogeneous materials. 

As a result of their outstanding physical and mechanical properties, aromatic polyamides are attractive materials for use in high-performance structural applications 853072 833611 820253, including aircraft components or fire protection garments, as constituents of both traditional, i.e., fibre-reinforced composites 774110 762844, and molecular composites. One of these applications takes advantage of their thermal stability 881232 825031 763791 755849 and allows the manufacturing of heat-resistant materials for fire protection 713906. In a different context, aromatic polyamides (aramid fibres) have been proposed in the past few years as precursors of activated carbon materials with distinctive adsorbent properties (thermally stable molecular sieves). Aramid fibres, e.g., poly(w-phenylene isophthalamide), poly(p-phenylene terephthalamide) 709654, etc., are a class of synthetic polymers that possess excellent thermal and oxidative stability, good flame resistance, and superior mechanical and dielectric behaviour. 

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