Reinforced plastic definition

Reinforced plastics (RPs) hold a special place in the design and manufacturing industry because they are unique materials (Figs. 6-11 and 6-12). During the 1940s, RPs (or low-pressure laminates, as they were then commonly known) was easy to identify. The basic definition then, as now, is simply that of a plastic reinforced with either a fibrous or nonfibrous material. TSs such as polyester (Table 6-19) and E-glass fiber dominated and still dominates the field. Also used are epoxies. 

A precise definition of reinforced plastics can be difficult (or impossible) to formulate because of the scale factor. At the atomic level all elements... 

Reinforcement fibres—Sampling plans applicable to received batches Plastics—Prepregs—Definitions of terms and symbols for designations Textile glass reinforced plastics—Sheet moulding compound (SMC)—Basis for a... 

Even this definition needs to be classified [7, 8]. To some researchers it is still too broad because it includes many materials that are not usually thought of as composites such as concrete, copolymers and blends, reinforced plastics, and carbon-black-filled rubber. On the other hand, some of the more recent composites are excluded from the category of composites if this definition is strictly applied. For example, many particulate-type composites such as dispersion-hardened alloys and cermets have composite structures that are microscopic rather than macroscopic [2,8]. In some cases, the composite structures are nano-scopic, with the physical constraint of several nanometers as the minimum size of the components [9-16]. The terms... 

When reinforced plastics are granulated, the length of their fibers is reduced. When they are reprocessed, with virgin materials or alone, their processability and performance definitely change. So it is important to determine if the change will affect final part performance if it will, a limit for the amount of regrind mix should be determined. 

Many unreinforced and reinforced plastics have a definite tensile modulus of elasticity where deformation is directly proportional to then-loads below the proportional limits. Since stress is proportional to load and strain to deformation, stress is proportional to strain. Fig. 2.4 shows this relationship. The top curve is where the S-S straight line identifies a modulus and a secant modulus based at a specific strain rate at point C that could be the usual 1% strain. Bottom curve secant moduli of different plastics are based on a 85% of the initial tangent modulus. 

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