Glass fiber reinforced plastic processes/properties

Table 7-2. Mechanical, Thermal, and Processing Properties of Glass Fiber Reinforced Plastics. (Courtesy of Owens-Corning Fiberglas Corp.)... 

Being polymeric materials, plastics are subject to degradation on exposure to hostile environments," particularly by photooxidative processes." Since the adherend is the most exposed part of a bonded structure, it is more susceptible to such reactions than is the more protected adhesive layer. Water can also be a factor in causing a deterioration in the performance of glass fiber-reinforced plastics. A substantial reduction in physical properties can result if the ingress of water destroys the strong interaction between the reinforcing fibers and the plastic matrix." ... 

In Table 4.12, the composite structure is stated for processing and testing of eight different glass fiber reinforced plastic laminates (EP, UP, VE). Their dynamic properties are listed in Table 4.13 [148]. With fiber contents (p ranging from 0.22 to 0.66%, tensile-fracture stresses (short-term) between 80 and 750 N/mm are achieved at fracture strains of 0.88 and 3.47%. 

Some of the common types of plastics that ate used ate thermoplastics, such as poly(phenylene sulfide) (PPS) (see Polymers containing sulfur), nylons, Hquid crystal polymer (LCP), the polyesters (qv) such as polyesters that ate 30% glass-fiber reinforced, and poly(ethylene terephthalate) (PET), and polyetherimide (PEI) and thermosets such as diaHyl phthalate and phenoHc resins (qv). Because of the wide variety of manufacturing processes and usage requirements, these materials ate available in several variations which have a range of physical properties. 

This moldable material primarily consists of TS polyester resin, glass fiber reinforcement, and filler. Additional ingredients, such as low-profile additives, cure initiators, thickeners, and mold-release agents are used to enhance the performance or processing of the material. As with any material, such as metallics and plastics, SMC can be formulated in-house or by compounders to meet performance requirements of a particular application such as tensile properties or Class A surface finish. Varying the type and percentage of the composition will result in variations in mechanical properties and processability. 

The RIM process predominantly uses TS polyurethane (PUR) plastics. Others include nylon, TS polyester, and epoxy. PUR offers a large range of product performance properties. As an example PUR has a modulus of elasticity in bending of 200 to 1400 MPa (29,000 to 203,000 psi) and heat resistance in the range of 90 to 200°C (122 to 392°F). The higher values are obtained when glass-fiber reinforces the PUR (also with nylon, etc.). The reinforced RIM process is called RRIM or... 

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