Glass fiber reinforcement tensile strength

Union Carbide Chemical Plastics Co. [5] reports that adding 3% of one or two organosilicone compounds (Ucarsil PC-IA and PC-IB) to GE s recycled Azdel polypropylene/glass fiber sheet in regrind form increases the mechanical properties of the recycled sheet, which contains 38% glass fiber reinforcement. Tensile and flexural strength were increased some 35%-40%, and Izod impact strength increased some 30%. 

Glass-fiber-reinforced (increased stiffness and tensile strength) and mineral filled (reduced shrink and warp) grades also have been developed. 

The effect of fiber diameter on the tensile strength of a glass-fiber-reinforced polystyrene composite is shown in Figure 5.100. Some reinforcements also have a distribution of fiber diameters that can affect properties. Recall from the previous section that the fiber aspect ratio (length/diameter) is an important parameter in some mechanical property correlations. 

Calculate (a) the modulus of elasticity, (b) the tensile strength, and (c) the fraction of the load carried by the fibers for a continuous glass fiber-reinforced epoxy resin, with 60% by volume E-glass fiber, stressed under isostrain conditions. The tensile strength and modulus of the fibers are 1800 MPa and 76 GPa, respectively, and the values of these quantities for the matrix are 60 MPa and 2.4 GPa, respectively. 

Both ciystal forms of titania, rutile and anatase, have a high Mohs hardness rating and are abrasive. For example, the pigment particles can etch glass fibers and greatly reduce the tensile strength of glass fiber reinforced thermoplastic blends and alloys. 

It is recognized that glass-fiber reinforcement can be replaced by superior fiber materials offering high improvements over the upper limit of properties in GRP. As an example the carbon fibers modulus ranges from 0.17 x 10 to 0.34 MPa (25 x 10 to 50 x 10 psi) and tensile strength at 2,760 MPa (400,000 psi). Densities of RPs made from these fibers would only be less than 75% of the weight of GRP. 

Since it is silica-based, glass fiber for polymer reinforcement could be thought of as a cousin to mineral fillers. But glass fiber is more carefully produced in controlled, uniform, and symmetrical shapes with extremely high aspea ratios, with particle dimensions that are (usually) visible to the human eye. Glass-fiber reinforcement is probably the most cost-effective and most proven way of reinforcing polymers to inaease tensile and flexural modulus and strength. 

Fig. 4.17 Tensile strength of glass fiber reinforced PBT in dependence on temperature [12Cam].

Fig. 4.157 Tensile-creep strength of glass fiber reinforced and unreinforced styrene-acrylonitrile at different test temperatures [12Els].

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