Glass fiber-reinforced polymer composite manufacturing

After introducing incorporation costs, the cost of the composite may be higher or lower than that of the unfilled polymer. For low-cost commodity plastics, the term filler (implying cost reduction) may be a misnomer since manufacturing costs may offset the lower cost of most mineral fillers. For higher cost specialty high-temperature thermoplastics, the final cost of, for example, glass fiber-reinforced polyetherimide is usually less than that of the unmodified polymer. 

For composite reinforcement appUcations such as fiber-reinforced polymers (FRPs), also known as glass-fiber-reinforced plastic (GRP), the fiber can be supplied as chopped strands (at several standard lengths, from 3 to 12 mm) or continuous roving, which can be chopped at the point of composite manufacture. It can also be supplied as milled fiber, with lengths of about 0.2 mm. Roving can be woven into a wide variety of two-dimensional and three-dimensional shapes for polymer impregnation. The relationships between the various process steps and the resulting types of reinforcement fiber products are shown in Fig. 6.41. 

A new type of polymer-polymer composites, the microfibrillar reinforced composites (MFC) from thermoplastic polymer blends, was created about ten years ago. Unlike the classical macro-composites e.g., glass fiber-reinforced ones) and the in situ composites (TLCP rod-like macromolecules and mostly their aggregates as reinforcing elements), the MFC are reinforced by microfibrils of flexible chains. The microfibrils are created during the MFC manufacturing. 

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