Reinforcement forms

Miscellaneous uses include textile bobbins, guns for hot melt adhesives and bilge pump housings. These materials are normally found in reinforced form. In addition to glass fibres, other fillers such as glass beads, talc and mica are used in conjunction with coupling agents. 

Use of a reduction factor assigned to the reinforcement form and loading direction... 

The adhesion of thermoplastic to glass cannot be explained by copolymerization of the coupling agent with the matrix. The polymers have essentially fully reacted. Chemical reactivity on the polymer backbone is now of interest. The picture is also more complex in that the number of polymers to be reinforced is much larger than for the thermosetting materials. Virtually every polymer which is being injection molded is also being used in its reinforced form. 

There are two major allyl plastics, diallyl phthalate (DAP) and diallyl isophthalate (see Diallyl phthalate). Both of these are widely used in fiber reinforced forms. The allyl plastics are usually compression or... 

Figure 15.1 Classification of composites according to the reinforcement forms.

Hence PBT is more commonly employed in the formulation of blends also. PBT has generally been preferred over PET in the engineering plastics industry because of its superior process-ability, faster crystallization rate, shorter molding cycles and better properties (DTUL/impact balance) in the molded parts, particularly in the unfilled form. Nevertheless, PET is also used primarily in glass or mineral reinforced form along with nucleators and crystaUization promoters. 

Table 2.8 Typical properties of moldings with various glass reinforcement forms...

MAJOR APPLICATIONS Poly(p-phenylene sulfide) (PPS) is mainly used in the reinforced form with glass fiber or mineral fillers as a high-performance thermoplastic. It is used for electrical and electronic parts (e.g., plugs and multipoint connectors, bobbins, relays, switches, encapsulation of electronic component, etc.), automobile parts (air intake systems, pumps, valves, gaskets, components for exhaust gas recirculation systems, etc.), and as components for mechanical and precision engineering. Nonfiller PPS is used for fiber, film, sheet, nonwoven fabric, etc. 

Superior mechanical properties, including impact strength and resistance to delamination, are claimed for reinforced plastics made from three-dimensional fabrics [1], Other reinforcement forms include continuous swirl mat, designed to have a minimum of fibre ends, and hybrid fabrics containing two different reinforcing fibres, for example, glass and aramid. There are many different ways in which two different fibres can be combined together. 

Other thermoset resins such as epoxides, phenolics and polyurethanes are also used in reinforced form, as are some thermoplastic polymers. Many need to be protected by surface coatings if retention of properties after extended weathering is important. 

Preform—A preshaped fibrous reinforcement formed by distribution of chopped fibres by air, water flotation or vacuum over the surface of a perforated screen to the approximate contour and thickness of the final part. Also, a preshaped fibrous reinforcement of mat or cloth formed to desired shape on a mandrel or mock-up prior to being placed in a mould press. 

Polyurethanes find application in many areas. They can be used as impact modifiers for other plastics. Other applications include rollers or wheels, exterior body parts, drive belts, and hydraulic seals. Polyurethanes can be used in film applications such as textile laminates for clothing and protective coatings for hospital beds. They are also used in tubing and hose in both unreinforced and reinforced forms because of their low-temperature properties and toughness. Their abrasion resistance allows them to be used in applications such as athletic shoe soles and ski boots. Polyurethanes are also used as coatings for wire and cable. ... 

Polysulfone was also blended with PET for the purposes of cost reduction and improvement in solvent stress-crack resistance. The blend was developed in the glass-reinforced forms for applications in electrical and electronic markets (Mindel B, Amoco). However, the DTUL, flexural strength, and impact strength of this PSU/PET blend were inferior to those of PET at comparable levels of glass reinforcement and hence no longer offered. 

Cork composite n. A compound consisting of ground cork, resins, and other additives and reinforcements, formed into rods, sheets, etc. Cork composites have relatively low density and are used in sporting goods, for thermal insulation, and ion ablative material. 

Preform . (1) The test tube shape that is used to form the final blown product in injection blow molding. (2) A compressed tablet or biscuit of plastic composition used for efficiency in handling and accuracy in weighing materials, particularly thermosets. (3) Foamed perform. (4) A pre-shaped fibrous reinforcement formed by the distribution of chopped fibers or... 

TABLE 2.21 Glass Rber Reinforcement Forms (Continued)... 

It is seen that many of these formulations are available in glass fibre or carbon fibre reinforced forms. Thus, polyether ether ketone (PEEK) is available in a 30% carbon fibre or in 20 or 30% glass fibre reinforced forms. Similarly, polysulfone (PSU) is available in a 30% carbon fibre or 10% glass-reinforced form. 

Boisse, P., Hamila, N., Vidal-Salle, E., Dumont, F., 2011. Simulation of wrinkling during textile composite reinforcement forming. Influence of tensile, in-plane shear and bending stiffnesses. Compos. Sci. Technol. 71 (5), 683-692. 

---