Glass chopped

CG = chopped glass, GF = glass fiber, and MIN = mineral filler. 

The tensile and flexural properties as well as resistance to cracking in chemical environments can be substantially enhanced by the addition of fibrous reinforcements such as chopped glass fiber. Mechanical properties at room temperature for glass fiber-reinforced polysulfone and polyethersulfone are shown in Table 5. 

Rotational molding is used to form large shells of thermoplastic resin and chopped strands for such appHcations as agricultural tanks and fertilizer hoppers. The resin and chopped glass are placed in the metal mold that is then rotated in an oven where the thermoplastic resin melts and deposits the fiber on the metal surface. When cooled, the mold is opened and the part is removed. 

The physical properties of the reinforced polyester product made from chopped glass are Hsted in Table 1. The chemical resistance varies according to the composition but is generally good. Its principal uses in building products are for sanitary ware, eg, tub-shower units, and for panels, especially translucent or cement-filled types for roofing and walls of commercial or industrial buildings. 

This is also known as Bulk Moulding Compound (BMC). It is blended through a mix of unsaturated polyester resin, crosslinking monomer, catalyst, mineral fillers and short-length fibrous reinforcement materials such as chopped glass fibre, usually in lengths of 6-25 mm. They are all mixed in different proportions to obtain the required electromechanical properties. The mix is processed and cured for a specific time, under a prescribed pressure and temperature, to obtain the DMC. 

Fig. 7-2 An example of a range in tensile strength, modulus of elasticity, and elongation of some TPs with and without chopped glass fibers by weight and type of reinforcement.

Fig. 8-59 SMC production line with chopped glass fibers.

Different materials can be used such as nylon, polyester (TS), and epoxy, but TS polyurethane (PUR) is predominantly used. Almost no other plastic has the range of properties of PUR. Modulus of elasticity range in bending is 200 to 1,400 MPa (29,000-203,000 psi) and heat resistance from 90 to over 200°C (122-392°F). The higher values are for chopped glass-fiber-reinforced RIM (RRIM). 

The properties of polymers reinforced with chopped glass fibres dispersed in the polymer matrix depend on ... 

The relevant properties of these materials for the torsional-mechanical analysis are listed in Table 8.11. On the basis of specific elastic modulus and specific shear modulus, the best materials are the graphite-fiber-reinforced epoxy resin, followed by either of the alloys, then the Kevlar fiber-reinforced epoxy. The chopped glass sheet molding compound is obviously not a good choice. 

In the use of preform and mat-reinforced molding, the plastic may be added either before or after the reinforcement is positioned in the cavity. The preform can be a spray-up of chopped glass fibers deposited... 

Tank bottom corrosion is a function of the water layer that exists on the bottom of most tanks. The presence of sulfate-reducing bacteria, characterized by shiny pits, is more of a problem in heavy stocks because oxygen cannot reach the bottom. The most common way to control tank bottom corrosion is to drain the water from the tank bottom periodically. Both epoxy and polyester coatings reinforced with chopped glass fiber have been used successfully in places where severe corrosion has occurred. For new tanks in which corrosion is expected, coal-tar epoxy is usually specified for the bottom. Corrosion of the underside of the tank bottom does not usually occur if a proper oH and sand base is used. Cathodic protection is used when water cannot be prevented from contacting the underside of the tank bottom. 

Calcium Carbonate, Calcium Silicate, Powdered Aluminium, Copper Alumina, Flint Powder, Carborundum, Silica, Molybdenum Disulphide Chopped Glass Mica, Silica, Powdered or flaked Glass Metallic Filler or Alumina Colloidal Silica, Bentonite Clay Improved Thermal Conductivity Improved Machinability Improved Abrasion Resistance Improved Impact Strength Improved Electrical Conductivity Improved Thixotropic Response... 

FRU-M the prescribed amount of chopped glass strand (13 mm in length) was mixed with the prescribed amount of isocyanate-component and thoroughly dispersed before the addition of the polyol component. Then the following operations were carried out according to the procedure of FRU-L without strand mat. 

FRU-S Every operation was carried out according to the FRU-M using chopped -glass strand 3 mm in length instead of 13 mm. The physical properties of these foams wiU be discussed later. 

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