Fibrous glass properties

The fibrous glass used for insulation materials does not require starting materials of high purity. Beach sand, which consists largely of the mineral quartz, is easily obtainable and quite inexpensive. Alternatively, silicate slags or waste rock from mining can be melted and processed to create the products called rock-, slag-, and mineral-wool. Such materials are used for insulation. Where specific properties are desired, such as resistance to ultra-... 

Polymer-Fibrous Glass Composites Advances and Potential Properties... 

Two specific areas are covered more comprehensively fibrous glass polyesters and fibrous glass thermoplastics. The advances in reinforced polyesters have been in the materials and process areas. These changes are more profound than those related to mechanical properties. Hence, a treatment of mechanical properties of reinforced polyesters is not attempted. On the other hand, the reinforced thermoplastics advances are essentially in terms of many new reinforced polymers as well as a greater variety of compounds. For these reasons, it seems appropriate to discuss advances in this area in terms of properties. 

By definition, thermoplastics have limitations at elevated temperatures. It is in this particular property that fibrous glass can lead to remarkable improvements. However, a sharp division exists for reinforced thermoplastics. The various reinforced thermoplastics can be put in two groups relative to DTUL. These consist of amorphous and crystalline or semicrystalline polymers. The amorphous polymers such as styrene-acrylonitrile, polystyrene, polycarbonate, poly (vinyl chloride), and acrylo-nitrile-butadiene-styrene are generally limited to modest DTUL improvements, usually on the order of 20°F with 20% glass. However, crystalline polymers such as the nylons, linear polyethylene, polypropyl-... 

In a discussion of why fibrous glass is used in combination with various polymers, two important questions must be answered. First, what properties of fibrous glass are responsible for its use in combination with plastics Secondly, why does it work ... 

Properties of Glass. Some important properties of fibrous glass are listed in Table III. The 400,000-psig tensile strength and 10,000,000-psig modulus are the two key mechanical properties. When these are com-... 

Boiler, K,H Fatigue properties of fibrous glass reinforced laminates subjected to variorts conditions, Afocfenn PTastfcs, 1957. 

F. G. Krautz, Polymer-Fibrous Glass Composites Advances and Potential Properties, in 99 Adv. Chem. Ser. 1971, p. 452. 

In summary, this paper has presented data on the low-temperature vacuum thermal conductivity ofvarious fibrous glass materials. In addition, the utilization of reflective septa has been discussed and the availability of new insulating systems combining extremely low conductivity with light weight and good mechanical properties has been announced. 

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. 

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. 

Laminated composite materials consist of layers of at least two different materials that are bonded together. Lamination is used to combine the best aspects of the constituent layers and bonding material in order to achieve a more useful material. The properties that can be emphasized by lamination are strength, stiffness, low weight, corrosion resistance, wear resistance, beauty or attractiveness, thermal insulation, acoustical insulation, etc. Such claims are best represented by the examples in the following paragraphs in which bimetals, clad metals, laminated glass, plastic-based laminates, and laminated fibrous composite materials are described. 

Polymeric binder can be added to the network either as an aqueous latex dispersion or as a solution that should be dried prior to lamination in this process. In either case, the polymer should form a film and join adjacent fibers together and thus improve the stress transfer characteristics of the fibrous network. Provided that the proper film forming conditions are available, the property profile of the bonded network is determined to a significant degree by the properties of the polymeric binder at the temperature of use [20,22]. For example, if a softer type of product is desired, a binder with a relatively low glass transition temperature Tg) is often chosen. 

Fibrous fillers are now gaining more importance over particulate fillers due to the high performance in mechanical properties. The influence of fiber diameter on the tensile behavior of short glass fiber on polyimide was reported [95], At higher concentrations thick fibers seem to be more advantageous probably because of the... 

The mechanical properties of plastics materials may often be considerably enhanced by embedding fibrous materials in the polymer matrix. Whilst such techniques have been applied to thermoplastics the greatest developents have taken place with the thermosetting plastics. The most common reinforcing materials are glass and cotton fibres but many other materials ranging from paper to carbon fibre are used. The fibres normally have moduli of elasticity substantially greater than shown by the resin so that under tensile stress much of the load is borne by the fibre. The modulus of the composite is intermediate to that of the fibre and that of the resin. 

Wollastonite is a preferred filler in some instances due to its fibrous form. While not as effective in improving the mechanical properties as glass fibers, it will give more strength than spherical fillers and less anisotropy than longer glass fibers. 

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