Glass fibre development

Uniroyal Ltd C Glass Fibre Developments Ltd STC (Standard Telephones a Cables) Ltd... 

Glass Fibre Developments Ltd Alpine Works Newton Road Crawley Sussex Crawley 25692... 

In the late 1970s several developments occurred causing renewed interest in poly(ethylene terephthalate) as a plastics material. These included the development of a new mouldable grade by ICI (Melinar) and the development of a blow moulding technique to produce biaxially oriented PET bottles. In addition there appeared a glass-fibre filled, ionomer nucleated, dibenzoate plasticised material by Du Pont (Rynite) (see Chapter 26). 

The commercial appearance of phenolic resins fibres in 1969 is, at first consideration, one of the more unlikelier developments in polymer technology. By their very nature the phenolic resins are amorphous whilst the capability of crystallisation is commonly taken as a prerequisite of an organic polymer. Crystallisability is not, however, essential with all fibres. Glass fibre, carbon fibre and even polyacrylonitrile fibres do not show conventional crystallinity. Strength is obtained via other mechanisms. In the case of phenolic resins it is obtained by cross-linking. 

Epoxide resins reinforced with carbon and Aramid fibres have been used in small boats, where it is claimed that products of equal stiffness and more useable space may be produced with a 40% saving in weight over traditional polyester/ glass fibre composites. Aramid fibre-reinforced epoxide resins have been developed in the United States to replace steel helmets for military purposes. Printed circuit board bases also provide a substantial outlet for epoxide resins. One recent survey indicates that over one-quarter of epoxide resin production in Western Europe is used for this application. The laminates also find some use in chermical engineering plant and in tooling. 

The reinforced reaction injection moulding (RRIM) process is a development of RIM in which reinforcing fillers such as glass fibres are incorporated into the polymer. One advantage of such a system is to reduce the coefficient of thermal expansion, and with a 40-50% glass fibre content the coefficient is brought into line with those of metals. 

One of the most spectacular modern developments in materials has been the design, improvement and exploitation of fine glass fibres for purposes of large-scale communication. Messages, above all telephone conversations, but also TV signals... 

As microwave sample preparation has evolved, standard microwave procedures have been developed and approved by numerous standard methods organisations (ASTM, AOAC International, EPA, etc.), see ref. [64]. Examples are standard test methods for carbon black/ash content (ASTM Method D 1506-97), lead analysis in direct paint samples (ASTM Method E 1645-94), etc. Table 8.15 shows some microwave ashing references (detection weight). A French AFNOR method utilises the atmospheric pressure single-mode microwave method as an alternative sample preparation procedure for Kjeldahl nitrogen determination [84], The performance of a microwave-assisted decomposition for rapid determination of glass fibre content in plastics for QC has been described [85]. 

The polyester resins, reinforced with glass fibre, are the most common thermosetting plastics used for chemical plant. Complex shapes can be easily formed using the techniques developed for working with reinforced plastics. Glass-reinforced plastics are relatively... 

Alternative forms of sorbent bed have been developed. These include thin porous glass-fibre or PTFE disks in which sorbent particles are embedded, and disposable plastic pipette-tips fitted with small sorbent beds. 

Mat and continuous glass fibre reinforcements theoretically all the thermoplastics are usable in these forms, but up to now developments have concentrated on polypropylenes (PP), polyamides (PA) and thermoplastic polyesters (PET) fibre-reinforced PEEK, polyetherimide (PEI) and polyphenylene sulfide (PPS) are used for high-performance applications. They are presented in a range of forms from stampable sheets to pellets, prepregs, ribbons, impregnated or coated continuous fibre rods. More rarely (as in the case of PA 12, for example), the thermoplastic is provided in liquid form. 

Use a reinforced grade to reduce the wall thickness and consequently the material weight. In ascending order of performance but also of cost, the most-used reinforcements are natural fibres, glass fibres, aramid fibres, carbon fibres. Carbon fibres, if their development leads to a substantial lowering of their cost, could solve many cost problems. 

A typical development is the front-end of recently introduced cars such as the Mini Cooper from BMW or Mazda 6 in which long glass fibre reinforced polypropylene is injected onto stamped metal. The weight saving is in the range of 30-35% compared to traditional solutions with a high function integration. 

Borealis has developed a high-performance short glass fibre reinforced polypropylene (HPGF) family that has the technological and economical potential to replace long glass fibre (LFRT) in highly stressed parts for technical automotive applications. 

Zoltek anticipates that a price of 12/kg could involve the use of carbon fibres in mass production. This is not unrealistic and the replacement of glass fibres for highly-loaded body components is foreseen. Today, 14/kg appears to be a sustainable prospect and is leading to new developments. 

Polylactic acid (PLA) reinforced with kenaf fibres developed by NEC for personal computer housings. With a 20% level of kenaf fibres, the main properties compete with glass fibre reinforced ABS but the cost is 50% higher. The flexural modulus is more than 4.5 GPa and the HDT reaches 120°C. 

Results are presented of experiments undertaken by Gaiker in the manufacture of sandwich panels containing foam cores based on PETP recycled by a solid state polyaddition process developed by M G Ricerche. Panels were produced with glass fibre-reinforced unsaturated polyester and epoxy resin skins, and allthermoplastic panels with PE, PP, PS and glass fibre-reinforced PETP skins were also produced. EVA hot melt adhesives and thermoset adhesives were evaluated in bonding glass fibre-reinforced PETP skins to the foam cores. Data are presented for the mechanical properties of the structures studied. 

Developments by BASF in high-impact propylene copolymers produced by reactive blending, random propylene copolymers, glass fibre-reinforced PP composites and PP foams are reported. Properties and applications of these materials are described. 4 refs. BASF AG... 

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