Reinforcing fibres polyethylene

Polyethylene fibres are made by several different processes and their thermal characteristics vary, but lack of high temperature resistance is very noticeable compared with other reinforcing fibres. Most polyethylene fibres begin to lose their mechanical properties at about 120°C and they melt soon afterwards. 

Primitive reinforced plastics products were known in the 1920s and 1930s, but the more advanced fibre reinforced materials we know today only became significant commercially as structural materials in the 1950s, and even then, the more recent reinforcing fibres such as carbon/graphite, aramid (e.g. Kevlar , Twaron ) and polyethylene (e.g. Dyneema ) fibres were all still completely unknown. The great majority of reinforced plastics articles we use today have been manufactured since 1975. 

The potential of these nano-sized structures can be found in different areas of application [33,37,38,40-43]. They are briefly referred as potential reinforcement in polyethylene, since the focus in this chapter is on the potential of different lignocellusic materials produced from natural fibres or agri-cultural/forest crops or residues. 

Since high density polyethylene (HOPE) is relatively inert it is difficult to achieve good interfacial adhesion in composites. Often maleic anhydride grafted polyethylene is added to HOPE to improve interfacial adhesion to the reinforcing fibres [56]. 

The combined effect of high modulus polyethylene fibre which can be considered as the reinforcing fibre and fibrillated polypropylene pulp, which is effective for processing, was reported by Souroshian etal. [107] showing positive interactions between the two with respect to hardened composite properties. 

The flexible, tubular hner of a CIPP is typically made of polyester fabric that is a needled, woven or knitted reinforced fibre sheet using carbon, glass or aramid fibres or a combination of both. Depending on its application, the hner is coated with an impervious film such as polyethylene for the transport of drinking water or polyester for gas pipes. Other coatings include urethane and polyvinyl chloride (PVC). The final smooth surface reduces the surface friction and provides an additional corrosion barrier for the pipe. Liner tube sizes range from 100 to 2500 mm in diameter with... 

In the special case of pipelines operating at relatively high temperatures such as for the transmission of heavy fuel oil at up to 85°C, heat insulation and electrical insulation are provided by up to 50 mm of foam-expanded polyurethane. As a further insurance against penetration of water, and to prevent mechanical damage, outer coatings of polyethylene (5 mm), butyl laminate tape (0-8 mm) or coal-tar enamel reinforced with glass fibre (2-5 mm) have been used. 

The trade name of a polyester fibre used as textile reinforcement for mbber in products such as tyres, belting and hose. It is a truly synthetic fibre made from polyethylene terephthalate, a condensation product of terephthalic acid and ethylene glycol. 

For the global advanced composites market, the average cost of high-performance fibre reinforcements (carbon, aramid, high modulus polyethylene, boron, R/S/T-glass and some E-glass) is estimated from 5.5 to 6 per kg. This moderate price is due to the decrease in the carbon fibre price. Some grades could fall to less than 10/kg in the short or medium term. 

A. M. CunUffe and P. T. Williams, Characterisation of products from the recycling of glass fibre reinforced polyester waste by pyrolysis. Fuel, 82, 2223-2230, (2003). J. H. Harker and J. R. Backhurst, Fuel and Energy, Academic Press London, 1981. A. C. Albertson and S. Karlsson, Polyethylene degradation products, In Agricultural and Synthetic Polymers, ACS Symposium Series 433, J. E. Glass and G. Swift (eds), American Chemical Society, Washington DC, 60-64, 1990. 

Polyester polymers are materials which exhibit various chemistries but all contain ester linkages in the polymer chain. They have attained industrial importance as moulded materials, fibres, packaging film and as structural materials which are reinforced with fibres and fillers. Chemists, John Rex Whinfield and James Tennant Dickson, employees of the Calico Printer s Association of Manchester, patented polyethylene terephthalate in 1941, after advancing the early research of Wallace Carothers. Poly (ethylene terephthalate) is the basis of polyester fibres and fizzy drinks botdes. The first polyester fibre known as Terylene was also developed in 1941. 

Ahmed, S.F.U., Maalej, M. and Paramasivam, P. (2006). Flexural responses of hybrid steel-polyethylene fibre reinforced cement composites containing high volume fly ash. Journal of Construction and Building Materials, 21 1088-1097. 

Kalaprasad, G. Francis, Bejoy Thomas, Selvin Kumar, C. Radhesh Pavithran, C. Groeninckx, G. Thomas, Sabu, Effect of fibre length and chemical modifications on the tensile properties of intimately mixed short sisal/glass hybrid fibre reinforced low density polyethylene composites. Polymer Intenuitional, 53(11), 1624—1638 (2004). 

Torres, F.G., Aragon, C.L. Final product testing of rotational moulded natural fibre-reinforced polyethylene. Polym. Testing 25, 568-577 (2006)... 

The word reinforcement will refer in this book exclusively to strong, stiff fibres. They can be made of glass, aramid (e.g. KevlaT (DuPont)) or high molecular weight polyethylene (e.g. Dyneema (DSM)), carbon/graphite, polyamide (nylon), jute, and so on. The fibres can be long, virtually continuous or short (e.g. 1mm). 

R Frissen, L Govaert and T Peijs, ModelUng of the baUistic impact behaviour of polyethylene-fibre reinforced composites . Proceedings ICCM-10, Whistler, BC, Canada. Cambridge, Woodhead, 1995, Volume 5, pp 759-766. 

The fibres such as E-glass, ECR (see Section 2.8) or other kinds of glass carbon, aramid, or polyethylene and/or the particulate reinforcement, which is often a mineral filler. 

High performance polyethylene fibres such as Dyneema (a reinforcing polyethylene fibre from DSM) show a pronounced time-dependent behaviour under static loading conditions. An increase in strain rate and/or decrease in temperature results in an increase in fibre modulus and strength, but a decrease in work of fracture [33]. It is also known that creep can be observed even in unidirectional PE-fibre reinforced laminates. How far this specific behaviour influences the fatigue behaviour is of great interest and has to be investigated in order to find the appropriate applications for PE-composites. 

To summarize, many fibre-reinforced thermoplastics are not suitable for extended exterior exposure where the maintenance of appearance is important unless their surface is protected. Some unprotected applications that are found include car door handles, rear-view mirror housings and body panels (for all of which polyamides, polyethylene terephthalate and polybutylene terephthalate are used), as well as parts for caravans, boats and snowmobiles. 

Kitano, T. Kataoka, T. Nagatsuka, Y. (1984). Dynamic Flow Properties of Vinylon Fibre and Glass Fiber Reinforced Polyethylene Melts. Rheologica Acta, Vol.23, No.4, PP.408A16 ISSN 0035-4511... 

Lee BL, Song JW, Ward JE. Failure of Spectra polyethylene fibre-reinforced composites under ballistic impact loading. J Compos Mater 1994 28 1202-25. 

Fibre glass-reinforced plastic. Low-density polyethylene. Source [49]. 

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