Essay: Glass Fibre-Reinforced Polymers (GFRP)

ABSTRACT
Within this report, the development of Glass Fibre-Reinforced Polymers in the 1930s has been discussed, along with their use in industry. They were thought to be resistant to all weather conditions, however after significant periods of time they can develop defects including blistering. They are made of layers of glass fibres and thermoplastic resins that can be altered depending on the specific properties required. There are some environmental drawbacks to this material, however they are being combatted by developments in bioplastics and UV-degradable plastics.
INTRODUCTION
This report details the history and development of Glass Fibre-Reinforced Polymers, along with their composition and properties, manufacture and use in industry and health and safety implications. Furthermore, it details the impact posed on the environment through the use of this material.
HISTORY
Fibre-reinforced polymers, or fibre-reinforced plastics were first invented in 1907 by Leo Baekeland, who invented and patented Bakelite. This thermosetting phenol-formaldehyde resin was widely used in the early 20th century due to its beneficial properties: high resistance to heat, electricity and chemical wear [1]. Following the creation of this material, further composites (materials formed of multiple individual materials with varying properties that when combined, form a new material with different characteristics) were developed using fibres of materials including, but not limited to, glass, basalt, wood, carbon and aramid.
“Fibreglas” was created in 1933 and patented in 1936 by Owens Corning; it is a form of glass wool that entraps gas, therefore creating an effective insulator. It was created by hitting a stream of molten glass with compressed air [2]. In 1936, du Pont then created a composite using plastic and the aforementioned “fibreglas” which were combined using a resin. This new material again showed high strength and promise, despite being less insulating than other plastics. It was first picked up by naval and military aircraft industries as materials used to construct these were in short supply due to overuse in WWII. In 1942, Ray Greene produced the first fibreglass sailing dinghy and soon many others followed; it is thought that by the end of the 1940s, there were thousands of fibreglass boats and even some fibreglass surfboards in existence. Many of these still stand now, as they were over-engineered. This has not occurred maintenance-free, as people at the time expected, as blisters due to osmosis and subsequent hydrolysis can often cause difficulties. These do not mean that the structure cannot be used, however, and can be managed to allow use of the vessels [3]. In the 1950s, carbon-fibre and aramid fibres were being produced and are used widely in automotive, aerospace and sporting goods industries. Along with glass fibre, carbon and carbon-aramid are the most widely used forms of fibre-reinforced polymers [4].
COMPOSITION AND PROPERTIES
Glass fibre-reinforced polymers are made from a combination of thermosetting resins and glass fibre. An exothermic reaction in which molecules are formed ensures that the new material is fire resistant. Thermosetting resins made of materials including polyester, epoxy and polyurethane are used depending on the properties required [5]. The orientation of fibres within the resin can significantly alter the properties of the material, including strength and elasticity. GFRP offers a number of advantages over steel equivalents as it is resistant to corrosion and chemicals, particularly chloride ions and other harsh conditions. It also has high tensile strength if the correct ratio between glass and resin is used, partially due to the fact that it is around 75% lighter than steel equivalents. This has a positive effect on transport costs, therefore reducing the carbon footprint the industry leaves. It is an effective electromagnetic and thermal insulator meaning that it is not affected by electromagnetic fields or radio waves. As it is non-sparking, it is effective in environments where gases may ignite. It is able to withstand sudden point loading and does not surpass the yield point easily. It has a lifespan of approximately fifty years and is extremely low-maintenance within this timeframe. This makes it extremely cost effective [6].
MANUFACTURE OF PRODUCTS USING GFRP AND ECONOMIC MARKETS INVOLVED
The automotive industry is increasingly using GFRP to create lightweight bodywork. These vehicles have a high strength-to-weight ratio therefore increasing the fuel economy of both vehicles and aerospace vessels. This material allows for vast amounts of customisation, which adds value for commercial companies. The material can also be employed within the building of bridges and pavilion structures as it can support vast amounts of weight without hitting the yield point or limit of elasticity. As it is also weather-resistant and durable, it is perfect for this situation. In a more obscure application, a New York hydroelectric power plant is using GFRP to divert fish from dangerous machinery and back to the harbour as it has extremely low toxicity, therefore does not harm the fish, and is corrosion-resistant [7]. Wind energy developers often use this material within turbines, allowing for maximum energy efficiency.
HEALTH AND SAFETY IMPLICATIONS
GFRP are liable to many issues within plastic waste disposal. It is extremely difficult to separate the matrix from the glass fibres and therefore recycling challenges are amplified further compared to those of normal plastics. These are being combatted through the use of bioplastics and UV-degradable plastics [8].
CONCLUSIONS
Glass-fibre reinforced polymers were discovered by accident, however have impacted society in a vast array of industries. This material has extremely desirable properties including high strength-to-weight ratios, insulation properties and resistance to chemicals and is therefore able to be used in a variety of situations. It does, however, have drawbacks as it is difficult to recycle at present.
REFERENCES
[1] American Chemical Society National Historic Chemical Landmarks. (1993) “Bakelite: The World’s First Synthetic Plastic”. Smithsonian Institution. Available from http://www.acs.org/content/acs/en/education/whatischemistry/landmarks/bakelite.html [February 19, 2019]
[2] US Patent Number 2133235: Method & Apparatus for Making Glass Wool First Slayter glass wool patent, (1933). https://patents.google.com/patent/US2133235?oq=%22G.+Slayter%22
[3] George Marsh. (2006) 50 years of reinforced plastic boats. [online] https://www.materialstoday.com/composite-applications/features/50-years-of-reinforced-plastic-boats/ [February 18th 2019]
[4] Erhard, Gunter. Designing with Plastics. Trans. Martin Thompson. Munich: Hanser Publishers, 2006.
[5] Glass Reinforced Plastics (GRP), Unknown. https://www.plasticon.co.uk/composites/glass-reinforced-plastics [February 17, 2019]
[6] Why GRP?, Unknown. https://www.engineered-composites.co.uk/why-grp/ [February 19, 2019]
[7] Craig Barry (2017) 4 Unexpected Applications of Glass Fibre Reinforced Polymers. http://info.bwfiberglass.com/blog/4-unexpected-applications-of-glass-fiber-reinforced-polymers [February 19, 2019]
[8] Smallman, R.E., and Bishop R.J. (1999) Modern Physical Metallurgy and Materials Engineering. 6th ed. Oxford: Butterworth-Heinemann.
2019-2-19-1550620307