Properties of GRP
Glass Reinforced Plastic, in a nutshell, is a combination of thermoset resin – usually polyester - which has been reinforced by fibreglass rods.
The resin is treated, or cured, either by heating and the introduction of a catalyst or by the use of an accelerator and a catalyst, both of which serve to basically change the molecular structure of the material to give it its inherent strength.
The most common types of catalyst used are organic peroxides such as Methyl Ethyl Ketone Peroxide, Cyclohexanone Peroxide, Acetyl Acetone and Benzoyl Peroxide. Whilst these materials are unstable in their pure form, they are mixed with inert compounds – either liquids or chalk – to make them safe for use before being commercially supplied.
The curing process enables the bonds between the molecules of the resin to form a three-dimensional network, making them super-strong and resistant to chemical attack or corrosion.
The most common grade of GRP for example, E-glass, has the equivalent strength under tension three times greater than silkworm silk and six times greater than human hair.
Glass fibres used for reinforcement purposes are created by a process known as pultrusion, which sees the ingredients - including silica sand, limestone, kaolin clay, fluorspar, dolomite, colemanite and other minerals - melted in large furnaces before being drawn through holes of the appropriate size to make strands. E-glass, by way of demonstration, typically uses strands between 5 and 25 micrometres in diameter. To put this into context, a cotton fibre is typically 10 micrometres in diameter.
The glass fibres are treated with a chemical solution before being bundled together in what is known as a roving. This is then either used directly in a composite application – added to the resin - or further processed depending on the requirements of the final item and could include being formed into chopped strand mat, where shorter cut lengths of fibres are randomly arranged, flattened and bonded together, or uni-directional strands.
The ultimate composite of the GRP material will be determined by the purpose and environment in which the finished product will be sited, so the exact make-up of the resin and the arrangement of the glass fibres can vary from product to product
IJF Developments pride ourselves on our expertise and technical ability to both design and create products that are tailored to be specific to each purpose and function.
By adapting the composites, it is even possible to change the behaviour of the organic compounds that make up the resin to provide them with different properties. Using a pre-accelerated, filled unsaturated resin, for example, enables us at IJF Developments to create fire-resistant products, particularly suitable for external cladding for buildings or other environments where fire may be a hazard.
Advantages of GRP