GRP Design Principles | P-TREX
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GRP Design Principles

The great power of Fibres

We know that Glass Fibre Reinforced Polyester (GRP) composites are increasingly being used as structural materials in many manufacturing sectors, such as transportation, construction and in the energy sector, thanks to their lightweight and corrosion resistance compared to metals. This historic moment is a favourable one for these materials, because industries are looking for lightweight, environmentally friendly and cost-effective materials.


Where do all the advantages of GRP come from and what determines its unquestionable superiority over traditional materials?

In order to be able to answer this question, it is necessary to refer to the technology through which GRP profiles are produced, namely pultrusion. In this process, each element has some intrinsic properties that determine a given feature rather than another, resulting in a customised semi-finished product.

Technically speaking, polymer-matrix fibre-reinforced materials (FRP) are obtained by combining continuous long fibres with very high mechanical properties impregnated in a thermosetting polymer resin. The Fibres provide the composite material with strength and stiffness.

The Matrix (or thermosetting resin) has the dual function of protecting the fibres from external chemical agents and of ensuring the transfer of stresses from fibre to fibre and between the substrate and the FRP reinforcement.

It can therefore be stated that the mechanical, chemical and physical properties of the profile depend on:


1. The nature of the fibre used (glass fibre, carbon fibre, etc.)


2. The fibre arrangement (roving, met, mats, etc.)

Glass roving consists of a spool composed of glass yarns. The fibres that make up the roving are easily impregnated with epoxy or polyester resins and provide an excellent structural rigidity of the item and at the same time a significant weight reduction, so that an excellent end result is achieved. The finished product, reinforced with roving fibres, results in very high performance. The roving fibres to be used are different depending on the specific processing and vary according to the type of fibre making up the roll (e.g. carbon fibre…).




3. The nature of the resin and of the additives used

In fact, in order to meet different application and operating requirements, P-TREX products can be made with thermosetting resins with different features.

The table below summarises the performance that can be achieved using different resins.



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