Reinforcement material for FRP composite systems

The production of carbon fiber fabrics for structural reinforcement is a highly specialized, multi-stage process that extends from the raw material to the finished product. Carbon fiber itself is not produced directly; it is derived from a precursor material - most commonly polyacrylonitrile (PAN). This polymer is spun to create PAN fibers, which serve as the base for the subsequent carbonization process. During carbonization, PAN fibers undergo pyrolysis in an inert atmosphere (usually nitrogen) and at very high temperatures, which can exceed 1500 °C. Throughout this thermal treatment, non-carbon elements (mainly hydrogen and nitrogen) are removed, leaving a structure composed almost entirely of carbon atoms arranged in crystalline layers. The result is an incredibly strong and lightweight filament.

These extremely thin carbon filaments are then grouped into bundles known as tows (or yarns). These tows are wound onto spools, ready for the next stage: weaving, which is the most crucial stage in producing the textile. In this phase, the tows are interlaced on a loom to form a mat or textile, properly referred to as a "fabric" (or bare fabric). After weaving, the fabric may undergo further processing. Commonly, an epoxy or other polymer resin is applied, sometimes via a pultrusion process, to create a composite strip known as a "laminate". Both fabrics and laminates are supplied to the construction site, where they are installed using the same epoxy resin employed for structural reinforcement. The main distinction between fabrics and laminates lies in their geometry and mechanical performance. Laminates, being significantly stronger, are more rigid and limited in shape adaptability, whereas fabrics offer greater flexibility, allowing easier application on complex structural geometries requiring reinforcement.