Chopped Strand Mat (CSM) Emulsion Bound
Chopped strand mat (CSM or fibreglass matting as it is often known) is the most widely used of all composite reinforcement materials.
Short strands of glass are randomly scattered and bound to create a mat which can then be wetted out with resin and used as a general purpose reinforcement for traditional fibreglass (GRP/FRP) moulds or parts.
Due to its comparatively low performance compared with alternative reinforcements (woven glass fabric, carbon fibre, Kevlar etc.) chopped strand mat is certainly not at forefront of advanced composites but there are still applications where it is used in parts and it is still used extensively in the production of patterns and moulds for more advanced composites.