Carbon fiber reinforced polymer as epoxy, but other thermoset or thermoplastic polymers, such as polyester, vinyl ester, or nylon, are sometimes used. The composite material may contain aramid (e.g. Kevlar, Twaron), ultra-high-molecular-weight polyethylene (UHMWPE), aluminium, or glass fibers in addition to carbon fibers. The properties of the final CFRP product can also be affected by the type of additives introduced to the binding matrix (resin). The most common additive is silica, but other additives such as rubber and carbon nanotubes can be used. The material is also referred to as "graphite-reinforced polymer" or "graphite fiber-reinforced polymer" ("GFRP" is less common, as it clashes with
Polymer fractionation Polymer fractionation Polymers are chainlike molecules that are made of the same repetition unit. With a few exceptions such as proteins, a polymer consists of a mix of molecules with different chain lengths. Therefore average values are given for the molecular weight like the number average, the weight average or the viscosity average molar mass. A measure for the width of the molecular weight distribution is the polydispersity index. The targeted manipulation of the molecular weight distribution of a polymer by removing short and/or long chain material is called polymer fractionation. The molecular weight of polymers has a large influence