Method for manufacturing a fibrous material impregnated with thermoplastic polymer

An impregnated fibrous material comprising a fibrous material of continuous fibers and at least one thermoplastic polymer matrix,

• wherein at least one thermoplastic polymer is a non-reactive amorphous polymer whose glass transition temperature is such that Tp≥80° C., or a non-reactive semi-crystalline polymer whose melting temperature is Tf≥150° C., where Tg and Tf are determined by differential scanning calorimetry (DSC) according to standard 11357-2:2013 and 11357-3:2013 respectively, a fiber content by volume is constant in at least 70% of the volume of the impregnated fibrous material, the fiber content in said impregnated fibrous material being between 45 and 65% by volume on both sides of said fibrous material, a porosity rate in said impregnated fibrous material being less than 10%,
• said impregnated fibrous material being free of non-reactive liquid crystal polymers (LCP),
• wherein a number average molecular weight (Mn) changes by less than 50% during its implementation,
• wherein impregnation is carried out with at least one expansion.