| abstract |
An alkaline aluminosilicate geopolymeric matrix for the production of composite materials with a fibre reinforcement is described, wherein the composition of said geopolymeric matrix after dehydration, expressed as oxides, is as follows: yM2O:Al2O3:xSiO2, where 'x' is 6.5-70, 'y' is 0.95-9.50 and M is Na, K or Na + K. The geopolymeric matrix comprises a nanocomposite material with at least two phases, with (a) a first nodular silicious phase composed of nanospheres with diameters of less than 1 micron, preferably less that 500 nm, and (b) a second polymeric phase essentially composed of alkaline poly(aluminosilicate) having one or more sialate bridge (-Si-O-Al-O) cross-linking sites of total formula M4Si2AlO10 to M2Si4AlO16, such that, in the alkaline poly(aluminosilicate), the ratio of Si(O4) to Al(O4) is > 3.5, preferably > 5. The geopolymeric matrix has a spectrum of 29Si MASNMR with three resonance regions: - 87 ± 5 ppm, - 98 ± 5 ppm, - 107 ± 5 ppm, and prevents the oxidation at high temperatures of the carbon fibre. The resulting composite materials can be used at temperatures of up to 1000 °C. |