Low-molar-mass organogelators (LMOG) can turn liquids into thermoreversible gels because they self-assemble into a fibrous network. In contrast, using the same kind of low-molar-mass additives to harden materials, which are already solidlike on their own, has been hardly exploited. We show here that simple dicarboxylic acids are very efficient low-molar-mass organogelators (LMOG) for bitumen. Indeed, they increase the range of temperature where bitumen is a solid. Moreover, the hardness and elastic modulus of bitumen at room temperature are also improved. This concept of improving the mechanical properties of a solid with an LMOG can probably be applied to other materials.

37-3 FIELD Section Title:Plastics Manufacture and Processing UMR 7610, Chimie des Polymeres, UPMC Univ Paris 06, Paris, Fr. FIELD URL: written in EnglishWe report the straightforward photo-polymn. of polyacrylate films contg. bis-urea based self-assembled nanotubes. The obtained materials are characterized by gas adsorption measurements, 129Xe NMR spectroscopy and WAXS. The presence of the bis-ureas is shown by butane adsorption (at 273 K and ambient pressure) to be responsible for the formation of a significant microporosity. This porosity is however not detected by the classical argon adsorption procedure (at 77 K and low pressure). This effect is attributed to the contraction of the material at low temp. and pressure, and may be of general concern for other org. porous materials. One of the potential advantages of the present materials is that the porosity results from the self-assembled nanotubes and should therefore be independent of the matrix mech. properties. It should in particular be possible to adjust the flexibility of the matrix by changing the monomer compn. [on SciFinder(R)