This work deals with a new strategy for the elaboration of macro- to nanoporous materials. The
adopted scheme involves the in-situ generation of foaming agents (CO2 and isobutene) during the thermal treatment
of a poly(phenylquinoxaline) (PPQ) film bearing thermolabile (tert-butyloxycarbonyl, i.e., Boc) groups (PPQ-Boc). For this purpose, a bis-diketone monomer having phenolic groups has been first synthesized and polymerized
with a bis-diamine monomer. The resulting PPQ was postmodified by introducing Boc groups. After a kinetic
and mechanistic study of the Boc thermal decomposition reaction, the influence of different experimental parameters
on the final porosity formation has been investigated, such as the foaming temperature which is a key parameter.
The porous materials obtained were characterized by different techniques (density, SEM, TEM) in order to
determine the cell density as well as the size and morphology of the porous structure. Depending on the thermal
treatment conditions, our strategy enables to obtain a wide range of porous materials, from nanoporous (10 nm,
1016 cells/cm3) to macroporous (200−700 nm, 1012 cells/cm3).
International audienceThe composition of the fatty acids of the roots and aerial parts of Aritolochia longa (Aristolacheae) and Bryonia dioica (Cucurbutaceae) was analyzed by gas chromatography (GC-FID) and gas chromatography-mass spectrometry (GC-MS). The oils extracted from the aerial parts of both species were rich in polyunsaturated fatty acids with the essential linolenic and linoleic acids being the most prominent compounds. Oleic and linoleic acids were the majors fatty acids in the roots of both species. Whatever the plant part analyzed and the species, the saturated fatty acids were predominantly composed of palmitic and stearic acids. The antibacterial activity, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the lipid extracts were determined against a panel of five bacterial strains. The results showed that the sensitivity to the lipid extracts was different for the test bacterial strains, and the susceptibility of gram positive bacteria was found to be greater than gram negative bacteria. The antibacterial activity of the root lipid extracts was particularly important against Enterococcus feacium (CMI value of 125 mu g/mL; CMB values > 250 mu g/mL) and Streptococcus agalactiae (CMI value of 125 mu g/mL; CMB values 250 mu g/mL for A. longa roots). These results indicate that A. longa and B. dioica could be considered as good sources of essential fatty acids which can act as natural antibacterial agents
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