A series of hybrid materials incorporating imide-modified silica (IM-silica) network structures into a polyimide (PI) matrix were produced with a sol-gel technique from solution mixtures of poly(amic acid) and tetraethoxysilane (TEOS) containing alkoxysilane-terminated amic acids with various degrees of polymerization. The hybrid films, obtained by solvent evaporation, were heated successively to a maximum temperature of 3008C to carry out the imidization process and silica network formation in the PI matrix. The morphology and mechanical properties of these hybrids with IM-silica networks were studied and compared with the properties of one in which reinforcement of the matrix was achieved with a pure silica network generated from TEOS. The introduction of longer imide spacer groups into the silica network led to a drastic decrease in the silica particle size. Improved tensile modulus was observed in such compatibilized hybrid systems.Comparative thermogravimetric measurements of these hybrids showed improved thermooxidative resistance. A PI hybrid with 30% IM-silica had a thermal decomposition temperature nearly 2608C higher than that of the pure PI matrix. The high surface area of the interconnected silica domains and increased interfacial interaction were believed to restrict the segmental motion of the polymer and thus slow the diffusion of oxygen in the matrix, thereby slowing the oxidative decomposition of the polymer. The reinforcement of existing and new PIs by this method offers an opportunity for improving their thermooxidative stability without degrading their mechanical strength.

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This study was conducted to evaluatethe degree of biosecurity level with especial reference to Salmonella Spp as an example to explain the expected causes and risk factors that leads to spread them in poultry flocks in Egypt then studied farms evaluated for the sensitivity of Salmonella isolates to the most common disinfectants used in Egypt.About 300 samples (100 cloacal swabs, 100 liver and intestinal samples,100 litter samples) were collected from 10 broiler farms with different age (at 0 old day, one week,2,4 and 6 weeks of age)then the samples were investigated for Salmonella Sppand subsequently identified based on biochemical and serological tests.The obtained results showed that 35 Salmonella species were isolated from 10 broiler poultry houses (25%);(6%) and (4%) from cloacal swab;liver and litter, respectively. Average prevalence of Salmonella spp. was 11.33 % in open broiler houses whether raised Cobb, Ross or Sasso breeds. Salmonella Typhimurium, S. enteritidisand S. Kentuckywerethe most serovars out of the 35 detected isolates.There was great statistical significant difference in the sensitivity of Salmonella isolates to the most common disinfectants(P<0.05)asVerkon-S ® achieved 3 log reduction , after 5-minute,Formalin and Phenique were achieved 3 log reductions against S. entriditisafter one-minute Aldekol Des-Gda ® achieved one log reduction after one minute, TH4 ® ,Biosentry ® 904 and Iodophoreachieved 2 log reductions after 5 minutes.

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