SYNOPSISThe reactions of an epoxy prepolymer based on bisphenol A diglycidylether (DGEBA) with y-aminopropyltriethoxysilane ( y-APS) are studied. The results of different techniques are compared: size exclusion chromatography, differential scanning calorimetry, chemical titration, and Fourier Transform Infrared absorption. Epoxy amine reactions are shown to be faster than the crosslinking reactions between alkoxysilane and hydroxy groups, and thus, can be studied separately. The reactivity of the epoxy group in DGEBA is compared with that of phenylglycidylether ( P G E ) . And the reactivity of the amine group of 7-APS is compared with that of hexylamine. The kinetic constants are calculated with a mechanism which takes into account both the catalytic and noncatalytic reactions. The ratio r = k,/ kl of the reactivity of the secondary to the primary amino-hydrogens was also determined. The values of r are 1.4 for hexylamine and 1.2 for y-APS. The reactivities of the epoxy groups are the same for both PGE and DGEBA.

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Polypropylene (PP) and high density polyethylene (HDPE) was melt-blended in pairs at a constant of 80:20 (mm) compositions; this blend is prepared by one-step reactive extrusion in a single-screw extruder. The present study aims to investigate the effect of thermoplastic starch (TPS) on the properties of PP and HDPE blend. This later has been investigated in the absence and presence of maleic anhydride grafted polyethylene (PE-g-MA), and reinforced by nano-clay. All the blends/ nano-bio-composites were prepared in an internal mixer. The results indicates changes in the blends in terms of morphological, Mechanical, Thermal, structural and rheological properties. However, the different blends and nano-bio-composites were studied by means of Thermogravimetry (TG), Differential scanning calorimeter (DSC), Melt flow index (MFI), Izod impact (unnotched) tests, Scanning Electron Microscopy (SEM) and x-ray diffraction (XRD).

SYNOPSISThe hydrolysis and reactions of alkoxy silane groups have been studied on a model compound ( T A ) prepared from 2 mol of phenyl glycidyl ether and 1 mol of aminopropyl triethoxy silane. At low (40°C) and high (140°C) temperatures, the monomer conversion and the evolution of the molecular mass are followed by size exclusion chromatography (SEC) .During the same reaction time, the evolution of the functional groups, hydroxyl CH-OH, ethoxy -O-CC2H5, and siloxane Si-0-Si, is observed by FTIR spectroscopy. Without the presence of water, reactions between hydroxyl and ethoxy silane lead to gelation at the end of the reaction. A by-product, probably a cyclic tetramer is also formed. After the hydrolysis, the reaction of the model compound is quite different. The product of reaction is always soluble, even after a treatment a t high temperatures, and the evolution of the molecular mass versus the reaction time seems to correspond to the condensation giving a dead cyclic tetramer. From this study it is evident that the curing cycle has a great influence on the properties of the interface of a composite based on a epoxy matrix.

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This work treats the behavior of a glass fibre/unsaturated polyester (UP) composite with structural defects subjected to the attack of two corrosive solutions: H2SO4and NaOH. The gravimetric analysis, the uptake mass of the resin, and the interfaces in the composite are established according to the proportion of the matrix/composite. The obtained results showed that, in the acidic solution, the glass fibre and the fibre/matrix interface absorption share is more significant than the alkaline solution. While the Fourier transform infrared analysis (FT-IR) of the UP resin revealed the presence of chemical degradation phenomenon (hydrolysis), the fibre corrosion was characterized by the atomic absorption analysis (AAS). The fibres/matrix interfaces degradation was confirmed by microscopic observations (SEM). The diffusion kinetics of the both acid and alkaline solutions and chemical and mechanical degradation are affected by the presence of the pores in elaborated material.

The addition of treated nanoclay as the reinforcement agent modifies the melt behavior of PP/PA66 nanocomposites, but also profoundly decreases the burning rate of reinforced formulations. To modify the flammability of PP/PA66 nanocomposites, various amounts (0-6 wt%) of treated nanoclay were added to improve the fire performance of PP/PA66 nanocomposites. Horizontal flame test according UL94 was used to evaluate the fire performance of the reinforced formulations, and the results proved that the addition of more than 2 wt% treated nanoclay lead the improvements in flame retardancy through the reduced burning rate. The melt behavior of PP/PA66/Nanoclay nanocomposites was also investigated. It is proposed that, in the presence of clay, the combustion surface changed to a compact carbonaceous-silicate structure. When the clay content was 4-6 wt%, the layered silicates became enriched on part of the surface and formed an island-like structure; the islands displayed a loose cinder structure with much higher silicon content, in contrast to a surface with low silicon content in the surrounding polymers substrate. As the clay content continued to increase, the char covered most of the combustion surface and more clay accumulated on the burning surface. In addition, the clay particles promoted the formation of the carbonaceous-silicate structure. The melt behavior of the PP/PA66 nanocomposites was affected with increasing addition of clay. J.