African Linguistics in Central and Eastern Europe, and in the Nordic Countries

Non peer reviewe

Effect of compatibilizing agents on the mechanical properties of high-density polyethylene/olive husk flour composites

International audienceThe main objective of this research was to investigate the effect on the thermal and mechanical properties of the addition of two different compatibilizing agents, malefic anhydride-grafted polyethylene (PE) [synthesized in a solution state (MAPE) and commercial (XA255)], to olive husk flour, high-density polyethylene (HDPE) composites. The composites contain 30 wt % of olive husk flour and a variable proportion of compatibilizer (3, 5, and 7 wt %). The grafting reaction was followed by Fourier transform infrared, and the grafting degree was evaluated by means of titration. The effect of grafting on the thermal properties of MAPE was observed by ATG/DTG. The mechanical and thermal properties of the composite were investigated. A morphological study of the composite reveals that there is a positive effect of compatibilizing agent on interfacial bonding

Chemical modification of olive pomace by various esters and silane

International audienceThe olive pomace was modified chemically to improve the interface between the polymer matrix and the cellulosic fillers. The modification was done using various ester types having the same nature, however, with different chain lengths and one silane. Before the surface treatment, the olive pomace was extracted with acetone to remove contaminants on the surface, using Soxhlet apparatus. The transesterification of olive pomace with the different ester components, i.e., vinyl acetate, vinyl propanoate, and vinyl butanoate, and the condensation reaction with dichlorodimethylsilane was confirmed by Fourier transform infrared (FTIR) analysis. Moreover, the treatment of olive pomace with vinyl acetate improves the thermal stability and the sample records higher onset temperature of degradation as measured by thermogravimetric analysis (TGA). The results obtained indicated also that the reaction between the hydroxyl groups of waste flour and the acetyl, propionyl, pivalyl, and silane groups have occurred. The modified wood flours exhibited a decrease in the hydrophilicity as supported by the lower moisture content

Synthesis and characterization of rubbery epoxy/organoclay hectorite nanocomposites

International audienceThe present research investigates the morphology, the mechanical, and the viscoelastic properties of rubbery epoxy/clay nanocomposites synthesized by in situ polymerisation of a prepolymer diglycidyl ether of bisphenol-A crosslinked with an aliphatic diamine based on a polyoxypropylene backbone. The inorganic phase was hectorite, exchanged with octadecylammonium ions in order to give organophilic properties to the phyllosilicate. An ultrasonicator was used to disperse the silicate clay layer into epoxy-amine matrix. The morphology of epoxy-hectorite nanocomposites examined by transmission electron microscopy (TEM) showed that mixed delamination or intercalation or microdispersion could occur depending on type of organoclay. Moreover, the mechanical and viscoelastic properties were found to be improved with only the treated hectorite

Hydrothermal ageing of alfa fiber reinforced polyvinylchloride composites

International audienc

Effect of surface treatment on the physicomechanical and thermal properties of high-density polyethylene/olive husk flour composites

International audienceIn this study, a particular interest was focused on the recovery of lignocellulosic waste of olive husk flour (OHF) by its incorporation as filler in manufacturing composite materials based on high-density polyethylene (HDPE) matrix with various filler contents (10, 20, and 30 wt %). The problem of incompatibility between the hydrophilic filler and the hydrophobic matrix was treated with two methods: the first method consists of using maleic anhydride-grafted polyethylene (MAPE) as compatibilizer in HDPE/OHF composites. The second method, was focused on the chemical modification of OHF by vinyl-triacetoxy-silane (VTAS). Fourier transform infrared spectroscopy is used to analyze both grafting and silanization reactions involved. Scanning electron microscopy was used to show the morphology of the flour surface. Furthermore, the physicomechanical and thermal characteristics of the various composite samples were investigated as a function of filler contents and treatment types. The results showed that the properties of the composite materials are positively affected by the silanization treatment of OHF and also by MAPE addition. However, better mechanical and thermal properties with less moisture absorption were obtained for the composite materials compatibilized with MAPE

Thermal, dielectric and mechanical study of poly(vinyl chloride)/olive pomace composites

International audienceComposites from PVC and chemically treated olive pomace have been prepared. The effect of the incorporation of virgin and benzylated olive pomace in the poly(vinyl chloride) matrix on dielectric, mechanical and thermal stability properties, of olive pomace composites was studied. The mechanical properties of the benzylated composites were improved. Furthermore, the thermal characterization of the different samples carried out by thermogravimetric analysis revealed an increase in the onset temperatures of decomposition for treated composites. The dielectric investigation indicated that the samples containing olive pomace treated with the benzyl chloride can be used in electrical applications as insulators