In this study, microcrystalline cellulose (MCC) was isolated from walnut and apricot shells (WS and AS) as agricultural wastes in order to use it as reinforcement in polymer composites. The microcrystalline cellulose was extracted by alkaline treatment and bleached by peroxide as an environmentally friendly treatment, called walnut cellulose (WC) and apricot cellulose (AC). The chemical composition of the samples was set according to the Technical Association of Pulp and Paper Industry (TAPP). After treatments, the alpha-cellulose content increased by about 23 % for the two used cellulose sources. The structural and morphological properties of the samples were investigated by Fourier transform infrared spectroscopy in the attenuated total reflectance mode (ATR-FTIR), optical microscopy (OM), X-ray diffraction and scanning electron microscopy (SEM). The crystallinity index values evaluated for WC and AC via X-ray diffraction were respectively 86.4 and 80.3 %. The alkaline soluble fractions of walnut (ASW) and apricot (ASA) shells were recovered and characterized by OM and ATR-FTIR spectroscopy. Furthermore, their chemical composition was analyzed. The characterization and the properties of the WC and AC were similar to those of commercial MCC and MCC prepared in literature from wood and some agricultural wastes.

In this study, we propose a novel conducting and soluble polyaniline salt prepared by chemical polymerization in the presence of new doping agent (IAs). This last is prepared by sulphonation of itaconic acid (IA) with concentrated sulphuric acid in THF. The obtained doped polyaniline (PANI-IAs) is extremely soluble in dimethyl sulfoxyde (DMSO) at room temperature, in which the solubility reach 44 mg mL-1. The conductivity measurement of doped polyaniline powder precipitated in THF as dispersing medium gave a value of 0.13 S cm-1 when the emeraldine base form of polyaniline is fully protonated. The polyaniline salt sample is characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction, UV-Visible spectra and FTIR spectra.

In this work, a new elaboration method for nanostructured foam polyurethane/organo-modified montmorillonite (PUR/OMMT) by in situ polymerization is proposed. A twin-screw extruder in the contra-rotation mode combined with reaction injection molding (RIM) as the polymerization process was used. The blended polyols, copolymer polyol (CPP) were included between the OMMT layers via the twin-screw extruder. Both the formulation of the PUR and the inter-foliar distance in the montmorillonite (MMT) were optimized. The effect of some parameters such as OMMT content and catalyst (triethylenediamine for PUR 3 and triethylenediamine+diamino-1,2 propane for PUR 4) was also investigated. The synthesized materials (OMMT, PUR and PUR/OMMT) were characterized by different methods, i.e., Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results of evaluation tests, such as flammability and the tensile for the PUR 3+OMMT foams revealed that the optimum properties were obtained for PUR 3+2 % OMMT. The PUR 4 foam showed better mechanical and flame--retardant properties than the PUR 3 (r = -NCO/-OH = 1.15) foam. However, the PUR 4 + 2 % OMMT formula exhibited the most delayed flame diffusion and pronounced rigidity.Available on line at www.shd.org.rs/JSCS/ 1364 MAHMOUD, SAFIDINE and ZEGHIOUD motive, naval, furniture and building industries, and for shock absorption, padding and thermal or acoustic insulation. 1-5 PUR foams are present in all areas of daily life due to their various properties and applications. Despite all these advantages, these foams can constitute a peril in the event of fire. Currently, public opinion is very aware of this inflammability problem. Among the solutions to address this issue is the addition of organic flame-retardants in the polymer matrix. 6-8 However, most organic flame-retardants emit toxic gases.Nevertheless, both researchers and industrialists are interested in finding other solutions, such as the addition of graphite, 9-12 fibers, 13,14 montmorillonite, 15-26 nanocoating, 27,28 etc. The addition of montmorillonite in the polyurethane imparts noteworthy improvement to the relevant properties, especially if it is distributed on the nanometric scale. It enhances mechanical, thermal, barrier and flame retardant properties. 3 These improvements depend on the type of polymer, the ingredients used, the preparation process and the dispersion of the clay in the matrix. 3,29,30 Much work on the development of polyurethane foams modified with montmorillonite are reported in the literature. 15,[21][22][23][31][32][33] However, the use of a combination of grafted polyol (CPP) and polymeric diphenylmethane diisocyanate (PMDI) and/or diamino-1,2 propane as a catalyst has not been considered.The main goal of the present study consisted in the preparation of nanostructured foam polyurethane/OMMT with enhanced mechanical and flame-retardant properties. In order to incorporate the grafted polyols into the OMMT galleries, a twin-screw extruder oper...

In this work, various microcrystalline celluloses were extracted from apricots shells (AC) and walnut shells (WC) by alkaline treatments combined with hydrogen peroxide blanching. Different composites-based poly (lactic acid) (PLA) and microcrystalline cellulose PLA/AC and PLA/WC were successfully prepared by the cast-solution method with various PLA/AC and PLA/WC ratios. PLA and prepared composites were characterized by tensile test, Fourier transform infrared spectroscopy (FTIR), melt flow index (MFI), thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). Results showed an increase in Young’s modulus from 802.6 MPa (PLA) to 1412.9 MPa (10% AC) and to 1145,6 MPa (7% WC) in PLA composites. A decrease in degradation temperature was recorded with increasing microcrystalline cellulose percentage in PLA composites from 354°C (PLA) to 328°C (PLA/10% AC) and 339°C (PLA/10% WC). An enhancement in crystallinity rate was observed after incorporation of the microcrystalline cellulose from 30.42% (PLA) to 37.97% (PLA/7% WC) and 38.47% (PLA/10% AC). Furthermore, the biodegradation was evaluated by a soil burial test. A loss in composites weights of 38% (PLA/7% WC), 13% (PLA/7% AC) and 14% (PLA) was obtained after 12 months within soil burial test. Finally, the presence of MCC extracted from walnut shells in PLA matrix at 7% of content exhibited the best mechanical properties, crystalline structure and biodegradability rate.