No abstract

In this paper, different types of polyurethane foams (PUR) having various chemical compositions have been produced with a specific density to monitor the microstructure as much as possible. The foam may have a preferential orientation in the cell structure. The cellular polyurethane tends to have stubborn, typical cellular systems with strong overlap reversibility. Free expansion under atmospheric pressure enables formulas to grow until they are refined. Moreover, the physicochemical characterization of the developed foams was carried out. They later are described by apparent density, Shore hardness, Raman spectroscopy analysis, X-Ray diffraction analysis, FTIR, TGA, DSC, and compression tests. The detailed structural characterization was used by scanning electron microscope (SEM) and an optical microscope (MO) to visualize the alveolar polymer’s semi-opened cells, highlighting the opened-cell morphology and chemical irregularities. Polyurethane foams with different structural variables have a spectrum characterization that influences the phase separation and topography of polyurethane foam areas because their bonding capability with hydrogen depends on chain extender nature. These studies may aid in shock absorption production; a methodology of elaboration and characterization of filled polyurethane foams is proposed.

No abstract

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.

No abstract