Elaboration of nanostructured polyurethane foams/OMMT using a twin-screw extruder in counter-rotating mode

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

Chemical synthesis and characterization of highly soluble conducting polyaniline in the mixtures of common solvents

This work presents the synthesis and characterization of soluble and conducting polyaniline PANI-PIA according to chemical polymerization route. This polymerization pathway leads to the formation of poly(itaconic acid) doped polyaniline salts, which are highly soluble in a number of mixtures between organic common polar solvents and water, the solubility reaches 4 mg mL-1. The effect of synthesis parameters such as doping level on the conductivity and the study of solubility and other properties of the resulting PANI salts were also undertaken. The maximum of conductivity was found equal to 2.48×10-4 S cm-1 for fully protonated PANI-EB. In addition, various characterizations of the synthesized materials were also done with the help of viscosity measurements, UV-vis spectroscopy, XRD, FTIR and finally TGA for the thermal properties behaviour

Experimental study of the dynamic behaviour of loaded polyurethane foam free fall investigation and evaluation of microstructure

International audienceWe aim to maintain as much control over the microstructure development during the manufacture of polyurethane foam with a specific density. As a result, the finished product contains the shock absorber’s required characteristics. That is why polyurethane foam loaded with zinc oxide and silica must sustain the cellular structure and strengthen it. First, mechanical characterization was carried out utilizing a dynamic drop impact test conducted on locally developed and constructed equipment.Polyurethane foams’ mechanical properties rely on their density, cell structure (size and shape), and the fraction of open or closed cells. Within the cell structure, the foam may be directed preferentially. Following that, Raman spectroscopy and SEM investigation to visualize the semi-opened cells of the cellular polymer. The cellular polymer appears to possesspermanent, regular cellular structures with a high degree of reversibility in terms of overlap

Development and Characterization of Tailored Polyurethane Foams for Shock Absorption

International audienceIn 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