1,721,078 research outputs found
Hydrotalcite and nanometric silica as finishing additives to enhance the thermal stability and flame retardancy of cotton
No full textSuspensions of nanoparticles (namely, hydrotalcite and nanometric silica) have been employed during the finishing of cotton in order to improve its thermal stability and/or flame retardancy. The immersion approach has also been coupled to a surface pre-treatment of the textile by cold oxygen plasma in order to load a higher amount of nanoparticles onto fibres. The time of immersion and the resulting distribution of the nanoparticles onto the fibres, evaluated by scanning electron microscopy in combination with elemental analysis, have been thoroughly investigated. The present study has shown that the above parameters are functions of nanoparticle type. Pre-treatment by cold plasma has been found to be more effective than the immersion only. As far as the thermal stability and the combustion behaviour of treated cotton are concerned, the nanoparticles turned out to be able to delay the degradation in air, modifying mechanism and kinetics, and at the same time enhancing the flame retardancy of cotton by increasing the time to ignition and decreasing the heat release rate peak during the combustion. The joint effect of the two nanoparticles has also been evaluated and found more efficient than the effect of single species
Flame retardancy properties of α-Zr phosphate based composites
No full textα-Zr phosphate (hereafter referred to as ZrP) based composites were prepared by melt blending in order to improve the flame retardancy properties of polyamide 6 (PA6), polyethylene terephthalate (PET), polypropylene (PP) and ethylene vinyl acetate copolymer (EVA). Different morphologies are distinguishable by electron microscopy: PA6-ZrP seems to be a nanocomposite by Transmission Electron Microscopy (TEM) whereas PET-, PP- and EVA-ZrP blends appear micro-composites by X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) analyses. ZrP acts as flame retardant in PA6 reducing the total heat evolved and consequently the heat release rate during the combustion measured by cone calorimetry. Moreover, ZrP reduces the flammability of PET and EVA acting in synergistic effect with phosphorous based flame retardants. Indeed, it is showed that it is possible to reduce the amount of phosphorous flame retardant adding ZrP to reach UL94 classification V0 for both polymers
Structural Characterization of Co- and Si-Substituted ALPO-34 Synthesised in the Presence of Morpholine
No full textTAPO-34 and TAPSO-34 Synthesized by Using Morpholine as Templating Agent: Spectroscopic Studies
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Poly(ethylene terephthalate)-carbon nanofiber nano composite for fiber spinning; properties and combustion behavior
Full text linkCarbon nanofiber (CNF)-polyethylene terephthalate (PET) blends were previously prepared by melt blending and, subsequently, melt spun in order to obtain nanostructured fibers characterized by high flame retardant properties and resistance to the combustion. The morphological analysis showed that CNFs are homogeneously distributed and finely dispersed within PET matrix. The mechanical properties in tensile testing of the fibers change in the presence of CNFs: the elongation at break increases, whereas the tenacity and the tensile strength decrease. The combustion tests by cone calorimetry reveal a relevant decrease of heat release rate, total heat evolved and total smokes released by the nanocomposites as compared to neat PET
The effect of annealing conditions on the intercalation and exfoliation of layered silicates in polymer nanocomposite
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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