MWNT Surface Self-Assembling in Fire Retardant Polyethylene-Carbon nanotubes nanocomposites

Multiwall carbon nanotubes (MWNT) were melt blended at different concentration with linear low density polyethylene (LLDPE). The nanotubes impart the fire-retardant characteristics to the polymer by formation of a thin protective film of MWNT/carbon char generated on the surface of the nanocomposites. The film formation mechanism is discusse

Thermal Evolution of Nanocomposites. When Nanoparticles are Effective in Polymer Fire Retardancy

A decade of research and development concerning polymer nanocomposites has shown the essential features of their combustion process. Nanocomposites actually display a fire retardant behaviour because they avoid fire propagation by dripping of hot and flaming polymer particles and reduce the rate of combustion. The mechanism involved in nanocomposites fire retardance is based on formation on heating of a ceramic protective, insulating layer on the surface of the burning material resulting from coalescence of nanofillers enclosing char from surface polymer charring, catalysed by the nanofiller. The thermal evolution of nanocomposites to the fire protective structure is discussed in relation with dispersion and distribution of the nanofillers in the polymer matrix either as it results from nanocomposite preparation or from its thermal evolution. Evaluation of the fire retardant performance of polymer nanocomposites in fire tests representing different fire scenarios (i.e. ignition, flammability and forced combustion) will be discussed in this talk

Synergistic effects of zinc borate and aluminiumtrihydroxide on flammability behaviour of aerospaceepoxy system

The flame retardancy of mono-component epoxy resin (RTM6), widely used for aerospace composites, treated with zinc borate (ZB), aluminium trihydroxide (ATH) and their mixtures at different concentrations have been investigated by morphological and thermal characterization. Cone calorimeter data reveal that combustion behaviour, heat release rate peak (PHRR) and heat release rate average (HRR Average) of RTM6 resin decrease substantially when synergistic effects of zinc borate and aluminium trihydroxide intervene. Thermogravimetric (TGA) results and analysis of the residue show that addition higher than 20% w/w of ZB, ATH, and their mixture greatly promotes RTM6 char formation acting as a barrier layer for the fire development. Depending upon the different used flame additives, SEM micrographs indicate that the morphology of residual char could vary from a compact amalgam-like structure, for the RTM6+ZB system, to a granular structure, characterized by very small particles of degraded resin and additive for the AT

Characterisation of the dispersion in polymer flame retarded nanocomposites

Flame retardant nanocomposites have attracted many research efforts because they combine the advantages of a conventional flame retardant polymer with that of polymer nanocomposite. However the properties obtained depend on the dispersion of the nanoparticles. In this study, three types of polymer flame retarded nanocomposites based on different matrices (polypropylene (PP), polybutadiene terephtalate (PBT) and polyamide 6 (PA6)) have been prepared by extrusion. In order to investigate the dispersion of nanoparticles in the polymer containing flame retardant, conventional methods used to characterise the morphology of composites have been applied to FR composites containing nanoclays. XRD, TEM and melt rheology give useful information to describe the dispersion of the nanofiller in the flame retarded nanocomposite. In the PA6-OP1311 (phosphorus based flame retardant) materials, the clay is well dispersed unlike in PBT and PP materials where microcomposites are obtained with some intercalation. The poor dispersion is also highlighted by NMR measurements but the presence of flame retardant particles interferes in the quantitative evaluation of nanoclay dispersion and underestimations are made

Isolation of tenebrio molitor enterobacteriaceae (coleoptera: tenebrionidae) as degrading organisms of expanded polystyrene under laboratory conditions

El proyecto de investigación se realizó con la premisa de hacer uso de la biotecnología como una alternativa de solución para un problema aún difícil de resolver como es la biodegradación de plásticos de un solo uso. El objetivo fue aislar bacterias de la microbiota intestina de las larvas de Tenebrio molitor como organismos degradadores del poliestireno expandido, identificar el género de bacterias aisladas, determinar el volumen de poliestireno consumido por las larvas como fuente única de alimentación, bajo condiciones de laboratorio y finalmente valorar la composición bioquímica de los desechos generados como parte del proceso de digestión de las larvas de Tenebrio molitor. El tracto digestivo extraído fue introducido en un microtubo eppendorf con 0,2 mL de agua peptonada al 10% y usando el vórtex por 30s se logró separar los microorganismos de las paredes del tejido, se hizo un cultivo en Chromagar y el repique en agar telurito de K a 37ºC por 48 horas, para la identificación de la especie de las enterobacterias aisladas. De acuerdo con la coloración de las colonias aisladas, y por el patrón de identificación, se pudo determinar que se trataba de la especie Enterococcus faecalis ATCC 29212 (Gram+). La composición bioquímica de los desechos generados como parte del proceso de digestión de las larvas, por espectrometría, evidenció que los polímeros sintéticos habían sido digeridos por las enterobacterias generó excretas contenidas en O, N, P y K demostrando la capacidad de convertir sustancias no biodegradables, en sustancias químicas potencialmente asimilables.The research project was carried out with the premise of making use of biotechnology as an alternative solution for a problem that is still difficult to solve, such as the biodegradation of single-use plastics. The objective was to isolate bacteria from the intestinal microbiota of the larvae of Tenebrio molitor as degrading organisms of expanded polystyrene, identify the genus of isolated bacteria, determine the volume of polystyrene consumed by the larvae as the sole source of food, under conditions of laboratory and finally assess the biochemical composition of the waste generated as part of the digestion process of the larvae of Tenebrio molitor. The extracted digestive tract was introduced into an eppendorf microtube with 0.2 mL of 10% peptone water and using the vortex for 30s it was possible to separate the microorganisms from the tissue walls, a culture was made on Chromagar and the peal on tellurite agar of K at 37ºC for 48 hours, for the identification of the species of the isolated Enterobacteriaceae. According to the coloration of the isolated colonies, and by the identification pattern, it could be determined that it was the species Enterococcus faecalis ATCC 29212 (Gram +). The biochemical composition of the waste generated as part of the digestion process of the larvae, by spectrometry, showed that the synthetic polymers had been digested by the Enterobacteriaceae generated excreta contained in O, N, P and K demonstrating the ability to convert non-biodegradable substances, in potentially assimilable chemicals