112 research outputs found
Investigation of Different Types of Biochar on the Thermal Stability and Fire Retardancy of polymer
No full textL'abstract è presente nell'allegato / the abstract is in the attachmen
PET Foams Surface Treated with Graphene Nanoplatelets: Evaluation of Thermal Resistance and Flame Retardancy
No full textIn this work, fire-retardant systems consisting of graphene nanoplatelets (GNPs) and dispersant agents were designed and applied on polyethylene terephthalate (PET) foam. Manual deposition from three different liquid solutions was performed in order to create a protective coating on the specimen’s surface. A very low amount of coating, between 1.5 and 3.5 wt%, was chosen for the preparation of coated samples. Flammability, flame penetration, and combustion tests demonstrated the improvement provided to the foam via coating. In particular, specimens with PSS/GNPs coating, compared to neat foam, were able to interrupt the flame during horizontal and vertical flammability tests and led to longer endurance times during the flame penetration test. Furthermore, during cone calorimetry tests, the time to ignition (TTI) increased and the peak of heat release rate (pHRR) was drastically reduced by up to 60% compared to that of the uncoated PET foam. Finally, ageing for 48 and 115 h at 160 °C was performed on coated specimens to evaluate the effect on flammability and combustion behavior. Scanning electron microscopy (SEM) images proved the morphological effect of the heat treatment on the surface, showing that the coating was uniformly distributed. In this case, fire-retardant properties were enhanced, even if fewer GNPs were used
Investigation of different types of biochar on the thermal stability and fire retardance of ethylene-vinyl acetate copolymers
No full textIn this work, three biochars, deriving from soft wood, oil seed rape, and rice husk and differing as far as the ash content is considered (2.3, 23.4, and 47.8 wt.%, respectively), were compounded in an ethylene vinyl acetate copolymer (vinyl acetate content: 19 wt.%), using a co-rotating twin-screw extruder; three loadings for each biochar were selected, namely 15, 20, and 40 wt.%. The thermal and mechanical properties were thoroughly investigated, as well as the flame retardance of the resulting compounds. In particular, biochar, irrespective of the type, slowed down the crystallization of the copolymer: this effect increased with increasing the filler loading. Besides, despite a very limited effect in flammability tests, the incorporation of biochar at increasing loadings turned out to enhance the forced-combustion behavior of the compounds, as revealed by the remarkable decrease of peak of heat release rate and of total heat release, notwithstanding a significant increase of the residues at the end of the tests. Finally, increasing the biochar loadings promoted an increase of the stiffness of the resulting compounds, as well as a decrease of their ductility with respect to unfilled ethylene vinyl acetate (EVA), without impacting too much on the overall mechanical behavior of the copolymer. The obtained results seem to indicate that biochar may represent a possible low environmental impact alternative to the already used flame retardants for EVA, providing a good compromise between enhanced fire resistance and acceptable mechanical properties
Samuele R. Bacchiocchi and Family
No full textSeventh-day Adventist author and theologian, Samuele R. Bacchiocchi and his wife and their children at a graduation ceremony at Pontifical University
Flame retardant polymer systems containing biochar: current state-of-the-art and perspectives
No full textBoth in the academic and industrial worlds, the field of flame retardance of plastics and textile materials is currently experiencing the use of bio-sourced and low
environmental impact products for the design of effective and ‘green’ alternatives to common flame retardants. Among them, biochar, a solid product obtained from the thermo-chemical conversion of biomasses in an oxygen-limited environment, is gathering great interest as a cheap carbon source, suitable, in combination with standard flame retardant additives, for enhancing the resistance of different polymer-based systems to a flame application or to the exposure of an irradiative heat source. This chapter will thoroughly describe the novel current state-of-the-art concerning the use of this carbon material as a flame retardant, discussing the recent advances and highlighting some future possible developments
Flame retardant potential of Tetra Pak®-derived biochar for ethylene-vinyl-acetate copolymers
No full textFood packaging waste-stream is a serious threat for current lifestyle sustainability. Among all the materials, Tetra Pak® is one of the most employed to produce food and beverage containers. Its composition represents a challenge for waste management due the simultaneous presence of poly(ethylene), paper and aluminum,
wrapped together into a multilayered packaging. In this work, we report on the pyrolytic conversion of Tetra Pak® to produce alumina-rich biochar (BC), to be used as a flame retardant for an ethylene-vinyl-acetate (EVA) copolymer. In particular, the obtained biochar was incorporated either into bulk EVA through compounding or
just as a surface coating. For the surface approach, a masterbatch of biochar and EVA was prepared and then applied to the surface of unfilled EVA specimens. Both the strategies turned out to significantly improve the overall flame retardant features of the copolymer: as compared to unfilled EVA, the bulk approach promoted a
remarkable decrease of peak of heat release rate (-45 and -65%, for the compounds containing 20 and 40 wt.% of BC, respectively) and of total heat release (-16.9% for the compounds filled with 40 wt.% of BC), combined with a significant increase of the residues at the end of forced combustion tests; conversely, the surface approach was capable of delaying the time to ignition and the time to peak of heat release rate, depending of the BC amount: more specifically, for the surface-coated EVA with the lowest BC loading (i.e. 3 wt.%), the two parameters increased by about 34 and 21%, respectively. The thermal, rheological and mechanical properties were also investigated, as well as the morphology of the BC particles and their dispersion in the copolymer matrix. In particular, increasing the biochar loading promoted an increase of the stiffness of the resulting compounds, as well as a decrease of their ductility with respect to unfilled EVA
sd920/FIJI-macros-for-IHC-and-SHG-analysis: Batch Split Channels (3 channels)
No full textThis macro allows to split channels for Z-stack .tiff files and save them in a new folder in batch mode.
Author: Samuele Di Carmine, [email protected]
Version 1.0
July 13, 2021
//License: BSD3
Copyright 2021 Samuele Di Carmine, Imperial College Londo
Evaluation of nanocomposites containing graphene nanoplatelets: Mechanical properties and combustion behavior
No full textPolypropylene (PP) nanocomposites containing graphene nanoplatelets (GNPs) with different loadings were fabri- cated via masterbatch compounding–melt blending processing technique. Morphological studies showed that the method employed provided uniform GNPs dispersion in the matrix, orienting the nanoplatelets along the same direction the flow of matter. Enhancements of storage and Young’s modulus occurred, increasing GNP content, and the improvement was more obvious when a compatibilizer, the PP-grafted-maleic anhydride, was introduced to achieve a better GNP dispersion and distribution within the matrix. For all the nanocomposites, even for those com- patibilized, it was not possible to fully exploit the GNP toughening effect since a stiffening and embrittling effect prevailed. Thermogravimetric analysis showed that GNP incorporation has improved the thermal stability of the nanocomposites. In addition, cone calorimetry results showed that GNPs can act as intumescent flame retardant and significantly reduced the heat release rate, thus improving the flame retardancy of the PP matrix
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