Search results for " fibre"
showing 10 items of 285 documents
Morphology and properties of CNTs and carbon black filled polyamide fibres
2011
On the role of extensional flow in morphology and properties modifications in MW-CNTs and carbon black polyamide-based fibres
2011
Hydrolytic degradation of PLA/Posidonia Oceanica green composites: A simple model based on starting morpho-chemical properties
2021
Abstract In this work, we studied the degradability of PLA-based biocomposites containing Posidonia Oceanica flour at different loading levels and aspect ratios. Hydrolytic tests were carried out in neutral (pH = 7.4) and alkaline (pH = 10) environment. Time-dependent evolution of some key features, including residual mass and solution uptake, was monitored, and correlated with the changes observed in both morphology and chemical structure of the matrix. The results pointed out that biocomposites degraded much faster than neat PLA in both conditions, up to lose 70% of their initial weight after 1000 h immersion. A complex mechanism was unveiled, evidencing the crucial role of the fillers, c…
Modeling the nonlinear deformation of flax-fiber-reinforced polymer matrix laminates in active loading
2015
In an attempt to fully utilize the mechanical properties of bast fibers in polymer-matrix composites, unidirectional (UD) or quasi-UD flax-fiber-reinforced composites are being developed and characterized. Their response in tension is markedly nonlinear both in on- and off-axis loading. A semiempirical tensor-linear model is applied to describe such deformation nonlinearity in active combined loading. The deformation model of UD ply, combined with an elementary laminate theory, is used to predict the stress–strain curves of laminated composites in tension. Reasonable accuracy of prediction is demonstrated for fiber-dominated layups.
Improving the properties of polypropylene–wood flour composites by utilization of maleated adhesion promoters
2007
Polymer composites filled with natural organic fillers have gained a significant interest during the last few years, because of several advantages they can offer compared with properties of inorganic-mineral fillers. However, these composites (based, in most cases, on polyolefins) often show a reduction in some mechanical properties. This is mainly due to the problems regarding dispersion of the polar filler particles in the non-polar polymer matrix and their interfacial adhesion with polymer chains. In this work, polypropylene-wood flour composites were prepared and the effect of the addition of a maleated polypropylene was investigated. The two materials were compounded by an industrial c…
243 HISTAMINE-IONTOPHORESIS FOR DIFFERENTIATION OF C-FIBRE FUNCTION IN POST-HERPETIC NEURALGIAS
2007
Design ed eco-sostenibilità: le fibre vegetali in Sicilia tra tradizione ed innovazione
2012
Il dibattito sulla questione ambientale, sorto tra gli anni ‘60 e ‘70 del secolo scorso, con la formazione delle prime associazioni ambientaliste, ebbe come nodo centrale il rapporto tra economia e ambiente, nella sempre più evidente necessità di preservare la qualità del patrimonio naturale e nella consapevolezza che, essendo le risorse del pianeta tendenzialmente esauribili, dovessero essere rivisti ed equilibrati i modelli di sviluppo. Gli oggetti, secondo la lezione di Bruno Latour, simboleggiano stili di vita che comprendono al loro interno processi comunicativi e riguardano in ogni caso la sfera dell’informazione, dell’interazione, del ricordo e anche del desiderio. L’omologazione del…
Calcestruzzi rinforzati con fibre di PET. Sperimentazioni sull'impiego delle fibre di PET provenienti dalla raccolta differenziata nella produzione d…
2013
La sperimentazione esposta tratta dell’impiego di fibre di PET, ricavate dal semplice taglio di contenitori per bevande, nel rinforzo di calcestruzzi destinati anche a impieghi strutturali. Indaga la durabilità delle fibre in ambiente fortemente basico e le caratteristiche meccaniche di calcestruzzi rinforzati con differenti dosaggi di fibre. Le osservazioni al microscopio elettronico a scansione (SEM) di fibre di PET immerse per 13 giorni a 65°C in acqua distillata e in due soluzioni fortemente basiche mostrano la buona durabilità delle fibre in soluzione 0,103 M di NaOH, che simula la basicità della soluzione acquosa che permea la matrice cementizia. L’influenza delle fibre e del loro dos…
On the role of extensional flow in morphology and property modifications of MWCNT/polyamide-based fibres
2011
Unfilled and MWCNT-filled PA fibers are prepared and the effect of the extensional flow on their mechanical performance and morphological variations is investigated. Morphological analyses using SEM, TEM, and SAXS suggest a stronger orientation of the MWCNTs along the fiber direction with increasing extensional flow. A particular MWCNT bundle formation in the PA drawn nanocomposite fibers is observed for the first time, and a pull-out of the central nanotube in some bundles is noted. The maintenance of the “shish-kebab” structure upon extensional flow is responsible for the mechanical improvements and dimensional stability in MWCNT-filled PA fibers.
Determination of intrinsic scatter in lifetimes of carbon fibre epoxy pressure vessels in view of defining fundamental safety factors
2011
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