1,721,037 research outputs found
Ski Boot Soles Based on a Glass Fiber/Rubber Composite with Improved Grip on Icy Surfaces
Full text linkAbstractA study on the effect of glass fibers/rubber composites on the grip on ice has been conducted in order to develop new materials for ski boot soles with increased grip in winter environments. The study has been conducted analyzing the friction of a composite material and of a ski boot sole containing an insert made of the composite material and comparing the results with those obtained using rubber and a thermoplastic elastomer. The analysis of the morphology of the composite surface, by Scanning Electron Microscopy, shows a homogenous distribution of glass fibers of approximately 10μm of diameter in the rubber matrix. Moreover, the measure of the contact angle shows that the composite material has a higher water repellency compared to the rubber matrix. The measure of the coefficient of friction indicates a significant effect of the glass fibers on the grip on icy surfaces. The increased grip can be ascribed to the stiffness of the glass fibers that are able to have a mechanical grip on the ice surface and to the increased contact angle and water repellency of the composite that decrease the formation of a water layer below the sole
Hydroxydes doubles lamellaires organo-modifies et materiaux polymeres composites les comprenant
No full textHydroxide doubles lamellaire organo-modifiespar l'acide 3-(4-hydroxyphenyl)propionique (HPPA) par l'acide 2-(4-hydroxyphenyl)ethylsulfonique ou par un acide hydroxphenylypropenoique, et materiaux polymeres composites les comprenant. les materiux composites sont avantageusement a base de polymeres biosources comme le poly(butylene succinate). Ces materiaux composites presentent des proprietes ameliorees par rapport aux polymeres entrant dans leur composition, et par rapport aux composites de l'art anterieur
Poly(1,4-dimethylcyclohexane adipate) nanocomposites with organoclays modified with ionic liquid based on phosphonium salt
Full text linkUse of ionic liquids based on phosphonium salts for preparing biocomposites by in situ polymerization
No full textA sodium montmorillonite, Dellite HPS, was modified with ionic liquids based on phosphonium salts, such as octadecyltriphenylphosphonium
tetrafluoroborate and octadecyltriphenylphosphonium bromide. Thanks to their high thermal stability, these
salts can be used during in situ polymerization, a method that favors the achievement of a good dispersion of the clay. Poly(1,4-dimethylcyclohexane
adipate) (PCHA), was chosen as an example of aliphatic polyester which can be a suitable matrix for new biocomposites
with organo-clays. The organo modified clays prepared were characterized by X-ray diffraction (XRD), ATR-FTIR spectroscopy,
and thermal gravimetric analysis (TGA) while biocomposites were analyzed in terms of molecular structure, thermal and thermomechanical
properties. The degree of dispersion of the clays in the polymer matrix was studied by XRD. The results show that the clays
are well dispersed in the biocomposites, despite an intercalated structure highlighted by XRD analysis. Moreover, the clays confer a
certain improvement in mechanical properties to the final materials
Marinobacter sp. from marine sediments produce highly stable surface-active agents for combatting marine oil spills
Full text linkBackground: The application of chemical dispersants as a response to marine oil spills is raising concerns related to their potential toxicity also towards microbes involved in oil biodegradation. Hence, oil spills occurring under marine environments necessitate the application of biodispersants that are highly active, stable and effective under marine environment context. Biosurfactants from marine bacteria could be good candidates for the development of biodispersant formulations effective in marine environment. This study aimed at establishing a collection of marine bacteria able to produce surface-active compounds and evaluating the activity and stability of the produced compounds under conditions mimicking those found under marine environment context.Results: A total of 43 different isolates were obtained from harbor sediments. Twenty-six of them produced mainly bioemulsifiers when glucose was used as carbon source and 16 were biosurfactant/bioemulsifiers producers after growth in the presence of soybean oil. Sequencing of 16S rRNA gene classified most isolates into the genus Marinobacter. The produced emulsions were shown to be stable up to 30 months monitoring period, in the presence of 300 g/l NaCl, at 4 °C and after high temperature treatment (120 °C for 20 min). The partially purified compounds obtained after growth on soybean oil-based media exhibited low toxicity towards V. fischeri and high capability to disperse crude oil on synthetic marine water.Conclusions: To the best of our knowledge, stability characterization of bioemulsifiers/biosurfactants from the non-pathogenic marine bacterium Marinobacter has not been previously reported. The produced compounds were shown to have potential for different applications including the environmental sector. Indeed, their high stability in the presence of high salt concentration and low temperature, conditions characterizing the marine environment, the capability to disperse crude oil and the low ecotoxicity makes them interesting for the development of biodispersants to be used in combatting marine oil spills
Multicomponent reinforcing system for poly(butylene succinate): Composites containing poly(l-lactide) electrospun mats loaded with graphene
No full textGiven the increasing relevance of poly(butylene succinate) (PBS) and poly(l-lactide) (PLLA) as bio-based thermoplastics, and the need to improve the properties of such polymers, a novel multicomponent reinforcing system was devised. Nanofibrous electrospun mats of PLLA containing graphene were incorporated into the PBS matrix via the conventional thermo-pressed molding technique. The final biocomposites were characterized in terms of morphological characteristics via SEM and STEM; TGA and DSC were used to investigate the thermal properties and tensile testing used to assess the mechanical properties. The results showed that PBS matrix does not have modified thermal behaviour in the presence of PLLA and graphene. On the contrary, the tensile strength of the composites was gradually enhanced with the addition of PLLA mats, and the improvement was found to be proportional to the number of PLLA layers and to the amount of graphene added. The huge potential of this multicomponent reinforcing system is highlighted by the 21% increment in tensile strength
From food residues to eco-friendly packaging: how it is possible to valorise agro-industrial residues to obtain CO2-neutral biomaterials
No full textFormulation of Green Particulate Composites from PLA and PBS Matrix and Wastes Deriving from the Coffee Production
No full textParticulate composites based on poly(lactic acid) and poly(butylene succinate) biopolymers have been formulated. Silver skin, the by-product derived from the roasting of coffee beans, has been used as a filler up to a 30 wt% of loading. The microstructure, crystallinity, thermal stability, mechanical properties and water absorption of the derived composites have been investigated. Data so far collected underline that a trade-off of the mechanical properties can be obtained by adding the filler, while the overall amount of crystallinity remains constant. Up to the highest filler content, moisture uptake follows a Fichian behaviour while the value of the contact angle is slightly increased by modification. Thus, silver skin, which actually is used for fuel or soil fertilization, finds here a different environmentally friendly valorization into the field of biocomposites
From food residues to eco-friendly packaging: how it is possible to valorise agro-industrial residues to obtain CO2-neutral biomaterials
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