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  • Author or Editor: C. Ferrero x
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Abstract  

Electro-conducting doped polypyrrole was deposited by in situ oxidative polymerisation on PET non-wovens. Thermal properties were evaluated by means of DSC and TG in nitrogen and air. Flame resistance tests reveal that coated PET fibres resist to direct contact with fire. By thermal analysis, it was found that PPy reduces the temperature at which thermo-oxidative degradation of PET occurs. Polypyrrole-coated PET non-wovens were heated above the melting point of PET for 30 min. After the heating the fibres become brittle and frail, but SEM observations revealed that they maintained their fibrous shape. A loss of chlorine was found because of intense heating.

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Differential scanning calorimetry (DSC) was used to analyze the influence of different hydrocolloids (xanthan, guar, and locust bean gums, carboxymethylcellulose and sodium alginate) on the gelatinization of corn starch in systems with starch concentration ranging between 0.1 and 0.7 g starch/g mixture. The reduction of available water produced a shift in gelatinization temperature, especially of the conclusion temperature. The effect was more marked for ionic hydrocolloids. The influence of hydrocolloids on glass transition temperature (T g) of gelatinized starch suspensions and on the glass transition temperature of the maximally freeze-concentrated solute/unfrozen water matrix (T′ g) was also studied.T′ g onset values ranged between −4.5 and −5.5‡C for corn starch pastes with and without hydrocolloids. Those hydrocolloids that increased the viscosity of the unfrozen matrix inhibited additional ice formation during thawing (devitrification).

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Abstract  

Blends of poly(ethylene oxide) (PEO) and keratin were prepared with the aim of obtaining bio-compatible materials suitable for film and fibre production. Aqueous keratin solutions, prepared by keratin extraction from wool with urea, m-bisulphite and sodium dodecyl sulphates (SDS), filtration and dialysis, were added with different amounts of PEO and solid films were prepared by casting. The addition of SDS prevents protein aggregation. Morphological, thermal and spectroscopic analysis of the films pointed out that keratin hinders the PEO crystallization process, since a progressive decrease in the size of PEO spherulites is observed and the melting point and the related enthalpy decrease with increasing the keratin content. On the other hand, according to thermal and spectroscopic investigations. PEO seems to interfere with the keratin self-assembling giving the protein a different thermal behaviour.

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Abstract  

We present examples of the application of the X-ray fluorescence (XRF) to the study of the artistic and cultural patrimony of the Comunidad Valenciana in the following areas: a) Valencian paintings of the XV and XVI centuries; b) silver ornaments coming from Iberian towns (s. III b.C.); c) ink and paper samples in manuscripts and engravings of the XVII and XIX centuries. The non destructive analyses are carried out “in situ” using a XRF system that consists of a tube of X-rays of 50 kV and 1 mA, and a detector of Si(Li) with an energy resolution 140 eV (FWHM at 5.9 keV).

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