1,721,070 research outputs found
Renewable materials. Il design della materia rinnovabile
No full textIl contributo propone un approccio metodologico ed i risultati di esperienze di sperimentazioni scientifiche e progettuali sui temi dei materiali rinnovabili, del design sostenibile, e del riuso di scarti
Renewable polymers and plastics: Performance beyond the green
No full textRenewable bio-based polymers are one of the effective answers that the bioeconomy offers to solve the environmental emergency connected to plastics and more specifically fossil-based plastics. Previous studies have shown that more than 70 % of the natural capital cost associated with plastic derives from the extraction and processing of fossil raw materials and that the price of fossil plastic would be on average 44 % higher if such impact was fully paid by businesses. The disclosure of the hidden costs of plastics will contribute to dispelling the myth of the expensiveness of renewable polymers. Nevertheless, the adoption of bio-based plastics in the market must be motivated by their functional properties and not merely by their green credentials. This article highlights some successful examples of synergies between chemistry and biotechnology in achieving a new generation of bio-based monomers and polymers. Their success is justified by the combination of scientific advances with positive environmental and social fallouts
Physical Properties of Innovative Spray Biodegradable Coatings for Soil Mulching in Greenhouse Cultivation
No full textIn order to overcome the serious drawback of huge quantities of plastic
waste obtained at the end of the life of agricultural plastic mulching films,
researches on innovative biodegradable materials have been developing. The paper
examines a new sustainable approach in which a water solution of natural
biodegradable polymers is sprayed on a cultivation area in order to form a mulch
coating. The material used is a blend of two polysaccharides, such as Guar Gum and
Locust Bean Gum additivated with glycerol. A protected field experiment was
conducted to test the effectiveness of spray black biodegradable mulching coating in
a tomato crop in Southern Italy. Field performance and physical properties,
evaluated by means of laboratory tests, are compared to those of commercial low
density polyethylene and biodegradable starch based mulch films. The spray
mulching coating is opaque in the solar radiation range and behaved as a black
body. The tested spray coating showed much lower values of tensile stress and
elongation at break in comparison with the values of commercial low density
polyethylene and biodegradable starch based mulch films. Such innovative coatings
were characterised by functionality during their use in field. Results indicate that
the biodegradable spray coatings could be a sustainable alternatives to plastic films
based on fossil raw materials
Development of a new calcium sulphate-based composite using alginate and chemically modified chitosan for bone regeneration
No full textIn this work we developed a novel calcium sulphate-
based composite in which the hemihydrate calcium
sulphate (CHS) can be encapsulated in a polymeric biodegradable
and biocompatible matrix, in order to retain the
structural integrity and decrease the bioresorption rate in bone
regeneration applications. Two polymers were employed to
realize this system: chitosan (Ch) and sodium alginate (Alg),
both already widely used in biotechnological and biomedical
applications. Chitosan was modified in order to obtain a
water soluble polymer, the N-succinylchitosan (sCh). The reaction
was performed with succinic anhydride in presence of
pyridine and confirmed by FT-IR and NMR analyses. Finely
ground Alg and sCh powders were mixed in different compositions
with CHS and by adding water to the powder mixture
it was obtained a mouldable paste that sets in few hours.
Thermogravimetric analyses coupled with solvent extraction
performed on the composite proved the alginate crosslinking
in the presence of CHS. Mechanical studies carried out on
composites of different compositions demonstrated that the
blend of the two polymeric components causes a substantial
synergistic reinforcement of composites. The presence of carboxylic
groups on sCh chain in addition to those of alginate
could enhance the chelating power of polysaccharide mixture.
The results obtained with morphological analyses (SEM) further
confirmed the hypotesis of the synergistic effect between
alginate and N-succinylchitosan in presence of calcium sulphate.
In vitro cytotoxicity tests proved that the developed
system was not cytotoxic. 2007 Wiley Periodicals, Inc. J
Biomed Mater Res 81A: 811–820, 200
Immiscible Polymer Blends of Semycrystalline Biocompatible Components: Thermal Properties and Phase Morphology Analysis of PLLA/PCL Blends
No full textImmiscible Polymer Blends of Semycrystalline Biocompatible Components: Thermal Properties and Phase Morphology Analysis of PLLA/PCL Blends
No full textUnsaturated alkoxy-substituted poly(p-phenylene 1,3,4-oxadiazole)s: Synthesis and chemical-physical characterization
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