1,721,237 research outputs found
CONSERVAZIONE DI MANUFATTI LAPIDEI MEDIANTE MATERIALI POLIMERICI COMPOSITI
No full textUn fluoroelastomero fluorurato è stato studiato come protettivo idrorepellente su Pietra di Lecce. Il polimero, applicato come tale o addizionato PTFE sotto forma di polvere micrometrica, mostra promettenti proprietà se applicato in quantità uguali o maggiori di 50 g/m2. La presenza di PTFE nella matrice polimerica migliora l’efficacia protettiva a lungo termine; inoltre l’applicazione a pennello, rispetto a quella effettuata per assorbimento capillare, garantisce una migliore efficacia
(4-Nitrophenyl 1,3,5,8,12-pentaazacyclotetradec-3-yl ketone-N1,N5,N8,N12)copper(II) Dinitrate
No full textIn the crystal structure of [Cu(C16H26N6O3)]NO32, the metal ion lies in an elongated octahedral coordination. Only the four secondary amine N atoms of the macrocycle are bound to the Cu2+ centre which resides 0.080 (1) Å out of the N4 donor plane. The coordination sphere is completed by two nitrate O atoms axially coordinated with different Cu-O distances
Catalyzed hydrosilylation of 2-methyl-1-buten-3-yne with methyldichlorosilane; Promotional effect imparted by the presence of a different chlorosilane
No full textChloroplatinic acid catalyzed hydrosilylation of 2-Methyl-1-buten-3-yne with chlorosilanes is reinvestigated; the results can't be satisfactorily explained by Chalk and Harrod mechanism
Why, on Interaction of Urea Based Receptors with Fluoride, Beautiful Colors Develop.
Full text linkUrea-based receptors, containing electron-withdrawing chromogenic
substituents, in a DMSO solution, in the presence
of varying excess of fluoride, do not form H-bond complexes,
but undergo stepwise deprotonation of the two N-H fragments,
an event which is signaled by the development of
vivid colors. Double deprotonation is also observed in the
presence of hydroxide. Less basic anions (CH3COO-, H2PO4
-) induce deprotonation of only one N-H
Enhanced protection against mural writings by crosslinked fluorinated polymers
No full textA copolymer based on perfluoropolyether (PFPE) blocks and containing carboxylate functional groups interacts with epoxysilanes in acqueous microemulsion. Such reaction is followed by a crosslinking owing to the formation of siloxane bridges. The process can take place directly on a stone surface after the application of the PFPE derivative/epoxysilane mixture. The protecting effect of the resulting polymeric material is studied on samples of Pietra Serena sandstone. The application of this material improves not only the substrate hydrophobicity (as expected for a perfluoropolyether derivative) but also the resistance to the dirtying which could be caused by mural writings (e.g. by inks). The treatment generates a protecting layer which resists on the stone surface even after repeated staining/cleaning cycles, giving rise to a durable “antigraffiti” effect. The curing process improves protecting properties of the fluorinated polymer: in the absence of the epoxide curing agent the anti-graffiti effectiveness is much lowe
Copolimeri sililati dell' isobutilene reticolabili in condizioni ambientali e procedimento per la loro preparazione
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