1,721,200 research outputs found
riutilizzo dei materiali polimerici
No full textIl presente volume vuole sottolineare come le materie plastiche possono essere sempre recuperate e rivalutate sotto forma di recupero di materia e, quando non più possibile, di energia grazie al loro elevato potere calorifico. La crescita delle materie plastiche negli ultimi anni si è aggirata intorno al 6%, superiore a quella della carta e dell’acciaio, ne consegue la grande importanza del suo recupero a fine vita, dai cosiddetti “giacimenti metropolitani”.
Il testo è dedicato al recupero dei materiali plastici; vengono esaminate nei dettagli le operazioni di raccolta, di separazione e purificazione di tutti i rifiuti provenienti dalla raccolta differenziata, valutando gli aspetti normativi, gestionali e tecnologici di questi processi.
Viene trattato il riciclo partendo da una classificazione dei metodi che permettono di arrivare a potenziali materie prime e seconde e viene esaminato il processing di materiali polimerici post-consumo che, opportunamente miscelati, possono portare alla preparazione di nuovi materiali polimerici.
Si è dedicato spazio alle plastiche da imballaggio e al potenziale recupero delle plastiche dai veicoli a fine vita e dalle apparecchiature elettriche ed elettroniche e infine alle prospettive del riciclo considerando l’avvento delle nuove bioplastiche
Catalizzatori di transesterificazione nella miscelazione reattiva di polietilene funzionalizzato con dialchil maleati e PET
No full textNew materials and process to use post-consumer poly(ethylene terephthalate) as a component of polyolefins based blends
No full textPoly(lactic acid) (PLA) based blends and composites: new perspectives for biodegradable and renewable materials
No full textInfluence of the transesterification catalyst structure on the reactive compatibilization and properties of poly(ethylene terephthalate) (PET)/dibutyl succinate functionalized poly(ethylene) blends
No full textThe transesterification between poly(ethylene terephthalate) (PET) and dibutyl succinate functionalized polyethylene
(POF) was studied by preparing blends in a discontinuous mixer in the presence of different Zn and Ti catalysts. In particular
the catalytic activities of Zn(OOCCH3)2, Ti(OBu)4, ZnO and TiO(OCCH3)2 were compared. The mechanism of
reactions occurring in the melt was studied both by a model compounds approach and by characterizing the macromolecular
products of the melt processing by means of selective extractions, infrared analysis and the determinations of the
molecular weight of PET. The results are discussed in terms of electrophilicity and nucleophilicity of the different catalysts.
The catalysts structure also affected the phase distribution. In fact from a morphologic point of view in PET matrix blends
the use of zinc derivatives yielded preferentially dispersed-like phase distribution, while the use of titanium derivatives
resulted in partially co-continuous phase morphology. The stability of the attained phase distribution was also monitored
during compression moulding and it evolved rapidly in fully dispersed phase morphology. The tensile properties of compression
moulded films revealed that the occurred reactions and morphological assessment induced a general decrease of
tensile modulus and an increase of elongation at break
Influence of the transesterification catalyst structure on the reactive compatibilization and properties of poly (ethylene terephthalate) (PET)/dibutyl succinate functionalized poly(ethylene) blends
No full text
Effect of structure of functionalizing molecules on the inter-macromolecular reactions and blending of poly(ethylene-co-propylene) (EPM) with poly(6-aminohexanoic acid) (PA6)
No full textEffect of free radical reactions onto Structure and properties of poly(lactic acid) (PLA) based blends
No full textThe blending of PLA with poly(butylene-adipate-co-terephthalate) (PBAT) is a promising strategy to
achieve a toughened multiphase material. The blends ductility could be further improved through
reactive compatibilization, i.e. inducing the formation of comb PLA-PBAT copolymers during the melt
blending. In the present work a non-selective strategy was adopted which consisted in the use of
a peroxide, 2,5-Dimethyl-2,5-di(tert-butylperoxy)hexane. The phase morphology development and the
final properties (torque, fluidity in the melt, tensile behaviour, thermal and dynamicalemechanical
features) of the blends were studied as a function of the peroxide concentration. The elongation at break
was improved up to a maximum value thanks to this approach and a corresponding minimum was
observed in the value of the dispersed phase diameter. A structural characterization of the macromolecules
formed during the reactive process was attempted by using size exclusion chromatography of the
blends and comparison with the pure polymers obtained by processing in the presence of the peroxid
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