Search results for "MELT"

Photo-stabilization of biopolymers-based nanocomposites with UV-modified layered silicates

2020

Abstract Eco-friendly in-situ stabilised biopolymer nanocomposites based on polyamide 11 (PA11) and polylactic acid (PLA) were prepared by melt mixing in the presence of a modified organo-montmorillonite clay containing a chemically-bound hindered amine UV-stabilising function, [(UV)OM-MMt]. Characterisation of the newly synthesised organo-modifier containing the reactive hindered amine (HAS) UV-stabilising function [(UV)OM] has confirmed a successful synthesis. The (UV)OM was then introduced into NaMMt through ion exchange reaction to prepare the UV stabiliser-bound organo-modified-MMt, [(UV)OM-MMt]. The in-situ stabilised PA11- and PLA- nanocomposites (PA11-(UV)OM-MMt and PLA-(UV)OM-MMt) …

Development and characterization of antimicrobial PCL fibres for surgical suture applications

2011

Antimicrobial properties and release profile of monofilaments incorporating chlorhexidine for surgical applications

2011

BIODEGRADABLE BILAYER FILMS PREPARED BY CO-EXTRUSION

2017

The sensitivity for reducing packaging waste drove academic and industrial efforts to search compostable or biodegradable bio-sourced polymeric materials. Multilayer systems represent a suitable strategy to obtain the required properties and to improve biopolymer performance. The aim of the current work is the coextrusion film blowing of a biodegradable bilayer film PLA/MaterBi with the purpose to overcome the drawbacks of the individual components.

Resource or waste? A perspective of plastics degradation in soil with a focus on end-of-life options.

2018

‘Capable-of-being-shaped’ synthetic compounds are prevailing today over horn, bone, leather, wood, stone, metal, glass, or ceramic in products that were previously left to natural materials. Plastic is, in fact, economical, simple, adaptable, and waterproof. Also, it is durable and resilient to natural degradation (although microbial species capable of degrading plastics do exist). In becoming a waste, plastic accumulation adversely affects ecosystems. The majority of plastic debris pollutes waters, accumulating in oceans. And, the behaviour and the quantity of plastic, which has become waste, are rather well documented in the water, in fact. This review collects existing information on pla…

Oxazoline-containing compatibilizers for polyamide/SAN and polyamide/ABS blends

2002

Polyamide (PA) and acrylonitrile/butadiene/styrene copolymer (ABS) may appear as a mixture in the recycled plastic stream. The incompatibility of these blends results in a blend with poor mechanical properties. The aim of this work is to partially convert the nitrile groups of the acrylonitrile/styrene copolymer (SAN) into oxazoline groups by reaction with aminoethanol (AE). Such modified SAN (SAN-m) can react with the amine or carboxylic acid end groups of PA, and therefore used as compatibilizers for blends of PA with ABS. SAN-m was found to reduce the SAN-domain size in the PA/SAN-blends. The initial acrylonitrile content of SAN-m had a strong influence on the degree of conversion into o…

The origin and glaciodynamic significance of sandstone ridge networks from the Hirnantian glaciation of the Djado Basin (Niger)

2007

The Djado Basin (Niger) was located beneath the inner part of the Late Ordovician ice sheet. The Felar-Felar Formation consists mainly of glaciomarine deposits, associated with the major ice sheet recession within the glaciation, and is bounded by two glacial unconformities. Structures corresponding to sandstone ridges are found within the Felar-Felar Formation. Sandstone ridges are several metres high, about 10 m wide and hundreds of metres long. These structures are organized in extensive anastomosed to subpolygonal networks. The association of sandstone ridge networks with the later glacial unconformity and with other glacial evidence suggests sub-glacial conditions for their origin. San…

Comparing equilibration schemes of high-molecular-weight polymer melts with topological indicators.

2021

Abstract Recent theoretical studies have demonstrated that the behaviour of molecular knots is a sensitive indicator of polymer structure. Here, we use knots to verify the ability of two state-of-the-art algorithms—configuration assembly and hierarchical backmapping—to equilibrate high-molecular-weight (MW) polymer melts. Specifically, we consider melts with MWs equivalent to several tens of entanglement lengths and various chain flexibilities, generated with both strategies. We compare their unknotting probability, unknotting length, knot spectra, and knot length distributions. The excellent agreement between the two independent methods with respect to knotting properties provides an addit…

Partial melting of metagreywacke: a calculated mineral equilibria study

2008

Greywacke occurs in most regionally metamorphosed orogenic terranes, with depositional ages from Archean to recent. It is commonly the dominant siliciclastic rock type, many times more abundant than pelite. Using calculated pseudosections in the Na2O–CaO–K2O–FeO–MgO–Al2O3–SiO2–H2O–TiO2–O system, the partial melting of metagreywacke is investigated using several natural protolith compositions that reflect the main observed compositional variations. At conditions appropriate for regional metamorphism at mid-crustal depths (6–8 kbar), high-T subsolidus assemblages are dominated by quartz, plagioclase and biotite with minor garnet, orthoamphibole, sillimanite, muscovite and/or K-feldspar (±Fe–T…

Migmatites in the Ivrea Zone (NW Italy): Constraints on partial melting and melt loss in metasedimentary rocks from Val Strona di Omegna

2013

Abstract The mid to lower crustal metamorphic field gradient through amphibolite and granulite facies rocks in the Ivrea Zone offers the potential to study partial melting and melt loss in the crust. Metapelitic rocks in Val Strona di Omegna show a progressive evolution in migmatite structures from metatexites with rare isolated leucosome veins in the amphibolite facies rocks to stromatic migmatites and diatexites in granulite facies rocks. Little field or petrographic evidence for melting can be seen on crossing the position of the modelled wet solidus, consistent with the small amounts of melt predicted to occur by H2O-saturated melting. The first field evidence for partial melting, in th…