Search results for " Ethylene"

Structural and CO [sub] 2 capture properties of ethylenediamine-modified HKUST-1 metal-organic framework

2020

The high structural and compositional flexibility of metal–organic frameworks (MOFs) shows their great potential for CO2 capture and utilization in accordance with the environmental guidelines of low-carbon technology developments. HKUST-1 as one of the most intensively studied representatives of MOFs for such purposes excels because of its simplicity of production and high ability to tune its intrinsic properties by various functionalization processes. In the present work, ethylenediamine functionalization was performed for the first time in order to thoroughly investigate the amine sorption sites’ impact on the CO2 capture performance of HKUST-1. The placement of ethylenediamine moieties …

Characterization of blends with polyamide 6 and ethylene acrylic acid copolymers at different acrylic acid content

2002

In this work the morphological, calorimetric, rheological and mechanical behaviour and fourier transmission infrared analysis of blends made with polyamide 6 (PA6) and ethylene acrylic acid copolymers (EAA) containing different amount of acrylic acid were investigated. The results observed from the sample characterizations evidenced as acrylic acid cause a compatibilizing effect between polyethylene and polyamide components with modifications of blends morphology and mechanical behaviour. These effects are enhanced with increase of the acrylic acid content in the copolymer and they were attributed generally to hydrogen bond interactions among the acrylic acid group and the functional groups…

The effectiveness of Opuntia ficus-indica mucilage edible coating on postharvest maintenance of ‘Dottato’ fig (Ficus carica L.) fruit

2017

Abstract Breba figs are highly perishable and their shelf-life is very short. In this study, breba figs (cv. ‘Dottato’) were treated with a mucilage solution of Opuntia ficus-indica cladodes, sealed in plastic bags, and stored at 4 °C for 14 days. The effect of the edible coating on the shelf-life and qualitative attributes of the fruit were evaluated by colors, content of total soluble solids, titratable acidity, total phenol, total carotenoids. Results showed that coating improves the quality of breba fig during storage. The edible coating was effective in maintaining fruit fresh weight, visual score values, fruit firmness and total carotenoid content. Coated fruit showed a significantly …

Microstructure of ethylene-1-hexene and ethylene-1-octene copolymers obtained over Ziegler–Natta catalysts supported on MgCl 2 (THF) 2

2001

Abstract The ethylene copolymerizations with 1-hexene or 1-octene in the presence of hydrogen using three catalysts, MgCl 2 (THF) 2 /VOCl 3 /Et 2 AlCl, MgCl 2 (THF) 2 /VCl 4 /Et 2 AlCl, MgCl 2 (THF) 2 /TiCl 4 /Et 2 AlCl, were investigated. It was found that the addition of hydrogen into the copolymerization feed reduces the molecular weight of the copolymers produced and decreases the activity of all the studied catalysts. The microstructure of the copolymers obtained was determined on the basis of 13 C NMR investigations and the reactivity ratios of the comonomers were calculated. The lack of tendency of the olefin comonomers to the creation of the polymer block was confirmed. It was found…

Evolution of the optimal catalytic systems for the oxidative dehydrogenation of ethane: The role of adsorption in the catalytic performance

2022

Three samples that correspond to the evolution of optimal catalytic systems for the oxidative dehydrogenation of ethane have been synthesized and compared in terms of catalytic behavior and adsorption properties: (i) vanadium oxide supported on alumina, (ii) Sn-promoted NiO, and (iii) multicomponent MoVTeNbO with the M1 structure. The main difference in catalytic performance lies in the extent of the overoxidation of the ethylene formed, following the order VOx/Al2O3 > NiSnOx > MoVTeNb-M1. Accordingly, the selectivity to ethylene at medium and high ethane conversion follows the order MoVTeNb-M1 > NiSnOx > VOx/Al2O3. These results are confirmed by the relative reaction rates observed for the…

Application of MOOSY32 eNose to Assess the Effects of Some Post Harvest Treatments on the Quality of ‘Salustiana’ Orange Juice

2015

A new prototype of Electronic Nose instrument, Multisensory Odor Olfactory System MOOSY32, with a processing method based on a multivariate classification analysis was used to assess different postharvest and storage treatments effects to Salustiana oranges. The analysis method is based on the measurement of the volatile compounds produced under different environmental and operational conditions. The Electronic Nose system revealed that orange juice flavor changes even when juices are analyzed right after each treatment and fruits are stored under refrigerated conditions. The instrument was able to detect even small changes in the aromatic pattern of the juices, confirming that the packing …

Modification of EVOH copolymers with e-caprolactone: synthesis and compatibilization effects in PE/PVC blends

2001

Polyethylene-polycaprolactone graft copolymers with different chemical structures (i.e. different number and length of PCL grafts and molecular weight of PE backbone) were synthesized from various EVOH copolymers and e-caprolactone, using Aluminum isopropoxide as catalyst, and were tested for their compatibilizing capability in PE/PVC blends. PE and PCL segments in the graft copolymers were found completely immiscible, while PCL segments of the graft copolymers were found completely miscible with PVC. When graft copolymers were added to PE/PVC blends they proved to be good agents for the dispersion of PVC phase in the PE matrix. SEM showed also improved adhesion between the dispersed PVC ph…

Collapsibility of metastable sand by non-conventional oedometer tests

2018

The stability of foundations soils could represent a clear and present threat for the conservation of even well preserved buildings, particularly for Architectural heritage conservation and land art heritage. A dramatic case is the presence of collapsible metastable sands as foundation soils, as it occurs in the sacral complex Valle dei Templi in Agrigento. This site listed by UNESCO, stands on a crest of a calcarenite cuesta, overlaying a layer of these sands. When the collapsible sand is dry, the structure is strong enough to bond the sand particles together. When the sand becomes wet, a de-structuration mechanism occurs and the soil’s strength is compromised. This paper has a twofold aim…

Stereocomplex Formation in Polylactide Multiarm Stars and Comb Copolymers with Linear and Hyperbranched Multifunctional PEG

2013

Multicompartment Micelles with Adjustable Poly(ethylene glycol) Shell for Efficient in Vivo Photodynamic Therapy

2014

We describe the preparation of well-defined multicompartment micelles from polybutadiene-block-poly(1-methyl-2-vinyl pyridinium methyl sulfate)-block-poly(methacrylic acid) (BVqMAA) triblock terpolymers and their use as advanced drug delivery systems for photodynamic therapy (PDT). A porphyrazine derivative was incorporated into the hydrophobic core during self-assembly and served as a model drug and fluorescent probe at the same time. The initial micellar corona is formed by negatively charged PMAA and could be gradually changed to poly(ethylene glycol) (PEG) in a controlled fashion through interpolyelectrolyte complex formation of PMAA with positively charged poly(ethylene glycol)-block-p…