Search results for " density polyethylene"
showing 6 items of 6 documents
Sun radiation and temperature impact at different periods of the year on the photooxidation of polyethylene films
2017
Analysis of the IR spectra of weathered films exposed at different periods of the year reveals that, the main regions of the IR spectrum affected by solar irradiation and temperature variation are the complex carbonyls and unsaturations composite absorption bands. Their respective kinetics vary in different manner according to the period at which the exposure is started. Curve fitting has been performed to refine the analysis of the IR spectra and to identify all the chemical species constituting the complex absorption bands. The analysis of the results let appears that whatever the exposure period of the year is, it does not affect the type of developing products, but it has strong effect …
The antioxidant effect in controlling thermal degradation of a LDPE blow film
2004
It is well known that antioxidants are widely used to prevent thermal degradation of high density and linear low density polyethylene. Antioxidants are not always present in low density polyethylene and only small amounts are usually added to these resins. In this work the effect of an antioxidant system on a low density resin having MFI (190 °C/2.16 kg)=2 g/10′ and density 0.9230 g/cm3 has been studied. Its effect on melt viscosity has been studied by means of a batch mixer and the torque vs time behaviour has been analysed. The results show that a maximum in the torque vs time curve can be seen for the material containing antioxidant. In contrast, the material without antioxidant does not…
Effect of the additive level and of the processing temperature on the re-building of post consumer pipes from polyethylene blends
2007
Abstract One of the main shortcomings of the mechanical recycling is that the properties of the secondary materials are generally sensibly inferior with respect to the virgin ones. This feature implies, for sure, that they cannot be used for the same technological application but also other uses of the secondary material are impossible. The aim of this work is to study the re-building of recycled post-consumer pipes, made of a blend of different polyethylenes, by re-processing in the presence of a nitroxyl compound as radical generator. The processing temperature and the additive concentration have been varied in order to study the effect of these parameters on the final properties. The mec…
Morphology and mechanical properties of extruded ribbons of LDPE/PA6 blends compatibilized with an ethylene-acrylic acid copolymer
2003
Two grades of low density polyethylene (LDPE) were blended with polyamide-6 (PA) in the 75/25 and 25/75 wt/wt ratios and shaped into ribbons with a Brabender single screw extruder. An ethylene-acrylic acid copolymer (EAA) was used in the 2 phr concentration as a compatibilizer precursor (CP). The morphology of the ribbons and its evolution during high temperature annealing were investigated by scanning electron microscopy (SEM). The results confirmed that EAA does actually behave as a reactive compatibilizer for the LDPE/PA blends. In fact, in the presence of EAA, the interfacial adhesion is improved, the dispersion of the minor phase particles is enhanced and their tendency toward fibrilla…
One-step reactive processing of low density polyethylene and octavinyl polyhedral oligomeric silsesquioxane
2015
Polyhedral oligomeric silsesquioxane (POSS) are an innovative class of organosilicon compounds suitable for formulation of advanced organic-inorganic hybrid materials. Nanocomposites based POSS found application mostly in high-temperature resistance and fire-resistance materials. POSS are characterized by a three dimensional cage-like structure, made of Si-O bonds, with different organic groups directly linked to the Si atoms of the cage structure. The organic groups can be designed to facilitate the dispersion of the nanoparticle itself in the polymer matrix or also to react with the polymer chain. This work focuses on the possibility to obtain crosslinking of polyethylene using octavinyl-…
Durability of a strach-based biodegradable polymer
2007
Abstract The photo-oxidation and the photo-stabilization of a commercial biodegradable polymer have been investigated in order to establish the possibility of using this polymer as raw material for films for agriculture. The degradation has been followed by measuring the mechanical properties as a function of photo-oxidation time and in particular by following the elongation at break. The virgin polymer, made from maize starch and a synthetic biodegradable polyester, shows poor resistance to the UV irradiation as observed by the fast decay of the elongation at break, but the presence of small amounts of conventional UV stabilizers strongly improves the durability of this polymer. The UV sta…