Search results for "density polyethylene"

Study of thermal properties of polyethylene and polypropylene nanocomposites with long alkyl chain-substituted POSS fillers

2016

The effect of incorporation of octakis({alkyl}dimethylsiloxy)octasilsesquioxanes molecules with n-octyl, n-octadecyl and 4-methyl-hexyl substituents on thermal properties of polypropylene (PP), low-density polyethylene (LDPE) and high-density polyethylene (HDPE) was investigated. Thermal properties of those composite materials were evaluated by means of the differential scanning calorimetry (DSC) and thermogravimetric analysis (TG) methods. The type and mass% content of POSS nanofillers influenced the crystallization and melting properties as well as thermal stability of the obtained polyolefin nanocomposites. The incorporated POSS particles—acting as nucleating agents—improved the crystall…

Effectiveness of organoclays as compatibilizers for multiphase polymer blends - A sustainable route for the mechanical recycling of co-mingled plasti…

2014

We prepare and characterize multiphase systems in which small amounts of recycled polymer, namely polyethylene terephtalate (PET) ground from waste bottles, are dispersed in a co-continuous blend of high-density polyethylene (HDPE) and polypropylene (PP). Some of such ternary systems are also filled with plate-like clay nanoparticles with different polarities, in order to assess their influence on the morphology and mechanical behaviour of the blends. On the basis of preliminary wettability considerations and inspections by means of scanning electron microscopy (SEM), the PET is found to preferentially locate within the PP phase. Such a positioning is desirable in order to minimize the pres…

Heat shrinkable behavior, physico-mechanical and structure properties of electron beam cross-linked blends of high-density polyethylene with acryloni…

2016

Abstract In this study, heat-shrinkable composites of electron beam irradiated high-density polyethylene (HDPE) composites with acrylonitrile-butadiene rubber (NBR) were investigated. HDPE/NBR blends at a ratio of components 100/0, 90/10, 80/20, 50/50 and 20/80 wt% were prepared using a two-roll mill. The compression molded films were irradiated high-energy (5 MeV) accelerated electrons up to irradiation absorbed doses of 100–300 kGy. The effect of electron beam induced cross-linking was evaluated by the changes of mechanical properties, gel content and by the differences of thermal properties, detected by differential scanning calorimetry. The thermo-shrinkage forces were determined as the…

Influence of the e-beam irradiation and photo-oxidation aging on the structure and properties of LDPE-OMMT nanocomposite films

2012

Abstract In this paper two systems, polyethylene (LDPE) and polyethylene/commercial organo-modified montmorillonite (LDPE/OMMT) nanocomposite, were subjected to e-beam irradiation at different doses and both the molecular modifications and mechanical properties have been investigated through solubility, FT-IR, calorimetric and tensile tests. Moreover, in some of the irradiated systems photo-oxidation aging was performed and its effects were studied. The results show an enhancement with irradiation of the positive effect of the nano-filler loading, related to the increase of the mechanical properties, due to the increase of the nano-filler polymer interaction. Nevertheless calorimetric and F…

SHEAR BEHAVIOUR OF MOLTEN LINEAR LOW DENSITY POLYETHYLENE.

1984

The rheological behaviour of molten polyethylene has been widely studied especially with respect to the different structure of the high density and low density samplesI–I0. In particular it is well known that the presence in the LDPE of long chain branching alters dramatically the whole flow curve, the activation energy, the die-swell, the instability phenomena, etc.

1990

The countercurrent extraction method recently developed for the continuous polymer fractionation (CPF) was applied to linear polyethylene (Mw = 55 kg/mol; Mn = 16,7 kg/mol). At temperatures higher than 130°C, moderately concentrated solution of polyethylene were extracted to remove the low-molecular-weight components. Discontinuous fractionation experiments served to detect the best suited solvents. Diphenyl ether was chosen to demonstrate that the present extraction can be performed even with the same single solvent used to prepare the feed. For very high-molecular-weight polymers, mixed solvents are, however, normally better than single ones, since they allow an easier tailoring of thermo…

Combined SANS and SAXS experiments in polyolefins-hydrogenated oligocyclopentadiene (HOCP) blends

1998

Abstract Lamellar morphology in semicrystyalline polymer blends (iPP/HOCP and HDPE/HOCP) is investigated by means of Small Angle X-ray Scattering (SAXS) and Small Angle Neutron Scattering (SANS). The investigated blends present a complex phase diagram, as they show a miscibility gap. SAXS scattering curves of blends lying outside the miscibility gap can be analysed in the frame of the psuedo two phase model. In order to describe the complex morphology of blends lying inside the miscibility gap, the SANS technique revealed necessary. In this paper a novel method to describe the morphology of these complex systems by means of SANS is presented.

Influence of a sterically hindered amine on the photo-oxidation of low density/linear low density polyethylene blends

1990

Abstract Low density/linear low density polyethylene blends show a rate of degradation of the mechanical properties during photo-oxidation which increases with the content of the linear polymer. The use of a sterically hindered amine as UV stabilizer greatly improves the resistance of these blends to UV irradiation. The effectiveness of the stabilizer increases with the content of linear low density polyethylene.

Dielectric and dynamic-mechanical behaviour of ethylene-vinyl alcohol copolymers

1983

Abstract Dynamic-mechanical and dielectric measurements on ethylene-vinyl alcohol copolymers with two different vinyl alcohol contents and, for comparison on polyvinylalcohol and low density polyethylene, have been carried out in order to clarify the nature of the relaxation peak. The relaxation peak observable in the dielectric loss curves of the copolymers has been assigned to the interfacial polarization, MWS type, occurring between hydrogen bonded hydroxyl groups and the apolar polyethylene segments. The shoulder also present in the e″-T curves of the copolymers seems to correspond to the glass transition peak which is hidden since the dielectric loss curve increases quickly because of …

Extensional flow of HDPE/LDPE blends

1982

Elongational viscosity data, obtained through the converging flow analysis by Cogswell, are presented for two types of HDPE/LDPE blends at various compositions and different temperatures. The results relative to the homopolymer parents compare favourably with literature data obtained also with different and more sophisticated techniques. Those relative to blends show peculiar features for the two cases: when the newtonian viscosity of the LDPE is higher all the blends show a behaviour typical of the LDPE with a maximum in η el /η0 enhanced at small percentage of HDPE; when the newtonian viscosity of the LDPE is similar to that of the HDPE there is only a gradual change in the properties.