Observations are reported in isothermal torsional oscillation tests on melts of isotactic polypropylene (iPP) and low-density polyethylene (LDPE) in the intervals of temperature between 190 and 250 C (iPP) and between 120 and 190 C (LDPE). With reference to the concept of transient networks, constitutive equations are developed for the viscoelastic response of polymer melts at three-dimensional...

Cross-linked polyethylene (XLPE) is commonly used within high voltage cable insulation. It has improved thermal and mechanical resistance compared to normal low density polyethylene (LDPE). However, the cross-linking process may also vary the electrical characteristics of the material. This paper investigates changes in electrical properties of one type of LDPE before and after cross-linking. T...

In this paper the pendant drop method to measure interfacial tension between molten polymers is reviewed. A typical pendant drop apparatus is presented. The algorithms used to infer interfacial tension from the geometrical profile of the pendant drop are described in details, in particular a new routine to evaluate correctly the value of the radius at the apex of the drop, necessary to the calc...

Sequestering semi-polar compounds can be difficult with low-density polyethylene (LDPE), but those pollutants may be more efficiently absorbed using silicone. In this work, optimized methods for cleaning, infusing reference standards, and polymer extraction are reported along with field comparisons of several silicone materials for polycyclic aromatic hydrocarbons (PAHs) and pesticides. In a fi...

In this work, rheological properties of poly(lactic acid) (PLA), low density polyethylene (LDPE) polymer blends were investigated in the molten state. The experiments were carried on a capillary rheometer. The effect of shear stress, temperature and blending ratio on the flow activation energy at a constant shear stress and melt viscosity of the blends are described. The results showed that the...

The conductivity of high-resistivity polymer films is dependent on the magnitude of applied electric field, repeated electric field exposure, and sample temperature. A traditional constant voltage method was used, maintained under vacuum to more closely resemble the space environment. Both the strength of the applied voltage and the thickness of low-density polyethylene (LDPE) samples were vari...

Today, the economic consumption of biodegradable polymers is of capital importance in many applications. One of the most commonly used biopolymers is polylactic acid (PLA). The printability of the biodegradable film has not been fully investigated. This work tested the printability of polylactic acid (PLA) films and compared the print qualities to common packaging films like low density pol...

We estimate the energy content, the operational energy inputs, and the net energy ratio (NER) of an industrial tubular photobioreactor used for the photosynthetic production of H2 by microalgae. The calculated H2 output of the photobioreactor is based on a range of algal photosynthetic H2 generation efficiencies, and on the application of standard theory for tubular solar collectors. Small diam...

In this study, pyrolysis of low-density polyethylene (LDPE) and LDPE with aluminum (C/LDPE) wastes was carried out different heating rates (5, 10, 20 °C/min) at temperatures (400, 600, 800 °C). Product yields C/LDPE were compared, optimum liquid products analyzed to utilize as commercial waxes for future use. The properties pyrolyzed investigated proximate, elemental analysis, TGA. as-produced ...

The by-products of dicumyl peroxide (DCP) from the crosslinking process such as acetophenone, cumyl alcohol and α-methylstyrene are said to be the sources of space charge formation in XLPE cable due to deep traps in the chemicals. However, by using space-chargeexperimental approach, it appeared that these chemicals show a different trapping nature. This paper is intended to present this approac...