Virgin high-density polyethylene

ADH08] Adhkary K.B., Pang S., Staiger M.P., Dimensional stability and mechanical behaviour of wood-plastic composites based on recycled and virgin high-density polyethylene (HOPE) , Composites B, vol. 39, pp. 807-815,2008. 

In 2000, approximately 15,602 million pounds of virgin high-density polyethylene (HOPE) resin were used in the United States and Canada [3]. Packaging film and containers accounted for a major fraction of this use, over 38% if grocery sacks and merchandise bags are included as packaging (Fig. 4.6). 

Initially, the recyclability of virgin high-density polyethylene (HDPE) was assessed, on a labouratory-scale, by processing, regrinding, and reprocessing for 15 cycles, with property assessment after each cycle. 

Figure 9.7 Cycles to failure versus deflection in flexure at 23°C for recycled and virgin high-density polyethylene [2].

As an example of another form, co-extruded blow mouldings have been introduced to the market as containers for liquid detergents. The process used is known as sandwich blow moulding and provides a means by which recycled high density polyethylene can be incorporated again into a useful form by being employed between two layers of virgin material. 

N.K. Madi, Thermal and mechanical properties of injection molded recycled high density polyethylene blends with virgin isotactic polypropylene. Mater. Des. 46, 435-441 (2013)... 

S. Satapaihy, G.B. Nando, A. Nag, Dynamic mechanical analysis of electron beam irradiated waste polyethylene and its blends with virgin high density and low density polyethylene. 

Post-consumer waste consists of six major polymers polystyrene (PS), low density polyethylene (LDPE), high density polyethylene (HOPE), polypropylene (PP), polyvinyl chloride (PVC) and polyethylene terephthalate (PET). These polymers are incompatible and form separate phases on mixing. Fabricated products made directly from comingled plastics have poor physical properties, and can compete only with treated lumber at a price of roughly 20% of that for the virgin plastics. When freed of hidden and actual subsidies, this form of recycling is believed to have a negative economic value. 

A laser flash technique has been used to determine the diffusivity of pyroelectric polymers such as polyvinylidene fluoride [83], whereas hot-wire techniques have been used to determine the thermal diffusivity of high-density polyethylene, low-density polyethylene propylene, and polystyrene [83], Dos Santos and coworkers [84] utilized the laser flash technique to study the effect of recycling on the thermal properties of selected polymers. Thermal diffusivity expresses how fast heat propagates across a bulk material, and thermal conductivity determines the woiking temperature levels of a material. Hence, it is possible to assert that those properties are important if a polymer is used as an insulator, and also if it is used in applications in which heat transfer is desirable. Five sets of virgin and recycled commercial polymers widely used in many applications (including food wrapping) were selected for this study. 

Cruz and Zanin [25] determined the dielectric strength of virgin and up to 10% recycled high-density polyethylene. The introduction of recycled polymer reduced dielectric strength by up to 17% due to metallic impurities in the recycled polymer. 

A limited number of LCA studies have been conducted on composite polymer materials, more precisely with polyester, high-density polyethylene (RDPE) " and polypropylene (PP). The latter two polymers were tested virgin or recycled form. 

Lu N, Oza S. A comparative study of the mechanical properties of hemp fiber with virgin and recycled high density polyethylene matrix. Compos Part B 2013 45 (1) 1651-1656. 

Plastic Film, Polyester, Polyethylene Coated (For I.D. Cards) Plastic Tubes and Tubing, Heavy Wall, Teflon TFE Resin Thermoset Epoxy Resin Sheet, Paper Reinforced Insulation Tape, Electrical, Pressure Sensitive, Telfon TFE Resin Plastic Material for Molding and Extrusion, High Density Polyethylene and Copolymers Insulation Sleeving, Electrical, Flexible, Heat-Shrinkable Film Tape, Pressure Sensitive Plastic Sheets, Virgin and Borated Polyethylene Insulation Tape, Electrical, High Temperature, Teflon, Pressure Sensitive... 

A study was made of the effects of addition of recycled polypropylene on the incompatible blends of virgin polypropylene with high-density polyethylene. The characteristics of the recycled polypropylene were determined by spectrographic and thermal analysis means. The mechanical properties of the blends were determined. The 50/50 blend of the two virgin polymers benefited most from the addition of the recycled polypropylene. 9 refs. BRAZIL USA... 

J. Joshi, Lehman, R., Nosker, T., "Selected physical characteristics of polystyrene/high density polyethylene composites prepared from virgin and recycled materials," J. Appl Polym Sci 99, 2044-2051 (2005). 

VPVC-virgin polyvinyl chloride, WP+HDPE-wallpaper with high density polyethylene, WP- wallpaper only, WP+PVC-wallpaper with PVC. 

RBS has been widely used to study the concentration profiles of metals in polymers, often deposited during implantation processes. Implantation is often carried out to modify the surface properties of a polymer such as wear resistance, but can also be used to modify the ability of a polymer to trap metal ions. This process was demonstrated for polyethylene, which was irradiated with fluorine or arsenic ions at 150 keV. When these materials were exposed to lead acetate solutions, implantation was found to alter dramatically the diffusion of lead into the polymer. The high mass of lead makes it easy to measure as it diffuses into polymers. These experiments showed Fickian diffusion of lead into virgin polyethylene, but for heavily implanted polyethylene somewhat lower diffusion coefSdents were obtained, possibly because of the increased density of highly iuadiated samples. However, at relatively low implantation doses of fluorine or arsenic (< lO cm ), it appeared that lead ions were trapped in a concentration profile defined by the energy deposition profile of the implanted species. 

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