Virgin Polyethylene Research Articles

Fuel properties of the oils produced from the pyrolysis of commonly-used polymers: Effect of fractionating column

The effects of using a packed column as a fractionating system on thermal degradation of commonly-used polymers have been studied. The polymers investigated were virgin polyethylene (LDPE and HDPE), polypropylene (PP), and polystyrene (PS), as well as two post-consumer polymer mixtures, namely municipal plastic waste (MPW) and scrap tire. The experiments were carried out under atmospheric pressure in a 6L semi-batch stainless steel vessel equipped with the fractionating system. The system led to total elimination of wax formation, color improvement, and reduction in the density of the resultant pyrolysis oils. The oils were analyzed according to ASTM D86, the standard test method for boiling range distribution of petroleum fractions. The obtained values were compared to the Iran standard limits established for diesel (ISIRI4903) and gasoline (ISIRI4904). Furthermore, Fourier transform infrared spectroscopy (FT-IR) was utilized to determine the chemical composition of the oils. Finally, the spectra of the generated tire and MPW-derived oils were compared with the spectra of conventional fuels, gasoline and diesel.

Biodegradation of HDPE by Aspergillus spp. from marine ecosystem of Gulf of Mannar, India

High density polyethylene (HDPE) is the most commonly found non-degradable solid waste among the polyethylene. In this present study, HDPE degrading various fungal strains were isolated from the polyethylene waste dumped marine coastal area and screened under in vitro condition. Based on weight loss and FT-IR Spectrophotometric analysis, two fungal strains designated as VRKPT1 and VRKPT2 were found to be efficient in HDPE degradation. Through the sequence analysis of ITS region homology, the isolated fungi were identified as Aspergillus tubingensis VRKPT1 and Aspergillus flavus VRKPT2. The biofilm formation observed under epifluorescent microscope had shown the viability of fungal strains even after one month of incubation. The biodegradation of HDPE film nature was further investigated through SEM analysis. HDPE poses severe environmental threats and hence the ability of fungal isolates was proved to utilize virgin polyethylene as the carbon source without any pre-treatment and pro-oxidant additives.

The Effects of Partial Replacement of Virgin Polyethylene (vPE) with Recycled Polyethylene (rPE) in vPE/rPE/Ethylene Propylene Diene Terpolymer (EPDM) Blends: Thermal Properties and Swelling Behaviour

Studies on the thermoplastic elastomers (TPEs) had been extensively done. The incorporation of recycled materials into the TPEs formulation had been analysed, particularly involving recycled plastic due to its properties. The effects of partial replacement of virgin polyethylene (vPE) with recycled polyethylene (rPE) on the thermal properties and swelling behaviour of vPE/rPE/EPDM blends were studied. The discarded polyethylene used in the study was obtained from local wire insulation industry. The thermal properties and swelling behaviour of the blends were analyzed. Results show that increasing of sulfur loading had improved the thermal stability of the blends. The swelling percentage and swelling index of vPE/rPE/EPDM blends also decreased, inversely proportional to the increasing of sulfur loading. Thus, the increased incorporation of sulfur loading had improved the chemical and oil resistance of the blends.

Production and Evaluation of Liquid Hydrocarbon Fuel from Thermal Pyrolysis of Virgin Polyethylene Plastics

Pyrolysis of virgin polyethylene plastics was studied in order to produce hydrocarbon liquid fuel. The pyrolysis process carried out for low and high-density polyethylene plastics in open system batch reactor in temperature range of 370 to 450°C.
 Thermo-gravimetric analysis of the virgin plastics showed that the degradation ranges were between 326 and 495 °C. The results showed that the optimum temperature range of pyrolysis of polyethylene plastics that gives highest liquid yield (with specific gravity between 0.7844 and 0.7865) was 390 to 410 °C with reaction time of about 35 minutes. Fourier Transform Infrared spectroscopy gave a quite evidence that the produced hydrocarbon liquid fuel consisted mainly alkanes and the x-ray diffraction showed no sulfur in the produced hydrocarbon liquids.

Monitoring the degradation of partly decomposable plastic foils

Abstract We have monitored the behaviour of different polyethylene foils including virgin medium density polyethylene (MDPE), MDPE containing pro-oxydative additives (238, 242) and MDPE with pro-oxydative additives and thermoplastic starch (297) in the soil for a period of one year. A foil based on a blend of polyester and polylactic acid (BASF Ecovio) served as degradable control. The experiment was carried out by weekly measurements of conductivity and capacity of the soil, since the setup was analogous to a condenser, of which the insulating layer was the foil itself. The twelve replications allowed monthly sampling; the specimen taken out from the soil each month were tested visually for thickness, mechanical properties, morphological and structural changes, and molecular mass. Based on the obtained capacity values, we found that among the polyethylene foils, the one that contained thermoplastic starch extenuated the most. This foil had the greatest decrease in tensile strength and elongation at break due to the presence of thermoplastic starch. The starch can completely degrade in the soil; thus, the foil had cracks and pores. The polyethylene foils that contained pro-oxydant additives showed smaller external change compared to the virgin foil, since there was no available UV radiation and oxygen for their degradation. The smallest change occurred in the virgin polyethylene foil. Among the five examined samples, the commercially available BASF foil showed the largest extenuation and external change, and it deteriorated the most in the soil.

Evaluation of the Terms of Use of Recycled Polymer Packaging Co-Extruded

Waste recycling has been stepped up around the world to enhance the quality of the recycled product and provide greater efficiency in the production system. The increasing use of polymers has led to increasingly multiple uses of these materials due to their high degradation time. The polyethylene used in plastic co-extruded with the use of ethylene vinyl alcohol (EVOH) has been a major advantage in prolonging the useful cycle of the final product. Thus the technique of co-extrusion has become very attractive in the packaging industry because it enables the design of multi-layer structures. Thus, this work aims at assessing the conditions of use of recycled material in packaging for co-extruded with application properties of a biomaterial. The packages used in this study are composed percentages of high density polyethylene (HDPE) recycled, virgin polyethylene and gas barrier (EVOH), where they were subjected to 50 ° C in an oven stabilized at room temperature as well as the approximately 23 ° C, conditioned in the laboratory. The packages were characterized by spectroscopy techniques in the Region of Fourier Transform Infrared (FTIR), Surface Tension and optical microscopy (OM). With the technique, FTIR was possible to verify the presence of characteristic bands of polyethylene. As for the measures surface tension was possible to observe an increase in the wettability of containers subjected to high temperature. It was also possible to see through the optical microscope the difference of packaging is compounded by the EVOH. The results presented so far do not suggest an indication of the occurrence of rust on packaging, allowing an indication of use.

Diffusion of phenolic compounds through polyethylene films

ABSTRACT: This paper presents experimental results of the diffusion of phenolic compounds through virgin and aged polyethylene (PE) films. The study considers five chlorophenols contaminants (4-chlorophenol, 2,4-dichlorophenol, 2,4,6-tricholophenol, 2,3,5,6-tetrachlorophenol, and pentachlorophenol) that are known to be toxic even at very low concentrations. The concentration dynamics in the source and receptor chambers of the diffusion cells is interpreted using the numerical code Pollute. For virgin PE film, partition coefficients ranged from 0.68 to 278, which corresponded to 4-chlorophenol and pentachlorophenol, respectively. Diffusion coefficients ranged from 1.0 × 10−14 to 2.7 × 10−13 m2/s, which corresponded to pentachlorophenol and 2,4-dichlorophenol, respectively. The study also looked at how the partition and diffusion coefficients were affected by the aqueous solubility, n-octanol–water partition coefficient, molecular diameter, and molecular weight. The trends observed in this study are similar to those found for diffusion of phenolic compounds through PE geomembranes. The results also revealed trends that differ from those previously reported for diffusion of volatile organic compounds (VOCs) through geomembranes. The existing empirical relationships for VOCs are not applicable except for calculating how the diffusion coefficient evolves as a function of solubility in water. Increasing the number of chlorine atoms on the phenolic nucleus causes an increase in the partition coefficient, which is tentatively attributed to the polarity of the molecules under study.

Characterization of LDPE Reinforced with Calcium Carbonate—Fly Ash Hybrid Filler

The synergetic effect of calcium carbonate (CC)-fly ash (FA) hybrid filler particles on the mechanical and physical properties of low density polyethylene (LDPE) has been investigated. Low density polyethylene is filled with varying weight percentages of FA and CC using melt casting. Composites are characterized for mechanical, thermal, microstructural and physical properties. Results show that the flexural strength increases with increases in FA content of the hybrid filler. It is evident from the study that to achieve optimum density a certain combination of both fillers need to be used. The optimum combination of CC and FA for a higher density (1.78 g/cm3) is found to be at 20 wt% FA and 30 wt% CC. An increase of 7.27% in micro-hardness over virgin polyethylene is obtained in composites with 10 wt% FA and 40 wt% CC. The presence of higher amount of CC is seen to be detrimental to the crystallinity of composites. X-ray, FTIR and DSC results show that composite with 45 wt% CC and 5 wt% FA exhibits a typical triclinic polyethylene structure indicating that the composite is amorphous in nature. There was the synergy between FA and CC fillers on flexural strength and crystallinity of composite. However, the fillers show the antagonistic effect on energy at peak and micro-hardness.

The Influence of CB, Silica and CaCO<sub>3</sub> on Tensile and Morphological Properties of vPE/rPE/EPDM Blends

The virgin polyethylene (vPE) and recycled polyethylene (rPE) was melt blended with ethylene propylene diene terpolymer (EPDM) in different ratio by using a Haake Rheomix at 180°C and 50 rpm were prepared. The characterization such as tensile properties and morphology were examined. Results indicated that, the tensile strength and youngs modulus of vPE/rPE/EPDM with CB show the highest value compared to silica and CaCO3 except for elongation at break. The scanning electron microscopy (SEM) studies proved that, better dispersion and less agglomeration of CB and silica filled particles as compared to the CaCO3.

Ingested plastic transfers hazardous chemicals to fish and induces hepatic stress

Plastic debris litters aquatic habitats globally, the majority of which is microscopic (< 1 mm), and is ingested by a large range of species. Risks associated with such small fragments come from the material itself and from chemical pollutants that sorb to it from surrounding water. Hazards associated with the complex mixture of plastic and accumulated pollutants are largely unknown. Here, we show that fish, exposed to a mixture of polyethylene with chemical pollutants sorbed from the marine environment, bioaccumulate these chemical pollutants and suffer liver toxicity and pathology. Fish fed virgin polyethylene fragments also show signs of stress, although less severe than fish fed marine polyethylene fragments. We provide baseline information regarding the bioaccumulation of chemicals and associated health effects from plastic ingestion in fish and demonstrate that future assessments should consider the complex mixture of the plastic material and their associated chemical pollutants.

The Influence of CB, Silica and CaCO&lt;sub&gt;3&lt;/sub&gt; on Tensile and Morphological Properties of vPE/rPE/EPDM Blends

The virgin polyethylene (vPE) and recycled polyethylene (rPE) was melt blended with ethylene propylene diene terpolymer (EPDM) in different ratio by using a Haake Rheomix at 180°C and 50 rpm were prepared. The characterization such as tensile properties and morphology were examined. Results indicated that, the tensile strength and youngs modulus of vPE/rPE/EPDM with CB show the highest value compared to silica and CaCO3 except for elongation at break. The scanning electron microscopy (SEM) studies proved that, better dispersion and less agglomeration of CB and silica filled particles as compared to the CaCO3.

탄소섬유를 이용한 Polyethylene배관의 전기융착 기술

Fuel gas is an important energy source that is being increasingly used because of the convenience and clean energy provided. Natural gas is supplied to consumers safely through an underground gas-pipe network made of a polyethylene material. In electrofusion, which is one of the joining methods used, copper wire is used as the heating wire. However, it takes a long time for fusion to occur because the electrical resistance of copper is low. In this study, therefore, electrofusion was conducted by replacing the copper heating wire with carbon fiber to reduce the fusion time and improve the production when joining large pipes. Fusion and tensile tests were performed after the electrofusion joint was made in the polyethylene pipe using carbon fiber. The results showed that the fusion time was shorter and the temperature inside the pipe was higher with an increase in the current value. The ultimate tensile strength of specimens was higher than that of virgin polyethylene pipe, except for polyethylene pipes joined using a current of 0.8 A. The best fusion current value was 0.9 or 1.0 A because of the short fusion time and lack of transformation inside the pipe. Thus, it was shown that carbon fiber can be used to replace the copper heating wire.

Biodegradation of Low-Density Polyethylene (LDPE) by Mixed Culture of Lysinibacillus xylanilyticus and Aspergillus niger in Soil

In this study, two strains of Aspergillus sp. and Lysinibacillus sp. with remarkable abilities to degrade low-density polyethylene (LDPE) were isolated from landfill soils in Tehran using enrichment culture and screening procedures. The biodegradation process was performed for 126 days in soil using UV- and non-UV-irradiated pure LDPE films without pro-oxidant additives in the presence and absence of mixed cultures of selected microorganisms. The process was monitored by measuring the microbial population, the biomass carbon, pH and respiration in the soil, and the mechanical properties of the films. The carbon dioxide measurements in the soil showed that the biodegradation in the un-inoculated treatments were slow and were about 7.6% and 8.6% of the mineralisation measured for the non-UV-irradiated and UV-irradiated LDPE, respectively, after 126 days. In contrast, in the presence of the selected microorganisms, biodegradation was much more efficient and the percentages of biodegradation were 29.5% and 15.8% for the UV-irradiated and non-UV-irradiated films, respectively. The percentage decrease in the carbonyl index was higher for the UV-irradiated LDPE when the biodegradation was performed in soil inoculated with the selected microorganisms. The percentage elongation of the films decreased during the biodegradation process. The Fourier transform infra-red (FT-IR), x-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to determine structural, morphological and surface changes on polyethylene. These analyses showed that the selected microorganisms could modify and colonise both types of polyethylene. This study also confirmed the ability of these isolates to utilise virgin polyethylene without pro-oxidant additives and oxidation pretreatment, as the carbon source.

The Effects of Carbon Black, Silica and Calcium Carbonate in Virgin PE/Recycle PE/EPDM Blends: Thermal Properties &amp; Swelling Analysis

The effects of carbon black (CB), silica and calcium carbonate (CaCO3) in virgin polyethylene (vPE)/recycle polyethylene (rPE)/ethylene propylene diene terpolymer (EPDM) blends were investigated. rPE was melt blended with EPDM in different ratio by using a Haake Rheomix. The characterization such as swelling analysis and thermal properties were examined. Results indicated that, vPE/rPE/EPDM blend with CB show best oil (ASTM IRM 903) and toluene resistant and also thermal properties compared with silica and CaCO3.

The Effects of Dynamic Vulcanization in Virgin Polyethylene (vPE)/Recycled Polyethylene (rPE)/Ethylene Propylene Diene Terpolymer (EPDM) Blends: Thermal Properties and Swelling Behaviour

The effects of dynamic vulcanization on the thermal properties and swelling behaviour of vPE/rPE/EPDM blends were studied. The discarded polyethylene used in the study was obtained from local wire insulation industry. The thermal properties and swelling behaviour of the blends were analyzed. Results show that increasing of sulfur loading had improved the thermal stability of the blends. The swelling percentage and swelling index of vPE/rPE/EPDM blends also decreased, inversely proportional to the increasing of sulfur loading. Thus, the increased incorporation of sulfur loading had improved the chemical and oil resistance of the blends.

Eroded plastic pellets as monitoring tools for polycyclic aromatic hydrocarbons (PAH): laboratory and field studies

Through transportation accidents or intentional releases, plastic pellets (small granules 1-5 mm in diameter) are widely distributed in the ocean all over the world. These pellets accumulate organic pollutants and can be used for the determination of diffusive seawater pollution. Pellets demonstrating a certain degree of erosion are expected to have enough contact time with the water pollutants and thus, reach sorption equilibrium with the water phase. In the present study, eroded pellets collected from Greek beaches, were separated into polyethylene (PE) and polypropylene (PP). Polycyclic aromatic hydrocarbons (PAHs, i.e. naphthalene, phenanthrene, and pyrene) were used as model compounds to study the uptake kinetics into these eroded pellets. Naphthalene uptake demonstrates similar kinetics in both eroded PE and PP. Phenanthrene and pyrene uptake demonstrates slower kinetic rates by eroded PE than by virgin PE and similar kinetic rates by eroded and virgin PP. These observations are then used to evaluate PAHs measurements in pellets sampled from two sampling sites in Saronikos Gulf. It is concluded that seawater in Loutropyrgos beach is polluted by PAHs more than seawater in Aegena island. PAH pollution in both sampling sites is of pyrogenic origin.

Surface properties of beached plastic pellets

The presence of pollutants on plastic debris is an emerging environmental hot topic. Understanding the surface alteration of plastics while in the marine environment increases our understanding of the pollutant–plastic debris interaction. Plastic pellets are widely distributed throughout the world oceans. Eroded and virgin polyethylene (PE) and polypropylene (PP) pellets were studied for their surface properties to better understand the interaction between plastic and compounds in marine environment. Surface properties such as point of zero charge, surface area and pore volume, surface topography, functional groups and acid–base behavior are important factors which affect sorption. Virgin plastic pellets had homogeneous smooth surfaces that do not have any acid–base behavior. Eroded PE demonstrates an altered surface that at seawater pH acquires a negative charge due to ketone groups. The uneven surface and possible functional groups could have been formed from the erosion processes while floating at the sea surface and might explain the interaction of eroded plastics with microbes and metals.

Weathering Effect on Virgin Polyethylene and Polyethylene Coated with Polyamide/Nanosilica Composite Coating

Weathering Effect on Virgin Polyethylene and Polyethylene Coated with Polyamide/Nanosilica Composite Coating

Free radical graft modification of polyethylene with methacrylic acid and styrene monomer

Polar groups can be introduced on polyethylene by using polar monomer like acryl amide, acrylic acid and methacrylic acid. In present work binary monomer mixture of methacrylic acid and styrene were grafted onto low density polyethylene in the presence of dicumyl peroxide (DCP) as an initiator. Grafted polyethylene was characterized by using differential scanning calorimetry (DSC), melt flow Indexer (MFI) and Fourier transform infrared spectroscope (FTIR). Low value of MFI as compared to virgin polyethylene, presence of carbonyl peaks in the spectrum of grafted polyethylene and higher endothermic peaks in thermogram of grafted polyethylene confirmed grafting of methacrylic acid and styrene onto polyethylene. MFI values at different loads were used for further rheological study of virgin & grafted polyethylene. Key words: Degree of grafting, Meth acrylic acid, Free radical, Vinyl monomer, DCP DOI: http://dx.doi.org/10.3329/cerb.v15i1.7419 Chemical Engineering Research Bulletin 15 (2011) 34-38

The effect of cross-shear on the wear of virgin and highly-crosslinked polyethylene

Abstract The phenomenon of orientation softening suggests that during multi-directional motion the principal direction experiences hardening due to molecular orientation, while the secondary direction experiences softening. Multi-directional motion occurs during gait for both hips and knees, and its effect on the wear of ultra-high molecular weight polyethylene (UHMWPE) is still not fully understood. The purpose of this study was to evaluate the phenomenon of orientation softening using a highly crosslinked polyethylene (HXPE). Both virgin polyethylene and HXPE pins were articulated against cobalt-chromium discs using an OrthoPod™ wear tester. Six different motion paths were used, ranging from a square pattern to a linear track. Gravimetric weight measurements were periodically collected and scanning electron micrographs were taken after the completion of each motion path. The results show the motion path has a significant effect on the wear rate of virgin polyethylene, but no significant effect on the wear of HXPE.