High Density Polyethylene Containers Research Articles

Bioremediation of leachate from a green waste composting facility using waste-derived filter media

The evaluation of two waste-derived materials used to treat compost leachate by biofiltration is described in this paper. Nine biofilters were constructed using 240l, high density polyethylene containers. Three containers were filled without compaction with 200l of each of three types of filter media. Waste-derived filter media (compost and oversize) were compared to a mineral control (granite chips). The filters were fed with compost leachate from a typical green waste composting facility at hydraulic loading rates ranging from 0.05m3/m3/day to 0.5m3/m3/day over a period of twelve months. The oversize medium emerged as the most effective demonstrating characteristics of consistency of effluent quality and resilience to stress. The oversize medium produced an effluent of <10mg/l ammoniacal nitrogen on >95% of sampling occasions. The organic component of compost leachate was dominated by compounds that proved to be recalcitrant to biodegradation. The solids content of the treated effluent remained too high to be acceptable for direct discharge to a watercourse without further treatment and if discharge to a watercourse is to be considered, a polishing stage (e.g., reed bed) able to remove solids and dampen occasional peaks of ammoniacal nitrogen should be employed.

Composition and Characteristics of Excavated Materials from a New Jersey Landfill

The composition of material excavated from the Burlington County landfill in New Jersey was determined, and the major reclaimed fractions characterized. Based on a waste age map, 98 samples (80kg each) collected from 13 gas extraction well borings were handsorted into 14 fractions and fines (<2.54cm) that fell through the screen were collected. At least 50%, by weight, of the material was fines. The most abundant oversize materials (overs) fractions, by weight, were miscellaneous items, wood, other plastics [not polyethylene terephthalate or high density polyethylene containers], and paper. Less paper was found in the oldest (7.5–11.5years) section of the landfill (P<0.10), most likely due to microbial degradation. Several of the characteristics of the materials excavated from the landfill, such as temperature, particle size, bulk density, volatile solids, and contamination were correlated with the age of the deposits made. High levels of adherent soil will likely prove to be an insurmountable obstacle to recycling most excavated waste fractions other than fines unless further processing is pursued.

Identification of 8-Nonenal as an Important Contributor to “Plastic” Off-Odor in Polyethylene Packaging

Food and beverage products stored in polyethylene (PE) containers may absorb some of PE's volatile minor components and become tainted by its characteristic "plastic" odor. High-density PE containers that had imparted "plastic" odor to an experimental corn chip product were analyzed by simultaneous distillation/extraction to remove the volatile components, by gas chromatography/olfactometry (GC/O) to locate the offending components and by 2-D GC/mass spectrometry (MS) to identify the major "plastic" odor contributor (8-nonenal). The identification was made using high-resolution electron ionization and chemical ionization MS data to narrow the possibilities to two isomers of nonenal, followed by retrieval of reference spectra and confirmatory synthesis. By monitoring 8-nonenal in HDPE containers and corn chips it was demonstrated that 8-nonenal tracks with "plastic" aroma observed in containers and with "plastic" flavor observed in corn chips stored in the containers.

The Effect of Packaging Materials and Storage Condition on the Oxidative Stability of Refined Sunflower Oil

In this research, refined sunflower oil was packed at various packaging materials namely: yellow PET (polyethylene terephtalate) bottles, clear PET bottles, yellow HDPE (high density polyethylene) containers and metal cans. Randomly selected packaged sunflower oils samples were packed in carton as dark condition and secondary container. The samples were stored at room temperature (26.9°C) for 365 days. At 45 days intervals, the peroxide values of stored samples were determined. Every 180 days the samples were analyzed for TBA and anisidine values. In order to determine the effect of storage temperature, some samples were stored at 38°C under dark condition for a period of 56 days. At 7 days intervals, the peroxide value of samples was determined. The results indicate that at room temperature, increase in peroxide value, thio-barbituric acid (TBA), anisidine value and totax value were significantly (p < 0.05) higher in sunflower oil stored in HDPE containers as compared to PET (yellow, clear) bottles and metal cans. No significant differences were observed in the capability of PET bottles and metals cans to protect the oil against the deterioration effect of primary and secondary oxidation. At 38°C, significant differences on peroxide value of sunflower oil in HDPE containers in comparison to the other packaging materials were observed (p < 0.05). The results indicate that, the estimated shelf life for sunflower oil in HDPE containers at room temperature were less than 180 days and decreased to 35 days at 38°C. Where as, the shelf life of sunflower oil in PET (yellow, clear) bottles and metal cans were estimated to be more than 365 days at room temperature. It seems that PET bottles and metal cans are suitable containers for sunflower oil that protect oil against oxidative deterioration, where as the HDPE container with the low oxidative stability is unsatisfactory.

Butyltin compounds in Portuguese wines.

Butyltin compounds are widespread contaminants that have also been found in some wines. The purpose of the present work was to make a survey of butyltin compounds in Portuguese wines. Forty-three table wines and 14 Port wines were analyzed for butyltin contents by using solid-phase microextraction gas chromatography mass spectrometry (SPME-GC-MS). In 14% of the analyzed wine samples, measurable dibutyltin (DBT) was found at concentrations ranging between 0.05 and 0.15 microg/L as Sn. Monobutyltin (MBT) was also observed (0.05 microg/L as Sn) in just a single wine. A search for the possible sources of DBT residues found in the wines was carried out. Therefore, some plastics and oak wood used in the process of wine-making, which have been directly in contact with the musts or the wines, were studied to check their possible release of butyltins. The eventual presence of DBT was also tested directly along the vinification process, from the must to the finished product. The results suggest that high-density polyethylene containers used in the transfer of wine in an early stage of the vinification process may be the main sources of these contaminants. Therefore, it is recommendable that plastic materials to be used in wineries be previously tested for the release of butyltin compounds.

Modelling migration from high-density polyethylene containers into concentrated solutions used as food flavourings

Migration from high-density polyethylene into different liquids (hexane, ethanol, lemon terpenes and their emulsions) was modelled using the response surfaces method. Polynomial equations (z = A + Bx + Cy + Dx2 + Ey2 + Fxy) were established and parameters determined for each compound. Correlation coefficients were generally >90%. Analysis indicated that 2,4-bis(1,1-dimethylethyl)phenol, probably due to the degradation of the antioxidant additive tris(2,4-bis(1,1-dimethylethyl)phenyl)phosphite, migrated into each liquid tested, whatever the temperature. Oligomers (10–30 carbons) terminated by a vinyl group were also detected.

Effectiveness of Poly(ethylene terephthalate) and High-Density Polyethylene in Protection of Milk Flavor

The development of certain off-flavors in whole milk (3.25% milk fat) as related to packaging material [glass, high-density polyethylene (HDPE), amber poly(ethylene terephthalate) (PETE), clear PETE, and clear PETE-UV] were evaluated after exposure to fluorescent light (1100 to 1300 lx) for 18 d at 4°C. Control samples packaged and stored under identical conditions were wrapped in foil to prevent light exposure. Selected flavor compounds in milk were measured analytically on d 0, 7, 14, and 18 of storage, while intensities of “oxidation,” “acetaldehyde,” and “lacks freshness” off-flavors were determined by sensory analysis at the same intervals. In light-exposed samples, oxidation off-flavor was significantly lower when packaged in amber PETE versus other containers. Milk packaged in HDPE containers showed a significantly higher level of oxidation off-flavor than milk packaged in PETE-UV containers but not higher than clear PETE or glass containers. No significant difference in acetaldehyde off-flavor was found between package material treatments (exposed or protected). Acetaldehyde concentration never exceeded flavor threshold levels, regardless of packaging material. Amber and PETE-UV materials proved to be a competitive packaging choice for milk in preserving fresh milk flavor.

Stability of dissolved metals in environmental aqueous samples: Rideau River surface water, rain and snow

The stability of nickel, lead, copper, cadmium, aluminium and zinc in the dissolved phase of environmental aqueous samples stored in common containers made of various materials was investigated. The samples were Rideau River surface water, rainwater and snow collected at Carleton University, Ottawa, Canada, and had concentrations of the above metals ranging from 0.5 to 90 ng l −1, and the samples were not acidified. The container materials studied were high-density polyethylene (HDPE), polypropylene (PP) and Teflon. The rate and the extent of metal loss were dependent on the container material, and the metal. Significant losses were observed in both polyethylene and PP containers even over periods as short as 30 min. The time taken for the concentration of the metals in the dissolved phase to be reduced to half was in the high-density polyethylene containers: 5, 15, and 20 min, for lead, copper and cadmium, respectively. With PP containers, only 15% lead, 25% copper, and 20% cadmium were lost in 2 h of storage. Teflon containers show no loss of dissolved metals from aqueous environmental samples over periods of 24 h, and hence, Teflon is the most suitable container material for the storage of environmental aqueous samples for trace metals for periods up to 24 h. The loss was the same for all environmental aqueous samples, river water, rainwater and snowmelt. This study shows the importance of the container material in preserving the sample integrity of environmental aqueous samples. Dissolved zinc was found to be stable in all the container materials studied. This aspect needs further experimental verification before any generalization is justified.

Extensional flow characterisation and extrusion blow moulding of high density polyethylene modified by calcium carbonate

Free surface elongational flow properties, including transient state stress growth and melt rupture data, have been measured on a range of calcium carbonate filled high density polyethylene (HDPE) compounds, using a Rutherford elongational rheometer operating at constant strain rate in the range 0·1–6·0 s-1. Results show that polymer molecular weight has a strong influence on both tensile stress growth and melt rupture data; in creasing elongational strain rate decreases the stress growth coefficient, in all compounds. At any specific elongational strain rate, the stress growth coefficient increases with volume fraction of particulate additives and also when using additives of fine particle size, as a result of packing fraction effects. Acid coatings added at super-monolayer levels influence the viscosity of highly filled compounds, by internal lubrication.Dynamic extrusion data obtained by experimental blow moulding of calcium carbonate modified HDPE materials show that modifications to melt state shear modulus result in reduced die swell, to an extent determined by filler coating. In combination with die swell, higher extensional viscosity of filled HDPE contributes significantly to enhanced parison sag resistance. Solid state modulus enhancement was consistently observed in calcium carbonate filled HDPE containers and if excellent filler dispersion can be achieved, it is feasible to retain the ductile mode failure of unfilled HDPE when containers are subjected to high velocity impact loads.

How accurate must a reference material be?

This article deals with reference materials (RMs) used for calibration purposes. For most common spectroscopic and chromatographic methods, RMs which have a relative content uncertainty of up to 3% can be used without considerably increasing the overall measurement uncertainty of the complete procedure. It is vital that the correct amount of the RM is used to ensure the quality of the quantitative chemical analyses. This can only be guaranteed if, in addition to the correct determination of the amount, the stability of the RM in the sales packaging is considered in the quoted uncertainty. For instance when the RM is packed in a container made of polyvinylidene fluoride water losses in hot climates can result in an increase in concentration which cannot be neglected. This is also true for high density polyethylene containers (PE-HD) although to a lesser degree. When mercury solutions of 1000 mg/l to 10 000 mg/l are kept in diluted nitric acid in PE containers, a relevant reduction in amount can be measured despite the water losses. However, the solutions remain stable in glass containers.

Recycling of high density polyethylene containers

The recycling of homogeneous high density polyethylene from containers for liquids gives rise to materials having mechanical properties that are strongly dependent on the reprocessing apparatus and the processing conditions. The thermomechanical degradation during processing gives rise to different modifications of the structure depending on the temperature, residence time and applied stress. In general, it is possible to say that if the reprocessing operations are carried out in apparatus with low residence time, the mechanical and rheological properties of the raw materials are only slightly influenced by the recycling operations. Significant degradation phenomena and reduction of some mechanical properties are observed on increasing the number of recycling steps in apparatus with large residence times. By adding antioxidant agents the polymer maintains the initial properties even after several recycling cycles. The competition between formation of chain branching and chain scission can be considered to be responsible for this behaviour.

Method comparison for the determination of labile aluminium species in natural waters

An inter-laboratory comparison project to evaluate the portability of a standard method for the determination of aluminium species in waters and to investigate the probability of producing reference waters for aluminium speciation analysis is described. High-density polyethylene containers were found to be appropriate for the storage of water samples, intended for speciation analysis, after leaching with 10% (v/v) nitric acid for 48 h. A quality control programme for total aluminium in water samples was completed by all participating laboratories, showing the value of such a parallel programme, especially for aluminium with its inherent problems with contamination. Water samples (lake and tap) proved to be stable for up to 30 days, after which increasing pH caused aluminium hydroxy species to precipitate. A defined Driscoll-Pyrocatechol Violet fractionation method was found to be robust enough to be fully portable, the participating laboratories achieving relative standard deviations of 15% for the toxic “labile monomeric” aluminium fraction in the more stable water samples.

Measuring the depth of fluorine incorporation in high and low density polyethylene by Rutherford backscattering spectrometry

We report on our efforts to apply Rutherford backscattering spectrometry (RBS) for measuring the permeation of fluorine into low (LDPE) and high density polyethylene (HDPE) that have been exposed to gas atmospheres containing fluorine. To address the issue of sample damage during RBS analysis, experimental conditions were chosen using polytetrafluoroethylene as a standard. Our studies of LDPE and HDPE containers exposed to 1% fluorine in nitrogen atmospheres show the depth of fluorine penetration to be approximately 400 Å. Though the depths of treatment for both materials are quite similar, we find that the amount of fluorine uptake per unit volume is significantly higher for LDPE. The information yielded by RBS (depth of treatment and uptake per unit volume) shows it to be a powerful method for evaluating surface and near surface treatments of polymeric materials.

Ozonation Effect on Taste in Water Packaged in High Density Polyethylene Bottles

The effect of ozonation on packaged water samples with high levels of a combination of monovalent ions and silica and elevated devalention was studied. The water samples were packaged in high density polyethylene bottles and exposed to either .3 or 3.0ppm ozone. A 12-member difference taste panel was used as a quality control screening tool. Also, the effect of blow molding temperature on product quality was evaluated (176.7 or 231.1°C). The amount of ash in the carton varied from .027 to .037%. The containers were treated with either 185 or 235ppm butylated hydroxytoluene. Using bottles with no holding period caused the development of a detectable taste no matter what the ozone level of the water. The level of the plastic off-taste increased with increasing ozone level. Increasing the level of butylated hydroxytoluene in the bottle decreased the extent of taste development. Catalyst residue in the polymer did not appear to contribute to the development of off-tastes in the bottle. There was a taste preference for the water stored in glass containers which decreased as the antioxidant content increased. Overall, the development of water off-taste occurred least in glass containers and most often in high density polyethylene containers with no butylated hydroxytoluene; off-taste was noted with increased frequency as levels of butylated hydroxytoluene were decreased in high density polyethylene. Also, softer water appeared to be less sensitive to development of off-taste than hard water treatments.

The representation of the fifth somatic sensory cortex(SV) in the cat

Dual ZnO/lignin hybrid fillers were obtained and subjected to detailed physicochemical and morphological-microstructural analysis. The effectiveness of combination of the components was assessed using Fourier transform infrared spectroscopy. It was shown that the addition of zinc oxide improves the thermal stability of the final hybrid filler. A hybrid material consisting of ZnO and lignin in a weight ratio of 1:5 exhibited very good antimicrobial activity, especially against Gram-positive bacteria (in both of the tested genera: Staphylococcus and Bacillus). In all cases, the action of this material was stronger than that of the positive control, the antibiotic tetracycline. Blow-molded containers made of polyethylene containing 5 wt% of ZnO/lignin with different lignin contents were prepared with a single-screw extruder. The effect of ZnO/lignin hybrid fillers on the properties of a high-density polyethylene container was investigated by means of a uniaxial compression test. Mechanical tests demonstrated a significant twofold increase in the compression force for blends with a ZnO:lignin ratio of 1:5. Additionally, DSC analysis was performed to study the influence of the dual fillers on the microstructure of the blended polyethylene.

Studies on Low Molecular Weight Constituents in High Density Polyethylene Containers

Studies on Low Molecular Weight Constituents in High Density Polyethylene Containers