Solid Plastics Research Articles

Development and validation of a new direct sampling method for coarse mono- and mixed waste fractions bound in bales

ABSTRACTSampling of coarse waste materials is considered to be a particularly challenging task and is at the same time the most crucial step in the overall data acquisition process. Despite this fact, research work on new sampling methods or new scientific approaches to sampling has been rather limited over the last decades. This paper focuses on a completely new sampling procedure for coarse two-dimensional materials similar to municipal solid waste or packaging plastics. The developed method is especially suitable for materials with particle sizes >100 mm and is based on the ‘press-and-drill method’ introduced by researchers from Fachhochschule Nordhausen. The basic idea is to sample the material in its compressed form (e.g. as bales) with a drilling tool in order to gain increments. The study presented in this paper shows the results of two extensive test series applying this new sampling technique to a middle-calorific fraction produced from packaging material (mainly plastics, textiles and paper). In parallel, the state-of-the-art approach was also applied on the same materials to gain valuable reference data. Results from both approaches are used for the extensive validation of the new sampling method. The verification of accuracy was realised by doping the material with defined pieces of foil containing molybdenum sulphide (MoS2) which acted as a tracer in the bale. The results obtained by the new direct bale sampling showed not only good accordance with the actual tracer content in each bale but also with results derived from the state-of-the-art approach. In this study, homogeneously distributed parameters (e.g. loss of ignition) were included just as inhomogeneously distributed elements (i.e. Cu). It is shown that sufficient representativeness for coarse materials (d95 > 300 mm) is obtained despite relatively small sample amounts and without previous comminution of the material.

Structural Stability Study Using Thermal and Structural Analysis of a Bimetal Cylinder in an Injection Molding Machine

사출성형기는 사출장치와 형체장치로 구분된다. 사출장치에서 고체의 플라스틱 수지는 밴드히터에 의한 열과수지간, 스크류 면, 그리고 실런더 내부 면과의 마찰로 인해 발생하는 열로 인해 용융된다. 용융된 수지가 특정한 형상을 가진 몰드 내로 사출될 때 실린더 선단부에는 높은 압력이 형성된다. 높은 압력으로 인해 실린더의 내부 면에 크랙이 발생한다. 실린더 내부의 압력을 지지하고 마모를 방지하기 위해 2개의 층으로 구성된 바이메탈 실린더가 제작되고 있다. 본 연구에서는 2개의 층으로 구성된 바이메탈 실린더의 구조적 안정성에 관하여 연구하였다. FEM 프로그램을 사용하여 열해석과 구조해석을 연계하여 분석하였다. 열해석을 통해서 바이메탈 실린더의 온도분포를 얻었다. 이 온도분포를 구조해석으로 연계하여 열과 사출압력에 따라 나타나는 실린더 선단에 발생하는 응력과 변형을 관찰하였다. 해석결과 실린더의 응력은 사출압력에 지배적이며 변형은 고온의 열에 지배적인 것으로 나타났다.

Bisphenol A in Solid Waste Materials, Leachate Water, and Air Particles from Norwegian Waste-Handling Facilities: Presence and Partitioning Behavior.

The plastic additive bisphenol A (BPA) is commonly found in landfill leachate at levels exceeding acute toxicity benchmarks. To gain insight into the mechanisms controlling BPA emissions from waste and waste-handling facilities, a comprehensive field and laboratory campaign was conducted to quantify BPA in solid waste materials (glass, combustibles, vehicle fluff, waste electric and electronic equipment (WEEE), plastics, fly ash, bottom ash, and digestate), leachate water, and atmospheric dust from Norwegian sorting, incineration, and landfill facilities. Solid waste concentrations varied from below 0.002 mg/kg (fly ash) to 188 ± 125 mg/kg (plastics). A novel passive sampling method was developed to, for the first time, establish a set of waste-water partition coefficients, KD,waste, for BPA, and to quantify differences between total and freely dissolved concentrations in waste-facility leachate. Log-normalized KD,waste (L/kg) values were similar for all solid waste materials (from 2.4 to 3.1), excluding glass and metals, indicating BPA is readily leachable. Leachate concentrations were similar for landfills and WEEE/vehicle sorting facilities (from 0.7 to 200 μg/L) and dominated by the freely dissolved fraction, not bound to (plastic) colloids (agreeing with measured KD,waste values). Dust concentrations ranged from 2.3 to 50.7 mg/kgdust. Incineration appears to be an effective way to reduce BPA concentrations in solid waste, dust, and leachate.

Numerical Modeling of Biomass and Solid Waste-Based Syngas Fuels Combustion

The combustion of syngas fuels in gas turbine combustor is presented in this paper. The principal objective is to test the performance of the combustion process using non-conventional fuels produced from the gasification of biomass and solid waste. Three dimensional syngas combustion simulations were performed in this study. The mixture fraction/pdf and the P1 radiation models were used to model the non-premixed turbulent combustion. The syngas fuels are derived from the gasification of wood saw dust, wooden pellet and nonrecycled solid waste plastics. The effect of syngas fuel compositions and lower heating values on the combustion process was investigated. The power from the combustor was kept constant at 60 kW for all the syngas fuels tested in this study. The results show a decrease of the peak gas temperature inside the combustor for the syngas fuels compared to conventional fossil gas fuel. The peak gas temperature inside the combustor decreases by 16.1%, 19.8%, and 17.2% respectively for the syngas 1 (derived from plastic waste), syngas 2 (derived from wood saw dust) and syngas 3 (derived from wooden pellets) compared to natural gas fuel. The highest average NO mass fraction at the combustor exit was obtained with syngas 1 (plastic waste) compared to the other syngas fuels due to the high lower heating value. The highest average CO2 mass fraction at the exit of the combustor was obtained with syngas 2 (wood saw dust) compared to the other syngas due to the high amount of CO2 in the syngas fuel (15%).

Feasibility Study on Power Generation from Waste Plastics with Partial Precombustion Carbon Capture and Conversion

AbstractThe feasibility of upcycling waste plastics into concurrent production of carbon nanotubes (CNTs) and of a hydrogen-enriched gaseous hydrocarbon stream was shown to be possible in a continuous steady-state steady-flow process. The feedstock was post-consumer (waste) low-density polyethylene (LDPE), which was pyrolyticaly gasified at 800°C, in a flow of nitrogen carrier gas. The evolving gaseous hydrocarbon pyrolyzates were first used as carbon growth agents for CNTs in a reactor, a process that lowered their carbon content and increased their hydrogen content. Thereafter, the unreacted hydrocarbon pyrolyzates and the generated hydrogen were mixed with air and burned. This conversion of solid waste plastics to gaseous fuels allowed thorough mixing with air and, upon ignition, the formation of environmentally benign fuel-lean premixed flames for subsequent power generation purposes. The CNT generation in the reactor took place by chemical vapor deposition (CVD) on untreated stainless steel mesh subs...

SU-E-T-590: An Activation Study of Materials and Devices Present in a Proton Treatment Room

Purpose: The use of protons for radiation therapy is growing rapidly. One consequence of protons interacting with different media is activation. These nuclear reactions induced by the protons, scattered neutrons, and gamma rays, activate different materials encountered, particularly by the therapists. The purpose of this study was to examine the derived nuclides from the activation, and also the decay rate. Methods: The study was conducted in our proton therapy facility. Protons are derived from a synchrocyclotron and pass through field shipping systems, apertures, and range compensators to define the beam within the patient.Included materials of concerns measured; the patient support couch, sheet rock in the wall, solid plastics used for quality assurance and dosimetry, and the passive scattering system itself, which includes brass apertures, and Lucite or blue wax compensators. All devices were studied post irradiation using gamma spectroscopy to determine the nuclides, and a sodium iodine scintillation detector to measure decay, particularly when the dose rate fell to background levels. Results: We have also determined from the measurements we will maintain brass apertures for three months before sending them for scrap. Some of the radionuclides arrived from these measurements included Na-22 for the blue wax compensator, C1-34m for themore » sheetrock, and Sc-44 and Co-60 for the brass apertures. We found compensators made out of Lucite or wax decayed to background in 2 hours. The patient support couch decayed to background in approximately 40 minutes, and sheet rock decayed in 80 minutes. In terms of the aperture layers, the most proximal aperture slab had much higher activity than the distal slab. Also the proximal sides of the slabs were much more activate than the distal. Conclusion: We have given proper instruction to therapists performing quality assurance in terms of the handled plastics, and to handle apertures rapidly as possible.« less

Silvergate's Optiblo colour range improves blow moulding processes

UK-based solid masterbatch producer Silvergate Plastics has launched Optiblo™, a range of colour masterbatches that it claims can ‘revolutionize’ blow moulding processes. The range is designed to significantly reduce cycle times and improve the surface finish of blow moulded parts, the company says.

Surgical waste audit of 5 total knee arthroplasties

Operating rooms (ORs) are estimated to generate up to one-third of hospital waste. At the London Health Sciences Centre, prosthetics and implants represent 17% of the institution's ecological footprint. To investigate waste production associated with total knee arthroplasties (TKAs), we performed a surgical waste audit to gauge the environmental impact of this procedure and generate strategies to improve waste management. We conducted a waste audit of 5 primary TKAs performed by a single surgeon in February 2010. Waste was categorized into 6 streams: regular solid waste, recyclable plastics, biohazard waste, laundered linens, sharps and blue sterile wrap. Volume and weight of each stream was quantified. We used Canadian Joint Replacement Registry data (2008-2009) to estimate annual weight and volume totals of waste from all TKAs performed in Canada. The average surgical waste (excluding laundered linens) per TKA was 13.3 kg, of which 8.6 kg (64.5%) was normal solid waste, 2.5 kg (19.2%) was biohazard waste, 1.6 kg (12.1%) was blue sterile wrap, 0.3 kg (2.2%) was recyclables and 0.3 kg (2.2%) was sharps. Plastic wrappers, disposable surgical linens and personal protective equipment contributed considerably to total waste. We estimated that landfill waste from all 47 429 TKAs performed in Canada in 2008-2009 was 407 889 kg by weight and 15 272 m3 by volume. Total knee arthroplasties produce substantial amounts of surgical waste. Environmentally friendly surgical products and waste management strategies may allow ORs to reduce the negative impacts of waste production without compromising patient care. Level IV, case series.

Release of Harmful Air Pollutants from Open Burning of Domestic Municipal Solid Wastes in a Metropolitan Area of Korea

Open burning of solid wastes, a potential nonpoint emission source, has recently become a topic of interests, particularly in the metropolitan area of Seoul, Korea. To estimate the effects of irregular open burning on local air quality, we evaluated the emission levels of harmful substances from test combustion of individual types of domestic municipal solid waste (MSW), including paper, wood, and plastics. The emission factors of PM10, PM2.5, PAHs, and heavy metals obtained from laboratory tests differed depending on the combustion material. A brief survey of residents and local government officials showed that more than 10.6% of homes in the metropolitan area have eliminated waste by irregular burning. Based on the public survey in the test area, the average annual emissions of hazardous materials from frequent open burning was estimated to be 71 tons for PM10, 46.6 tons for PM2.5, 914 kg for heavy metals, and 67 kg for PAHs. Open burning creates nearly 0.44% of regional air pollution from PM10.

Rapid and simple colorimetric assay for detecting the enzymatic degradation of biodegradable plastic films

We developed a rapid and simple method for evaluating the degradation of solid biodegradable plastics (BPs). Dye-containing BP films were used as substrates and the release of dye caused by the degradation of BPs was confirmed by a color change in the enzyme solution after a reaction time of 24 h.

Theory and Experimental Research on Inclusions Aggregation in Molten Steel

A mechanism of particles aggregation in liquid media is analyzed by applying the theory of aggregation which was developed in the field of colloid engineering. Hydrophobic particles are liable to aggregate in collision. Inclusions aggregation by using solid plastics particles in various solvent is observed in the course of floatation. Aggregation rate and size distribution of particles in turbulent dispersions has been studied. The aggregation contributed by plastic particles based on surface energy density and the droplet surface oscillation is considered. Hydrophobic particles, generally having a tendency to aggregate in water, disperse well in ethanol, particles in the mixture of water and ethanol are much better disperse than separately in water. The solvent properties, temperature and simulation particles are influence to the aggregation from the experiment that we can discover. The aggregation rate and size distribution were determined by wettabiliy.

New Apparatus for Measuring Ultrahigh Viscosity of Plastics

A new apparatus for measuring the viscosity of plastics of 108–1014 Pa·s from room temperature to 100 °C was developed. This is considered to be an absolute measurement method that requires no calibration. For the measurement of specimen deformation, dielectric capacitance detectors were used. By using the apparatus, the primary viscosities characterizing the short-time deformations with single relaxation times of five plastics and lead were determined. This apparatus is expected to usher in a new academic and industrial field of the rheology of solid plastics.

Thermal analysis of flammability

A thermal analysis method that separately reproduces the gas and condensed phase processes of flaming combustion in a single laboratory test is described. Anaerobic pyrolysis of solid plastics at a constant heating rate and complete thermal oxidation (nonflaming combustion) of the evolved gases provides the rate, amount, and temperatures over which heat is released by a burning solid. A physical basis for the method, the test procedure, and the relationship of flammability parameters to fire response and flame resistance of plastics are described.

Thermal Degradation of LDPE−Vacuum Gas Oil Mixtures for Plastic Wastes Valorization

The thermal degradation of blends of different percentages of low-density polyethylene (LDPE) in vacuum gas oil (VGO) has been carried out in a fluidized-bed reactor. A wide range of percentages of the polymer has been selected for the study, including 0, 5, 25, 75, and 100% LDPE by weight. The strategy of mixing plastics with a solvent to be degraded avoids the possible heat-transfer limitations and other problems present in the cracking of solid plastics. A temperature of 500 °C has been selected as the degradation temperature in order to simulate industrial conditions of a refinery and, in this way, to evaluate the applicability of the products generated. The results show a significant increase of the volatile yields by increasing the amount of LDPE present in the blend, dry gas, and liquefied petroleum gas, increasing with the percentage of polymer mixed with VGO. Condensable products exhibit a decrease of their yield with this variable. The influence of the temperature at the exit of the reactor is also evaluated in the present work. Significant differences have been observed in the product distribution as a function of this parameter, showing the importance of the temperature profile on the results obtained in this type of reactor. The methodology shown in the present work could suggest the possibility of using a refinery stream of secondary interest (such as the VGO employed) and, simultaneously, recycling plastics, reducing the environmental problems they cause.

Analysis of products from the pyrolysis and liquefaction of single plastics and waste plastic mixtures

Waste plastics in the form of two examples of real world municipal solid waste plastics and a simulated mixture of municipal waste plastics were pyrolysed and liquefied under moderate temperature and pressure in a batch autoclave reactor. In addition, the five main polymers which constitute the majority of plastics occurring in European municipal solid waste comprising, polyethylene, polypropylene, polystyrene, polyethylene terephthalate and polyvinyl chloride were also reacted. The plastics were reacted under both a nitrogen (pyrolysis) and hydrogen pressure (liquefaction) and the yield and composition of products are reported. The hydrocarbon gases produced were mainly methane, ethane, propane and lower concentrations of alkene gases. A mainly oil product was produced with the mixed plastic waste with significant concentrations of aromatic compounds, including single ring aromatic compounds. The composition of the oils and gases suggested that there was significant interaction of the plastics when they were pyrolysed and liquefied as a mixture compared to the results expected from reactions of the single plastics.

Experimental and numerical analysis of the body of a refuse collecting vehicle

Object of the present work is the body of a vehicle for the refuse collection. The main part of the body and the hatchback door have been studied, both experimentally, by means of strain gauges measurements and numerically, by means of finite element models. The aim of the study was to determine the pressure profile generated by refuse of different kind on the body walls during the typical operating conditions of the vehicle and to analyse the correspondent stress and strain distribution. The strain gauges measurements were carried out different days on the vehicle operating in the field, during the collection of solid urban refuse, paper and plastics. Eighty grids were applied to the vehicle body for this aim and the measurements were taken during the charging of the refuse from the boxes and during the subsequent tamping and discharging phases. A numerical model of the body was also developed, and an unit pressure was applied on different zones of it, calculating the correspondent strains the strain gauges locations and determining this way the influence coefficients. The pressure distribution was then evaluated by minimising the differences between the so calculated strains and those experimentally measured: it shows different profiles, depending on the refuse type. Finally, the global stress and strain state of the body was numerically determined applying the pressure profiles found as above: the highest stresses were found the back-lower part of the body and particular the hatchback door.

The radial dose function of low-energy brachytherapy seeds in different solid phantoms: comparison between calculations with the EGSnrc and MCNP4C Monte Carlo codes and measurements

The use of low-energy photon emitters for brachytherapy applications, as in the treatment of the prostate or of eye tumours, has drastically increased in the last few years. New seed models for 103Pd and 125I have recently been introduced. The American Association of Physicists in Medicine recommends that measurements are made to obtain the dose rate constant, the radial dose function and the anisotropy function. These results must then be compared with Monte Carlo calculations to finally obtain the dosimetric parameters in liquid water. We have used the results obtained during the characterization of the new InterSource (furnished by IBt, Seneffe, Belgium) palladium and iodine sources to compare two Monte Carlo codes against experiment for these low energies. The measurements have been performed in three different media: two solid water plastics, WT1 and RW1, and polymethylmetacrylate. The Monte Carlo calculations were made using two different codes: MCNP4C and EGSnrc. These codes use photon cross-section data of a different origin. Differences were observed between both sets of input data below 100 keV, especially for the photoelectric effect. We obtained differences in the radial dose functions calculated with each code, which can be explained by the difference between the input data. New cross-section data were then tested for both codes. The agreement between the calculations using these new libraries is excellent. The differences are within the statistical uncertainties of the calculations. These results were compared with the experimental data. A good agreement is reached for both isotopes and in the three phantoms when the measured values are corrected for the presence of the TLDs in the phantom.

Valorization by thermal cracking over silica of polyolefins dissolved in LCO

A study has been made of the cracking of polyethylene (PE) and polypropylene (PP) (which are the main components of post-consumer plastic wastes) dissolved in the Light Cycle Oil (LCO) product stream of a commercial Fluid Catalytic Cracking (FCC) unit. The cracking has been carried out on a mesoporous silica (pore size between 3 and 30 nm) in the 723–823 K range. This strategy for upgrading plastics and solvents together avoids heat transfer limitations and other problems inherent to the cracking of solid plastics. The polyolefins are transformed mainly into the components that make up the pool of gasoline (C 5–C 12). Furthermore, the incorporation of polyolefins has a synergistic effect on the cracking of LCO and causes a major decrease in the content of aromatics of the pool of gasoline and an increase in the content of olefins, paraffins and i-paraffins.

Synthesis of novel brominated bis‐tetrahydrophthalimides and bis‐nadimides and their possible application as flame‐retardant additives for polystyrene composites

Ten tetrabrominated bisimides of which eight were novel were tested as flame-retardant additives. They were prepared from corresponding bisimides by the addition of bromine. Structural properties and related thermal characteristics of these brominated compounds were determined. Flame-retardant properties of tetrabrominated bisimides were tested on high-impact polystyrene, containing various amounts of brominated bisimides, according to ASTM-D-3801, “Standard Test Method for Measuring the Comparative Extinguishing Characteristics of Solid Plastics in a Vertical Position,” and DIN-51960, “Testing of Organic Floor Coverings Assessment of Flammability.” It was observed that tetrabrominated bis-imides had improved flame resistance of high-impact polystyrene. In addition, thermoxi-dative stability of novel three bisimides, 04, 14, and 05, were compared with the others. © 1996 John Wiley & Sons, Inc.

Synthesis of novel brominated bis‐tetrahydrophthalimides and bis‐nadimides and their possible application as flame‐retardant additives for polystyrene composites

SYNOPSIS Ten tetrabrominated bisimides of which eight were novel were tested as flame-retardant additives. They were prepared from corresponding bisimides by the addition of bromine. Structural properties and related thermal characteristics of these brominated compounds were determined. Flame-retardant properties of tetrabrominated bisimides were tested on high-impact polystyrene, containing various amounts of brominated bisimides, according to ASTM-D-3801, “Standard Test Method for Measuring the Comparative Extinguishing Characteristics of Solid Plastics in a Vertical Position,” and DlN-51960, “Testing of Organic Floor Coverings Assessment of Flammability.” It was observed that tetrabrominated bisimides had improved flame resistance of high-impact polystyrene. In addition, thermoxidative stability of novel three bisimides, 04, 14, and 05, were compared with the others. 0 1996 John Wiley & Sons, Inc.