scholarly journals Chemical Recycling of Mixed Plastics in Electronic Waste Using Solvent-Based Processing

Processes ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 66
Author(s):  
Lester Anderson ◽  
Evan Yu ◽  
Wan-Ting Chen
Keyword(s):  
Flame Retardants ◽  
Electronic Waste ◽  
Acrylonitrile Butadiene Styrene ◽  
Weight Fraction ◽  
Embodied Energy ◽  
Dissolution Time ◽  
Recycling Rate ◽  
Chemical Recycling ◽  
High Molecular Weight Fraction ◽  
Shredder Residue

Currently, less than 20% of electronic waste (E-waste) produced in the U.S. is recycled. To improve the recycling rate of E-waste, the study aimed to: (1) identify the major plastics found within electronic shredder residue (ESR), (2) design solvents and processing conditions capable of separating out 90% of the plastic in ESR, and (3) estimate the energy efficiency of the solvent-based process developed. Preliminary screening showed 25 wt.% of the ESR was composed of plastics, with two polymers dominating the sorted plastic fraction—polystyrene (PS, 40 wt.%) and acrylonitrile butadiene styrene (ABS, 25 wt.%). Subsequently, solvents and anti-solvents were screened using Hansen Solubility Parameter Theory for PS, ABS, and ESR dissolution. The pre-screening results showed dichloromethane (DCM) and tetrahydrofuran (THF) as the most effective solvents for PS and ABS, with methanol (MeOH) and ethylene glycol (EG) as the most effective anti-solvents. By optimizing the dissolution time and the solvents used, the highest polymer dissolution yield (99 wt.%) was achieved using DCM for 48 h. Both MeOH and EG precipitated 71 wt.% of the polymer fraction of ESR. EG removed more phosphorus containing flame retardants (94 wt.%) than MeOH (69 wt.%). Energy analysis indicated that the solvent-based processes could save 25–60% of the embodied energy for PS and ABS. Characterization showed that the solvent-based processing could preserve the high molecular weight fraction of the polymers while removing flame retardants at the same time. The results from this study prove the potential of solvent-based processing to produce secondary plastic materials from E-waste for cross-industry reuse.

PC/ABS Nanocomposites with Layered Silicates Obtaining, Structure and Properties

2016 ◽  
Vol 721 ◽  
pp. 38-42 ◽  
Author(s):  
Rūta Saldābola ◽  
Remo Merijs Meri ◽  
Janis Zicans ◽  
Tatjana Ivanova ◽  
Rita Berzina
Keyword(s):  
Flame Retardants ◽  
Electronic Waste ◽  
Thermal Characteristics ◽  
Acrylonitrile Butadiene Styrene ◽  
Layered Silicates ◽  
Structure And Properties ◽  
Mechanical Stiffness ◽  
Binary Blends ◽  
Thermal Stability Of ◽  
Butadiene Styrene

Due it increasing use in electronics, polymers, mainly acrylonitrile-butadiene-styrene (ABS) and its blend with polycarbonate (PC), are making considerable part of electronic waste. It has been proven that halogenated flame retardants used in polymers for electronics are toxic to environment and human health. Aim of the research is to evaluate the effects of nanostructured montmorillonite clay (D43B) addition on the mechanical and thermal characteristics of PC, ABS and its binary blends. The effect of substitution of virgin polymers in the blend with recycled ones has been also investigated. It has been determined that as far as the recycled polymer content in the composites does not exceed 10wt.%, tensile and thermal properties of the systems are not considerably affected. Addition of D43B up to 1,0-1,5wt.% contributes to the increment of mechanical stiffness, strength and thermal stability of the composites.

Fibrillin molecules aggregate to form an extendible beaded structure which is a major component of “Elastin Associated” microfibrils

1989 ◽  
Vol 47 ◽  
pp. 246-247
Author(s):  
Douglas R. Keene ◽  
B. Kerry Maddox ◽  
Marie B. Spurgin ◽  
Lynn Y. Sakai ◽  
Robert W. Glanville
Keyword(s):  
Molecular Sieve ◽  
Room Temperature ◽  
Culture Medium ◽  
Weight Fraction ◽  
Ammonium Bicarbonate ◽  
High Molecular Weight Fraction ◽  
Bicarbonate Buffer ◽  
Human Amnion ◽  
Gold Conjugate ◽  
Ammonium Bicarbonate Buffer

A mouse monoclonal antibody was used to identify beaded aggregates found in guanidine extracts of human amnion as assemblies of fibrillin molecules. These aggregates were also shown to be a major component of extracellular matrix microfibrils. We further demonstrated that the periodicity of these aggregates can be increased when subjected to mechanical stress.Human amnion was extracted with guanidine and the extracted material purified using ion exchange and molecular sieve chromatography. A high molecular weight fraction was precipitated by dialyzing against dilute acetic acid. Part of the precipitate was suspended in 0.2 M ammonium bicarbonate buffer and rotary shadowed. A second portion was resuspended in culture medium containing antibody which recognizes matrix microfibrils, diluted 1:5 in ammonium bicarbonate and reacted for 120 minutes at room temperature. Antibody labeled precipitate was washed by repeated pelleting and resuspension in buffer and then incubated in Janssen GAM 5 nm gold conjugate for 60 minutes at room temperature.

Studies on the Functionality of Newly Synthesized Fibrinogen after Treatment of Acute Myocardial Infarction with Streptokinase, Increase in the Rate of Fibrinopeptide Release

1993 ◽  
Vol 70 (06) ◽  
pp. 0978-0983 ◽  
Author(s):  
Edelmiro Regano ◽  
Virtudes Vila ◽  
Justo Aznar ◽  
Victoria Lacueva ◽  
Vicenta Martinez ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Molecular Weight ◽  
Steady State ◽  
High Molecular Weight ◽  
Coronary Arteries ◽  
Risk Index ◽  
Weight Fraction ◽  
High Molecular Weight Fraction ◽  
Fibrinopeptide A

SummaryIn 15 patients with acute myocardial infarction who received 1,500,000 U of streptokinase, the gradual appearance of newly synthesized fibrinogen and the fibrinopeptide release during the first 35 h after SK treatment were evaluated. At 5 h the fibrinogen circulating in plasma was observed as the high molecular weight fraction (HMW-Fg). The concentration of HMW-Fg increased continuously, and at 20 h reached values higher than those obtained from normal plasma. HMW-Fg represented about 95% of the total fibrinogen during the first 35 h. The degree of phosphorylation of patient fibrinogen increased from 30% before treatment to 65% during the first 5 h, and then slowly declined to 50% at 35 h.The early rates of fibrinopeptide A (FPA) and phosphorylated fibrinopeptide A (FPAp) release are higher in patient fibrinogen than in isolated normal HMW-Fg and normal fibrinogen after thrombin addition. The early rate of fibrinopeptide B (FPB) release is the same for the three fibrinogen groups. However, the late rate of FPB release is higher in patient fibrinogen than in normal HMW-Fg and normal fibrinogen. Therefore, the newly synthesized fibrinogen clots faster than fibrinogen in the normal steady state.In two of the 15 patients who had occluded coronary arteries after SK treatment the HMW-Fg and FPAp levels increased as compared with the 13 patients who had patent coronary arteries.These results provide some support for the idea that an increased synthesis of fibrinogen in circulation may result in a procoagulant tendency. If this is so, the HMW-Fg and FPAp content may serve as a risk index for thrombosis.

In Vivo Studies on the Inhibition of Coagulation by Fractionated Heparin and by a Heparin Analogue I. Effects of Heparin Fractions

1981 ◽  
Vol 46 (03) ◽  
pp. 612-616 ◽  
Author(s):  
U Schmitz-Huebner ◽  
L Balleisen ◽  
F Asbeck ◽  
J van de Loo
Keyword(s):  
Molecular Weight ◽  
Day Treatment ◽  
Gel Filtration ◽  
Weight Fraction ◽  
In Vivo Studies ◽  
Low Molecular Weight ◽  
High Molecular Weight Fraction ◽  
Platelet Factor ◽  
Heparin Fractions

SummaryHigh and low molecular weight heparin fractions obtained by gel filtration chromatography of sodium mucosal heparin were injected subcutaneously into six healthy volunteers and compared with the unfractionated substance in a cross-over trial. Equal doses of 5,000 U were administered twice daily over a period of three days and heparin activity was repeatedly controlled before and 2, 4, 8 hrs after injection by means of the APTT, the anti-Xa clotting test and a chromogenic substrate assay. In addition, the in vivo effect of subcutaneously administered fractionated heparin on platelet function was examined on three of the volunteers. The results show that s.c. injections of the low molecular weight fraction induced markedly higher anti-Xa activity than injections of the other preparations. At the same time, APTT results did not significantly differ. Unfractionated heparin and the high molecular weight fraction enhanced ADP-induced platelet aggregation and collagen-mediated MDA production, while the low molecular weight fraction hardly affected these assays, but potently inhibited thrombin-induced MDA production. All heparin preparations stimulated the release of platelet Factor 4 in plasma. During the three-day treatment periods, no side-effects and no significant changes in the response to heparin injections were detected.

Brominated flame retardants (BFRs) in PM2.5 associated with various source sectors in southern China

2021 ◽  
Author(s):  
qiqi li ◽  
Tao Wang ◽  
yuan zeng ◽  
yun fan ◽  
Shejun Chen ◽  
...  
Keyword(s):  
Flame Retardants ◽  
Southern China ◽  
Electronic Waste ◽  
Brominated Flame Retardants ◽  
Waste Recycling ◽  
Recycling Facilities

The present study investigated legacy and novel brominated flame retardants (BFRs) in atmospheric PM2.5 associated with various urban source sectors in a city and electronic waste (e-waste) recycling facilities in...

scholarly journals ‘Tanned’ gelatin spheres and granules for exclusion chromatography

1968 ◽  
Vol 108 (4) ◽  
pp. 641-646 ◽  
Author(s):  
A. Polson ◽  
W. Katz
Keyword(s):  
Molecular Weight ◽  
Polyethylene Glycol ◽  
High Molecular Weight ◽  
Weight Fraction ◽  
High Flow ◽  
High Molecular Weight Fraction ◽  
Flow Rates ◽  
Protein Molecules ◽  
Exclusion Chromatography

1. The preparation of tanned gelatin spheres and granules from high-molecular-weight gelatin is described. This material is comparatively hard, giving high flow rates, is insoluble in water at temperatures between 0° and 100° and is resistant to digestion by trypsin and chymotrypsin. The high-molecular-weight fraction of gelatin was prepared by precipitation with polyethylene glycol, and the spheres and granules prepared from this fraction were hardened and insolubilized by tanning with either formalin or chromium salts or both. 2. The spheres and granules were used successfully for the separation of protein molecules and other protein-aceous materials ranging in molecular weight from 200 to greater than 6000000. This gel exclusion material has several properties superior to those of other products used for similar purposes. Further, it was noticed that the porosity of the spheres differed considerably from that of the granules.

scholarly journals Recycling Potential for Non-Valorized Plastic Fractions from Electrical and Electronic Waste

Recycling ◽  
2021 ◽  
Vol 6 (2) ◽  
pp. 33
Author(s):  
Laura Strobl ◽  
Thomas Diefenhardt ◽  
Martin Schlummer ◽  
Tanja Leege ◽  
Swetlana Wagner
Keyword(s):  
Flame Retardants ◽  
Electronic Waste ◽  
Gel Permeation Chromatography ◽  
Scanning Calorimetry ◽  
Separation Processes ◽  
Melt Flow Rate ◽  
Density Fractions ◽  
Material Recycling ◽  
Other Substances ◽  
Electrical And Electronic Waste

This paper describes a study for waste of electrical and electronic equipment (WEEE) to characterise the plastic composition of different mixed plastic fractions. Most of the samples studied are currently excluded from material recycling and arise as side streams in state-of-the-art plastics recycling plants. These samples contain brominated flame retardants (BFR) or other substances of concern listed as persistent organic pollutants or in the RoHS directive. Seventeen samples, including cathode ray tube (CRT) monitors, CRT televisions, flat screens such as liquid crystal displays, small domestic appliances, and information and communication technology, were investigated using density- and dissolution-based separation processes. The total bromine and chlorine contents of the samples were determined by X-ray fluorescence spectroscopy, indicating a substantial concentration of both elements in density fractions above 1.1 g/cm3, most significantly in specific solubility classes referring to ABS and PS. This was further supported by specific flame retardant analysis. It was shown that BFR levels of both polymers can be reduced to levels below 1000 ppm by dissolution and precipitation processes enabling material recycling in compliance with current legislation. As additional target polymers PC and PC-ABS were also recycled by dissolution but did not require an elimination of BFR. Finally, physicochemical investigations of recycled materials as gel permeation chromatography, melt flow rate, and differential scanning calorimetry suggest a high purity and indicate no degradation of the technical properties of the recycled polymers.

scholarly journals Calcium Binding by Particle-Free Supernatants of Homogenates of Skeletal Muscle

1965 ◽  
Vol 49 (1) ◽  
pp. 131-149 ◽  
Author(s):  
F. Norman Briggs ◽  
Martin Fleishman
Keyword(s):  
Skeletal Muscle ◽  
Molecular Weight ◽  
Stability Constant ◽  
Calcium Binding ◽  
Weight Fraction ◽  
Preliminary Evidence ◽  
High Molecular Weight Fraction ◽  
Total Calcium ◽  
Chelex 100 ◽  
Binding Substance

A high molecular weight fraction of a soluble Marsh muscle-relaxing preparation has been shown to contain a calcium-complexing substance. By examining the nature of the competition between this fraction and chelex-100 for calcium at various total calcium concentrations it has been possible to calculate the concentration and calcium stability constant of this calcium-complexing substance. Taking into account dilutions which occur during the preparation of fractions containing this substance its concentration may be estimated at about 2·10-4 in muscle and its calcium stability constant was found to be about 1.5·105 M-1. Preliminary evidence suggests that the calcium-binding substance is a protein.

Sorption of GR-S Type of Polymer on Carbon Black. III. Sorption by Commercial Blacks

1953 ◽  
Vol 26 (1) ◽  
pp. 102-114 ◽  
Author(s):  
I. M. Kolthoff ◽  
R. G. Gutmacher
Keyword(s):  
Molecular Weight ◽  
Carbon Black ◽  
Intrinsic Viscosity ◽  
Benzene Solution ◽  
Weight Fraction ◽  
High Molecular Weight Fraction ◽  
Molecular Weights ◽  
Bound Rubber ◽  
Flow Through ◽  
Peculiar Behavior

Abstract The sorption capacities toward GR-S five commercial carbon blacks are in decreasing order: Spheron-6, Vulcan-1, Philblack-0, Sterling-105, Philblack-A. Apparently, the sorption is not related to surface area. The sorption on Vulcan-1 of GR-S from its solutions in seven different solvents or mixtures of solvents increases with decreasing solvent power for the rubber. The sorption curves of two “cold rubbers,” polymerized at −10 and +5° respectively, showed little difference from that of 50° GR-S. Previous heating of carbon black in nitrogen at 500 or 1100° increased the sorption by about 20 per cent over unheated carbon. Air-heating of carbon black at 425° did not cause a difference in the sorption from benzene solution, but produced an increase in the sorption of rubber from n-heptane solution. In the range 75% butadiene-25% styrene to 5% butadiene-95% styrene, there is practically no effect of the degree of unsaturation on the sorption. Polystyrene of high intrinsic viscosity exhibits a peculiar behavior with furnace blacks. Vulcan-1 sorbed microgel as well as the sol fraction from n-heptane solutions of GR-S containing microgel (conversion 74.7 and 81.5 per cent). There was no appreciable difference in the amount of sorption of rubber fractions having average molecular weights varying from 433,000 to 85,000. There is little change in the amount sorbed after two hours of shaking, but the intrinsic viscosity of the residual rubber decreases with time. The low molecular-weight rubber is sorbed more rapidly, but is slowly replaced by the more tightly sorbed high molecular weight fraction. Partial fractionation of a rubber sample can be achieved by allowing the rubber solution to flow through a column of weakly sorbing carbon black. A large portion of the sorbed rubber can be recovered from the column by washing it with a good solvent such as xylene. Bound rubber is produced by intimate mixing of equal parts of carbon black and rubber swollen in chloroform, when the mixture is dried in vacuum at 80° or at room temperature. Milling is not essential to get bound rubber.

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