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1.
Anthony L. Andrady Jan E. Pegram Shuji Nakatsuka 《Journal of Polymers and the Environment》1993,1(1):31-43
Studies on three types of enhanced photodegradable polyethylenes showed tensile elongation at break to be a suitable parameter for assessing disintegration due to outdoor weathering. Disintegration rates varied greatly with exposure location, with Arizona the harshest environment and Washington and New Jersey the mildest. The rate of breakdown of the enhanced degradable polyethylenes relative to unmodified plastic was termed an enhancement factor. For the materials studied, average enhancement factors generally ranged from five to fifteen. The location-dependent variability in rate parameters can be mostly explained in terms of different average radiation levels and temperatures at these locations. A duplicate exposure protocol was developed to determine if the test data were complicated by short-term fluctuations in sunlight or temperature during exposure. 相似文献
2.
Anthony L. Pometto III Kenneth E. Johnson Meera Kim 《Journal of Polymers and the Environment》1993,1(3):213-221
Eleven starch-polyethylene degradable plastic films were prepared from masterbatches from Archer Daniels Midland Inc. (ADM), EcoStar Inc. (SLS), and Fully Compounded Plastic Inc. The biodegradability of initial and 70°C heat-treated materials was determined using a pure-culture assay withStreptomyces badius 252,S. setonii 75Vi2, orS. viridosporus T7A or without bacterial culture (control). Films were treated with 10-foldS. setonii culture concentrates and compared with inactive enzyme controls. Changes in each films mechanical property, molecular weight distribution, and Fourier-transformed infrared spectrum (FT-IR) were determined, and results were evaluated for significant differences by analysis of variance. Cell mass accumulation on each film was quite pronounced. In pure-culture studies, biodegradation was demonstrated for ADM-7 and SLS-2 initial films and for ADM-6 heat-treated films, whereas after 3-week treatment with activeS. setonii culture concentrates (enzyme assay), reductions in mechanical properties and changes in FT-IR spectrum were illustrated by all the films except SLS-2. Thus the absence of biofilm formation on the film surface permitted enzymatic attack of the materials. Furthermore, inhibition of chemical oxidative degradation in the pure-culture assay was demonstrated for ADM-11, SLS-5, and SLS-10 initial materials and for ADM-4, ADM-7, SLS-8, and SLS-10 heat-treated films. These data suggest that biological and chemical degradation were directly affected by the reduction in oxygen tension on the plastic film surface due to cell mass accumulation. This same phenomenon could be the cause for slow degradation rates in nature.Journal Paper No. J-15061 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa. Project Nos. 0178 and 2889. 相似文献
3.
Todd A. Anderson Devin M. Scherubel Rong Tsao Alan W. Schwabacher Joel R. Coats 《Journal of Polymers and the Environment》1997,5(2):119-124
Determining the fate of xenobiotic materials in the environment can be aided by the use of radioactive isotope technology.
Previous research on the degradation of polymers such as polyethylene (PE) was aided by the utilization of radiotracers. In
order to study the environmental fate of degradable (PE/starch) plastics, we synthesized3H-labeled PE. Results of soil incubation studies indicate that only minimal degradation of the PE component, as indicated
by the production of water-soluble metabolites, occurred during 2 years of incubation in soil. Despite the minimal degradation,
the3H label did not allow for detection of the degradation products. In addition, the3H-PE was particularly useful for tracing the fate of degradable plastics after consumption by terrestrial isopods. The detection
of aqueous-soluble radioactivity in isopod frass was used to indicate degradation of the plastic film. 相似文献
4.
Meera Kim Anthony L. Pometto III Kenneth E. Johnson Alfred R. Fratzke 《Journal of Polymers and the Environment》1994,2(1):27-38
Linear low-density polyethylene films were prepared that contained native corn starch (7, 14, or 28%), low or high molecular weight oxidized polyethylene (15%), and a prooxidant mixture (18% POLYCLEAN II) that contains manganese and vegetable oil. For each mixture all components were first mixed at high temperatures in a twin-screw extruder and pelletized. The pellets were cast into films using a single-screw extruder. Oxidized-polyethylene addition did not impair the transparency and thickness of the films and did not reduce the percentage elongation, whereas significant reductions in film mechanical properties were observed. Thermal and photodegradation properties of each film were evaluated by 70°C forced-air oven treatment (20 days), by high-temperature, high-humidity treatment in a steam chamber (20 days), and by exposure to ultraviolet light (365 nm; 4 weeks). Changes in the mechanical properties of the films were determined by an Instron Universal Test Machine; in the carbonyl index, Fourier transform infrared spectroscopy; and in molecular weight, by high-temperature gel-permeation chromatography (HT-GPC). The addition of oxidized polyethylene, especially high molecular weight oxidized polyethylene, and up to 14% starch to the films significantly increased the rate of thermal and photodegradation.Journal Paper No. J-15363 of the Iowa Agriculture and Home Economics Experiment Station, Ames. Project No. 0178 and 2889. 相似文献
5.
Biodegradability of degradable plastics exposed to anaerobic digested sludge and simulated landfill conditions 总被引:3,自引:0,他引:3
The biodegradabilities of various plastics by anaerobic digested sludge were measured and compared with the biodegradabilities
under simulated landfill conditions. Bacterial poly(3-hydroxy-butyrate-co-3-hydroxyvalerate) (PHB/HV; 92/8, w/w), a natural
aliphatic polyester, degraded nearly to completion within 20 days of cultivation by anaerobic digested sludge, while synthetic
aliphatic polyesters such as poly-lactic acid, poly(butylene succinate), and poly (butylene succinate-co-ethylene succinate)
did not degrade at all in 100 days. Cellophane, which was used as a control material, exhibited a similar degradation behavior
to PHB/HV. Under simulated landfill conditions, PHB/HV degraded quite well within 6 months. Synthetic aliphatic polyesters
also showed significant weight losses through 1 year of cultivation. The acidic environment inside simulators generated by
the degradation of biodegradable food wastes which comprised 34 % of municipal solid waste seems to cause the weight loss
of synthetic aliphatic polyesters. 相似文献
6.
Solid phase microextraction (SPME) as an effective means to isolate degradation products in polymers 总被引:2,自引:0,他引:2
Minna Hakkarainen Ann- Christine Albertsson Sigbritt Karlsson 《Journal of Polymers and the Environment》1997,5(2):67-73
A new sample preparation technique, solid phase microextraction (SPME), was compared with direct headspace-GC-MS with respect
to the type and amount of identified compounds. Three types of LDPE films containing photosensitising additives according
to the Scott-Gilead patents and pure LDPE were used as model substances. The polyethylene films were thermally aged at 80‡C
after the induction period was surpassed by subjecting the materials to 100 h of UV radiation. The new SPME method was developed
using nonpolar poly(dimethylsiloxane) and polar carbowax fibers to extract the low molecular weight products formed in the
polyethylene films during aging. Many more products were identified after SPME followed by GC-MS than after direct headspace-GC-MS
of the samples. The SPME method allowed the identification of homologous series of carboxylic acids, ketones, and furanones,
while direct headspace-GC-MS identified only a few carboxylic acids (C1-C6) and small amounts of some ketones and furanones.
In general, SPME was more effective in extracting less volatile products, and in particular, the polar carbowax fiber identified
also C7-C12 carboxylic acids and 4-oxopentanoic acid. By SEC and FTIR we confirmed that the number and amount of former degradation
products correlated well with the decrease in molecular weights and the amount of formed carbonyl compounds. 相似文献
7.
Akio Kamimura Eisuke Konno Shigehiro Yamamoto Takeru Watanabe Kazuo Yamada Fumiaki Tomonaga 《Journal of Material Cycles and Waste Management》2009,11(1):38-41
To develop a new method for the chemical recycling of plastics, we examined the formation of recycled polymers from the recovered
monomeric materials of solubilized waste fiber-reinforced plastics (FRP) under supercritical alcoholic conditions. Treatment
of waste FRP with supercritical MeOH resulted in the formation of monomeric organic compounds that mainly contained dimethyl
phthalate (DMP) and propylene glycol. The presence of these materials was confirmed by gas chromatography and nuclear magnetic
resonance analyses and they were mixed with new DMP and glycols in various ratios to form unsaturated polyesters. The polymerization
progressed successfully for all mixing ratios of the recovered and new DMP. Hardness tests on these recycled polymers indicated
that the polymer made from a 1:1 mixture of recovered and new dimethyl phthalate had almost the same level of hardness as
the polymers made from new materials. We also examined the formation of recycled FRP by using glass fibers and monomeric materials
recovered through the present depolymerization method.
Chemical Feedstock Recycling & Other Innovative Recycling Techniques 6 相似文献
8.
Thermal cracking of oils from waste plastics 总被引:2,自引:0,他引:2
Thermal cracking of decomposed waste plastic oil produces a good yield of olefins. The solvent extraction of such waste plastic oil seems to be efficient for increasing gas yields and recycling monomers. To assess the potential of monomer recovery from municipal waste plastics, the oils were cracked using a laboratory-scale quartz-tube reactor. The waste plastic oils were provided by two commercial plants of the Sapporo Plastic Recycle Co. and the Dohoh Recycle Center Co. in Japan. A model waste plastic oil made in a laboratory was also examined. Yields of ethene, propene, and other products were measured at different temperatures. Two-step pyrolysis reduces coking compared with the direct thermal degradation of plastics. The raffinates from waste plastic oils extracted by sulfolane were also cracked. The primary products were almost the same as those from nontreated oils. The maximum total gas yield was 78wt%–85wt% at 750°C, an increase of about 20wt% compared with that of nonextracted oil. Solvent extraction removes stable aromatic hydrocarbons such as styrene, which is more coked than cracked. 相似文献
9.
Masaaki Fukushima Misao Shioya Keiji Wakai Hidetoshi Ibe 《Journal of Material Cycles and Waste Management》2009,11(1):11-18
Sapporo Plastics Recycling Co., Ltd., (SPR) started its commercial operation of waste plastics liquefaction in 2000. At first
only hydrocarbon oil was reclaimed, this being derived from the waste plastics liquefaction process under the Japanese Containers
and Packaging Recycling Law. Presently, thermal degradation residue and hydrochloric acid are being produced as by-products
in addition to the hydrocarbon oil. As a result, the SPR plastics liquefaction plant has achieved a high reclamation rate
of 96%, and 93% of the recycled products have been reused in Hokkaido, where SPR is located. The technical problems caused
by corrosion and clogging have been solved.
Chemical Feedstock Recycling & Other Innovative Recycling Techniques 6 相似文献
10.
针对挥发性有机化合物(VOC)气体在现实中的危害,对废物原料检验的标准进行了探讨,对废物原料检验中如何进行VOC检测进行分析并提出建议。 相似文献
11.
Development of a catalytic cracking process for converting waste plastics to petrochemicals 总被引:2,自引:0,他引:2
Junya Nishino Masaaki Itoh Tadashi Ishinomori Nobuhiko Kubota Yoshio Uemichi 《Journal of Material Cycles and Waste Management》2003,5(2):89-93
The catalytic degradation of polyolefin using H-gallosilicates was examined using a bench-scale reactor (0.8kg/h) with semicontinuous feeding and the following plastics: (1) low-density polyethylene (LDPE) pellets; (2) linear low-density polyethylene (L-LDPE) pellets; (3) high-density polyethylene (HDPE) pellets; (4) polypropylene (PP) pellets; (5) polyolefin obtained from pulverized industrial waste plastics. The yields of liquid compounds from these materials, which were aromatics in most cases, ranged from 55wt% to 68wt%. With an increase in the ratio of total reactant to catalyst, the liquid yield remained the same. Yields of benzene, toluene, and xylenes (BTXs) decreased rapidly to below 50wt% at a ratio of more than 30. Differences in this ratio for BTXs were always small and were independent of the material. Only about half of the gas product was propane with a fresh catalyst. When the experiments were repeated, propylene, isobutane, and isobutene were found to increase. 相似文献
12.
Utilization of red mud as catalyst in conversion of waste oil and waste plastics to fuel 总被引:4,自引:0,他引:4
The aim of this study was to investigate the possibilities of using a by-product (red mud) from alumina production as a catalyst for recovery of waste. The conversion of waste mineral oil (WMO) and waste mineral oil/municipal waste plastic (WMO/MWP) blends over red mud (RM), a commercial hydrocracking catalyst (silica–alumina), and a commercial hydrotreating catalyst (Ni–Mo/alumina) to fuel has been studied. The effect of the catalyst and the temperature on the product distribution (gas, liquid, and wax) and the properties of liquid products were investigated. In the case of hydrotreatment of WMO, the liquids obtained over RM at both 400° and 425°C had larger amounts of low-boiling hydrocarbons than that of thermal or catalytic treatment with hydrotreating catalyst. Gas chromatography and nuclear magnetic resonance analysis of the liquid products showed that RM had hydrogenation and cracking activity in hydrotreatment of WMO. In coprocessing of WMO with municipal waste plastics, temperature had an important effect as well as the amount of MWP in the blend and the catalyst type. The hydrocracking at 400°C produced no liquid product. In hydrocracking at 425°C, the product distribution varied with catalyst type and MWP amount. The commercial hydrocracking catalyst had more cracking ability in the conversion of WMO/MWP to liquid and gas fuel than RM. In the case of hydrocracking over RM, the largest amount of liquid having satisfactory quality was obtained only from the blend containing 20% MWP. 相似文献
13.
Recycle technology for waste plastics containing polyvinyl chloride (PVC) has been developed in the Hokkaido National Industrial
Research Institute for the production of solid and liquid fuel, and has established a recycling process which includes a dechlorination
process for PVC plastics, and a two-stage catalytic pyrolysis process for plastics using zeolite catalysts. The dechlorination
equipment consists of a two-axis screw extruder with a heating element, which can remove chlorine up to 99.9 wt. % from PVC
containing plastics as hydrogen chloride. The product had about 44 000 kJ/kg calorific value and was fed into the next oil
production process, although it could also be used as a solid fuel. Natural and synthetic zeolite were used as catalysts for
the two-stage catalytic process, which produced a light oil with a boiling point which was between those of kerosene and gasoline.
The yield of this oil reached 82 wt. %. The chemical type was analyzed using liquid chromatography, and was found to have
many aromatic compounds. These technologies make it possible to produce a nonpolluting, high-calorie solid fuel and a liquid
fuel very efficiently.
Received: July 19, 2000 / Accepted: September 21, 2000 相似文献
14.
作为资源的重要补充,近年来国内塑料加工行业对进口废塑料的需求市场不断扩大,但作为原油的下游产品,因原油价格波动带来的经营影响和环保风险不容忽视。为有效规避风险,提升行业竞争力,在源头控制、行业转型、通关便利等方面提供可行性建议。 相似文献
15.
Two enhanced-photodegradable polyethylenes were studied to determine the effect of photooxidative degradation upon transport properties. Water vapor permeability of LDPE films containing metal compound prooxidants, weathered to different extents under outdoor exposure was studied. A film made of LDPE blended with 20 wt% of polycaprolactone was also examined to determine if biodegradation over a 40-day period resulted in a measurable change in its water vapor transport characteristics. A gravimetric technique was used to study the effects of outdoor and weather-ometer exposures on the permeability of carbon dioxide of both the LDPE film and (ethylene-carbon monoxide) copolymer films. Generally, photooxidative degradation was seen to be accompanied by a change in transport characteristics of the polymer films. 相似文献
16.
M. Day K. Shaw D. Cooney J. Watts B. Harrigan 《Journal of Polymers and the Environment》1997,5(3):137-151
The degradability of several degradable polymers was examined using three types of degradation environments. These include
exposure in a laboratory-scale composting test system containing material representative of the organic fraction of municipal
solid waste (MSW), exposure in a thermal hydrolytic environment consisting of water at 60‡C, and exposure in a thermal-oxidative,
dry oven environment of 60‡C. The results of the investigation clearly indicate that, in addition to chemical and biological
activity which can lead to polymer degradation, physical restructuring and reorganization of the macromolecular structure
may also occur at temperatures typically found in a compost environment, resulting in changes in the mechanical properties
of the polymer films. In the case of the polyethylene-modified polymers evaluated in this study, all behaved similarly, but
differently from the other polymer types. The polyethylene-based films appeared to be susceptible to oxidative degradation
and should degrade in a composting environment providing that there is sufficient air in contact with the film for a sufficient
period of time. However, when exposed in a laboratory composter, it appears that although ideal temperature-time curves may
be obtained, the test time period was insufficient in comparison to the induction period required to achieve the desired thermal
oxidative degradation.
Issued as NRCC No. 37620. 相似文献
17.
Kenneth Lee Gary WohlgeschaffenGilles H Tremblay B Thomas Johnson Roger C Prince Chantal C Guénette Edward H Owens 《Spill Science & Technology Bulletin》2003,8(3):273-284
Changes in the toxicity levels of beach sediment, nearshore water, and bottom sediment samples were monitored with the Microtox® Test to evaluate the two in situ oil spill treatment options of natural attenuation (natural recovery--no treatment) and sediment relocation (surf washing). During a series of field trials, IF-30 fuel oil was intentionally sprayed onto the surface of three mixed sediment (pebble and sand) beaches on the island of Spitsbergen, Svalbard, Norway (78°56′ N, 16°45′ E). At a low wave-energy site (Site 1 with a 3-km wind fetch), where oil was stranded within the zone of normal wave action, residual oil concentrations and beach sediment toxicity levels were significantly reduced by both options in less than five days. At Site 3, a higher wave-energy site with a 40-km wind fetch, oil was intentionally stranded on the beach face in the upper intertidal/supratidal zones, above the level of normal wave activity. At this site under these experimental conditions, sediment relocation was effective in accelerating the removal of the oil from the sediments and reducing the Microtox® Test toxicity response to background levels. In the untreated (natural attenuation) plot at this site, the fraction of residual oil remaining within the beach sediments after one year (70%) continued to generate a toxic response. Chemical and toxicological analyses of nearshore sediment and sediment-trap samples at both sites confirmed that oil and suspended mineral fines were effectively dispersed into the surrounding environment by the in situ treatments. In terms of secondary potential detrimental effects from the release of stranded oil from the beaches, the toxicity level (Microtox® Test) of adjacent nearshore sediment samples did not exceed the Canadian regulatory limit for dredged spoils destined for ocean disposal. 相似文献
18.
The oxidative degradation of polyolefins in the presence of transition metal catalysts is well known in the patent and technical literature. It has been suggested that a properly designed oxidatively degradable polymer could be used in limited lifetime articles and also on those whose primary method of disposal is composting, wherein the thermal activity is used to accelerate the oxidation process. The results of a detailed study of transition metal reactivity in the presence of numerous oxidation promoting species in polyolefins are presented. The oxidative degradation of these polyolefins was demonstrated at moderate temperatures under air and in a simulated compost environment. Approaches to determining the ultimate fate of these materials are discussed. 相似文献
19.
S. H. Imam S. H. Gordon A. Burgess-Cassler R. V. Greene 《Journal of Polymers and the Environment》1995,3(2):107-113
Most of the starch in starch-polyethylene-co-acrylic acid (EAA)-polyethylene (PE) composites prepared by injection molding was not accessible to starch-hydrolyzing enzymes. Even when these composites were treated with enzyme in the presence of Triton X-100 for 96 h, little starch hydrolysis was observed. However, when the starch-plastic material was pulverized, both the extent and the rate of starch hydrolysis increased dramatically, with about 70% hydrolysis of the starch within 18 h. Reactions carried out for up to 96 h showed that, while the enzyme was active, the reaction reached a plateau, achieving a total of 80% starch hydrolysis. Fourier transform infrared (FTIR) spectroscopy revealed that only starch, and not EAA or PE, was affected by enzyme in pulverized samples. Results indicated that while 80% of the starch in these composites was transiently inaccessible, perhaps due to EAA and PE forming an impermeable barrier to the enzyme, the other 20% remained inaccessible to enzymes. Also, the rate of starch digestion as determined by solubilized reducing sugar correlated with the particle size of the pulverized material, suggesting that a large available surface area is critical for rapid starch degradation in such composites.The mention of firms names or trade products does not imply that they are endorsed or recommended by the U.S. Department of Agriculture over the firms or similar products not mentioned. All programs and services of the U.S. Department of Agriculture are offered on a nondiscriminatory basis without regard to race, color, national origin, religion, sex, marital status, or handicap. 相似文献