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1.
In this paper investigation on thermoplastic elastomers (TPE) and thermoplastic vulcanizates (TPV) derived from waste polypropylene
(WPP) of Municipal Solid Waste (MSW) and acrylonitrile-butadiene rubber (NBR) are reported. The WPP was segregated, cleaned,
dried and melt processed with NBR at 180 °C in a Brabender Plasticorder at different blend ratios. TPV was prepared by dynamic
vulcanization of the TPE with conventional sulfur accelerator curing system. The mechanical properties measured were found
to decrease with increase in NBR proportion in the blend; however the dynamic vulcanization of the nitrile rubber phase enhanced
the strength properties of the corresponding TPE. The crystallinity of the WPP reduced with increase in NBR ratio. The dynamic
modulus decreased with nitrile rubber content in the TPE. Interestingly, the storage modulus of the TPV at higher rubber content
enhanced significantly and damping characteristics increased sharply. The rheology studies reveal that the damping of the
blend has been reduced with the addition of high storage modulus rubber at melt processing conditions and hence increased
viscosity. The amorphous rubber content with higher storage modulus imparts higher viscosity for the polypropylene (PP) matrix
at the processing temperature. The SEM study reveals that the dynamic vulcanization of the rubber phase in the blend caused
a smoother and finer surface morphology. 相似文献
2.
Angelaki A. Sakellariou-Makrantonaki M. Tzimopoulos C. 《Water, Air, & Soil Pollution: Focus》2004,4(4-5):241-251
Soil water cumulative infiltration affects the environment by controlling the irrigation rate and consequently the water and pollutants movement through the ground. In order to study the cumulative infiltration in a sandy soil sample, experiments were performed in the laboratory. The sample was placed uniformly in a transparent column with an inner diameter of 6 cm. A constant head boundary condition of a 2 mm height was applied on the surface of the sample and the cumulative volume of the incoming water was measured. Soil moisture at four locations of the column was measured, by using the TDR method in order to obtain the moisture profiles. By comparing the values of the infiltrated water volumes with those calculated by the integration of the moisture profiles, a good agreement was found out. Also the Parlange theoretical model fitted very well with the infiltration experimental points. 相似文献
3.
Francesco Di Maria Caterina Micale Alessio Sordi Giuseppe Cirulli Moreno Marionni 《Waste management (New York, N.Y.)》2013,33(12):2594-2599
The mechanically sorted dry fraction (MSDF) and Fines (<20 mm) arising from the mechanical biological treatment of residual municipal solid waste (RMSW) contains respectively about 11% w/w each of recyclable and recoverable materials. Processing a large sample of MSDF in an existing full-scale mechanical sorting facility equipped with near infrared and 2-3 dimensional selectors led to the extraction of about 6% w/w of recyclables with respect to the RMSW weight. Maximum selection efficiency was achieved for metals, about 98% w/w, whereas it was lower for Waste Electrical and Electronic Equipment (WEEE), about 2% w/w. After a simulated lab scale soil washing treatment it was possible to extract about 2% w/w of inert exploitable substances recoverable as construction materials, with respect to the amount of RMSW. The passing curve showed that inert materials were mainly sand with a particle size ranging from 0.063 to 2 mm. Leaching tests showed quite low heavy metal concentrations with the exception of the particles retained by the 0.5 mm sieve. A minimum pollutant concentration was in the leachate from the 10 and 20 mm particle size fractions. 相似文献
4.
Films of whey protein and chitosan acetic acid salt have lower oxygen permeability than, for example, ethylene-co-vinylalcohol under dry conditions, but water and water vapor seriously impair the gas barrier properties. To reduce the oxygen permeability at 90% relative humidity and the water-vapor transmission rate at 100% relative humidity, the films were coated with an alkyd, a beeswax compound, or a nitrocellulose lacquer. Permeability and transmission rate measurements were performed in accordance with standard methods and showed that the beeswax compound and the nitrocellulose were appropriate as water-vapor barriers. Overall migration to water was measured after 10 days exposure time, with the coated surface exposed to the water, showing that the alkyd-coated and the nitrocellulose-coated films were both below the safety limit for food contact. Water absorbency tests, performed by the Cobb method, showed that the films coated with the beeswax compound or with nitrocellulose lacquer exhibit lower absorbency than the alkyd-coated films. 相似文献
5.
Kris E. Spence Jay-lin Jane Anthony L. Pometto Jr 《Journal of Polymers and the Environment》1995,3(2):69-74
Dialdehyde starch (DAS) and zein, a hydrophobic corn protein, were investigated to produce biodegradable plastics with improved water resistance and mechanical properties. In the study, dialdehyde starch and zein ratio, plasticizers, and degree of starch oxidation were examined. Increased molding temperature and level of starch oxidation decreased water absorption of the plastic. Tensile strength and Young's modulus increased with starch oxidation. The biodegradation of starting materials and ground plastic specimens was studied in aerobic soil reactors maintained at 25°C for 180 days. Biodegradation of corn starch, zein, and dialdehyde starch for 180 days produced CO2 equivalent to 64, 63, and 10% of theoretical carbon, respectively. Specimens of molded DAS and zein (3 : 1) plastic showed accelerated CO2 evolution compared to DAS and other raw materials alone. By 180 days, specimens made with starch of low oxidation (1 and 5% oxidized) demonstrated a 60% biodegradation, and specimens with highly oxidized starch (90% oxidized) achieved 37% biodegradation.Paper presented at the Bio/Environmentally Degradable Polymer Society—Third National Meeting, June 6–8, 1994, Boston, Massachusetts.Journal Paper J-15927 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Project No. 3258. 相似文献
6.
The use of proteins in blending with traditional polymers in the formation of thermoplastics can produce plastics with properties that are superior to traditional petroleum-based plastics. We investigated the physical and thermal properties of albumin and zein thermoplastic blends plasticized with glycerol and mixed with varying amounts of low-density polyethylene (LDPE). Several mechanical models were utilized to determine how tensile properties will be altered when varying amounts of protein/LDPE were added into the thermoplastic blend. When analyzed for thermal properties, we found that as the amount of LDPE in the thermoplastic blend increased, the resulting plastic possessed thermal properties that were more similar to pure LDPE plastics. In terms of mechanical properties, comparison between the experimental data and model predictions points to a synergistic effect between albumin and LDPE that leads to higher modulus, while a potential lack of compatibility between zein and LDPE leads to a plastic with lower modulus. Based on our results, the use of albumin and zein proteins when blended with LDPE in the production of thermoplastics has potential use in the areas of medical and food packaging applications. 相似文献
7.
H. N. Cheng Catrina Ford Francis J. Kolpak Qinglin Wu 《Journal of Polymers and the Environment》2018,26(10):4114-4123
Although hemicellulose is found widely in nature, it is currently under-utilized as a raw material for commercial applications. It would be desirable to find new uses for hemicellulose in order to add value to this agro-based material. A common type of hemicellulose is xylan, which is found in a number of wood species and in cotton. In this work we prepared cationic and anionic xylan derivatives and characterized them by 13C NMR, FT-IR, size exclusion chromatography (SEC), thermal analysis, and rheology. In particular, the 13C NMR spectra of carboxymethyl xylan (CMX) and quaternary ammonium-adducted xylan (QAX) were fully assigned with the help of samples with different degrees of substitution. SEC indicated that the beechwood xylan showed a bimodal molecular weight distribution, but with derivatization the distribution tended to become unimodal. Thermal analysis and rheology studies did not uncover any surprises; the solution of xylan and its derivatives exhibited mostly Newtonian behavior. The blends of CMX and QAX produced a precipitate at almost all ratios, indicating the formation of a polyelectrolyte complex. When cationic and anionic xylan samples were added together to paper, the paper dry strength increased. Thus, the combination of cationic/anionic xylan may be of interest in selected applications. 相似文献
8.
Nour F. Attia Ahmed M. Eid Mohamed A. Soliman Mohamed Nagy 《Journal of Polymers and the Environment》2018,26(3):1072-1077
High quality graphene sheets (GRP) have been exfoliated using facile one pot method through direct ultrasonication of graphite in the presence of polyvinyl alcohol. The GRP were decorated with silver nanoparticles (AgNPs) producing graphene–silver nanoparticle composites. The effect of variation of graphite and silver salt mass ratios on the morphology and performance of produced composites was studied. The size of AgNPs decorated on GRP has been tuned with synthesis method optimization. The average size of AgNPs was found to be in the range of 8.6–15.6 nm. Cotton–polyester blend textile fabrics were treated with the new smart developed composite as antibacterial agent producing new composites. A significant inhibition of bacterial growth has been observed for graphene–silver nanoparticle composite and the antibacterial efficiency was optimized. The clear inhibition zone for textiles treated with new developed composite and AgNPs alone was recorded as 12 and 1.75 mm respectively, achieving more than six fold improvement. 相似文献
9.
Investigation and optimization of composting processes-test systems and practical examples 总被引:4,自引:0,他引:4
Körner I Braukmeier J Herrenklage J Leikam K Ritzkowski M Schlegelmilch M Stegmann R 《Waste management (New York, N.Y.)》2003,23(1):17-26
To determine the optimal course of composting it is useful to carry out experiments. The selection of the right experimental set-up depends on the question of concern. Each set-up is useful for a particular application and has its limits. Two test systems of different scales (up to 1500 ml; up to 100 l) are introduced. The purpose and importance of each system design shall be highlighted by application examples: (1). Suitability of a liquid industrial residue as composting accelerator; (2). Determination of the compost maturity; (3). Behaviour of odor-reducing additives during waste collection and composting; (4). Production of tailor-made compost with respect to Nitrogen (5). Suitability of O(2)-enriched air for acceleration of composting. Small-scale respiration experiments are useful to optimize parameters which have to be adjusted during substrate pre-treatment and composting, with the exception of particle size and temperature, and to reduce the number of variants which have to be investigated in greater detail in larger scale experiments. As all regulation possibilities such as aeration, moistening, turning can be simulated with the technical scale set-up, their complex cooperation can be taken into consideration. Encouraging composting variants can be tested, compared and optimized. 相似文献
10.
Thermodynamic and Diffusion Properties of Biodegradable Systems Based on Starch and Cellulose Derivatives 总被引:1,自引:0,他引:1
A. I. Suvorova I. S. Tjukova E. I. Trufanova 《Journal of Polymers and the Environment》1999,7(1):35-40
The interval sorption and diffusion of water vapor were studied for two systems: methylcellulose (MC)/starch and carboxymethylcellulose (CMC)/starch. The diffusion coefficient of water vapor and the Gibbs free energy of swelling of these blends in water were estimated. The Gibbs free energy of mixing starch with the cellulose derivatives was determined using the thermodynamic cycle. CMC/starch was shown to be more compatible than MC/starch. Biodegradation of these systems in the water–soil environment was measured and found to increase with the concentration of starch in its blends with cellulose derivatives. 相似文献
11.
Tadeusz Grega Dorota Najgebauer Marek Sady Piotr Tomasik 《Journal of Polymers and the Environment》2004,12(1):17-25
Novel biodegradable materials were prepared from potato starch enriched in phosphato moieties (DS 0.018 and 0.033) and casein in defatted milk. The components were blended in proportions providing starch: casein ratios of 2:1, 1:1, and 1:2 and were then precipitated with hydrochloric acid. Aqueous solubility, water-binding capacity, infrared spectra, and thermal analysis (thermogravimetry[7] and differential thermogravimetry of the precipitates revealed that they were not simple physical mixtures of the components. The components interacted with one another electrostatically with involvement of the phosphate groups of starch and the peptide bond of casein, as documented by infrared spectra. Because of insolubility in 7 M aqueous urea solution, they might also be considered as complexes in which the components were chemically bound. 相似文献
12.
13.
In this study, polyethylene terephthalate (PET) waste from post-consumer soft-drink bottles and crude glycerol from the biodiesel industry were used for the preparation of polyols and polyurethane foams. PET waste was firstly depolymerized by the glycolysis of diethylene glycol. The glycolyzed PET oligomers were then reacted with crude glycerol at different weight ratios to produce polyols via a series of reactions, such as esterification, transesterification, condensation, and polycondensation. The polyols were characterized by titration, viscometry, gel permeation chromatography (GPC), and differential scanning calorimetry. Subsequently, polyurethane (PU) foams were made via the reaction between the produced polyols and polymeric methylene-4,4′-diphenyl diisocyanate and were characterized by mechanical testing, scanning electron microscopy, and thermogravimetric analysis. Polyols from crude glycerol and their PU foams were also prepared to compare properties with those of polyols and PU foams from PET and crude glycerol. The influence of aromatic segments existing in glycolyzed PET and glycerol content on the properties of the polyols and PU foams was investigated. It was found that aromatic segments of polyols from glycolyzed PET helped increase their molecular weights and improve thermal stability of PU foams, while high glycerol content in polyols increased the hydroxyl number of polyols and the density and compressive strength of PU foams. 相似文献
14.
15.
Glutaraldehyde cross-linked gelatin was graft copolymerized with acrylic acid, acrylamide, vinyl acetate, methyl acrylate, and methyl methacrylate either individually or in combination. The enzymatic and fungal degradation of these graft copolymers with trypsin, pepsin, and mixed cultures ofAspergillus niger, Penicillium ochrochloron, Penicillium funiculosum, andTrichoderma viride was studied for short and extended periods. The weight loss suffered by the samples, the weight of biomass formed, the nitrogen content, and the pH of the culture medium were determined. With the help of these data, the extent of utilization of graft copolymers by fungi as a sole source of carbon was estimated. The samples with less than 100% grafting and with a ratio of polymethyl methacrylate content (L) to polyacrylic acid (H) content (L/H values) lower than 1.0 were readily and extensively degraded.IICT Communication No. 3375. 相似文献
16.
17.
郑伯康 《再生资源与循环经济》2011,4(11)
在我国转变经济发展方式、调整经济结构的转型期,供销社再生资源行业面临重大的机遇和挑战。对传统再生资源回收企业如何抓住机遇、转变观念、突破创新,进行了深入、全面的分析。 相似文献
18.
This study evaluates the effects of co-gasification of municipal solid waste with and without the municipal solid waste bottom ash using two large-scale commercial operation plants. From the viewpoint of operation data, there is no significant difference between municipal solid waste treatment with and without the bottom ash. The carbon conversion ratios are as high as 91.7% and 95.3%, respectively and this leads to significantly low PCDD/DFs yields via complete syngas combustion. The gross power generation efficiencies are 18.9% with the bottom ash and 23.0% without municipal solid waste bottom ash, respectively. The effects of the equivalence ratio are also evaluated. With the equivalence ratio increasing, carbon monoxide concentration is decreased, and carbon dioxide and the syngas temperature (top gas temperature) are increased. The carbon conversion ratio is also increased. These tendencies are seen in both modes.Co-gasification using the gasification and melting system (Direct Melting System) has a possibility to recover materials effectively. More than 90% of chlorine is distributed in fly ash. Low-boiling-point heavy metals, such as lead and zinc, are distributed in fly ash at rates of 95.2% and 92.0%, respectively. Most of high-boiling-point heavy metals, such as iron and copper, are distributed in metal. It is also clarified that slag is stable and contains few harmful heavy metals such as lead. Compared with the conventional waste management framework, 85% of the final landfill amount reduction is achieved by co-gasification of municipal solid waste with bottom ash and incombustible residues. These results indicate that the combined production of slag with co-gasification of municipal solid waste with the bottom ash constitutes an ideal approach to environmental conservation and resource recycling. 相似文献
19.
Thermodynamic analysis of the role of chlorine and sulfur environments during combustion and incineration processes 总被引:1,自引:0,他引:1
Iddi S.N. Mkilaha Hong Yao Ichiro Naruse 《Journal of Material Cycles and Waste Management》2002,4(2):143-149
In order to control the emission of trace metals from combustion and incineration systems, sorbents and filters are sometimes
used. However, the effectiveness of these methods is greatly affected by the volatility of the metals and the way in which
they speciate during combustion, and afterwards during condensation, and physical or chemical sorption. Although there has
been a lot of research into the mechanisms by which trace metals speciate and subsequently appear in submicron particles,
the details of these mechanisms are not yet thoroughly understood. In this study, a chemical equilibrium approach was used
to qualitatively determine the speciation of lead, cadmium, and chromium in Cl and S environments. The reaction conditions
of sorbents were also tested numerically in order to understand the reaction behavior of metals with sorbents. This article
reports the influence of different concentrations of Cl and SO2 on Pb, Cd, and Cr speciation, as representatives of other trace elements. The partitioning behavior of metals during combustion
was also examined for Cl and S. The results obtained indicate that most metals exist in the vapor phase, even at low temperatures,
when chlorine is present. However, the addition of SO2 enhances the formation of the condensed phase, except at extremely high temperatures. This observation was not significant
for Cd or Cr. The higher the concentration of Cl the higher the retention of trace metals in the vapor phase, even at low
temperatures. Results from comparisons of the reactivities of mixed metals with Cl indicate that the presence of Fe limits
the reactivity of most trace metals with Cl except at higher concentrations. In the presence of Fe, alkali metals are the
first to react with Cl. If Fe is not present, most trace metals react with Cl, and the activity increases with higher concentrations.
On the other hand, the partitioning characteristics of S show that its presence generally means that metals remain in the
condensed phase. Sulfur is more reactive with alkali metals than with other trace metals.
Received: June 6, 2001 / Accepted: April 30, 2002 相似文献
20.
Shouhai Li Chunpeng Wang Xiaowei Zhuang Yong Hu Fuxiang Chu 《Journal of Polymers and the Environment》2011,19(1):301-311
Renewable resource-based composites were prepared with acorn powder and Thermoplastic resin poly(lactic acid) (PLA) by twin-screw
extrusion followed by injection molding processing or hot-compression molding processing. The study of the composites microstructure
showed poor adhesion between acorn powder and PLA matrix. The hygroscopicity, mechanical properties and melt flow property
of composites were promising even though the composites had a 70 wt% content of acorn powder. Silane coupling agent, 4,4′-Methylenebis
(phenyl isocyanate) and PLA grafted with maleic anhydride did not show obvious effect on mechanical properties of composites.
The impact resistance strength of reinforced composites with steel fiber webs were improved greatly in comparison with those
having no steel fiber webs. Thermal properties results of DSC and DMA showed that the presence of acorn powder significantly
affected the crystallinity, crystallization temperature (Tc), glass transition temperature (Tg) and melting temperature (Tm) of PLA matrix. The study results proved that composites had superior mechanical properties, enough to partially replace
the conventional thermoplastic plastics. 相似文献