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C. Wretfors S.-W. Cho M. S. Hedenqvist S. Marttila S. Nimmermark E. Johansson 《Journal of Polymers and the Environment》2009,17(4):259-266
The next generation of manufactured products must be sustainable and industrially eco-efficient, making materials derived
from plants an alternative of particular interest. Wheat gluten (WG) is an interesting plant material to be used for production
of plastic similar materials due to its film-forming properties. For usage of plastics in a wider range of applications, composite
materials with improved mechanical properties are demanded. The present study investigates the possibilities of reinforcing
WG plastics with hemp fibers. Samples were manufactured using compression molding (130 °C, 1600 bar, 5 min). Variation in
fiber length, content (5, 10, 15 and 20 wt%) and quality (poor, standard, good) were evaluated. Mechanical properties and
structure of materials were examined using tensile testing, light and scanning electron microscopy. Hemp fiber reinforcement
of gluten plastics significantly influenced the mechanical properties of the material. Short hemp fibers processed in a high
speed grinder were more homogenously spread in the material than long unprocessed fibers. Fiber content in the material showed
a significant positive correlation with tensile strength and Young’s modulus, and a negative correlation with fracture strain
and strain at maximum stress. Quality of the hemp fibers did not play any significant role for tensile strength and strain,
but the Young’s modulus was significantly and positively correlated with hemp fiber quality. Despite the use of short hemp
fibers, the reinforced gluten material still showed uneven mechanical properties within the material, a result from clustering
of the fibers and too poor bonding between fibers and gluten material. Both these problems have to be resolved before reinforcement
of gluten plastics by industrial hemp fibers is applicable on an industrial scale. 相似文献
3.
Extruded films of plasticized starch were doped with metal halides to produce solid ion-conducting materials. The electrical conductance of the material increased from 10–11 to 10–6 Siemens/cm. The type and amount of dopant affects the conductance of the material. Although the materials are moisture sensitive, water content does not have a significant effect on the conductance of doped films. Mechanical properties of doped films indicate that the starch is plasticized and that the ion-conducting material is strong and tractable. Unlike intrinsically conductive polymers, electroactive starch materials can be extruded in thin films or molded into any shape. 相似文献
4.
Solidification of sewage sludge has been actively investigated in Japan and Europe since the 1970s. Most previous studies
have focused on only the mechanical aspects of potential alternative cover soil made using sewage. Most solidification processes,
however, suffer from severe odor problems because of the high alkalinity of the material. The objectives of this study are
to develop a cost-effective solidifying agent for conversion of sewage sludge in order to reduce the odor generation, as an
alternative to the conventional cement lime-based solidifying agent, and to demonstrate its applicability in the field experimentally.
Field test results showed compressive strength well above the 1.0 kg/cm2 criterion for landfill cover soil in Korea. Also, the permeability coefficient was far below the 5 × 10−5 cm/s design criterion for landfill cover soil. Even in harsh weather conditions, such as in winter and summer, the compressive
strength was increased. In addition, the permeability was decreased from 3.45 × 10−6 cm/s to 4.78 × 10−7 cm/s, and from 2.27 × 10−6 cm/s to 3.62 × 10−7 cm/s, at 7 days after placement in January and August, respectively. It can therefore be postulated that the proposed solidification
process is an appropriate alternative for production of daily landfill cover material. Concerning the odor problem, 5 min
of mixing of sewage with TS103, one of the proprietary agents used in this work, was sufficient to suppress the concentration
of ammonia emitted to below 10 ppm. Considering all of these experimental field test results, it is expected that the proposed
method could be a competitive approach for manufacture of alternative landfill cover material. 相似文献
5.
The Effect of Masterbatch Addition on the Mechanical, Thermal, Optical and Surface Properties of Poly(lactic acid) 总被引:1,自引:0,他引:1
F. Byrne P. G. Ward J. Kennedy N. Imaz D. Hughes D. P. Dowling 《Journal of Polymers and the Environment》2009,17(1):28-33
There has been considerable interest in the use of the biodegradable polymer poly(lactic acid) (PLA) as a replacement for
petroleum derived polymers due to ease of processability and its high mechanical strength. Other material properties have
however limited its wider application. These include its brittle properties, low impact strength and yellow tint. In an attempt
to overcome these drawbacks, PLA was blended with four commercially available additives, commonly known as masterbatches.
The effect of the addition of 1.5 wt% of the four masterbatches on the mechanical, thermal, optical and surface properties
of the polymer was evaluated. All four masterbatches had a slight negative effect on the tensile strength of PLA (3–5% reduction).
There was a four fold increase in impact resistance however with the addition of one of the masterbatches. Differential scanning
calorimetry demonstrated that this increase corresponded to a decrease in the polymer crystallinity. However there was an
associated increase in polymer haze with the addition of this masterbatch. The clarity of PLA was improved through the addition
of an optical brightener masterbatch, but the impact resistance remained low. The glass transition and melting temperatures
of PLA were not affected by the addition of the masterbatches, and no change was observed in surface energy. Some delay in
PLA degradation, in a PBS degradation medium at 50 °C, was observed due to blending with these masterbatches. 相似文献
6.
Shin-ichi Sakai Yasuhiro Hirai Hirofumi Aizawa Shizuko Ota Yasuhiro Muroishi 《Journal of Material Cycles and Waste Management》2006,8(1):56-62
Atmospheric emissions of deca-brominated diphenyl ether (DBDE) in Japan were estimated based on the material flow of DBDE
products and their emission factors. In 2002, the demand for DBDE in Japan was 2200 ton/year and the stock level was about
60 000 ton. The DBDE flow into the waste stream was estimated to be about 6000 ton/year and the flow out through second-hand
product exports was more than 700 ton/year. Home appliance recycling facilities dismantle and crush domestic wastes containing
about 600 ton of DBDE annually. Material recycling of crushed plastics is not commonly practiced as yet. Emission factors
from plastics processing (2 × 10−9–1 × 10−7), textile processing (9 × 10−7), home appliance recycling (8 × 10−9–5 × 10−6), and waste incineration (1 × 10−7–2 × 10−6) were estimated using field measurement data. The DBDE emission rate through house dust during the service life of final
products (2 × 10−7–9 × 10−7 per year) was estimated using the DBDE concentration in dust and the amount of dust in used televisions. Emission factors
from previous studies were also used. The estimated total DBDE emission was 170–1800 kg/year. These results suggest the necessity
of characterizing emissions during the service life of products, which is essential information for formulating an appropriate
e-waste recycling strategy. 相似文献
7.
Volatilization and biodegradation are major competitive volatile organic compound (VOC) removal mechanisms in biological wastewater
treatment process, which depend on compound specific properties and system design/operational parameters. In this study, a
mathematical model was used to determine major removal pathways at various organic loading rates (OLR), solids residence time
(SRT) and dissolved oxygen (DO) concentrations in a biological process for vinyl acetate. Model results showed that biological
treatment process should be designed with long SRT, high OLR and low DO concentrations to maximize biodegradation and minimize
volatilization of VOCs. Unless a VOC is toxic to microorganisms under the given conditions, low VOC emission rates are an
inherent advantage of MBRs, which operate at higher OLR and longer SRT compared to conventional activated sludge process.
A lab scale membrane bioreactor (MBR) was operated at varying OLR to investigate the relative volatilization and biodegradation
rates for acetaldehyde, butyraldehyde and vinyl acetate. Synthetic wastewater containing three VOCs was introduced to the
MBR. The DO concentration and SRT was maintained at 2.0 mg L− 1 and 100 days, respectively. The overall VOC removal rate was more than 99.7% for three VOCs at all the OLR. For vinyl acetate,
the biodegradation rate increased from 93.87 to 99.40% and the volatilization removal rate decreased from 6.09 to 0.59% as
OLR was increased from 1.1 to 2.0 kg COD m− 3 d− 1. It was confirmed that a MBR can be a promising solution to reduce VOC emissions from wastewater. 相似文献
8.
Effect of Crystalline and Amorphous Structures on Biodegradability of Poly(Tetramethylene Succinate)
The effect of orientation in the amorphous and crystalline regions on the biodegradability of PTMS [poly(tetramethylene succinate)] was studied using the amorphous orientation function, birefringence, and crystallinity. The crystalline and amorphous intrinsic lateral sonic moduli, E
t,c
0
and E
t,am
0
, were 2.61 × 103 and 0.41 × 103 MPa, respectively. Using the data on birefringence, crystalline and amorphous orientation function (f
and f
am), crystallinity, and sonic modulus of the oriented PTMS fibers, the intrinsic birefringence of the crystalline (
c
0
) and amorphous (
am
0
) regions were evaluated to be 0.0561 and 0.0634, respectively. The biodegradabilities of oriented PTMS films were reduced as the elongation increased, i.e., the amorphous orientation increased. At low elongation (100 and 150%), however, biodegradabilities remained unchanged when the degradation test was performed in activated sludge, which was attributed to the amorphous orientation occurring even at 100% elongation, though the amorphous orientation direction was perpendicular to the fiber axis. 相似文献
9.
Improvement in the feeding method to an inclined conveyor designed for the recycling of foundry sand
H. Ohya S. Endoh T. Honma Y. Hamano 《Journal of Material Cycles and Waste Management》2003,5(1):0049-0054
The goal of the inclined conveyor method for particle shape separation is to process a large amount of feed material for
recycling technology. The high feed rate has been achieved because the movement of particles is faster than for other previously
introduced equipment. The separation performance of the apparatus was tested with foundry sand. A large amount of sand was
treated, and various processing capacities were studied experimentally. The feed method was improved from point to line with
wide troughs to process the higher feed rate. We succeeded in attaining a feed rate of 1.49 × 10−3 kg/s with a 0.3-m trough. The space filling, which was an important factor in deciding the capacity of the feed rate, was
defined. This method is useful for any kind of line-feed method.
Received: March 25, 2002 / Accepted: August 5, 2002 相似文献
10.
Switchgrass (SG) stems with lengths up to 10 cm have been used as reinforcement to make lightweight composites with polypropylene
(PP) webs. The long SG stems, with simple cut or split and without chemical treatment, were used directly in the composites.
Utilizing SG stems for composites not only increases the values of SG but also provides a green, sustainable and biodegradable
material for the composites industry. Lightweight composites are preferred, especially for automotive applications due to
the potential saving in energy. In this research, the effects of manufacturing parameters on the properties of composites
have been studied. Although the tensile properties of SG stem are significantly worse than jute fiber, SG stem with low bulk
density is found to better reinforce the lightweight composites. Compared with the jute-PP composites of the same density
(0.47 g/cm3), composites reinforced by the split SG stems have 56% higher flexural strength, 19% higher modulus of elasticity, 15% higher
impact resistance, 63% higher Young’s modulus, 52% lower tensile strength, and similar sound absorption property. The SG-PP
composites with optimized properties have the potential to be used for industrial applications such as the support layers
in automotive interiors, office panels and ceiling tiles. 相似文献
11.
M. Masud K. Khan Carlos J. Hilado Sushant Agarwal Rakesh K. Gupta 《Journal of Polymers and the Environment》2007,15(3):188-194
Acrylonitrile–Butadiene–Styrene (ABS), Polycarbonate (PC) and their alloys are widely used in automotive industry, computer
and equipment housings. With increasing disposal of end-of-life electronic equipment, there is also an increased demand for
recycling of these materials so that they do not pose environmental challenge as solid waste. One of the recycling approaches
is mechanical recycling of these thermoplastics where recycled plastic is melt blended with virgin materials to obtain a high
quality product. Besides obtaining desirable mechanical properties, such blends should also conform to fire safety standards.
In this work, a series of blends were prepared using PC and ABS recovered from discarded computers and virgin materials using
a twin-screw extruder. Their flammability properties were evaluated using burner flammability tests and Ohio State University
(OSU) release rate tests. It was found that the extinguishing time, burning extent and weight loss appears to progressively
decrease with the addition of both virgin or recycled PC to virgin or recycled ABS. It was also seen that the addition of
the 70% of PC, virgin or recycled, to ABS virgin or recycled, appears to significantly decrease heat release and smoke evolution.
The results of this study indicate that recycled polycarbonate can be used as an additive for virgin or recycled ABS, as a
means of giving flame resistance to ABS in high-value applications. This result is significant when related to the result
obtained by a separate study indicating that up to 25% of recycled material can be used without degradation of mechanical
properties in the presence of 15% short glass fiber reinforcement. 相似文献
12.
Masahiro Shimada Takahiko Iida Kensuke Kawarada Takayuki Okayama Masami Fushitani 《Journal of Material Cycles and Waste Management》2001,3(2):135-143
We have already reported the adsorptivity and pore structure of activated carbon made from waste newspaper in order to use
the waste paper for purposes other than paper-making stock. However, manufacturing the activated carbon may not necessarily
be an advantageous method based on environmental concerns and the effective use of the resource because the reaction during
the activating process is endothermic and the amount of carbon consumed is significant. Here, we examine the pore structure
and adsorption properties of waste newspaper used as an adsorbent in the form of a carbonized material. Waste newspaper was
carbonized for 2 h in the temperature range 400°–1000°C. The specific surface area of the carbonized material obtained, 418 m2/g, was highest for the sample carbonized at 800°C, which was equal to or greater than that of commercially available charcoal.
Moreover, the iodine adsorption number of 581 mg/g was the highest and the rate of adsorption was the fastest for the sample
carbonized at 800°C. However, the humidity control capability was highest for the material carbonized at 600°–700°C. It has
been determined that it is advantageous to carbonize waste paper at 800°C in order to use the carbonized material as an adsorbent,
while carbonization at 600°–700°C is more advantageous for use as a humidity control material.
Received: June 23, 2000 / Accepted: January 17, 2001 相似文献
13.
A fed-batch process was developed, which allowed biotechnological production of the homopolyester poly(3-hydroxyvaleric acid) [poly(3HV)], in a mineral salts medium containing valeric acid as carbon source and complex nutrients as supplements byChromobacterium violaceum at a 10- and 300-L fermentation scale. This process yielded up to 40 g dry cell matter per L fermentation broth, and the cells contained up to 70% (w/w) poly(3HV). Poly(3HV), which was extracted from the cells with chloroform and was precipitated from this solvent with ethanol, was processed to test bars by injection molding or by press processing and to fibers by melt spinning. The unprocessed and processed poly(3HV) material was characterized with respect to the molecular weight and with respect to thermal, rheological, and mechanical properties. It was shown that it is possible to process biodegradable poly(3HV) thermoplastically and to obtain a polymer suitable for applications with low strength requirements. 相似文献
14.
Sílvia Maria Martelli Geovana Rocha Plácido Moore João Borges Laurindo 《Journal of Polymers and the Environment》2006,14(3):215-222
In poultry industry chicken feathers are normally hydrolyzed and used to prepare animal feed. In this work the use of this material to prepare films was investigated. Keratins were extracted from chicken feathers with 2-mercaptoethanol in concentrated urea solution using sodium dodecyl sulfate (SDS). The effect of varying the amount of sorbitol on properties of chicken feather keratin (CFK) was investigated. As the concentration of plasticizer increased, the moisture content (MC) of these films increase, the monolayer MC increased from 0.060 (without plasticizer) to 0.482 g water/g dry matter (0.30 g sorbitol/g keratin). The water vapor permeability (WVP) varied between 0.096 g/m s Pa and 8.098 g/m s Pa for films without sorbitol and with 0.30 g sorbitol/g keratin, respectively. Film strength decreased from 5.13 MPa to 0.45 MPa and the elongation at break achieved the maximum value of 52.75% for samples with 0.02 g sorbitol/g keratin. The dry matter density didn’t change significantly, varying between 0.86–0.89 g/cm3 for all samples. Films with potential applications in food packaging can be obtained from CFKs. However, further researches are necessary to decrease film solubility and increase mechanical resistance. 相似文献
15.
J. P. Lopez J. Girones J. A. Mendez J. Puig M. A. Pelach 《Journal of Polymers and the Environment》2012,20(1):96-103
The effect of multiple injection-moulding reprocessing of three biodegradable matrices on their mechanical properties, melt
flow rate, molecular weight, phase transition temperatures and degradation temperature is presented. It has been found that,
with successive reprocessing, tensile, flexural and impact strength decreased. Drop in mechanical properties has been assigned
to degradation of the matrices, as corroborated by melt flow and molecular weight analysis. Although reprocessing did not
significantly affect the glass transition, it diminished the melting point and degradation temperature of polymers. Results
indicate that neat PLLA can be recycled for up to five times without suffering a drastic loss in mechanical and thermal properties.
The aliphatic polyester Mater-Bi TF01U/095R can be recycled for up to 10 times, whilst starch-based Mater-Bi YI014U/C wastes
should be destined to composting, since its recyclability is very poor. The effect of reprocessing on composites reinforced
with chemithermomechanical pulp (CTMP) followed the tendencies observed for the neat matrices. Whilst CTMP-fibres behave mainly
as filler in PLLA composites, reinforced thermoplastic starch-based composites presented enhanced mechanical properties and
recyclability. 相似文献
16.
Mahesh A. Kotnis Gregory S. O'Brien J. L. Willett 《Journal of Polymers and the Environment》1995,3(2):97-105
Poly(hydroxybutyrate-co-valerate) (PHBV) is a completely biodegradable thermoplastic polyester produced by microbial fermentation. The current market price of PHBV is significantly higher than that of commodity plastics such as polyethylene and polystyrene. It is therefore desirable to develop low-cost PHBV based materials to improve market opportunities for PHBV. We have produced low-cost environmentally compatible materials by blending PHBV with granular starch and environmentally benign CaCO3. Such materials can be used for specific applications where product biodegradability is a key factor and where certain mechanical properties can be compromised at the expense of lower cost. The inclusion of granular starch (25 wt%) and CaCO3 (10 wt%) in a PHBV matrix (8% HV, 5% plasticizer) reduces the cost by approximately 40% and has a tensile strength of 16 MPa and flexural modulus of 2.0 Gpa, while the unfilled PHBV/plasticizer matrix has a tensile strength of 27 MPa and a flexural modulus of 1.6 GPa.Paper presented at the Bio/Environmentally Degradable Polymer Society—Third National Meeting, June 6–8, 1994, Boston, Massachusetts.The mention of firm names or trade products does not imply that they are endorsed or recommended by the U.S. Department of Agriculture over other firms or similar products not mentioned. 相似文献
17.
This paper investigates and compares the performances of polylactic acid (PLA)/kenaf (PLA-K) and PLA/rice husk (PLA-RH) composites
in terms of biodegradability, mechanical and thermal properties. Composites with natural fiber weight content of 20% with
fiber sizes of less than 100 μm were produced for testing and characterization. A twin-screw extrusion was used to compound
PLA and natural fibers, and extruded composites were injection molded to test samples. Flexural and Izod impact test, TGA,
soil burial test and SEM were used to investigate properties. All results were compared to a pure PLA matrix sample. The flexural
modulus of the PLA increased with the addition of natural fibers, while the flexural strength decreased. The highest impact
strength (34 J m−1), flexural modulus (4.5 GPa) and flexural strength (90 MPa) were obtained for the composite made of PLA/kenaf (PLA-K), which
means kenaf natural fibers are potential to be used as an alternative filler to enhance mechanical properties. On the other
hand PLA-RH composite exhibits lower mechanical properties. The impact strength of PLA has decreased when filled with natural
fibers; this decrease is more pronounced in the PLA-RH composite. In terms of thermal stability it has been found that the
addition of natural fibers decreased the thermal stability of virgin PLA and the decrement was more prominent in the PLA-RH
composite. Biodegradability of the composites slightly increased and reached 1.2 and 0.8% for PLA-K and PLA-RH respectively
for a period of 90 days. SEM micrographs showed poor interfacial between the polymer matrix and natural fibers. 相似文献
18.
We investigated the thermal properties and behavior of bromine on the thermal decomposition of paper-based phenolic laminate
wastes containing polybrominated flame retardants. The thermal properties of the phenolic laminate wastes were measured with
a thermogravimeter and a conduction-type scanning calorimeter (TG-CSC). The weight loss of the wastes on thermal decomposition
was mainly in three phases between 40°C and 600°C. The enthalpy (ΔH) of the thermal decomposition was 104 cal/g. The material balance of the decomposition components was measured with batch-type
thermal decomposition equipment. The ratios of carbon residue, liquid, and gas on decomposition at 800°C in a vacuum were
37 wt. %, 48 wt. %, and 15 wt. %, respectively. The bromine contents in the carbon residue and liquid were less than 0.02 wt.
% and 10 wt. %, respectively. These results are useful both in the carbonization process of these wastes and in the application
of carbon residue as carbon materials.
Received: August 11, 2000 / Accepted: March 7, 2001 相似文献
19.
Mining activities generate a large amount of solid waste, such as waste rock and tailings. The surface disposal of such waste can create several environmental and geotechnical problems. Public perception and strict government regulations with regards to the disposal of such waste compel the mining industry to develop new strategies which are environmentally sound and cost effective. In this scenario, recycling of such waste into mining or civil engineering construction materials have become a great challenge for the mining and civil engineering community. Hence, in this study, taking advantage of the inherent low hydraulic conductivity of paste tailings (pastefill), small amounts (0.05, 0.1, 0.2, 0.5%) of a super absorbent polymer (SAP) are added to the latter after moisturizing the tailings. The resulting densified polymer-pastefill (PP) materials are compacted and submitted to permeability tests at room temperature and performance tests under cyclic freeze–thaw and wet–dry conditions to evaluate their suitability as a barrier for waste containment facilities. Valuable results are obtained. It is found that the hydraulic conductivity of the proposed barrier material (PP) decreases as the amount of SAP increases. Hydraulic conductivity values as low as 1 × 10?7 and 6 × 10?9 cm/s are obtained for PPs which contain 0.1–0.5% SAP, respectively. The PP material also shows relatively good resistance to cyclic freeze–thaw and wet–dry stresses. The results show that negligible to acceptable changes in hydraulic conductivity occur after five freeze–thaw and six wet–dry cycles. None of the changes reach one order of magnitude. As a final step, a cost analysis is undertaken to evaluate the economical benefits that could be drawn from such a proposed barrier material. When compared to a conventional compacted sand–bentonite barrier with 12% bentonite concentration, it is found that the benefit realized could be estimated to 98, 96 and 90% when using PP material that contains 0.10, 0.20 and 0.5% of SAP. From this study, it can be concluded that PP materials show encouraging performance properties for barrier design. 相似文献
20.
Fabian Knappich Martin Schlummer Andreas Mäurer Harald Prestel 《Journal of Material Cycles and Waste Management》2018,20(3):1541-1552
Galvanized or “chromium-plated” plastics are well known to the consumer from the automotive sector and sanitary area. Polymers such as acrylonitrile butadiene styrene (ABS) are typically coated with a layer system of chromium, nickel and copper to obtain the characteristic optical surface and resistance properties. Due to the complex manufacturing process and high quality requirements, the production of these plastic metal composites generates 10–30% of rejects. We, therefore, developed an innovative process cascade for the recovery of both components (metal and polymer) applying established technologies (mechanical pre-treatment, classification, melt filtration, CreaSolv® Process) and were able to obtain ABS regranulate having excellent properties regarding the characteristic values for strength but slight compromises in impact characteristics. Blends with different amounts of virgin ABS, virgin PC and recycled ABS material as well as the pure cases were successfully re-metallized, all of them passing adhesion test, thermal shock resistance and CASS test. The high purity of the recovered materials led to increased redemption prices for metal and polymer by a factor of 6 and 2.5, respectively. Thus, the value added of metallized plastic waste is maximized, revealing a highly positive economic prognosis of a commercial implementation of the developed process—even at moderate scale. 相似文献