共查询到20条相似文献,搜索用时 46 毫秒
1.
The aim of the present study is to study the effect of γ-dose rate on the biodegradation of γ-sterilized polyolefins. Films
of isotactic polypropylene, high density polyethylene and ethylene-propylene (EP) copolymer were sterilized under γ-radiation
with doses of 10 and 25 kGy. Two different 60Co sources were used with dose rate 600 and 780 Gy h−1. Neat and sterilized samples were incubated in compost and fungal culture environments. The changes in functional groups,
surface morphology and intrinsic viscosity in polymer chains were characterized by FT-IR spectroscopy, SEM and viscometric
measurements, respectively. It was observed that both γ-degradation and biodegradation processes depend on the dose rate of
γ-source. It was found that the biodegradation of γ-sterilized polyolefins in composting and microbial culture environments
increased with decreasing the γ-dose rate. 相似文献
2.
Guirong Peng Haifeng Wang Haiyan Wang Qiuyun Liu Wenguang Hao 《Journal of Polymers and the Environment》2009,17(3):159-164
Carbonyl iron/epoxy coatings are widely used in military as a radar absorbing coating (RAC). The behaviors of RACs under working
environments are very important, especially in the new environments such as ozone appeared with widening of the application
fields. The effects of ozone degradation on pure epoxy cured with anhydride and the influence of carbonyl Fe on the degradation
of epoxy are studied. The results indicate that if the peak at 1,510 cm−1 was used as the inner standard, the intensity of absorption peaks at 1,738, 1,247 and 1,182 cm−1 increases with exposure time for pure epoxy resin, while for the carbonyl iron/epoxy coatings, the three peaks changes insignificantly
with the exposure time. The results indicates the oxidation process begins at the hydroxyl and methyl groups, and finally
ozonide and carbonyl are formed on the surface for pure epoxy, and epoxy is eroded gradually in depth by ozone. Carbonyl iron
could hinder the meeting of ozone with epoxy with dilution or hindrance effect and could protect epoxy resin from ozone and
thus delay the deterioration of the coating performance. 相似文献
3.
S. P. C. Gon?alves S. M. Martins-Franchetti 《Journal of Polymers and the Environment》2010,18(4):714-719
Poly(hydroxybutyrate-co-valerate) (PHBV) and poly(ε-caprolactone) (PCL) PCL/PHBV (4:1) blend films were prepared by melt-pressing.
The biodegradation of the films in response to burial in soil for 30 days was investigated by Fourier transform infrared spectroscopy
(FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermogravimetry (TG). The PHBV film
was the most susceptible to microbial attack, since it was rapidly biodegraded via surface erosion in 15 days and completely
degraded in 30 days. The PCL film also degraded but more slowly than PHBV. The degradation of the PCL/PHBV blend occurred
in the PHBV phase, inducing changes in the PCL phases (interphase) and resulting in an increase of its crystalline fraction. 相似文献
4.
A. L. S. Schneider D. D. Silva M. C. F. Garcia V. H. Grigull L. P. Mazur S. A. Furlan G. F. Arag?o A. P. T. Pezzin 《Journal of Polymers and the Environment》2010,18(3):401-406
The environmental impact caused by the disposal of plastics has motivated the development of biodegradable materials. Recent
studies showed that supplementation with oleic acid (OA) in cultures producing poly(3-hydroxybutyrate), P(3HB), increased
the polymer productivity. However only few studies have shown the properties and biodegradation profile of the polymer obtained.
This research investigated the influence of OA concentration on the biodegradation of the P(3HB) obtained from cultures of
Cupriavidus necator. The crystallinity of the casting films determined by differential scanning calorimetry (DSC) was reduced from 70% (0 g L−1 of OA) to 52% (3.0 g L−1 of OA). A reduction of 11 °C in the melting temperature was observed with 3.0 g L−1 of OA. The kinetic of biodegradation was: 3.0 > 1.5 > 0.9 > 0.3 > 0 g L−1 of OA. 相似文献
5.
High polymer blends of Polymethyl methacrylate (PMMA) with cellulose acetate (CA) and Cellulose acetate phthalate (CAP) of varying blend compositions have been prepared to study their biodegradation behavior and blend miscibility. Films of PMMA–CA, and PMMA–CAP blends have been prepared by solution casting using Acetone and Dimethyl formamide(DMF) as solvents respectively. Biodegradability of these blends has been studied by four different methods namely, soil burial test, enzymatic degradation, and degradation in phosphate buffer and activated sludge degradation followed by water absorption tests to support the degradation studies. Degradation analysis was done by weight loss method. The results of all the tests showed sufficient biodegradability of these blends. Degradability increased with the increase in CA and CAP content in the blend compositions. The miscibility of PMMA–CA and PMMA–CAP blends have been studied by solution viscometric and ultrasonic methods. The results obtained reveal that PMMA forms miscible blends with either CA or CAP in the entire composition range. Miscibility of the blends may be due to the formation of hydrogen bond between the carbonyl group of PMMA and the free hydroxyl group of CA and CAP. 相似文献
6.
The development of biodegradable mulching films is a great direction for environment protecting and oil saving problems. In
this paper, it was used three kinds of biodegradable mulching films named a, b and c (different ratio between modified starch
and poly-CL with pro-oxidant additives) in microorganism culture test and soil burial test was investigated under laboratory
conditions. The index of degradation was assessed by visual observation, weight loss and SEM analysis from quantitative and
qualitative aspect. The results of both tests showed that these biodegradable mulching films were more readily degraded than
the common plastic film. The percentage weight loss was in sequence of biodegradable mulching film c > biodegradable mulching
film b > biodegradable mulching film a, while common plastic film basically had no changes. Weight loss was not as obvious
as the visual degradation and suggested broader types of microbial attack. SEM analysis clearly indicated that the changes
of surface morphology of these samples after the soil burial exposure. 相似文献
7.
Tadeusz Spychaj Ewa Fabrycy Stanislawa Spychaj Michal Kacperski 《Journal of Material Cycles and Waste Management》2001,3(1):24-31
This paper describes the chemical degradation of waste poly(ethylene terephthalate) (PET) with polyamines or triethanolamine,
the characteristics of the products, and a search for ways to use these products. Solvolysis of the polymer ester bonds was
caused by diethylenetriamine, triethylenetetramine, and their mixtures, as well as mixtures of triethylenetetramine and p-phenylenediamine or triethanolamine. Products of aminolysis or aminoglycolysis of PET obtained in reactions performed at
200–210°C (with a molar ratio of the recurrent polymer unit to amine of 1 : 2) have been characterized using nuclear magnetic
resonance (NMR). Viscosity and hydroxyl number measurements have been done for PET/triethanolamine products. Substances from
aminolytical reactions with polyamines were tested as hardeners for liquid epoxy resins, and the product of polymer aminoglycolysis
with triethanolamine was tested as an epoxy resin hardener, e.g., for water-borne paints, and a polyol component for rigid
polyurethane foams. The compositions of epoxy resin hardeners have been characterized using DSC and rheometry. Comparative
analyses of the hardened epoxy materials have been done on the basis of glass temperature and mechanical properties data,
as well as some specific properties of the coating materials and rigid polyurethane foams.
Received: September 15, 2000 / Accepted: September 21, 2000 相似文献
8.
Charles M. Buchanan Barry G. Pearcy Alan W. White Matthew D. Wood 《Journal of Polymers and the Environment》1997,5(4):209-223
The miscibility of cellulose acetate (CA; degree of substitution = 2.5) and poly(ethylene succinate) (PES) has been investigated
using a variety of thermal techniques and by solid-state carbon13 NMR spectroscopy. The blends containing greater than ca.
70% CA were found to be miscible. In the case of blends containing less than ca. 70% CA, a combination of thermal and NMR
analyses suggests that these blends are not fully miscible on a 2.5- to 5-nm scale. On the scale which can be probed by dynamic
mechanical thermal analysis (15 nm), the low-percentage CA blends exhibit “significant local concentration fluctuations≓.
Investigation of the biodegradation of the blend components and of the blends revealed that PES degraded relatively rapidly
and that CA degraded slowly. The blends degraded at a rate essentially identical to that of CA. Miscibility (75% CA blend)
or crystallization of PES (30% CA blend) had no significant effect. These data suggest that a significant mode of degradation
ófPES during composting involves chemical hydrolysis of the polymer followed by biological assimilation of monomers. Degradation
of the blends is initiated in the amorphous phase. Because CA is a significant component of the amorphous phase, a small amount
of CA significantly impacts the biodegradation rates of the blends. 相似文献
9.
Vinay Sharma J. S. Banait R. C. Larock P. P. Kundu 《Journal of Polymers and the Environment》2010,18(3):235-242
Linseed oil-based polymers have been synthesized via cationic and thermal polymerization and characterized through various
techniques, such as SEM, DMA, DSC and TGA. The morphology of the polymer samples after extraction reveals the smooth structure
of the polymer matrix. With an increase in oil content, the morphology is observed to be more loosely bound. With an increase
in linseed oil content in the samples, the room temperature storage modulus (E′) varies from 10.4 × 107 to 1.8 × 107 Pa. The glass transition temperatures measured through DMA of the cationic samples ranges from 70 to −6 °C and the crosslink
densities range from 18.4 × 103 to 3.4 × 103 mol/m3. The glass transition temperatures of the thermal samples range from 106 to −4 °C and the crosslink densities range from
7.7 × 103 to 2.4 × 103 mol/m3. The TGA results show three stages of degradation of the polymer samples and it is also revealed that these polymers are
stable up to 200 °C, showing negligible decomposition. 相似文献
10.
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
11.
Pilar D. S. C. Mariani Antonio P. Vinagre Neto José P. da Silva Jr. Elke J. B. N. Cardoso Elisa Esposito Lucia H. Innocentini-Mei 《Journal of Polymers and the Environment》2007,15(1):19-24
The biodegradability properties of poly(ɛ-caprolactone) (PCL) and modified adipate-starch (AS) blends, using Edenol-3203 (E)
as a starch plasticizer, were investigated in laboratory by burial tests of the samples in previously analyzed agricultural
soil. The biodegradation process was carried out using the respirometric test according to ASTM D 5988-96, and the mineralization
was followed by both variables such as carbon dioxide evolution and mass loss. The results indicated that the presence of
AS-E accelerated the biodegradation rate as expected. 相似文献
12.
S. P. C. Gonçalves S. M. Martins-Franchetti D. L. Chinaglia 《Journal of Polymers and the Environment》2009,17(4):280-285
Films of poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) and poly(propylene) (PP), PP/PHBV (4:1), blends were prepared by
melt-pressing and investigated with respect to their microbial degradation in soil after 120 days. Biodegradation of the films
was evaluated by Fourier transform infrared spectroscopy, scanning electron microscopy, differential scanning calorimetry,
and X-ray diffraction. The biodegradation and/or bioerosion of the PP/PHBV blend was attributed to microbiological attack,
with major changes occurring at the interphases of the homopolymers. The PHBV film was more strongly biodegraded in soil,
decomposing completely in 30 days, while PP film presented changes in amorphous and interface phase, which affected the morphology. 相似文献
13.
Flávia Gonçalves Domingues Ferreira Maria Alice Gomes de Andrade Lima Yêda Medeiros Bastos de Almeida Glória Maria Vinhas 《Journal of Polymers and the Environment》2010,18(3):196-201
Blends of LDPE/modified starch were prepared, sterilized by gamma radiation and investigated with respect to their microbial
degradation by a mixture of fungal strains in liquid medium after 90 days, was analyzed by carbon dioxide (CO2) production (Sturm test). Biodegradation of blends was evaluated by Fourier transform infrared spectroscopy (FTIR) and X-ray
diffraction; mechanical testing, scanning electron microscopy (SEM). The biodegradation of LDPE/modified starch blends was
attributed to microbiological attack, with alterations in the chemical structure of the blend with an increase in the carbonyl
and vinyl indices and the appearance of new crystalline symmetry generating a crystalline domain not existing before in the
blend and decrease in the mechanical properties. 相似文献
14.
Biofouling and ensuing microbial mediated degradation of Bisphenol A polycarbonate was studied by immersing the samples in
sea water of Bay of Bengal (Chennai, India) for 3 months and also under controlled laboratory conditions with marine mixed
microbial consortia for 12 months. A 9% weight loss in the sample was observed after 1 year of incubation under in vitro laboratory
conditions. A 5% reduction in number average molecular weight and an additional oligomer with a molecular weight of 930 was
observed in the same sample. Contact angle decreased by 11% indicating an increase in the surface hydrophilicity. The specific
heat decreased by 44% and glass transition temperature decreased by 3 °C with respect to the control indicating chain scission.
Formation of new hydroxyl groups and cleavage of carbonate bonds in polycarbonate suggested biodegradation. About 9 μg mL−1 of Bisphenol A, a monomer of polycarbonate, as well as its oxidized products were detected in the supernatant. The nature
of degradation in field and in vitro was different. It was predominantly oxidation in the former and hydrolysis in the later
environment. A strain exhibiting hydrolase activity was isolated at the end of the 12 months from the in vitro mixed consortia
and was identified, based on biochemical and 16S rDNA tests, as Pseudomonas sp. BP2 (GenBank accession no. EU920674). 相似文献
15.
Hynek Beneš Renáta Černá Andrea Ďuračková Petra Látalová 《Journal of Polymers and the Environment》2012,20(1):175-185
The model polyurethane foam and model compact polyurethane material were prepared and then decomposed by means of natural
oils. Castor oil and fish oil based polyol were used in this study. Optimal conditions for the polyurethane decomposition
were found. Temperature 250 °C was necessary for efficient polyurethane decomposition by castor oil whereas 200 °C is sufficient
in the case of fish oil based polyol. Prepared products have hydroxyl number in the range of 95–168 mg KOH g−1. During the polyurethane decomposition no cleavage of double bonds in the fatty acid chains of castor oil and fish oil based
polyol was observed. 相似文献
16.
D. S. Rosa C. G. F. Guedes C. M. Oliveira M. I. Felisberti 《Journal of Polymers and the Environment》2008,16(4):230-240
Mixtures of poly-β-(hydroxybutyrate-co-valerate) PHB-V with virgin and post-consumer low density polyethylene (LDPE) were
prepared by melt mixing in proportions of 100/0, 90/10, 80/20, 70/30 and 0/100 (wt/wt%). The mixtures were analysed by infrared
spectroscopy, differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), melting flow index (MFI),
tensile tests, scanning electron microscopy (SEM) and biodegradation in simulated soil. The DMTA and DSC curves of post-consumer
LDPE suggested that this polymer was a mixture of LDPE and linear low density polyethylene (LLDPE). Virgin and post-consumer
LDPE had lower MFI than PHB-V, but the blends showed higher index as the content of LDPE increased. The addition of LDPE reduced
the tensile strength and Young’s modulus of the mixtures compared with PHB-V. SEM indicated poor interfacial adhesion between
PHB-V and LDPE. PHB-V degraded slow and gradually, while both LDPE showed virtually no degradation under the conditions studied.
The biodegradability of the blends depended on their composition and of the type of LDPE. LDPE improved the biodegradability
of the mixtures. 相似文献
17.
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
18.
Swarnalata Sahoo Hemjyoti Kalita Smita Mohanty Sanjay K. Nayak 《Journal of Polymers and the Environment》2018,26(4):1528-1539
The current study focuses on the development of a formulation of polyester polyurethane (PEPU) samples using castor oil (CO) modified polyester polyol and partially biobased aliphatic isocyanate. The CO modified polyester polyol was synthesized employing transesterification reaction between CO and diethylene glycol in the presence litharge (PbO) catalyst. Subsequently, the modification of CO was confirmed using proton nuclear magnetic resonance (1HNMR) spectra analysis. In the next stage, the biobased polyester polyurethane nanocomposites (PEPUNC) were prepared by incorporating 3 wt% OMMT nanoclay within PEPU through in situ polymerization technique. The produced PEPU was confirmed by Fourier transform infrared spectroscopy (FTIR) and 1HNMR spectra analysis. Further, the degradation properties of developed PEPU subjected to soil-burial, UV exposure and hydrolytic-salt water medium were noted by FTIR spectroscopy. Corresponding weight loss, mechanical measurements and morphological studies through scanning electron microscopy (SEM) analysis were studied. The results showed that the addition of OMMT nanoclay within the PEPU matrix produces significant improvement in the degradation rate which indicated the susceptibility of OMMT nanoclay to humidity upon exposure to soil burial. The produced microorganisms from the soil resulted in significant chemical and morphological changes in the entire structure of the PEPU. Additionally, the highest degradation and percentage of weight loss was observed under soil burial as compared to UV exposure and hydrolytic-salt water medium. 相似文献
19.
Koffi L. Dagnon Christopher Thellen Jo Ann Ratto Nandika A. D’Souza 《Journal of Polymers and the Environment》2010,18(4):510-522
The degradation of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P(3HB-co-4HB)) coated brown Kraft paper and its components in a constructed soil environment was investigated. Soil burial tests were
carried out over 8 weeks. Weight loss measurements, photographic analysis, environmental scanning electron microscopy (ESEM),
dynamic mechanical analysis (DMA) and differential scanning calorimetry (DSC) were conducted to assess the physical, structural,
mechanical and thermal behavior before and after the soil burial test. Paper showed the highest physical degradation and weight
loss. With respect to the control samples, the stiffness of the partially degraded samples decreased. The overall crystallinity
of the biopolymer and the coated paper was affected significantly by burial. The pure biopolymer’s weight loss was substantially
enhanced when coated on paper. This result reveals a possible increased microbial population in the coated paper relative
to the pure biopolymer. 相似文献
20.
Mohammad Taghi Taghizadeh Reza Abdollahi Naser Sadeghpour Orang 《Journal of Polymers and the Environment》2012,20(1):208-216
The degradation of chitosan by means of ultrasound irradiation and its combination with homogeneous photocatalysis (photo-Fenton)
was investigated. Emphasis was given on the effect of additive on degradation rate constants. 24 kHz of ultrasound irradiation
was provided by a sonicator, while an ultraviolet source of 16 W was used for UV irradiation. To increase the efficiency of
degradation process, degradation system was combined with Fe(III) (2.5 × 10−4mol/L) and H2O2 (0.020–0.118 mol/L) in the presence of UV irradiation and the rate of degradation process change from 1.873 × 10−9−6.083 × 10−9 mol1.7 L s−1. Photo-Fenton process led to complete chitosan degradation in 60 min with the rate increasing with increasing catalyst loading.
Sonophotocatalysis in the presence of Fe(III)/H2O2 was always faster than the respective individual processes. A synergistic effect between ultrasound and ultraviolet irradiation
in the presence of Fenton reagent was calculated. The degraded chitosans were characterized by X-ray diffraction (XRD), gel
permeation chromatography (GPC) and Fourier transform infrared (FT-IR) spectroscopy and average molecular weight of ultrasonicated
chitosan was determined by measurements of intrinsic viscosity of samples. The results show that the total degree of deacetylation
(DD) of chitosan change, partially after degradation and the decrease of molecular weight led to transformation of crystal
structure. A negative order for the dependence of the reaction rate on total molar concentration of chitosan solution within
the degradation process was suggested. Results of this study indicate that the presence of catalyst in the reaction medium
can be utilized to reduce molecular weight of chitosan while maintaining the power of irradiated ultrasound and degree of
deacetylation. 相似文献