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951.
Poly-β-hydroxybuyrate (PHB) is a carbon—energy storage material which is accumulated as intracellular granule in variety of
microorganism under nutrient starved conditions. Solid PHB is a biodegradable thermoplastic polymer and is utilizable in various
ways similar to many conventional plastics. Ralstonia eutropha (Alcaligenes sp.), a gram negative bacteria accumulates PHB as insoluble granules inside the cells when nutrients other than carbon are
limited. In this report effort has been made to analyze PHB granule synthesis inside Alcaligenes sp. NCIM 5085 by transmission electron microscopy and qualitative estimation of PHB was carried out by fourier transform
infrared spectroscopy which provide better precision compared to other conventional techniques previously applied for PHB
determination. Maximum PHB concentration of 2.20 ± 0.40 g/L and cell biomass of 3.42 ± 0.20 g/L was obtained after 48.0 h
of fermentation. Leudking-Piret equation deduced mixed growth associated product formation which varies from earlier reports. 相似文献
952.
K. Abdel Tawab M. M. Magida Sayeda M. Ibrahim 《Journal of Polymers and the Environment》2011,19(2):440-446
Blends of water—soluble polymers based on Poly vinyl alcohol (PVA) and Polyethylene glycol (PEG) have been prepared by the
solution casting technique. The effect of various doses of γ-radiation on the structural properties of PVA/PEG polymer blends
with all its compositions has been investigated. From the visual observation of all the blend compositions, it was found that,
the best compatibility of the blend is up to 40% PVA/60%PEG. The structure–Property behavior of all the prepared blends before
and after γ-irradiation was investigated by IR Spectroscopy, thermogravimetric analysis (TGA), mechanical properties and Scanning
electron microscope (SEM). The gel content and the swelling behavior of the PVA/PEG blends were investigated. It was found
that the gel content increases with increasing irradiation dose and PVA concentration in the blend. Swelling percent increased
as the composition of PEG increased in the blend. The results obtained by FTIR analysis and SEM confirm the existence of possible
interaction between PVA and PEG homopolymers. TGA of PVA/PEG blend, before and after γ-irradiation, showed that the unirradiated
and irradiated PVA/PEG blends are more stable against thermal decomposition than pure PVA. Improvement in tensile mechanical
properties of PVA/PEG blends was occurred. 相似文献
953.
Mojtaba Taran Elham Azizi Shahein Taran Nadia Asadi 《Journal of Polymers and the Environment》2011,19(3):750-754
In this study the possibility of poly (3-hydroxybutyrate) production from glycerol was investigated and optimized by Halorcula sp. IRU1, a novel archaea isolated from Urmia lake, Iran in batch experiments. Using Taguchi methodology, three important
independent parameters (glycerol, yeast extract and KH2PO4) were evaluated for their individual and interactive effects on poly (3-hydroxybutyrate) production. It was shown that the
glycerol concentration was the most significant factor affecting the yield of poly (3-hydroxybutyrate). The optimum factor
levels were a glycerol concentration of 8% (v/v), yeast extract 0.8% (w/v) and KH2PO4 0.002% (w/v). The predicted value obtained for poly (3-hydroxybutyrate) production under these conditions was about 81.87%.
We can conclude that Haloarcula sp. IRU1 has a high potential for synthesis of poly (3-hydroxybutyrate) from glycerol. 相似文献
954.
Altaf H. Basta Houssni El-Saied Jerrold E. Winandy Ronald Sabo 《Journal of Polymers and the Environment》2011,19(2):405-412
Investigations have continued for production high performance agro-based composites using environmentally acceptable approaches.
This study examines the role of adding amide-containing biopolymers during synthesis of urea–formaldehyde (UF) on properties
of adhesive produced, especially its adhesion potential. The environmental performance of UF-resin synthesized in the presence
of modified amide-containing biopolymer was evaluated by evaluating the free-HCHO of both adhesive (during processing) and
of the eventual engineered composite product. Also, the benefits of this synthesis-modified adhesive in enhancing the bondability
of sugar-cane fibers used in engineered composite panels was evaluated and compared to using UF-resin. The results obtained
show that, static bending of the produced composites varied from 27.7 to 33.13 N/mm2 of modulus of rupture (MOR) and from 2860 to 3374 N/mm2 of Modulus of Elasticity (MOE); while for internal bond (IB) it’s varied from 0.64 to 0.866 N/mm2. Based on the ANSI and EN Standards modified UF-based agro composites produced meet the performance requirements for high
grade particleboards with respect to static bending strength. These agro-based composite also tested out as having free-HCHO
values of ~13 mg/100 g board. 相似文献
955.
Amir Nourbakhsh Abdollah Hosseinzadeh Farshid Basiji 《Journal of Polymers and the Environment》2011,19(4):908-911
The study was carried out to investigate the effects of filler content and two different compatibilizing agents (Eastman G-3003
and G-3216) on the mechanical properties of polypropylene reinforced with corn stalk and wood flour. In the sample preparation,
three levels of filler loading (30, 40 and 50 wt%) and one level of compatibilizing agent content (2.5 wt%) were used. For
overall trend, with addition of both grades of the compatibilizing agents, tensile and flexural properties of the composites
significantly improved, as compared with the pure PP. Tensile and flexural properties reach a maximum at 40 wt% filler content
and gradually decrease with a further increase in wood particle content. The composites treated with G-3003 gave better results
in comparison with G-3216. This could be caused by the high melt viscosity of G-3003. In general, corn stalk flour filled
composites showed superior mechanical properties. 相似文献
956.
Guang Yang Bo Yang Chao Yuan Weiwei Geng Haizhou Li 《Journal of Polymers and the Environment》2011,19(1):146-151
The effects of manufacturing parameters on mechanical properties of medium density fibreboard (MDF) bonded with modified soy
protein-based glue were studied to find an appropriate manufacture technology. Physical properties of MDF made with different
amount of wax emulsion were measured. Results indicated that water repellent had no obvious influence on physical properties
of soy protein-based MDF boards. The fiberboards bonded with soy protein-based glue showed stronger water resistance properties
than those bonded with urea–formaldehyde (UF) resins. Furthermore, the soy protein-based MDF boards had good quality [25.2%
24 h soak thickness swell (TS), 29.9 MPa modulus of rupture (MOR), 3130 MPa modulus of elasticity (MOE)], which met requirements
of Chinese national standard. Practical processing parameters were obtained by orthogonal experiment, i.e., glue content 8.0%,
hot-press temperature 200 °C, and hot-press time 150 s. 相似文献
957.
Starch nanocomposites have been prepared using mineral clay. Montmorillonite, kaolin and a surface-modified montmorillonite
by dimethyl (hydrogenated tallow alkyl) ammonium cation were used. Starch-g-PCL nanocomposites have been prepared with graft
polymerization through in situ ring-opening polymerization of ε-caprolactone in the presence of starch, Sn(Oct)2 (Tin(II) 2-ethyl hexanoate) as an initiator/catalyst and silicate layers. In fact, the related composites were prepared in
solution method, bulk polymerization and in situ polymerization methods with introducing the mineral clay. The effect of kind
of clay on d-spacing of silicate layers was investigated and the obtained nanocomposites were analyzed using X-ray diffraction.
The obtained compounds were characterized by Fourier transform infrared (FT-IR). Morphology of the prepared nanocomposites
was investigated using scanning electron microscopy and DSC enhanced the study of thermal behaviour of the prepared composite
compounds. 相似文献
958.
Jorge Alberto Vieira Costa Bárbara Catarina Bastos Freitas Camila Gonzales Cruz Jéssica Silveira Michele Greque Morais 《Journal of environmental science and health. Part. B》2019,54(5):366-375
The loss of yields from agricultural production due to the presence of pests has been treated over the years with synthetic pesticides, but the use of these substances negatively affects the environment and presents health risks for consumers and animals. The development of agroecological systems using biopesticides represents a safe alternative that contributes to the reduction of agrochemical use and sustainable agriculture. Microalgae are able to biosynthesize a number of metabolites with potential biopesticidal action and can be considered potential biological agents for the control of harmful organisms to soils and plants. The present work aims to provide a critical perspective on the consequences of using synthetic pesticides, offering as an alternative the biopesticides obtained from microalgal biomass, which can be used together with the implementation of environmentally friendly agricultural systems. 相似文献
959.
es Ruiz de Arcaute Celeste Ossana Natalia A. Pérez-Iglesias Juan Manuel Soloneski Sonia Larramendy Marcelo L. 《Environmental science and pollution research international》2019,26(20):20485-20498
Environmental Science and Pollution Research - Pesticides might increase the production of reactive oxygen species (ROS). Dicamba (DIC) and 2,4-dichlorophenoxyacetic acid (2,4-D) are auxinic... 相似文献
960.
de Carvalho George Harrison Ferreira de Andrade Milene Aparecida de Araújo Carla Nunes Santos Maria Lucília de Castro Natália Alves Charneau Sébastien Monnerat Rose de Santana Jaime Martins Bastos Izabela Marques Dourado 《Environmental science and pollution research international》2019,26(6):5514-5523
Environmental Science and Pollution Research - Aedes aegypti and Culex quinquefasciatus are vectors of diseases that constitute public health problems. The discovery of products capable of... 相似文献