共查询到14条相似文献,搜索用时 15 毫秒
1.
Bruna Castro Porto Pedro Esteves Duarte Augusto Marcelo Cristianini 《Journal of Polymers and the Environment》2015,23(3):392-399
Arabic gum (AG) is the most common emulsifier used for beverage emulsions. Cashew tree gum (CG) is a biological macromolecule that has been proposed as a substitute for the AG, although their technological properties comparison is still necessary. The aim of this study was to evaluate an isolation method for CG, and then evaluate CG technological properties in comparison to AG. The CG isolation methodology was improved using a small solvent amount. CG zeta-potential ranged from +8.0 mV (pH 2) to ?9.7 mV (pH 5), while the electric charge in solution of AG ranged from ?2.7 mV (pH 2) to ?28.6 mV (pH 6). As compared to AG, the CG showed a 50 % higher swelling, a 36 % lower oil absorption capacity, a slightly lower (4–8 %) solubility and lower consistency. CG is a feasible polyelectrolyte, promotes lower consistency solutions, and exhibits good swelling property. 相似文献
2.
Present work deals with the surface modification of Cannabis indica fiber through benzoylation and graft copolymerization of acrylonitrile (AN) onto C. indica fibers under the influence of microwave radiations. The Benzoylation of C. indica fiber was carried out by treating raw fiber with varying concentrations of benzoyl chloride solution. Different reaction parameters for graft copolymerization, such as reaction time, initiator concentration, nitric acid concentration, pH and monomer concentration were optimized to get the maximum percentage of grafting (25.54%). A suitable mechanism to explain benzoylation and graft copolymerization has been also proposed. Raw C. indica fiber, graft copolymerized and benzoylated fibers were subjected to evaluation of some of their properties like swelling behavior, moisture absorbance and resistance towards chemicals. Cannabis indica fibers treated with 5% benzoyl chloride solution and AN graft copolymerized fibers have been found to show more resistant towards moisture, water and chemicals when compared with that of untreated fibers. Morphological, structural changes, thermal stability and crystallanity of raw, graft copolymerized and benzoylated fibers have also been studied by SEM, FTIR, TGA and XRD techniques. It has been observed that the crystallinity of fiber decreases but thermal stability increases on surface modification. 相似文献
3.
Soares Ana Paula S. Mothé Cheila G. Mothé Michelle G. 《Journal of Polymers and the Environment》2022,30(4):1380-1390
Journal of Polymers and the Environment - The present research aims to propose a comparative life cycle assessment (LCA) between the coffee capsules recycling process and the process of obtaining... 相似文献
4.
Jörg Müssig 《Journal of Polymers and the Environment》2008,16(2):94-102
Natural fibres offer an interesting alternative to petrochemical products. Reclaimed cotton is mainly used as a low cost fibre to “fill” composites used as interior parts in the automotive industry. Mechanical requirements of such composites are low and the potential of the cotton-fibre to reinforce plastics is not used adequately. This paper gives background information and discusses the use of the cotton fibres in composites compared to ramie fibres. In this study the fibre strength was tested with a Dia-Stron device, fineness was tested with Fibreshape. A roller card is well suited to process fibres to a multi layer web. Cotton and ramie fibres were embedded in epoxy resin and a bio-based resin PTP®. The composites were tested for impact and tensile properties. The results show that mechanical properties of the composites are strongly influenced by fibre properties. The data and results demonstrate the important role force-elongation characteristics of fibre play in optimising the properties of natural fibre composites. Cotton with its morphological and mechanical properties can play a more crucial role to optimise products with a view to improve the impact properties. 相似文献
5.
Meriem Fardioui Taoufik Guedira Abou El Kacem Qaiss Rachid Bouhfid 《Journal of Polymers and the Environment》2018,26(2):443-451
The aim of this paper was to study the effects of reinforcing low density polyethylene (LDPE) by using bio-fillers (Doum cellulose or Shrimp chitin) on the mechanical properties. Both, Doum cellulose extracted frsom Doum leaves and Shrimp chitin extracted from shrimp co-products were compounded with LPDE without and with compatibilizer. The biocomposites were prepared by melt blending in a twin-screw extruder. Torsion and flexural tests were performed to investigate the impact of each reinforcement on the biocomposite mechanical properties. The SEM was carried out to study the filler/polymer interface adhesion. The present study has demonstrated that Doum fibers and shrimp chitin succeed in improving the mechanical properties of LPDE bio-composites. The results also showed that the use of maleic anhydride-grafted polyethylene as a compatibilizer improves filler adhesion/matrix and mechanical properties. This study exhibits that polyethylene composites based on Doum fibers or shrimp chitin can be used to replace the polyethylene materials in several fields like packaging and automotive industries. 相似文献
6.
Performance of Trickle-Bed Air Biofilter: A Comparative Study of a Hydrophilic and a Hydrophobic Voc
Two lab-scale trickle-bed air biofilters were operated for investigating the difference in performance between a hydrophilic
and a hydrophobic volatile organic compound (VOC). Methyl isobutyl ketone (MIBK) and styrene were selected as a model hydrophilic
and hydrophobic VOCs, respectively. Effects of loading rates, biofilter re-acclimation, removal profile along biofilter depth,
nitrogen consumption, and CO2 production were compared under three operating conditions, namely, backwashing and two non-use periods (starvation and stagnant).
Consistent over 99% removal efficiency up to loading rates of 3.26 kg COD/m3-day was obtained for the MIBK biofilter at 0.76 min empty bed retention time (EBRT) and 1.5 L/d nutrient flow. A similar
performance for the styrene biofilter was obtained for loading rates up to 1.9kg COD/m3-day at 2.02 min EBRT and 2.4 L/d nutrient flow. The MIBK biofilter required only an initial acclimation period of 16 days
while styrene biofilter required 46 days. Non-use periods can be used as another means of biomass control for both biofilters
when the employed loading rate did not exceed 1.27 and 2.17 kg COD/m3-day for styrene and MIBK biofilters, respectively. The re-acclimation of both biofilter was delayed with increase of loading
rate. MIBK biofilter re-acclimated in 90 min, while styrene biofilter re-acclimated in more than 600 min. Under similar loading
rates, MIBK biofilter utilized less biofilter depth than styrene biofilter. Nitrogen consumption behaviors were apparently
different between the two biofilters. Styrene biofilter had higher CO2 production than MIBK biofilter and its CO2 production was closely related to the theoretical complete chemical oxidation. 相似文献
7.
Talaei Aisona Ashori Alireza Heydari Vahid 《Journal of Polymers and the Environment》2022,30(10):4263-4270
Journal of Polymers and the Environment - This study aims to make environment-friendly plywood panels acceptable in terms of both mechanical and physical properties using chitosan as a natural... 相似文献
8.
Tridib Tripathy Haradhan Kolya Subinoy Jana 《Journal of Polymers and the Environment》2018,26(3):926-937
Synthesis of sodium alginate-g-poly(acrylamide-co-N-methylacrylamide) [S-III], sodium alginate-g-poly(N-methylacrylamide-co-N,N-dimethylacrylamide) [S-II], sodium alginate-g-poly(acrylamide-co-N,N-dimethylacrylamide) [S-I]. Sodium alginate-g-poly(N,N-dimethylacrylamide) [SAG-g-PDMA] and sodium alginate-g-poly(acrylamide) [SAG-g-PAM] were prepared by solution polymerization technique using potassium peroxydisulfate as the initiator at 70?°C in water medium. The graft copolymers were characterized by FTIR and NMR (1H and 13C) spectroscopy, SEM and XRD studies. All the five graft copolymers were used to remove Pb(II) ions from the aqueous solution and also in flocculation studies of kaolin clay (1.0 wt%), silica (1.0 wt%) and iron ore slime (0.25 wt%) suspensions. A comparative studies of all the five graft copolymers were also made in both the two cases. The Pb(II) ion removal capacity of all the graft copolymers follows the order S-III?>?SAG-g-PAM?>?S-II?>?SAG-g-PDMA?>?S-I. But the flocculation performance of the graft copolymers follows the order S-II?>?S-I?>?S-III?>?SAG-g-PDMA?>?SAG-g-PAM. S-III was also used for the competitive metal ion removal with Hg(II), Cd(II), Cu(II) and Zn(II). Pb(II) adsorption of S-III (the best Pb(II) ion adsorber) follows pseudo second order rate equation and Langmuir adsorption isotherm. 相似文献
9.
Fajraoui Afef Nasr Jalel Ben Lacoste Catherine Dony Philippe Odof Serge Amar Mohamed Ben Halouani Foued El 《Journal of Polymers and the Environment》2022,30(4):1673-1681
Journal of Polymers and the Environment - In the context of sustainable development and natural products valorization, new ecological materials enter a logic aimed at removing the causes of... 相似文献
10.
R. Petrucci E. Fortunati D. Puglia F. Luzi J. M. Kenny L. Torre 《Journal of Polymers and the Environment》2018,26(5):1891-1902
Life cycle analysis (LCA) of limonene plasticized poly(lactic acid) (PLA) films containing cellulose nanocrystals (CNC) extracted, by acid hydrolysis, from Phormium tenax leaf fibres, was assessed and compared with the results of acetyl tributyl citrate (ATBC) plasticized PLA films, having equivalent mechanical properties, containing organo-modified montmorillonite (OMMT). Eco-Indicator 99 tool has been adopted as the main method for life cycle assessment. Results indicated that, despite CNC are biobased fillers obtained by natural sources, the related chemical extraction leads to a large environmental footprint and a relatively relevant energy expense. LCA characterization of these films demonstrated that the environmental impact of PLA/limonene film reinforced with 1% in weight of CNC (PLA/CNC/limonene) is comparable to the environmental impact of polylactic acid films reinforced with OMMT and plasticized with a petroleum based plasticizer (ATBC) (PLA/OMTT/ATBC). A “cradle to gate” approach has been considered for both the film typologies. 相似文献
11.
Environmentally friendly green composites were prepared by blending Wheat gluten (WG) as matrix, dialdehyde starch (DAS) as
filler and glycerol as plasticizer followed by compression molding of the mixture at 110 °C. The properties of the WG/DAS
composite are compared with those of the WG/native wheat starch (NWS) composites. While tensile strength and strain at break
decrease with increasing NWS content in the WG/NWS composites, a small content of DAS could improve tensile strength and strain
at break simultaneously in the WG/DAS composites. The WG/DAS composites exhibit reduced moisture absorption in comparison
with the WG/NEW composites. Formation of chemical bonding between DAS and WG is beneficial for the dispersion of DAS in the
WG matrix and WG/DAS composites exhibit improved mechanical properties and reduced moisture absorption over the WG/NWS composites. 相似文献
12.
Mazlita Yahya You Wei Chen Hwei Voon Lee Wan Hasamudin Wan Hassan 《Journal of Polymers and the Environment》2018,26(7):2825-2844
This study investigates for the first time the feasibility of isolating nanocellulose from several selected feedstocks via a novel Ni(II)-hydrolysis process, including lignocellulosic biomasses (oil palm trunk, banana peel and coconut husk) and processed biomasses (newspaper, tissue paper and cotton linter), with an obtained gravimetric yield ranging from 59.6 to 86.2%. The isolation of nanocellulose products from these selected feedstocks was verified by the successive removal of most of their non-cellulosic components (lignin and hemicellulose) and cellulose amorphous regions, the increase in the crystallinity index and the nanoscale of the individual crystals. Most importantly, the resultant nanocellulose products rendered better thermal stability than that of corresponding original sources, which are highly potential to be utilized as the new renewable sources of reinforcement materials with potential applications in bio-nanocomposites and thermoplastics. Therefore, this work proves the viability of direct production of nanocellulose from a variety of cellulosic sources by using Ni(II)-based transition metal salt catalyst. The results suggested that the concept of waste to wealth could be well executed from the obtained nanocellulose, which are greatly potential for various industrial applications. 相似文献
13.
Dario Frascari Young Kim Mark E. Dolan Lewis Semprini 《Water, Air, & Soil Pollution: Focus》2003,3(3):285-298
The focus of this study was to compare the behavior of different consortiums of aerobic propane-utilizing microorganisms, with respect to both the lag time for growth after exposure to propane, and their ability to transform three chlorinated aliphatic hydrocarbons (CAHs): chloroform (CF), cis-dichloroethylene (c-DCE) and trichloroethylene (TCE). Thirty-three slurry microcosms, representing seven combinations of aquifer solids and groundwater were constructed for this study. The lag time required for establishing propane-utilizing consortiums ranged between 24 and 29 days in 6 of the 7 combinations. Kinetic tests were performed with respect to propane utilization and CAH transformation. After CAH exposure, the ability of the microorganisms to metabolize propane was significantly reduced. CF and TCE were transformed more slowly than c-DCE, the average values of the initial transformation rates being equal to 0.10 ± 0.04, 0.09 ± 0.05 and 0.98 ± 0.18 mol/(L h),respectively. CF caused the greatest reduction in propane uptake rates, whereas c-DCE exhibited an apparently reversible negative effect on propane uptake rates. The estimates of the Monod half-saturation constants relative to CF, TCE and c-DCE resulted in the 2–3 mol/L range, but were characterized by a high degree of uncertainty. 相似文献
14.
Lundström U. S. Bain D. C. Taylor A. F. S. Van Hees P. A. W. Geibe C. E. Holmström S. J. M. Melkerud P.-A. Finlay R. Jones D. L. Nyberg L. Gustafsson J. P. Riise G. Strand L. Tau 《Water, Air, & Soil Pollution: Focus》2003,3(4):167-188
A joint multidisciplinary investigation was undertaken to studythe effects of lime and wood ash applications on two Norway spruce forest Spodosolic soils. The two sites, typical for southern Sweden, were treated in 1994 with either 3.25 t ha-1 dolomite or 4.28 t ha-1 wood ash (Horröd site) or in 1984 with either 3.45 or 8.75 t ha-1 dolomite (Hasslöv site). Both sites show signs of acidification by atmospheric anthropogenic deposition and possessed low soil pH(4.3) and high concentrations of inorganic Al (35 M) in theupper illuvial soil solution. The prevailing soil conditions indicated perturbed soil processes. Following treatment with lime or wood ash, the soil conditions were dramatically altered. Cation exchange capacity (CEC) and base saturation (BS) was considerable increased after addition. Four years after application most of the added Ca and Mg was still present in the mor layer. Fifteen years after application,Mg in particular, became integrated deeper in the soil profile with a greater proportion lost by leaching incomparison to Ca. The concentrations of these ions were greatestin the mor layer soil solutions and Mg had higher mobility givinghigher concentrations also deeper in the profile. Four years after treatment, the application of wood ash and limeresulted in lower pH values and higher inorganic Al in mineral subsoil solutions compared to the untreated soil. We hypothesize that this was probably due to an increased flow of hydrogen ionsfrom the upper soil as a result of displacement by Ca and Mg ionsin the enlarged exchangeable pool. In contrast, fifteen years after lime and wood ash application, the mineral subsoil horizonspossessed a higher pH and lower soil solution Al content than theuntreated plots.Liming promoted soil microbial activity increasing soil respiration 10 to 36%. This is in the same range as net carbon exchange for forests in northern Sweden and could potentially have a climatological impact. The turnover of low molecularweight organic acids (LMWOA) by the soil microbial biomass werecalculated to contribute 6 to 20% to this CO2 evolution.At Horröd, citrate and fumarate were the predominant LMWOAs with lowest concentrations found in the treated areas. In contrast, at the Hasslöv site, propionate and malonate were the most abundant LMWOAs. Higher microbial activity in the upper soil horizons was also theprobable cause of the considerably higher DOC concentrations observed in the soil solution of ash and lime treated areas. Thelime-induced increase in DOC levels at Hasslöv could be attributed to increases in the 3–10 kDa hydrophobic size fraction. Liming also promoted nitrification with high liming doses leading to extreme concentrations of NO3
- (1 mM) in soil solution.At Hasslöv the community of mycorrhizal fungi was dramatically changed by the addition of lime, with only four of 24 species recorded being common to both control and treated areas.Many of the observed effects of lime and ash treatment can be viewed as negative in terms of forest sustainability. After fouryears of treatment, there was a decrease in the pH of the soil solution and higher concentrations of inorganic Al and DOC. Increased organic matter turnover, nitrification and NO3
-leakage were found at Hasslöv. Considering that the weathering rate and the mineral nutrient uptake by trees is mostprobably governed by mycorrhizal hyphae etchingmineral grains in the soil, it is important to maintain this ability of the mycorrhizal fungi. The lime and ash-induced changed mycorrhizal community structure may significantly affect this capability. In light of this investigation and others, as reviewed by Lundström et al. (2003), the implications ofliming on forest health are multifaceted with complex relationships occurring over both space and time. 相似文献