共查询到20条相似文献,搜索用时 0 毫秒
1.
Ying Zhang Yangyang Zhang Qiang Wang Xuerong Fan 《Journal of Polymers and the Environment》2017,25(3):526-532
Electro conductive hydrogels, consisting of chitosan (CS), hyaluronic acid (HA), and polypyrrole (PPy), were prepared via an in situ enzymic polymerization of pyrrole in the CS–HA hydrogel, using laccase as the catalyst. This CS–HA–PPy composite hydrogel showed good conductivity. The chemical structure and morphology of this conductive hydrogel were studied by Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray diffraction technique. For CS–HA–PPy and CH–HA hydrogel, the temperature at which fastest decomposition occurred was 260 and 244 °C, respectively. That means the thermal stability of CS–HA–PPy is better than CS–HA hydrogel. The conductive hydrogel also showed excellent swelling and deswelling behaviors. 相似文献
2.
Ge Mingliang Li Xinxiang Li Yueying Jahangir Alam S. M. Gui Yuee Huang Yongchao Cao Luoxiang Liang Guodong Hu Guoqing 《Journal of Polymers and the Environment》2022,30(9):3890-3900
Journal of Polymers and the Environment - In this study, the nanohybrid drug carrier were synthesized by Pickering emulsion-templated encapsulation (PETE) method to control the... 相似文献
3.
Loganathan Tamil Moli Sultan Mohamed Thariq Hameed Ahsan Qumrul Shah Ain Umaira Md Jawaid Mohammad Talib Abd. Rahim Abu Basri Adi Azriff 《Journal of Polymers and the Environment》2021,29(11):3703-3720
Journal of Polymers and the Environment - The aim of this study is to investigate the effect of fiber length and loading on physico-mechanical and flammability properties of Cyrtostachys renda (CR)... 相似文献
4.
Green composite fibers (339?C612?nm in diameter) have been developed from wood pulp, acetylated wood pulp and polyethylene oxide under various concentrations by electrospinning process. A polymer solution concentration of 7 wt% with 5 wt% wood pulp have been found to produce uniform composite fibers. Scanning electron microscopy micro-images demonstrated that composite fibers diameter and morphology depended on the processing parameters, such as solution concentration and molecular weight of polymer. Transmission electron microscopy and laser confocal microscopy observations indicated that the acetylated wood was well dispersed and oriented along the length of composite fibers axis. X-ray diffraction studies revealed that the structure of electrospun composite fibers became more non-crystalline. 相似文献
5.
I. K. P. Tan E. S. Stuart R. W. Lenz R. C. Fuller 《Journal of Polymers and the Environment》1998,6(2):67-71
It is well known that Pseudomonas oleovorans can utilize sodium octanoate for both cell growth and the synthesis of polyhydroxyalkanoates (PHAs), but it can utilize sodium butyrate only for limited cell growth and not for the polyester formation when this substrate is the sole carbon source. Therefore, these two substrates were evaluated as cofeeds for the possible incorporation of 3-hydroxybutyryl groups in the resulting PHA. When sodium butyrate and sodium octanoate were fed to P. oleovorans as cosubstrates in various proportions, the resultant cell density and polymer content were proportional to the amount of sodium octanoate in the feed. The PHA extracted from cells grown in all combinations of these cosubstrates had similar unit compositions of approximately 8 mole % 3-hydroxyhexanoate, 91 mole % 3-hydroxyoctanoate and 1 mole % 3-hydroxydecanoate. 3-Hydroxybutyrate units were not detected in any of the PHAs isolated, indicating that these units could not be incorporated in the copolymer synthesized by P. oleovorans either because the cell did not synthesize that monomer or, if it did, the PHA synthase could not copolymerize it with the longer chain monomers. 相似文献
6.
The adsorption of two taste- and odor-causing compounds, namely MIB (2-methyl isoborneol—C11H20O) and geosmin (C12H22O) on activated carbon was investigated in this study. The impact of adsorbent pore size distribution on adsorption of MIB and geosmin was evaluated through single solute and multicomponent adsorption of these compounds on three types of activated carbon fibers (ACFs) and one granular activated carbon (GAC). The ACFs (ACC-15, ACC-20, and ACC-25) with different degrees of activation had narrow pore size distributions and specific critical pore diameters whereas the GAC (F-400) had a wider pore size distribution and lesser microporosity. The effect of the presence of natural organic matter (NOM) on MIB and geosmin adsorption was also studied for both the single solute and binary systems. The Myers equation was used to evaluate the single solute isotherms as it converges to Henry’s law at low coverage and also serves as an input for predicting multicomponent adsorption. The single solute adsorption isotherms fit the Myers equation well and pore size distribution significantly influenced adsorption on the ACFs and GAC. The ideal adsorbed solute theory (IAST), which is a well-established thermodynamic model for multicomponent adsorption, was used to predict the binary adsorption of MIB and geosmin. The IAST predicted well the binary adsorption on the ACFs and GAC. Binary adsorption isotherms were also conducted in the presence of oxygen (oxic) and absence of oxygen (anoxic). There were no significant differences in the binary isotherm between the oxic and anoxic conditions, indicating that adsorption was purely through physical adsorption and no oligomerization was taking place. Binary adsorptions for the four adsorbents were also conducted in the presence of humic acid to determine the effect of NOM and to compare with IAST predictions. The presence of NOM interestingly resulted in deviation from IAST behavior in case of two adsorbents, ACC-15 and F-400. 相似文献
7.
Yue Zhang Hongsheng Zhang Luping Ni Qilin Zhou Weihong Guo Chifei Wu 《Journal of Polymers and the Environment》2010,18(4):647-653
Recycled poly(ethylene terephthalate) (R-PET) was blended with 15–30 wt% of styrene–ethylene/butylenes–styrene (SEBS) block
copolymer and maleic anhydride grafted SEBS (SEBS-g-MA). Effects of nucleation and toughening of the elastomers were evaluated
systematically by study of morphology, crystallization, thermal and mechanical properties of the blend. The addition of 30 wt%
SEBS promoted the formation of co-continuous structure of the blend and caused the fracture mechanism to change from strain
softening to strain hardening. Addition of SEBS-g-MA resulted in significant modification of phase morphology and obviously
improved the impact strength. The compatibilization reaction of PET with SEBS-g-MA accelerated the crystallization of PET
and increased the crystallinity. The shifts in glass transition temperature of PET towards that of SEBS-g-MA and the higher
modulus for R-PET/SEBS-g-MA (70/30) blend found by DMA are also indications of better interactions under the conditions of
compatibilization and interpenetrating structure. 相似文献
8.
Hee-Soo Kim Byoung-Ho Lee Hyun-Joong Kim Han-Seung Yang 《Journal of Polymers and the Environment》2011,19(3):628-636
The mechanical–thermal properties and volatile organic compound (VOC) emissions of natural-flour-filled, biodegradable polymer
bio-composites were investigated according to variation in porous inorganic filler types. At a porous inorganic filler content
of 3%, the tensile and flexural strengths of the hybrid bio-composites were not significant changed. However, the coefficient
of thermal expansion and thermal expansion of the bio-composites were slightly decreased. Furthermore, the incorporation of
the porous inorganic materials into bio-composites slightly increased the E’ values of the hybrid bio-composites over the entire temperature range, although the tan δmax temperature (T
g) of the hybrid bio-composites was not significantly changed. At a porous inorganic filler content of 3%, the various odor
and VOC emissions of the hybrid bio-composites were significantly decreased because the various oxidation and thermal degradation
gases of the natural flour and matrix were absorbed in the pore structures of the porous inorganic fillers and thereby prevented
the migration into the final products. 相似文献
9.
Jawad Ahmad Khan Fahad Pervaiz Nazar Mohammad Ranjha Muhammad Naeem Nayab Khalid Zeeshan Javaid 《Journal of Polymers and the Environment》2017,25(3):556-568
In the present work covalently crosslinked smart polymeric system of hydrogel based on poly vinyl alcohol (PVA) and methacrylic acid (MA) was designed by free radical polymerization with different compositions using glyoxal (40 % water solution) as crosslinker. It was observed that swelling of hydrogel had a pronounced enhancing effect on increasing the concentration of MA due to availability of more ionized carboxylic groups of MA but produced an opposite effect on increasing the concentration of glyoxal owing to less porous structure. As far as PVA is concerned, swelling did not show significant effect on increasing the concentration of PVA. Hydrophilic polymer PVA rich in hydroxyl group pertained to be highly interactive with water. It was examined that the release of metoprolol tartrate decreased with increased concentration of glyoxal, but increased with increase in concentration of MA. PVA/MA hydrogel was characterized by Fourier transform infrared spectroscopy and X-ray diffraction to study the structure and crystallinity of hydrogel respectively. Morphology was studied through scanning electron microscopy. Furthermore differential scanning calorimetry and thermogravimetric analysis were also performed to characterize thermal stability. It may be concluded that the mechanism of drug release was mainly non-Fickian diffusion. 相似文献
10.
Nguyen Thi Hien Nguyen Thuy Chinh Nguyen Thi Minh Tu Hoang Dinh Hoa Tran Do Mai Trang Tran Dinh Thang Hoang Phuong Thai Le Van Tan Tran Thi Kim Ngan Thai Hoang 《Journal of Polymers and the Environment》2022,30(2):631-643
Journal of Polymers and the Environment - This study attempted to develop carrageenan/chitosan based microparticles loading α-mangostin which was extracted from Vietnamese mangosteen skin. The... 相似文献
11.
Zhiming Gu Quanyuan Cai Yan Liu Fengsheng Li 《Journal of Polymers and the Environment》2013,21(2):479-486
The electrochemical degradation of chitosan using Ti/Sb–SnO2 electrode was studied in this work. The experimental results showed that as a non-active electrode with high oxygen potential, Ti/Sb–SnO2 electrode had a good efficiency for degrading chitosan. The kinetic behavior of electrochemical degradation of chitosan using Ti/Sb–SnO2 electrode and the function relationship between experimental parameters and degradation rate constant were also investigated. The kinetic analysis revealed that this electrochemical process using Ti/Sb–SnO2 electrode obeyed the zeroth–order reaction kinetics under the experimental conditions examined. The degradation rate constant at Ti/Sb–SnO2 electrode had the linear relationship with 1.13 power of current density, ?1.36 power of initial concentration of chitosan and 0.19 power of concentration of acetic acid, The temperature dependences of the degradation rate constant could be expressed by the Arrhenius equation. The concentration of sodium acetate had a negligible influence on the degradation rate constant. 相似文献
12.
Du Yongsheng Guo Yuhang Wang Guangyu Zhang Hongxia Deng Leibo Chen Hua Zhao Ming 《Journal of Material Cycles and Waste Management》2023,25(5):3081-3092
Journal of Material Cycles and Waste Management - High-performance slag glass–ceramics were prepared by melting method using rare earth-containing blast furnace slag as the main raw material... 相似文献
13.
Wei Song Kaiqiang Zhang Zhenghao Chen Gonghua Hong Jianyong Lin Chengyi Hao Shuangbao Zhang 《Journal of Polymers and the Environment》2018,26(10):4019-4033
Diminishing wood supply and high formaldehyde emission from synthetic adhesive-bonded lignocellulose boards have become concerns. In this research, new adhesive-free boards made from xylanase–laccase-modified bamboo particles were developed. The bamboo particles were pretreated first with xylanase and then with laccase. The synergistic pretreatment was performed according to a Taguchi experiment that included six variables: xylanase treatment (enzyme concentration: 10, 20, 30 U/g; reaction pH: 8, 9, 10; reaction time: 30, 60, 90 min) and laccase treatment (enzyme concentration: 10, 20, 30 U/g; reaction pH: 2, 3, 4; reaction time: 30, 60, 90 min). The particles were hot-pressed to harvest the self-bonded boards, whose physical–mechanical properties were evaluated. The results showed that all six variables (except laccase reaction time) caused significant effects at 0.05 level on physical–mechanical properties of boards. The optimum pretreatment parameters were determined to be xylanase (20 U/g, pH 9, 60 min) and laccase (20 U/g, pH 4, 60 min). The optimized flexural strength, flexural modulus, internal bonding, and 2 h thickness swelling of boards met the highest requirements in Chinese national standard GB/T 4897 (2015) for particleboards. The performance of proposed boards was also better than that of reported self-bonded bamboo particleboards with only a laccase pretreatment. 相似文献
14.
Chong-qing Wang Hui Wang Qun Liu Jian-gang Fu You-nian Liu 《Waste management (New York, N.Y.)》2014,34(12):2656-2661
The objective of this research is flotation separation of polycarbonate (PC) and acrylonitrile–butadiene–styrene (ABS) waste plastics combined with ammonia pretreatment. The PC and ABS plastics show similar hydrophobicity, and ammonia treatment changes selectively floatability of PC plastic while ABS is insensitive to ammonia treatment. The contact angle measurement indicates the dropping of flotation recovery of PC is ascribed to a decline of contact angle. X-ray photoelectron spectroscopy demonstrates reactions occur on PC surface, which makes PC surface more hydrophilic. Separation of PC and ABS waste plastics was conducted based on the flotation behavior of single plastic. At different temperatures, PC and ABS mixtures were separated efficiently through froth flotation with ammonia pretreatment for different time (13 min at 23 °C, 18 min at 18 °C and 30 min at 23 °C). For both PC and ABS, the purity and recovery is more than 95.31% and 95.35%, respectively; the purity of PC and ABS is up to 99.72% and 99.23%, respectively. PC and ABS mixtures with different particle sizes were separated effectively, implying that ammonia treatment possesses superior applicability. 相似文献
15.
Abdin Mohamed Salama Mohamed Abdelbaset Gawad R. M. A. Fathi Mohamed Ahmed Alnadari Fawze 《Journal of Polymers and the Environment》2021,29(11):3679-3692
Journal of Polymers and the Environment - An efficient method based on encapsulation efficiency of Syzygium cumini anthocyanin extract (ANC.E) was established by using a stable concentration from... 相似文献
16.
Jyh-Horng Wu Chien-Pang Wu M. C. Kuo Yuhsin Tsai 《Journal of Polymers and the Environment》2016,24(2):129-138
A hydrophilic copolymer, ethylene–vinyl alcohol (EVOH), was incorporated into the poly(lactic acid) (PLA) matrix to improve the barrier property of PLA through twin-screw extrusion rather than the typical coextrusion process. A chain extender, poly[(ethylene)-co-(methyl acrylate)-co-(glycidyl methacrylate)] (PEMG), was used to reduce the probability of the thermal degradation of PLA during melt compounding. Biaxial stretching was used to enhance the microstructure and barrier property of PLA-PEMG/EVOH films. Experimentally, PEMG considerably reduced the probability of the thermal degradation of the PLA-PEMG sample. Biaxial stretching increased the tensile strength and decreased the value of elongation at break of the PLA-PEMG/EVOH80 (PLA/EVOH 100/80) film. Because of the efficient blending of PLA/EVOH in the twin-screw extruder, the dispersion of EVOH in the PLA matrix revealed homogeneous dispersion with a domain size of 1–5 μm. EVOH effectively improved the water vapour transmission rate (WVTR) of PLA through melt blending. Blending PLA-PEMG with EVOH substantially decreased the WVTR from 250 cc—20 μm/m2-day-atm for neat PLA to approximately 65 cc—20 μm/m2-day-atm for the PLA-PEMG/EVOH80 film, a decrease of approximately 74 % compared with neat PLA. Moreover, the WVTR decreased further from 65 cc—20 μm/m2-day-atm for the unstretched PLA-PEMG/EVOH80 film to 6.3 cc—20 μm/m2-day-atm for the film stretched at a stretch ratio of 3.5 × 3.5 and at 100 %/s, a decrease of approximately 90 % compared with neat PLA. 相似文献
17.
Mohammad Farsi 《Journal of Polymers and the Environment》2017,25(2):308-314
The aim of this study is to evaluate the impact of nano-SiO2 and bark flour (BF) on the natural fiber–plastic composites engineering properties made from high density polyethylene (HDPE) and beech wood flour (WF). For this purpose, WF and BF in 60 mesh size and weight ratio of (50, 0 %), (30, 20 %), (10, 40 %) and (0, 50 %) respectively were mixed with HDPE. In order to increase the interfacial adhesion between the filler and the matrix, the maleic anhydride grafted polyethylene was constantly used at 3 wt% for all formulations as a coupling agent. The nano-SiO2 particles with weight ratio of 0, 1, 2, and 4 % were also utilized to enhance the composites properties. The materials were mixed in an internal mixer (HAAKE) and then the bark and/or wood–plastic composite samples were made utilizing an injection molding machine. The physical tests including water absorption and thickness swelling, and mechanical tests including bending characteristics and un-notched impact strength were carried out on the samples based on ASTM standard. The results indicated that as the BF content increased in the composite, mechanical and physical properties were reduced, but the given properties were increased with the addition of nano-SiO2. The addition of nano-SiO2 had a negative impact on the physical properties, but when it was up to 2 %, it increased the impact strength. 相似文献
18.
Mehdihasan I. Shekh Kaushal P. Patel Rajnikant M. Patel 《Journal of Polymers and the Environment》2018,26(12):4376-4387
Coaxial electrospinning technique was used to fabricate the core–sheath composite nanofibers of ZnO nanoparticle (Nps) (10%, 20% w/w) doped polymethyl methacrylate (PMMA) (as sheath) and polyvinyl alcohol (PVA) (as core). Fourier transform infrared (FT-IR) spectra were confirmed the weak forces arise between ZnO Nps, PMMA and PVA matrixes. The hexagonal (wurtzite) structure of ZnO Nps with ~?30.8 nm of diameter was confirmed from the X-ray diffraction pattern. The morphology and microstructure of core–sheath composite nanofibers were confirmed from the scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It is clearly seen from the TEM images that the PMMA encapsulate the PVA core. Core–sheath composite nanofibers were assessed against Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis) bacteria through quantitative, disk diffusion and viable cell count methods. It was found that ZnO Nps doped core–sheath nanofibers were effectively inhibit the growth of gram positive bacteria, B. subtilis. 相似文献
19.
Verónica P. Martino Eric Pollet Luc Avérous 《Journal of Polymers and the Environment》2011,19(4):819-826
The swelling capability of chitosan was explored in order to use water both, as volatile plasticizer and as pore-forming agent.
Chitosan powder was swelled in acidic aqueous solution and melt blended with poly(ε-caprolactone) (PCL). After stabilization
at 57% RH and 25 °C, samples suffered a water mass loss of around 30 wt% without dimensions variation. Despite the low miscibility
of these biopolymers, quite homogeneous dispersion of chitosan within the polyester matrix was obtained. Some interactions
between both biopolymers could be observed. To obtain chitosan phase with a thermoplastic-like behaviour, the plasticization
effect was also studied by the addition of 25 wt% glycerol as non volatile plasticizer. The equilibrium moisture content of
samples increased with the incorporation of glycerol due to its hydrophilic nature. Morphology, thermal and mechanical properties
of the blends were determined after stabilization. The preparation of rich PCL blends allowed the formation of macroporous
structures since samples were not contracted after water loss and stabilization. These biomaterials with such a porous structure
could be used for biomedical applications. 相似文献
20.
Ana F. L. Godoi Eliza Y. Sawada Mary Rosa R. de Marchi René Van Grieken Ricardo H. M. Godoi 《Water, Air, & Soil Pollution: Focus》2009,9(3-4):163-169
The use of inks containing organic solvents by the offset printing process implies in the release of volatile organic compounds to the work environment. Many of these compounds such as benzene, toluene, ethylbenzene, and the xylene isomers (well known by the acronym BTEX) are extremely toxic. In this study, the BTEX concentrations were determined in two different printing plants that use distinct types of inks: the conventional and the so-called ecological, which is manufactured based on vegetal oil. Concentration ranges were 43–84, 15–3,480, 2–133, 5–459, and 2–236 μg m?3 for benzene, toluene, ethylbenzene, m?+?p-xylene, and o-xylene, respectively, for the conventional printing plant. At the ecological printing plant, concentration ranges were below limit of detection (<LD)-31, <LD-618, <LD-1,690, <LD-10,500, <LD-3,360 μg m?3 for benzene, toluene, ethylbenzene, m?+?p-xylene, and o-xylene, respectively. BTEX concentrations are lower at the ecological printing environment than in the conventional, where mineral oil-based inks are used. However, the worker who cleans the printing matrices is exposed to high concentrations of ethylbenzene and xylenes, due probably to the cleaning product’s composition (containing high amounts of BTEX). Although the BTEX concentrations found in both printing work environments were below the limits considered by the Brazilian Law for Activities and Unhealthy Operations (NR-15), the exposure to such vapors characterizes risk to the workers’ health for some of the evaluated samples, mainly the personal ones. 相似文献