共查询到20条相似文献,搜索用时 15 毫秒
1.
Nita Tudorachi Rodica Lipsa Cornelia Vasile Fanica Mustata 《Journal of Polymers and the Environment》2013,21(4):1064-1071
The synthesis and characterization of poly(lactic acid)-co-aspartic acid copolymers (PLA-co-Asp) were presented. Subsequently, the synthesized PLA-co-Asp copolymers were tested as biodegradable carriers in drug delivery systems. PLA-co-Asp copolymers were synthesized by solution polycondensation procedure, using different molar ratios PLA/l-aspartic acid (2.33/1, 1/1, 1/2.33), manganese acetate and phosphoric acid as catalysts and N,N′-dimethyl formamide (DMF)/toluene as solvent mixture. The copolymers were characterized by FT-IR and 1H-NMR spectroscopy, gel permeation chromatography (GPC), DSC and TG-DTG analyses. Diclofenac sodium, a non steroidal anti-inflammatory drug was subsequently loaded into PLA-co-Asp copolymers. The in vitro drug release experiments were done by dialysis of the copolymer/drug systems, in phosphate buffer solution (pH = 7.4, at 37 °C) and monitored by UV spectroscopy. 相似文献
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Bouti Mohamed Irinislimane Ratiba Belhaneche-Bensemra Naima 《Journal of Polymers and the Environment》2022,30(1):232-245
Journal of Polymers and the Environment - This study aims to improve low intrinsic ductility of poly (lactic acid) (PLA) by using a novel bio-sourced plasticizer environmentally friendly and... 相似文献
4.
Márcia Maria Favaro Ferrarezi Márcia de Oliveira Taipina Laura Caetano Escobar da Silva Maria do Carmo Gonçalves 《Journal of Polymers and the Environment》2013,21(1):151-159
A new route to prepare poly(lactic acid) (PLA)/thermoplastic starch (TPS) blends is described in this work using poly(ethylene glycol) (PEG), a non-toxic polymer, as a compatibilizer. The influence of PEG on the morphology and properties of PLA/TPS blends was studied. The blends were processed using a twin-screw micro-compounder and a micro-injector. The morphologies were analyzed by scanning and transmission electron microscopies and the material properties were evaluated by dynamic-mechanical, differential scanning calorimetry, thermogravimetric analysis and mechanical tests. PLA/TPS blends presented large TPS phase size distribution and low adhesion between phases which was responsible for the lower elastic modulus of this blend when compared to pure PLA. The addition of PEG resulted in the increase of PLA crystallization, due to its plasticizing effect, and improvement of the interfacial interaction between TPS and PLA matrix. Results show that incorporation of PEG increased the impact strength of the ternary blend and that the elastic modulus remained similar to the PLA/TPS blend. 相似文献
5.
Synthesis of Segmented Polyurethane Based on Polymeric Soybean Oil Polyol and Poly (Ethylene Glycol)
Polyurethane (PUR) plastic sheets were prepared by reacting hydroxylated polymeric soybean oil (PSbOH) synthesized from autoxidized
soybean oil with polyethylene glycol (PEG) in the presence of isophorone diisocyanate (IPDI). FTIR technique was used to identify
of chemical reactions. These polyurethanes have different valuable properties, determined by their chemical composition. The
effect of stoichiometric balance (i.e., PSbOH/PEG-2000/IPDI weight ratio) on the final properties was evaluated. The polyurethane
plastic sheets with the PSbOH/PEG-2000/IPDI weight ratio 1.0/1.0/0.67 and 1.0/0.3/0.3 had excellent mechanical properties
indicating elongation at break more than 200%. Increase in IPDI and decrease in PEG weight ratio cause the higher stress–strain
value. The properties of the materials were measured by differential scanning calorimetry (DSC), thermo gravimetric analysis
(TGA), stress–strain measurements and FTIR technique. 相似文献
6.
Six strains of Pseudomonas were tested for their abilities to synthesize poly(hydroxyalkanoate) (PHA) polymers from crude Pollock oil, a large volume
byproduct of the Alaskan fishing industry. All six strains were found to produce PHA polymers from hydrolyzed Pollock oil
with productivities (P; the percent of the cell mass that is polymer) ranging from 6 to 53% of the cell dry weight (CDW).
Two strains, P. oleovorans NRRL B-778 (P = 27%) and P. oleovorans NRRL B-14682 (P = 6%), synthesized poly(3-hydroxybutyrate) (PHB) with number average molecular weights (Mn) of 206,000 g/mol and 195,000 g/mol, respectively. Four strains, P. oleovorans NRRL B-14683 (P = 52%), P. resinovorans NRRL B-2649 (P = 53%), P. corrugata 388 (P = 43%), and P. putida KT2442 (P = 39%), synthesized medium-chain-length PHA (mcl-PHA) polymers with Mn values ranging from 84,000 g/mol to 153,000 g/mol. All mcl-PHA polymers were primarily composed of 3-hydroxyoctanoic acid (C8:0) and 3-hydroxydecanoic acid (C10:0) amounting to at least 75% of the total monomers present. Unsaturated monomers were also present in the mcl-PHA polymers at concentrations between 13% and 16%, providing loci for polymer derivatization and/or crosslinking.
Mention of trade names or commercial products in this article is solely for the purpose of providing specific information
and does not imply recommendation or endorsement by the U.S. Department of Agriculture. 相似文献
7.
A. H. Bhat H. P. S. A. Khalil Irshad ul Haq Bhat A. K. Banthia 《Journal of Polymers and the Environment》2012,20(2):395-403
Red mud emerges as the major waste material during production of alumina from bauxite by the Bayer??s process. Based on economics as well as environmental related issues, enormous efforts have been directed worldwide towards red mud management issues i.e. of utilization, storage and disposal. The present research work has been undertaken with an objective to explore the use of red mud as a reinforcing material in the polymer matrix as a low cost option. The silicate layered red mud was organophilized by aniline formaldehyde and to know the effect of various filler loading on the material properties of PVA-organophilized red mud composites, prepared by a conventional solvent casting technique and comparison of the same with that of the virgin poly (vinyl alcohol) (PVA), various characterizations was done. The modified red mud was typically characterized by X-ray diffraction. The X-ray diffraction pattern of the composite materials was also studied. The morphological image of the composite materials was studied by scanning electron microscopy (SEM). Transmission electron microscopy (TEM) was used to characterize the dispersion of the red mud within the composite materials. The surface topography of the composite materials was studied by Atomic Force Microscopy (AFM). The dielectric properties of composite materials were investigated in wide frequency ranges from 1?MHz to 1?GHz. 相似文献
8.
Photodegradation and Biodegradation Study of a Starch and Poly(Lactic Acid) Coextruded Material 总被引:1,自引:0,他引:1
Alain Copinet Céline Bertrand Antoine Longieras Veronique Coma Yves Couturier 《Journal of Polymers and the Environment》2003,11(4):169-179
To simulate the behavior of agricultural mulch coextruded poly(lactic acid)(PLA)/starch films, two stages were carried out. The first was an ultraviolet treatment (UV) at 315 nm, during which glass transition temperature Tg, weight, and molecular weight (MW) decreased and a separation between PLA and starch phase was observed. For the second stage, the mineralization of the carbon of the material was followed using the ASTM (D 5209–92 and 5338–92) and ISO/CEN (14852 and 14855) standard procedures. To measure the biodegradability of polymer material, the assessment of the carbon balance allowed determination of the distribution between the carbon rate used to the biomass synthesis or the respiration process (released CO2), as well as the dissolved organic carbon into the culture medium and the carbon in the residual insoluble material. The influence of the nature of the medium and the standardized procedures on the final rate of biodegradation was investigated. Whatever the standardized method, the biodegradation percentage was significantly stronger in liquid medium (92.4–93.4) than on inert medium (80–83%). In the case of the compost process, only released CO2 was measured and corresponded to 79.1–80.3%. 相似文献
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Gabriel L. Castiglioni Jorge Cuellar Raúl Rodrigo Jorge A. V. Costa Ranulfo Monte-Alegre 《Journal of Polymers and the Environment》2016,24(3):264-273
Macroporous poly(styrene-co-divinylbenzene) microparticles, with three different structural characteristics, have been synthesized and used as supports in the immobilization of lipase from Burkholderia cepacia. The best immobilization yield was found upon using microparticles with 35 % of divinylbenzene and the immobilized lipase on this type of particles was used as a catalyst to obtain biodiesel from soybean oil and ethanol. From the experimental results of the transesterification reaction, an empirical model quantitatively relating the temperature, the concentration of the enzyme and the transesterification yield was obtained. Statistical analysis of this model indicated that within the range of values of the variables studied (35–47 °C and 231–788 U/mg respectively) only the enzyme concentration exerted a significant influence on the reaction yield. Additionally, the good fit of a Michaelis–Menten-type model to the experimental results suggests that the limiting step of the reaction was the formation of the enzyme-substrate complex. 相似文献
11.
Fahmi A. Abu Al-Rub Mohammad M. Fares Tareq Talafha 《Journal of Polymers and the Environment》2018,26(6):2333-2345
Naturally-based poly(acrylic acid) grafted sodium alginate di-block hydrogels were investigated as high efficiency biosorbents for copper(II) ion. The grafted di-block hydrogel was characterized using FTIR, TGA and SEM techniques. Blank and immobilized algal biosorbent beads formed via 2.0% (w/w) calcium ions were also investigated. Batch adsorption experiments revealed optimal pH dependence of copper(II) ion biosorption at pH 5.5 with high efficient copper(II) ion uptake of 98.5 mg/g. The dynamics studies showed that the high efficiency copper(II) ion biosorption followed pseudo-second order kinetics with significant contribution of intraparticle diffusion mechanism. The equilibrium data fitted to Langmuir, Freundlich, and Dubinin–Radushkevich (D–R) adsorption isotherm models. Thermodynamics parameters for copper(II) biosorption on blank and immobilized algal beads depicted the spontaneous nature of the biosorption process. Such high efficiency, feasibility, simplicity, and low cost properties adapt the di-block biosorbent to be the next generation promising biosorbents for water decontamination and to help in the recovery of the missing ecologic harmony. 相似文献
12.
The influence of poly(dioxolane) (PDXL), a poly(ethylene oxide-alt-methylene oxide), as compatibilizer on poly(ɛ-caprolactone) (PCL)/tapioca starch (TS) blends was studied. In order to facilitate blending; PCL, PDXL and TS must be blended together directly; so that PDXL is partially adhered at the TS surface as shown by scanning electron microscopy. The molecular weight effect of PDXL on the PCL/TS blends showed that mechanical properties of PCL/TS/PDXL blends from low molecular weight (M
n=10,000) and high molecular weight (M
n=200,000) PDXL were rather dependent on TS content. The enzymatic degradability of PCL/TS/PDXL blends using α-amylase increased as the TS content increased but was independent on the dispersion of tapioca starch in the PCL matrix. 相似文献
13.
Manawwer Alam S. M. Ashraf Alok R. Ray Sharif Ahmad 《Journal of Polymers and the Environment》2010,18(3):208-215
Polyetheramide(PEtA) resin was synthesized by the condensation polymerization of N,N-bis(2-hydroxy ethyl) linseed oil fatty
amide diol (HELA) with resorcinol. It was further treated with different percentage of toluylene 2-4-diisocyanate (TDI) to
obtain the urethane modified polyetheramide resins (UPEtA). The structural elucidation of PEtA and urethane modified polyetheramide(UPEtA)
were carried out by FT-IR, 1H-NMR and 13C-NMR spectroscopic techniques. These analyses confirm the formation of PEtA and UPEtA. Physico-chemical and physico-mechanical
analysis were performed by standard laboratory methods. The resin composition UPEtA-24 showed best physico-mechanical properties
with scratch hardness 2.0 kg, impact resistance 150 lb/in. and good bending ability. The thermal stability and curing behavior
of polymers were respectively studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Thermal
analysis shows that these coatings can be used safely upto 190 °C. The coatings of UPEtA resins were prepared on mild steel
strips. The anticorrosive behavior of UPEtA coatings were investigated in acid, alkali, water and xylene. All the coatings
exhibit good chemical resistance performance in acid, alkali, saline and organic solvents, while the resin UPEtA-24 shows
the best performance. 相似文献
14.
Journal of Polymers and the Environment - This work describes synthesis of poly (sulfur/soya bean oil) composite material by co-polymerization of elemental sulfur and soya bean oil at... 相似文献
15.
Meri Suhartini H. Mitomo F. Yoshii N. Nagasawa T. Kume 《Journal of Polymers and the Environment》2001,9(4):163-171
Three kinds of poly(butylene succinate)s (PBS) with different molecular weight were irradiated with electron beams in the presence of inorganic material. Fourteen kinds of inorganic materials were used in this work. The presence of inorganic material inside cross-linked PBS samples enhances the yield of gel formation. The heat stabilities of PBS samples were checked; it was found that silicon dioxide and carbon black significantly improve these properties. Enzymatic and soil burial tests were performed; the presence of these inorganic materials in cross-linked PBS accelerates the rate of biodegradation. 相似文献
16.
The main purpose of this study is challenging to dramatically improve the toughness of poly(lactic acid) (PLA)/starch by adding poly (ethylene glycol) (PEG) into the composites and grafting PEG molecules onto the surface of starch particles. It was found that the surface grafting of PEG onto starch induced the presence of PEG-rich regions located around the starch particles, caused by migration and aggregation of free PEG molecules. A novel interphase transition layer between PLA and starch was formed, which showed great ability for cavitation and vested large-scaled plastic deformation to PLA matrix. Further mechanical properties tests indicated the formation of interphase layer significantly increase the elongation at break from 10.2 to 254.5%, and notched impact strength from 1.56 to 2.37?kJ/m2 for PLA/PEG/starch ternary composites. The influence of PEG component, ethanol extraction and annealing was also investigated. 相似文献
17.
Ashik Sathish Katherine Glaittli Ronald C. Sims Charles D. Miller 《Journal of Polymers and the Environment》2014,22(2):272-277
In addition to biodiesel production from algae, the production of other valuable bioproducts facilitates the development of an algae-based biorefinery platform. The goal of this study was to utilize the aqueous fraction from a novel algal wet lipid extraction procedure as the medium for the production of a bio product, poly(3-hydroxybutyrate) (PHB), via the growth of recombinant Escherichia coli. PHB yield was measured at 34 % of the E. coli dry cell mass, and was increased to 51 % when the algae aqueous medium was supplemented with glucose. While the addition of inorganic nutrients to the aqueous phase did not increase PHB production or growth of E. coli, growth of E. coli was observed to increase with the supplementation of carbon substrate (glucose). The addition of carbon rich waste to the aqueous fraction of wastewater-derived algae may in the future provide a sustainable alternative. Future research will be directed at evaluating this concept to develop a sustainable process for the production of bioplastics through an algae-based biorefinery platform. 相似文献
18.
Nur Zahidah Rozaki Seng-Neon Gan Desmond Teck-Chye Ang 《Journal of Polymers and the Environment》2017,25(2):286-295
Oil-modified polyesters were synthesized to serve as polymeric plasticizers for PVC. A total of four polymeric plasticizers with different average molecular weights were prepared. Characterizations were done using Fourier-transformed infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, and gel permeation chromatography. Some of the tests conducted on PVC films include thermal stability test using thermogravimetric analyser, determination of glass transition temperature (Tg), plasticizer migration and leaching resistance test, morphology study of plasticized PVC films using field emission scanning microscope, toxicity test, and tensile test. Owing to the plasticizing effect of the palm oil-based compound, Tg of the plasticized PVC has decreased to an average of 65 °C at 20 wt% loading. The polymeric plasticizer is also able to contribute positively to the thermal stability and mechanical properties of the PVC films. Some of the advantages of incorporating polymeric plasticizer with high molecular weight includes lower rate of leaching from plastic, and improved tensile strength and elongation at break. Besides, thermal stability of the plastic studied using Kissinger’s and Flynn–Wall–Ozawa’s approaches shows that PVC blended with high molecular weight oil-modified polyester is more thermally stable, evidenced by the increase in the activation energy of decomposition, Ed. Toxicity test using brine shrimp egg shows encouraging results, where the oil-based plasticizer is considerably less toxic compared to some of the commercial plasticizers. 相似文献
19.
Demir Didem Özdemir Sadin Ceylan Seda Yalcin M. Serkan Sakım Burcu Bölgen Nimet 《Journal of Polymers and the Environment》2022,30(6):2462-2473
Journal of Polymers and the Environment - In this study, styrax liquidus (sweet gum balsam) extracted from Liquidambar orientalis Mill. incorporated PCL fibrous scaffolds were prepared using the... 相似文献
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Naiwen Zhang Chao Zeng Liang Wang Jie Ren 《Journal of Polymers and the Environment》2013,21(1):286-292
Poly (lactic acid) (PLA) and poly (butylene adipate-co-terephthalate) (PBAT) are biodegradable polyesters and can be blended by twin-screw extrusion. Epoxy-functional styrene acrylic copolymer (ESA) was used as reactive agent for PLA/PBAT blends and the mechanical properties, phase morphology, thermal properties, melt properties, and melt rheological behaviors of the blends were investigated. During thermal extrusion, ESA was mainly a chain extender for the PLA matrix but had no evident reaction with PBAT. The great improvement in the toughness of PLA based blends was achieved by the addition of PBAT of no less than 15 wt% and that of ESA of no more than 0.5 wt%. Although SEM micrographs and the reduced deviation of the terminal slope of G′ and G″ indicated better compatibility and adhesion between the two phases, the blend with ESA was still a two-phase system as indicated in DSC curves. Rheological results reveal that the addition of ESA increased the storage modulus (G′), loss modulus (G″) and complex viscosity of the blend at nearly all frequencies. The melt strength and melt elasticity of the blend are improved by addition of ESA. 相似文献