Impregnation Of Poly Research Articles

Impregnation of poly(L-lactide-ran-\u03b4-valerolactone) with essential bark oil using supercritical carbon dioxide

This work studied the incorporation of essential bark oil from Thujopsis dolabrata var. hondae, which is known to repel various insects, in poly(L-lactide-ran-δ-valerolactone) [poly(L-LA-ran-VL)] using supercritical carbon dioxide (scCO2). The poly(L-LA-ran-VL) was synthesized by first purifying the monomers by azeotropic distillation with benzene, followed by polymerization with Sn(oct)2 using the same equipment, representing an efficient one-pot process. The copolymerization of L-LA with VL using this technique at a feed ratio of 90/10 mol/mol gave poly(L-LA-ran-VL) (91/9) with a molecular weight of 6.48 × 104 g/mol and a high yield of 74.9%. Products with molecular weights over 5.0 × 104 g/mol were obtained at L-LA feed proportions of 70 to 90%. Impregnation trials were conducted between 40 and 120 °C at 14 MPa for 3 h. The oil content of a 73/27 specimen was found to increase significantly during processing at 100 or 120 °C. During enzymatic degradation with proteinase K, the 91/9 specimen showed the fastest degradation rate. Although the 71/29 sample was slowly hydrolyzed in a phosphate buffer at pH 7.0, the release of oil vapor from this material was slightly higher than that from the 91/9 specimen, and the vapor release rate continuously increased throughout the hydrolysis process.

Impregnation of Poly(lactic acid) on Biologically Pulped Pineapple Leaf Fiber for Packaging Materials

Newly developed packaging paper made of biopulped pineapple leaf fiber (PALF) and poly(lactic acid)(PLA) was studied. PALF packaging sheets were solvent impregnated with PLA at different concentrations in order to improve their moisture barrier and mechanical performance. With the impregnation of PLA at a concentration of 4%, the packaging material exhibited a low moisture uptake and a high tear index. An electron micrograph of the sample at 4% impregnation revealed uniform and packed PLA reversed microsphere morphology. These results suggest that surface coating via biodegradable polymers, such as PLA, may be utilized for manufacturing packaging materials in industrial applications. This new packaging material could reduce the dependency on wood-based paper and plastic-based packaging.

Synthesis and biodegradation studies of gamma irradiated electrically conductive hydrogels

Abstract Poly(acrylamide-aniline)-grafted gum ghatti [Gg-cl-poly(AAm)] conducting hydrogel was prepared via 60 Co γ-irradiation using N, N′-methylene-bis-acrylamide as a cross linker. The effects of the reaction conditions (viz. gamma dose, monomer, solvent and cross linker concentration) were investigated on the degree of swelling of Gg-cl-poly(AAm). Results showed that optimum reaction conditions for maximum percentage swelling were 10 ml of solvent, 1.08 mol/L of monomer concentration, 0.324 × 10 −1 mol L −1 of crosslinker concentration and 1.5 kGy of total dose. The semi-interpenetrating network (Semi-IPN) was converted into an IPN through the impregnation of poly(aniline) chains followed by doping with HCl. The influence of dopant concentration on the conductivity of synthesized hydrogel was investigated. Different physical properties of the synthesized hydrogel were also studied. The candidate polymers were characterized using different techniques such as X-ray diffraction and thermogravemetric analysis techniques. The mechanism of graft copolymerization via 60 Co irradiation was discussed. Biodegradation studies of the synthesized hydrogels were carried out using a soil burial test. IPN showed better degradation efficiency than semi-IPN. Weight loss of semi-IPN and IPN was 68% and 78%, respectively, in 60 days. Different degradation stages were studied using FTIR and SEM techniques.

Guanidinylated poly(allylamine) supported on mesoporous silica for CO2 capture from flue gas

The CO2 adsorption performance of aminosilica adsorbents prepared by the impregnation of poly(allylamine) (PAA) and guanidinylated poly(allylamine) (GPAA) into silica mesocellular foam supports is evaluated. The effect of amine loading on the CO2 capacity is consistent with previous reports of poly(allylamine) impregnated adsorbents, whereby the capacity increases initially with increasing amine loading and then drops at very high amine loadings, due to restricted access to the amine sites at high loadings. The CO2 capacity of the new GPAA impregnated adsorbents decreases with an increase in adsorption temperature, showing comparable capacities to those for PAA impregnated adsorbents at low to moderate temperatures. However, at adsorption temperature higher than 75°C, the CO2 capacities of GPAA adsorbents are higher than those for PAA adsorbents, ∼70% higher at the highest temperature studied, 140°C. CO2 adsorption–desorption cycling experiments show that the GPAA adsorbents have a better stability and regenerability at higher temperatures, making this class of materials suited for temperature swing cycles operating in a higher temperature regime than traditional aminosilica adsorbents based on PEI.

Fabrication and characterization of gum ghatti-polymethacrylic acid based electrically conductive hydrogels

Gum ghatti-polymethacrylic acid-polyaniline based electrically conductive hydrogel with an interpenetrated network (IPN) structure was prepared through a two step aqueous polymerization. In the first step, cross linked network of polymethacrylic acid onto Gum ghatti was prepared using N,N′-methylene-bis-acrylamide (MBA) and ammonium persulfate (APS) as a cross linker-initiator system under microwave irradiation. Optimum reaction conditions affording maximum percentage swelling were: solvent (ml)=10, MAA (molL−1)=0.236×10−3, APS (molL−1)=0.175×10−1, MBA (molL−1)=0.32×10−1, reaction time (s)=85, microwave power (%)=100 and pH 7.0. The semi-interpenetrating networks was converted into a IPN through the impregnation of poly(aniline) chains and resulting IPN was doped with HCl. The maximum conductivity (2.69×10−4Scm−1) was observed with 2.0N HCl and 0.658×10−3molL−1 of aniline. Synthesized IPN was characterized using different techniques like FTIR, SEM and XRD. The candidate polymer was also subjected for evaluation of its thermal behavior using TGA.

Oxidative Stability of Amino Polymer–Alumina Hybrid Adsorbents for Carbon Dioxide Capture

Amine/oxide hybrid carbon dioxide adsorbents prepared via impregnation of low molecular weight polymeric amines into porous oxide supports are among the most promising solid adsorbents developed for postcombustion CO2 capture or CO2 extraction from ambient air. The oxidative stability of adsorbents prepared by impregnation of poly(ethylenimine) (PEI) or poly(allylamine) (PAA) into mesoporous γ-alumina under humid oxidation conditions is evaluated in this work. The PEI-based adsorbents, which contain primary, secondary, and tertiary amines, are shown to degrade drastically at elevated temperatures (110 °C) and in high oxygen concentrations (21%, akin to air), with these effects reduced by both reductions in temperature (70 °C) and oxygen concentration (5%, akin to flue gas). The oxidation behavior of PEI-based adsorbents supported on alumina is qualitatively similar to past work on silica-supported PEI adsorbents. In contrast, the alumina-supported PAA adsorbents that contain only primary amines show signi...

Ibuprofen impregnation into submicron polymeric films in supercritical carbon dioxide

The impregnation of ibuprofen into submicron films (25–250nm) of poly(methyl methacrylate), PMMA, under supercritical CO2 conditions (at 40°C and 50°C and 13.8 and 20.7MPa) was studied. The quartz crystal microbalance (QCM) was used to perform real-time, in situ impregnation measurements. The amount of ibuprofen uptake into the polymer film was calculated directly from the QCM results. Different aspects of the process were studied including: the effect of CO2 density on uptake, distribution uniformity across the film thickness, and impregnation rate. The partitioning coefficient of ibuprofen PMMA and CO2 was high, whereas the diffusivity of ibuprofen was found to be order of magnitudes lower than that of CO2. These two effects are believed to result in high drug loading in the polymer. It was also concluded that CO2 helped in producing uniform concentration profiles of ibuprofen in the PMMA films. Finally, preliminary studies on the impregnation of poly(vinyl pyrrolidone), PVP, with ibuprofen were performed. The QCM response in the case of PVP films was significantly larger than that with PMMA at the same conditions. Some possible causes for this unusual behavior are discussed.

Impregnation of poly(L‐lactide‐ran‐cyclic carbonate) copolymers with useful compounds with supercritical carbon dioxide

AbstractIn this article, we cover the development of L‐lactide (L‐LA) random copolymers into which useful compounds, such as repellents and antibacterial agents, were impregnated by high concentration. Outstanding controlled release materials were developed with statistical random copolymers of L‐LA with cyclic carbonate (CC) [2,2‐dimethyltrimethylene carbonate (2,2‐DTMC) or tetramethylene carbonate (TEMC)] with tin 2‐ethyL‐hexanoate as a catalyst at 150°C (2,2‐DTMC) or 120°C (TEMC) for 24 h without solvent. The preparation of improved controlled release materials was performed with useful organic compounds with low boiling points and synthetic L‐LA random copolymers containing CCs as base materials under supercritical carbon dioxide (scCO2). Low‐boiling‐point compounds, such as d‐limonene and hinokitiol, were used. In impregnation experiments with scCO2, the amounts of low‐boiling‐point compounds increased with increasings L‐LA content. The compound content impregnated into poly(L‐lactide‐ran‐cyclic carbonate) [poly(L‐LA‐ran‐CC)] was greater than that of the experiment with poly(L‐lactide‐ran‐ε‐caprolactone) previously studied. When the enzymatic degradation of poly(L‐LA‐ran‐CC) was performed with proteinase K, copolymers with a greater L‐LA content degraded more rapidly than did copolymers with a greater CC content. In a controlled release experiment with poly(L‐lactide‐ran‐2,2‐dimethyltrimethylene carbonate) (76/24) or poly(L‐lactide‐ran‐tetramethylene carbonate) (81/19), the rate of polymer degradation and the rate of impregnated compound release were almost the same. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Impregnation isotherms of hydroxybenzoic acid on PMMA in supercritical carbon dioxide

The use of supercritical fluid and specifically carbon dioxide as carrier to infiltrate various matrices is gaining importance. This study focuses on the impregnation of poly(methyl methacrylate) by a model drug, o-hydroxybenzoic acid ( o-HBA), using supercritical carbon dioxide (SCCO 2) as carrier and swelling agent, with special emphasis to equilibrium data. A stirred batch reactor equipped with sampling device was employed in order to determine the sorption isotherms with a concentration parameter independent of pressure. The impregnated amount of HBA/g polymer was determined at 40 °C and 12, 16 and 20 MPa for concentrations of HBA in SCCO 2 ranging from 0.05 to 0.7 mg/g. Reproducibility of the impregnated amount was below 3.2%. At the highest investigated concentrations, the uptakes were of 27 mg/g polymer when experiments were performed at 12 or 16 MPa, and of 20 mg/g polymer for the investigations carried at 20 MPa. Experimental data were further correlated by four isotherm types: Langmuir, Freundlich, Sips and Toth. Only the Toth model was found to fit satisfactorily the whole range of concentration, for the three pressures.

Photoacoustic response in a multivariable dyeing process: Comparison between conventional aqueous and supercritical CO2used for impregnating PET films

Photoacoustic (PA) spectroscopy is used to study impregnation of Poly (ethylene terephthalate) (PET). Films were produced in conventional aqueous bath (CAB) and supercritical carbon dioxide (SC-CO 2 ) and impregnated with disperse dyes Blue 79 (DB 79) and Red 60 (DR 60). It was treated in different temperature, concentration and pressure, and PA intensities used as the response in the multivariate method (Factorial Planning - FP). Results pointed out the SC-CO 2 process with DB 79 dye as more effective.

Chemically responsive microelectrochemical devices based on platinized poly(3-methylthiophene): variation in conductivity with variation in hydrogen, oxygen, or pH in aqueous solution

Abstract : In this paper we wish to show that metal impregnated conducting polymers can be useful as the active material in microelectrochemical devices that respond to certain chemical changes in aqueous solution. We report here the impregnation of poly(3-methylthiophene) with metallic Pt in order to make the conducting polymer responsive to oxidizing and reducing species, O2 and H2, respectively, in a reversible and reproducible manner at room temperature in aqueous solution. As recently described, poly(3-methylthiophene)-based transistors can be used in aqueous solution to reproducibly respond to a redox signal, e.g. 10 to the -16 power moles of IrC16(2-) can be detected. In principle, any oxidant capable of oxidizing poly(3-methylthiophene) can be detected. However, only those redox reagents capable of equilibrating with the poly(3-methylthiophene) can be useful in turning the transistor on or off. Since the poly(3-methylthiophene)-based transistor has impressive durability to aqueous solutions, rapid response, and excellent transconductance, this chemically sensitive device is an ideal candidate for microsensor development, provided that it can be made responsive to reagents of interest. Impregnation of the polymer with a noble metal capable of equilibrating with aqueous O2 and H2 is our first step in device modification that yields potentially useful functions for the device.