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1.
Interpenetrating polymer networks (IPNs) of glycerol modified castor oil polyurethane (GC‐PU) and poly(2‐ethoxyethyl methacrylate) poly(2‐EOEMA) were synthesized using benzoyl peroxide as initiator and ethylene glycol dimethacrylate (EGDM) as crosslinker. GC‐PU/poly (2‐EOEMA) interpenetrating polymer networks were obtained by transfer molding. The novel GC‐PU/poly (2‐EOEMA) IPNs are found to be tough films. These IPNs are characterized in terms of their resistance to chemical reagents thermal behavior (DSC, TGA) and mechanical behavior, including tensile strength, Young's modulus, shore A hardness, and elongation. The morphological behavior was studied by scanning electron microscopy. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1029–1034, 2004 相似文献
2.
Beri Rengaraju Prasannakumar Iyyaswami Regupathi Thanapalan Murugesan 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2009,84(1):83-91
BACKGROUND Removal of phenol from industrial waste waters involves basic techniques namely extraction, biodegradation, photocatalytic degradation, etc. Among the available processes, the oxidation of phenols using H2O2 is a suitable alternative because of low cost and high oxidizing power. The application of an oxidation process for the decomposition of stable organic compounds in waste water leads to the total degradation of the compounds rather than transferring from one form to another. Since oxidation using Fenton's reagent is more dependent on pH, in this present work it was proposed to use H2O2 coupled with microwave irradiation. The effects of initial phenol concentration, microwave power and the irradiation time on the amount of decomposition were studied. RESULTS: In the present work experiments were conducted to estimate the percentage degradation of phenol for different initial concentrations of phenol (100, 200, 300, 400 and 500 mg L?1), microwave power input (180, 360, 540, 720 and 900 W) for different irradiation times. The kinetics of the degradation process were examined through experimental data and the decomposition rate follows first‐order kinetics. Response surface methodology (RSM) was employed to optimize the design parameters for the present process. The interaction effect between the variables and the effect of interaction on to the responses (percentage decomposition of phenol) of the process was analysed and discussed in detail. The optimum values for the design parameters of the process were evaluated (initial phenol concentration 300 mg L?1, microwave power output 668 W, and microwave irradiation time 60 s, giving phenol degradation 82.39%) through RSM by differential approximation, and were confirmed by experiment. CONCLUSION: The decomposition of phenol was carried out using H2O2 coupled with microwave irradiation for different initial phenol concentrations, microwave power input and irradiation times. The phenol degradation process follows first‐order kinetics. Optimization of the process was carried out through RSM by forming a design matrix using CCD. The optimized conditions were validated using experiments. The information is of value for the scale up of the oxidation process for the removal of phenol from wastewater. Copyright © 2008 Society of Chemical Industry 相似文献
3.
Manayan Parambil Ajithkumar Malgar Puttaiahgowda Yashoda Shankarappa Prasannakumar 《Iranian Polymer Journal》2014,23(2):93-101
A series of poly(N-vinyl-2-pyrrolidone–maleic anhydride–styrene) terpolymers have been synthesized using titanium(III)-dimethylglyoxime redox initiator system. The usage of redox initiators in the terpolymerization was limited; hence it should be considered as a new approach. The reactivity of the monomers has been studied by well-accepted Kelen-Tudos and Fineman-Ross linear methods and compared with the nonlinear RREVM method. The results also suggested that the RREVM method is the most reliable and superior method for the estimation of reactivity ratios. The reactivity ratios for the terpolymer (r 1 0.99 and r 2 0.05) obtained from the RREVM method showed that the N-vinyl pyrrolidone-maleic anhydride complex was more predominant than styrene in the terpolymer and the complex had more attraction toward itself than styrene. The microstructure determination study depicts that alternating polymer can be prepared by increasing the styrene feed content. The resonance factor and polarity of the complex were calculated as 5.01 and 0.93, respectively, which were different from those of the individual monomers. These calculations would help in predicting the association of monomers during copolymerization. It was observed that the glass transition temperature of the terpolymer increased as the complex ratio in the terpolymer increased. The terpolymer was thermally stable up to 323 °C. 相似文献
4.
S. Vijay Kumar Namdev B. Shelke S. Prasannakumar Ajit P. Rokhade B. S. Sherigara Tejraj M. Aminabhavi 《应用聚合物科学杂志》2009,113(1):251-257
Novel biodegradable aliphatic poly(ester‐urethane)s (PEUs) based on polycaprolactone diol (PCL) and methoxypolyethyleneglycol grafted onto trimethylol propane (mPEG‐g‐TMP) were synthesized by solution polymerization technique and characterized using a variety of techniques. Microspheres ranging in size from 7 to 25 μm were prepared by the solvent evaporation technique and loaded with repaglinide up to 71 to 96%. Increasing molar ratios of mPEG‐g‐TMP propane with respect to polycaprolactone diol gave increase in particle size along with increase in % encapsulation efficiency. Surface morphology and spherical nature of the microspheres were confirmed by scanning electron microscopy (SEM). The release of repaglinide varied, depending upon the molar ratios of mPEG‐g‐TMP moieties with respect to PCL. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
5.
Sabir Ali Shehzad Basavarajappa Mahanthesh Bijjanal Jayanna Gireesha Nagavangala Shankarappa Shashikumar Macha Madhu 《亚洲传热研究》2019,48(5):1688-1708
This communication examines the impact of carbon nanotubes (single‐wall carbon nanotubes [SWCNT] and multi‐wall carbon nanotubes [MWCNT]) on magnetohydrodynamic Brinkman and Forchheimer flow in a planar microchannel with multiple slips. Flow through a porous medium is modeled via Brinkman and Forchheimer theory. The impacts of thermal‐dependent heat source (THS) and exponential space‐dependent heat source (ESHS) are deployed. Aspects of Joule and viscous dissipations are also retained. The dimensionless equations are solved using the Runge‐Kutta‐Fehlberg joint with shooting methodology. The significance of various nondimensional parameters on the flow distributions as well as skin‐friction and Nusselt number is illustrated and analyzed. Closed form solution of momentum quantity is developed for a particular case. Obtained numerical results are in perfect agreement with analytical results. Further, the results of SWCNT and MWCNT are compared. 相似文献
6.
Pavithra K. S. Yashoda M. P. Prasannakumar S. Mutalik Srinivas 《Iranian Polymer Journal》2020,29(2):185-196
Iranian Polymer Journal - In this work, the effect of poly(styrene-co-maleic anhydride)-grafted methoxy (polyethylene glycol) (SMA-g-MPEG) copolymer as dispersants on the viscosity and thermal... 相似文献
7.
K. Prashantha K. Vasanth Kumar Pai B. S. Sherigara S. Prasannakumar 《Bulletin of Materials Science》2001,24(5):535-538
Interpenetrating polymer networks (IPNs) of glycerol modified castor oil polyurethane (GC-PU) and poly[2-hydroxyethylmethacrylate]
(PHEMA) were synthesized using benzoyl peroxide as initiator and N,N-methylenebis acrylamide as crosslinker. GC-PU/PHEMA interpenetrating polymer networks were obtained by transfer moulding. These were characterized
with respect to their resistance to chemical reagents and mechanical properties such as tensile strength, per cent elongation
and shore A hardness. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were undertaken for thermal
characterization. The changes in NCO/OH ratio and GC-PU/PHEMA composition on the properties of the IPNs were studied. 相似文献
8.
S.?Vijay Kumar Namdev?B.?Shelke S.?Prasannakumar B.?S.?Sherigara Tejraj?M.?AminabhaviEmail author 《Journal of Polymer Research》2011,18(3):359-366
Free radical copolymerization of N-vinyl-2-pyrrolidone (NVP) with 2-ethoxyethyl methacrylate (EOEMA) was carried out with 2,2′-azobisisobutyronitrile (AIBN)
initiator in 1,4-dioxane solvent at 60 °C. The resulting copolymers were characterized by FTIR, 1H-NMR and 13C-NMR methods. Microspheres were prepared by varying the amount of NVP with respect to EOEMA. Nifedipine (NFD), a water-insoluble
antihypertensive drug, was loaded into these microspheres by the oil in water emulsion technique followed by solvent evaporation.
The effect of the proportion of NVP in the NVP/EOEMA copolymer on the controlled release of NFD from the microsphere matrix
was investigated. Scanning electron micrographs (SEM) of the microspheres indicated spherical shapes in the size range 17–47
μm, even after loading with NFD. In vitro studies of the release of NFD from the NVP/EOEMA microspheres in pH 7.4 medium showed
that the rate of NFD release was enhanced when the NVP content of the copolymer was high; the size of the microspheres also
increased with increasing NVP content of the copolymer. Release data were analyzed using an empirical relation in order to
elucidate the kinetics of the NFD release. This analysis indicated that a Fickian transport mode operates in this system. 相似文献
9.
Parvathi Varier Gayathri Raju Pallavi Madhusudanan Chinnu Jerard Sahadev A. Shankarappa 《International journal of molecular sciences》2022,23(2)
Nerve axonal injury and associated cellular mechanisms leading to peripheral nerve damage are important topics of research necessary for reducing disability and enhancing quality of life. Model systems that mimic the biological changes that occur during human nerve injury are crucial for the identification of cellular responses, screening of novel therapeutic molecules, and design of neural regeneration strategies. In addition to in vivo and mathematical models, in vitro axonal injury models provide a simple, robust, and reductionist platform to partially understand nerve injury pathogenesis and regeneration. In recent years, there have been several advances related to in vitro techniques that focus on the utilization of custom-fabricated cell culture chambers, microfluidic chamber systems, and injury techniques such as laser ablation and axonal stretching. These developments seem to reflect a gradual and natural progression towards understanding molecular and signaling events at an individual axon and neuronal-soma level. In this review, we attempt to categorize and discuss various in vitro models of injury relevant to the peripheral nervous system and highlight their strengths, weaknesses, and opportunities. Such models will help to recreate the post-injury microenvironment and aid in the development of therapeutic strategies that can accelerate nerve repair. 相似文献
10.
Boaz Mizrahi Sahadev A. Shankarappa Julia M. Hickey Jenny C. Dohlman Brian P. Timko Kathryn A. Whitehead Jung‐Jae Lee Robert Langer Daniel G. Anderson Daniel S. Kohane 《Advanced functional materials》2013,23(12):1527-1533
Injectable materials often have shortcomings in mechanical and drug‐eluting properties that are attributable to their high water contents. A water‐free, liquid four‐armed PEG modified with dopamine end groups is described which changes from liquid to elastic solid by reaction with a small volume of Fe3+ solution. The elastic modulus and degradation times increase with increasing Fe3+ concentrations. Both the free base and the water‐soluble form of lidocaine can be dissolved in the PEG4‐dopamine and released in a sustained manner from the cross‐linked matrix. PEG4‐dopamine is retained in the subcutaneous space in vivo for up to 3 weeks with minimal inflammation. This material's tailorable mechanical properties, biocompatibility, ability to incorporate hydrophilic and hydrophobic drugs and release them slowly are desirable traits for drug delivery and other biomedical applications. 相似文献