@article { ISI:000242209000043, title = {Poly(urethane methacrylate-co-glycidyl methacrylate)-supported-polypropylene biphasic membrane for lipase immobilization}, journal = {Journal of Membrane Science}, volume = {285}, number = {1-2}, year = {2006}, month = {NOV}, pages = {395-403}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Polypropylene (PP) was hydrophilized by coating followed by UV curing of a blend of 2-hydroxyethyl methacrylate (HEMA) terminated polyurethane prepolymer and glycidyl methacrylate (GMA). This allows formation of a hydrophobic membrane with increased surface hydrophilicity, biocompatibility and stability. Candida rugosa lipase (CRL) was covalently immobilized on this membrane using 5\% glutaraldehyde as a crosslinking agent for post immobilization stabilization of enzyme on membrane. The membrane obtained was placed in a batch membrane reactor where a model esterification of oleic acid with octanol was studied. Under optimum conditions, the biocatalytic membrane gave a specific activity of 796.27 units/mg and 90.26\% activity yield. Moreover, there was 85. 10\% retention of specific activity. The biocatalytic membrane was observed to retain about 84.23\% of its synthetic activity after six cycles. (c) 2006 Elsevier B.V. All rights reserved.

}, keywords = {Candida rugosa lipase, Enzyme immobilization, membrane bioreactor, urethane methacrylate}, issn = {0376-7388}, doi = {10.1016/j.memsci.2006.09.009}, author = {Pujari, N. S. and Vaidya, Bx and Bagalkote, S. and Ponrathnam, S. and Nene, Sanjay} } @article { ISI:000300929600025, title = {Photopolymerization kinetics of 2-phenylethyl (meth) acrylates studied by photo DSC}, journal = {Journal of Polymer Research}, volume = {19}, number = {2}, year = {2012}, month = {JAN}, pages = {9811}, publisher = {SPRINGER}, address = {VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS}, abstract = {

The present work deals with the photopolymerization of 2-phenylethyl (meth)acrylates and estimation of their kinetic parameters. Formulations were made by independently homogenizing the monomers with photoinitiators of two different classes. Two different compositions of photoinitiators were used to study the effect of concentration of photoinitiator on cure kinetics. These compositions obtained were tested for photo curing performance using differential photocalorimetry (DPC) or photo DSC under polychromatic radiation. The heat flow against time was recorded for all formulations under isothermal conditions and the rates of polymerization as well as the percentage conversions were estimated. It was observed that due to a longer timescale for reaction diffusion, the methacrylate formulations showed a higher conversion than acrylate formulations. Other parameters such as induction time, maximum rate and conversion attained as well as the time to attain peak maximum were noted. The photopolymerization and kinetic estimations of the formulations including evaluation of kinetic models are discussed.

}, keywords = {Bimolecular termination model, Photo DSC, Photopolymerization, Variable autocatalytic model}, issn = {1022-9760}, doi = {10.1007/s10965-011-9811-3}, author = {Ghorpade, Ravindra V. and Bhosle, Sonali Madhavrao and Ponrathnam, S. and Rajan, C. R. and Chavan, Nayaku and Harikrishna, Reghunathan} } @article { ISI:000309096400004, title = {Poly(allyl glycidyl ether-co-ethylene glycol dimethacrylate) copolymer beads as support for covalent immobilization of L-aminoacylase}, journal = {Reactive \& Functional Polymers}, volume = {72}, number = {10}, year = {2012}, month = {OCT}, pages = {687-694}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Porous epoxy-activated copolymer beads were synthesized as support for the covalent immobilization of Aspergillus melleus L-aminoacylase. Here, a series of copolymer bead were synthesized using either glycidyl methacrylate (GMA) or ally] glycidyl ether (AGE) as monomer units and ethylene glycol dimethacrylate (EGDM) as cross-linking agent. The effect of monomer used and the effect of amount of cross-linking agent on covalent immobilization of aminoacylase were studied. Furthermore, the effect of porogen on immobilization of aminoacylase was also evaluated. AGE-co-EGDM copolymer beads gave higher binding of aminoacylase than GMA-co-EGDM copolymer beads. AGE-co-EGDM copolymer beads synthesized with lauryl alcohol as porogen and having 150\% cross-linked density (i.e. AGE-(L)-150) gave maximum enzyme binding. Under optimum conditions, AGE-(L)-150 copolymer beads gave about 130 U/g of aminoacylase activity which corresponds to 72.24\% of activity yield. Immobilized aminoacylase showed a broader pH, higher temperature and extended storage stability. (C) 2012 Elsevier Ltd. All rights reserved.

}, keywords = {Enzyme immobilization, Epoxy-activated support, L-Aminoacylase}, issn = {1381-5148}, doi = {10.1016/j.reactfunctpolym.2012.06.012}, author = {Vaidya, Bhalchandra K. and Ingavle, Ganesh C. and Ponrathnam, S. and Nene, Sanjay N.} } @article { ISI:000318292400036, title = {Photopolymerization of bis-aromatic and alicyclic based solid urethane acrylate macromonomer in the presence of large excess of reactive diluent Kinetics and modeling}, journal = {Journal of Thermal Analysis and Calorimetry}, volume = {112}, number = {2}, year = {2013}, month = {MAY}, pages = {805-813}, publisher = {SPRINGER}, address = {VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS}, abstract = {

A solid urethane acrylate macromonomer with bis-aromatic as well as alicyclic moieties was synthesized and the kinetics of photopolymerization reactions were studied in the presence of varying concentration of photoinitiator and large excess of reactive diluent using photo DSC. The studies show that the rate of maximum polymerization was found to increase with increase in concentration of photoinitiator while a decrease was observed by an increase in temperature. The final conversion showed a decrease at highest isothermal condition due to vitrification. Estimation of kinetic parameters including applicability of autocatalytic and modified autocatalytic models were investigated by nonlinear regression. It was observed that the modified models gave a better fit with the experimental data and kinetic parameters showed a decrease with increase in temperature and an increase with increase in concentration of photoinitiator.

}, keywords = {Autocatalytic model, kinetics, Levenberg-Marquardt method, Photopolymerization}, issn = {1388-6150}, doi = {10.1007/s10973-012-2619-5}, author = {Harikrishna, Reghunathan and Ponrathnam, S. and Rajan, C. R. and Tambe, S. S.} } @article { ISI:000328434500029, title = {Photopolymerization kinetics of bis-aromatic based urethane acrylate macromonomers in the presence of reactive diluent}, journal = {Progress in Organic Coatings}, volume = {77}, number = {1}, year = {2014}, month = {JAN}, pages = {225-231}, publisher = {ELSEVIER SCIENCE SA}, address = {PO BOX 564, 1001 LAUSANNE, SWITZERLAND}, abstract = {

The present work deals with the photopolymerization of bis-aromatic based urethane acrylate macromonomers in the presence of excess end capping agent as reactive diluent and estimation of their kinetic parameters. Formulations were made by independently homogenizing the macromonomers with photoinitiators of three different classes. Three different compositions of photoinitiators were used to study the effect of concentration of photoinitiator on cure kinetics. These compositions obtained were tested for photo curing performance using photo DSC under polychromatic radiation. The heat flows against time were recorded for all formulations under isothermal condition and the rates of polymerization, peak maximum times as well as the percentage conversions were estimated. It was observed that due to a longer timescale for reaction diffusion, formulations with macromonomer containing propoxylated backbone showed higher conversions than the corresponding ethoxylated analogue. The photopolymerization and kinetic estimations of the formulations including evaluation of kinetic model are discussed. (C) 2013 Elsevier B.V. All rights reserved.

}, keywords = {Bimolecular termination model, kinetics, Macromonomer, Photopolymerization}, issn = {0300-9440}, doi = {10.1016/j.porgcoat.2013.09.006}, author = {Harikrishna, Reghunathan and Ponrathnam, S. and Rajan, C. R.} } @article { ISI:000325450600001, title = {Photopolymerization of high internal phase emulsions based on 2-ethylhexyl (meth)acrylates and ethylene glycol dimethacrylate}, journal = {Designed Monomers and Polymers}, volume = {17}, number = {1}, year = {2014}, month = {JAN}, pages = {1-6}, publisher = {TAYLOR \& FRANCIS LTD}, address = {4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND}, abstract = {

Photopolymerization of high internal phase emulsions based on 2-ethylhexyl (meth)acrylates and ethylene glycol dimethacrylate was carried out in presence of low concentration of different photoinitiators. The stable emulsions obtained by mixing with individual photoinitiators were subjected to low-intensity photopolymerization under UV-Visible lamp. Identical samples were irradiated for differing periods ranging from 2 to 10min at an interval of 2min. The percentage conversions of each monomer in the compositions with respect to the time of irradiation were determined using gas chromatography. It was observed that the formulations containing IRGACURE 819 showed the highest conversion while that containing IRGACURE 2959 showed the least conversion. The former showed high conversion due to the proximity of the absorption maxima of photoinitiator to the major emission line of mercury spectrum at 365nm while the latter showed least conversion due to non-availability of major absorption maxima within the irradiation range.

}, keywords = {(meth)acrylates, high internal phase emulsion, Photopolymerization, residual monomer analysis}, issn = {1385-772X}, doi = {10.1080/15685551.2013.771312}, author = {Harikrishna, Reghunathan and Shaikh, A. W. and Ponrathnam, S. and Rajan, C. R. and Bhongale, Sunil Sitaram} } @article { ISI:000371228200032, title = {Prediction of reactivity ratios in free radical copolymerization from monomer resonance-polarity (Q-e) parameters: genetic programming-based models}, journal = {International Journal of Chemical Reactor Engineering}, volume = {14}, number = {1}, year = {2016}, month = {FEB}, pages = {361-372}, publisher = {WALTER DE GRUYTER GMBH}, address = {GENTHINER STRASSE 13, D-10785 BERLIN, GERMANY}, abstract = {

The principal deficiency of the widely utilized Alfrey-Price (AP) scheme for computing reactivity ratios in the widely used free radical copolymerization is that it ignores important factors, such as the steric effects. This often leads to inaccurate reactivity ratio predictions by AP model. Accordingly, in this study, exclusively data-driven, Q-e parameter-based new models have been developed for the reactivity ratio prediction in free radical copolymerization. In the model development, a novel artificial intelligence formalism known as {\textquoteleft}{\textquoteleft}genetic programming (GP){\textquoteright}{\textquoteright} that performs symbolic regression has been employed. The GP-based models possess a different functional form than AP model. Further, parameters of GP-based models were fine-tuned using Levenberg-Marquardt (LM) nonlinear regression method. A comparison of AP, GP and GP-LM as well as artificial neural network (ANN)-based models indicates that GP and GP-LM models exhibit superior reactivity ratio prediction accuracy and generalization performance (with correlation coefficient magnitudes close to or greater than 0.9) when compared with AP and ANN models. The GPbased reactivity ratio prediction models developed here due to their higher accuracy and generalization capability have the potential of replacing the widely used AP models.

}, keywords = {Alfrey-Price scheme, free radical copolymerization, genetic programming, reactivity ratio, symbolic regression}, issn = {2194-5748}, doi = {10.1515/ijcre-2014-0039}, author = {Shrinivas, K. and Kulkarni, Rahul P. and Shaikh, Saif and Ghorpade, Ravindra V. and Vyas, Renu and Tambe, Sanjeev S. and Ponrathnam, S. and Kulkarni, Bhaskar D.} }