@article { ISI:000228765100019, title = {Structure of poly(L-lactic acid)s prepared by the dehydropolycondensation of L-lactic acid with organotin catalysts}, journal = {Journal of Polymer Science Part A-Polymer Chemistry}, volume = {43}, number = {10}, year = {2005}, month = {MAY}, pages = {2164-2177}, publisher = {JOHN WILEY \& SONS INC}, type = {Article}, address = {111 RIVER ST, HOBOKEN, NJ 07030 USA}, abstract = {

The synthesis of low-molecular-weight (weight-average molecular weight \< 45,000 g/mol) lactic acid polymers through the dehydropolycondensation of L-lactic acid was investigated. Polymerizations were carried out in solution with solvents (xylene, mesitylene, and decalin), without a solvent using different Lewis acid catalysts (tetraphenyl tin and tetra-n-butyldichlorodistannoxane), and at three different polymerization temperatures (143, 165, and 190 degrees C). The products were characterized with differential scanning calorimetry, size exclusion chromatography, vapor pressure osmometry, C-13 NMR, and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF). The resulting polymers contained less than 1 mol \% lactide, as shown by NMR. The number-average molecular weights were calculated from the ratio of the area peaks of ester carbonyl and carboxylic acid end groups via C-13 NMR. The stereosequences were analyzed by C-13 NMR spectroscopy on the basis of triad effects. Tetraphenyl tin was an effective transesterification catalyst, and the randomization of the stereosequence at 190 degrees C was observed. In contrast, the distannoxane catalyst caused comparatively less transesterification reaction, and the randomization of the stereosequences was slow even at 190 degrees C. The L-lactic acid and D-lactic acid isomers were added to the polymer chain in a small, blocky fashion. The MALDI-TOF spectra of poly(L-lactic acid) (PLA) chains doped with Na+ and K+ cations showed that the PLA chains had the expected end groups. The MALDI-TOF analysis also enabled the simultaneous detection of the cyclic oligomers of PLA present in these samples, and this led to the full structural characterization of the molecular species in PIA. (c) 2005 Wiley Periodicals, Inc.

}, keywords = {C-13 NMR, dehydropolycondensation, Lewis acid catalysts, MALDI, polymerization, randomization, stereosequence}, issn = {0887-624X}, doi = {10.1002/pola.20679}, author = {Shyamroy, S. and Garnaik, Baijayantimala and Sivaram, S.} } @article {42651, title = {Synthesis and characterization of novel value added biodegradable poly(aleuritic acid) from renewable resources(shellac) and invertible amphiphilic behaviors in various solvents}, journal = {E-Polymer}, year = {2010}, month = {NOV}, pages = {Article Number: 131}, abstract = {

A novel biodegradable polymer poly(aleuritic acid) (PAA) ( M̄w 120,000) was prepared from aleuritic acid, which was obtained from renewable resources (Lac) by using tin catalyst. Aleuritic acid (AL) was protected at 9, 10 position by dimethoxy propane. The protected AL (Pro.AL) was further polymerized to obtain linear protected polyaleuritic acid (PAL) by dehydropolycondensation. Effects of various kinetic and thermodynamic parameters were studied. After polymerization, the deprotection of PAL was carried out. The synthesized PAL and PAA were characterized by using various techniques such as FT-IR, LC-MS, SEC, NMR (1H and 13C), 13C CP/MAS (Cross Polarization / Magic Angle Spinning) of solid PAA, DSC, SEM and TEM etc. The micelle and inverted micelle -structure in polar and nonpolar solvents are highlighted

}, doi = {10.1515/epoly.2010.10.1.1476}, author = {Pandey, Asutosh K. and Nande, Smita S. and Selukar, Balaji S. and Garnaik, Baijayantimala} } @article {42647, title = {Synthesis of linear polylactic acid {\textendash}based urethanes using tin modified closite -30b catalyst}, journal = {Advance Material Letters}, volume = {3}, year = {2012}, month = {JAN}, pages = {161 - 171}, author = {Selukar, Balaji S. and Parwe, Sharad P. and Mohite, Kavita K. and Garnaik, Baijayantimala} } @article {42641, title = {Study of grafting of polylactic acid and its copolymer with 12-hydroxy stearic acid on the surface of MWCNT by 13CCP/MAS and AFM}, journal = {International Journal of Research in Pharmacy and Chemistry}, volume = {3}, year = {2013}, month = {JAN}, abstract = {

The purpose of this study to study the structure property relationship of grafted material on MWCNT, the determination of NMR nuclei spin-lattice (T1) and spin-spin (T2) relaxation times suggest that the broaden signals are associated with diamagnetic species namely the nanotube attached polymer moieties. the AFM image of PLA oligomer grafted MWCNTs and topography patterns comprised of height from 0-250 nm and the side lengths ranging from 0.0 to 7.7 {\textmu}m. Surface patches are formed randomly distributed employing that the presence of side chain hanged at 12-postion in the copolymer grafted on MWCNTs.

}, issn = { 2231-2781}, author = {Pandey, Asutosh K. and Garnaik, Baijayantimala} } @article { ISI:000333686000001, title = {Synthesis of ciprofloxacin-conjugated poly(L-lactic acid) polymer for nanofiber fabrication and antibacterial evaluation}, journal = {International Journal of Nanomedicine}, volume = {9}, year = {2014}, month = {MAR}, pages = {1463-1477}, publisher = {DOVE MEDICAL PRESS LTD}, address = {PO BOX 300-008, ALBANY, AUCKLAND 0752, NEW ZEALAND}, abstract = {

Ciprofloxacin was conjugated with polylactide (PLA) via the secondary amine group of the piperazine ring using PLA and 7-(4-(2-Chloroacetyl) piperazin-1-yl)-1-cyclopropyl-6-fluoro-1, 4-dihydro-4-oxoquinoline-3-carboxylic acid. Zinc prolinate, a biocompatible catalyst was synthesized, characterized, and used in ring opening polymerization of L-lactide. Five different kinds of OH-terminated poly(L-lactide) (two-, three-, four-, six-arm, star-shaped) homopolymers were synthesized by ring opening polymerization of L-lactide in the presence of dodecanol, glycerol, pentaerythritol, dipentaerythritol as initiator and zinc prolinate as a catalyst. The structures of the polymers and conjugates were thoroughly characterized by means of gel permeation chromatography, matrix-assisted laser desorption/ionization-time of flight mass spectrometry, and nuclear magnetic resonance spectroscopy. PLA (molecular weight = 100,000) and ciprofloxacin conjugated PLA were used for fabrication of nonwoven nanofiber mat (diameter ranges; 150-400 nm) having pore size (62-102 nm) using electrospinning. The microbiological assessment shows that the release of ciprofloxacin possesses antimicrobial activity. The drug-release behavior of the mat was studied to reveal potential application as a drug delivery system. The result shows that the ciprofloxacin release rates of the PLA conjugate nonwoven nanofiber mat could be controlled by the drug loading content and the release medium. The development of a biodegradable ciprofloxacin system, based on nonwoven nanofiber mat, should be of great interest in drug delivery systems.

}, keywords = {antibacterial activity, ciprofloxacin conjugated polylactides, CP-PLA, drug release, electrospinning, MDR, nonwoven nanofibers, zinc prolinate}, issn = {1178-2013}, doi = {10.2147/IJN.S54971}, author = {Parwe, Sharad P. and Chaudhari, Priti N. and Mohite, Kavita K. and Selukar, Balaji S. and Nande, Smita S. and Garnaik, Baijayantimala} } @article {46809, title = {Synthesis and characterization of biocompatible poly (L-lactide) using zinc (II) salen complex}, journal = {International Journal of Polymer Analysis and Characterization}, volume = {25}, year = {2020}, month = {JUL }, pages = {283-299}, type = {Article}, abstract = {

A biocompatible zinc (II) complex based on a tetradentate N,N,O,O-type salen ligand was synthesized, characterized and used for the solvent-free ring-opening polymerization (ROP) of L-lactide in bulk at 180 degrees C to prepare high molecular weight poly(L-lactide) (M-n: 82,600 Da;M-w: 140,000 Da; PDI: 1.70). Poly(L-lactide) (PLLA) was characterized using FTIR,H-1 NMR,C-13 NMR, GPC, TGA, DSC, WAXD, and MALDI-ToF. Kinetic measurement was carried out and first-order behavior to monomer was observed. Thek(app)was found as 6 +/- 0.001 x 10(-4 )s(-1). The biocompatibility of the PLLA was confirmed byin vitrocytotoxicity against NIH/3T3 fibroblast cell line and can be used in biomedical applications.

}, keywords = {Biocompatible, Biomedical Applications, in vitro, PLLA, zinc (II) salen complex}, issn = {1023-666X}, doi = {10.1080/1023666X.2020.1783496, Early Access Date = JUN 2020}, author = {Rade, Priyanka P. and Garnaik, Baijayantimala} }