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Das B.,Advanced Polymer and Nanomaterial Laboratory | Chattopadhyay P.,Indian Defence Research And Development Laboratory | Mishra D.,Indian Institute of Technology Kharagpur | Maiti T.K.,Indian Institute of Technology Kharagpur | And 3 more authors.
Journal of Materials Chemistry B | Year: 2013

This study focused on the design of novel mechanically tough, biocompatible, osteoconductive and biodegradable scaffolds based on sunflower oil modified hyperbranched polyurethane (HBPU)/functionalized multi-walled carbon nanotube (f-MWCNT) nanocomposites (NCs), and the response of an animal model on their post-implantation. The NC was prepared by an in situ polymerization technique with different wt% of f-MWCNTs. The tensile strength of the NCs was enhanced to 36.98-47.6 MPa from 23.93 MPa (HBPU) and toughness from 12 767 to 18 427-19 440 due to the addition and efficient dispersion of the f-MWCNTs in the HBPU matrix. The post-60 days in vitro biodegraded NC retained sufficient strength (39 ± 1.65 MPa). The increase in wt% of f-MWCNTs had a significant effect on tailoring the physico-mechanical properties of the polymer. The hematological, histological and immunological indices of toxicity suggested the safety potential of the prepared systems within the tested animal model. Moreover, the cytokines (viz. IL-6 and TNF-α) detection, MTT assay and anti-hemolytic assay boosted the non-toxic behavior of the systems. The NC with interconnected pores size (200-330 μm) showed better proliferation and adherence of osteoblast (MG63) cells compared to the HBPU and the results were comparable with the control. Thus the findings confirmed the non-toxicity of f-MWCNTs in association with the polymer and thereby endorsed the NC as a potential biomimetic scaffold for bone tissue engineering. This journal is © 2013 The Royal Society of Chemistry.


Konwar U.,Advanced Polymer and Nanomaterial Laboratory | Karak N.,Advanced Polymer and Nanomaterial Laboratory | Mandal M.,Tezpur University
Advanced Science Letters | Year: 2012

Mesua ferrea Linn seed oil-based highly branched polyester/multi-walled carbon nanotubes (MWCNTs) nanocomposites were prepared using intense mechanical shearing force and ultrasonication. The surface of MWCNTs was modified through an oxidative process using potassium permanganate as the oxidant and cetyltrimethyl ammonium bromide as the phase transfer catalyst. Homogeneous dispersion due to good interactions of MWCNTs with the polyester matrix was observed. This is confirmed by scanning electron microscopy, transmission electron microscopy and X-ray diffraction studies. The tensile strength of the nanocomposites was improved by more than 500% by incorporation of only 2 wt% of MWCNTs into the matrix as compared to the pristine system. Significant improvement in thermal stability up to 44 °C of the nanocomposites was found at low MWCNTs loading (2 wt%). Biodegradation of the nanocomposite films was evaluated using two strains of Pseudomonas aeruginosa (PN8A1 and vs1) and one strain of Bacillus subtilis (MTCC73). The nanocomposites exhibited noticeable biodegradability as compared to the pristine polymer. A cytocompatibility test based on hemolysis of red blood cells primarily indicates compatibility of the nanocomposites. The results indicate the potentiality of the nanocomposites as advanced bio-materials. © 2012 American Scientific Publishers. All rights reserved.


Kalita H.,Advanced Polymer and Nanomaterial Laboratory | Mandal M.,Tezpur University | Karak N.,Advanced Polymer and Nanomaterial Laboratory
Journal of Polymer Research | Year: 2012

Solvent-induced shape-memory polymers are of immense interest in various fields, especially biomedicine, as the high transition temperatures required to induce shape recovery in thermoresponsive shape-memory polymers can have adverse effects. In this work, hyperbranched polyurethane was prepared from poly (å-caprolactone)diol, butanediol, monoglyceride of Mesua ferrea L. seed oil, triethanolamine, and toluene diisocyanate by a pre-polymerization technique. Biodegradation of the polyurethane was assessed by the broth culture technique, and adequate biodegradation was noted in Fourier transform infrared spectroscopy and scanning electron micrography studies, thermogravimetric analysis, and measurements of mechanical properties. The shape recovery of this hyperbranched polyurethane was tested by immersing it in various solvents with differing solubility parameters. The prepared polyurethane showed excellent shape recovery within a short time (10 min) in dimethylformamide. A differential scanning calorimetric study showed decreases in the glass transition temperature and the melting temperature of the sample when it had recovered its shape. The solubility parameter, polarity, and size of the solventmolecules were found to exert the strongest influences on the shape recovery. The studied hyperbranched polyurethane has the potential to be used as an advanced solvent-responsive shape-memory material. © 2012 Springer Science+Business Media B.V.


Das B.,Advanced Polymer and Nanomaterial Laboratory | Konwar U.,Advanced Polymer and Nanomaterial Laboratory | Mandal M.,Tezpur University | Karak N.,Advanced Polymer and Nanomaterial Laboratory
Industrial Crops and Products | Year: 2013

The vegetable oil based biodegradable advanced materials with hyperbranched architecture has drawn tremendous attraction in recent years. In the present study, sunflower (Helianthus annuus L.) oil modified hyperbranched polyurethane (HBPU) and linear polyurethane (LPU) were synthesized by using toluene diissocyanate, poly(ε{lunate}-caprolactone), butanediol and monoglyceride of oil, with and without pentaerythritol as a multifunctional unit, respectively. The structures of polyurethanes were confirmed by Fourier transformed infrared (FTIR), nuclear magnetic resonance (NMR) spectroscopic and X-ray diffraction (XRD) studies. 1H NMR study confirmed the hyperbranched structure with degree of branching 0.76 for HBPU. Physico-mechanical properties like impact resistance (90cm vs. 100cm), scratch hardness (4.3kg vs. 4.7kg), tensile strength (18.9MPa vs. 23.18MPa) and elongation at break (750% vs. 700%); biodegradability as tested by broth culture technique using Pseudomonas aeruginosa and Bacillus subtilis strains, and thermal stability (239°C vs. 250°C) were found to be higher for HBPU than LPU. Therefore, the bio-based synthesized HBPU with the desired properties in terms of physico-mechanical, thermal, and biodegradability has the potential to be used as a thin film material for advanced multifaceted applications. © 2012 Elsevier B.V.

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