Tags

Type your tag names separated by a space and hit enter

Bacterial cellulose nanocrystals exhibiting high thermal stability and their polymer nanocomposites.
Int J Biol Macromol. 2011 Jan 01; 48(1):50-7.IJ

Abstract

Nanocrystals prepared from bacterial cellulose are considered as 'green nanomaterials' depending on their renewable nature and ease of production without the involvement of hazardous chemical treatments. In this investigation, a top down approach was followed for the preparation of bacterial cellulose nanocrystals (BCNC) using a commercially available cellulase enzyme so as to retain native properties of bacterial cellulose even in its nanodimensional form. The morphological and dimensional parameters of BCNC were studied using atomic force microscope (AFM) and transmission electron microscope (TEM). Thermal properties of BCNC produced using the novel enzyme treatment and conventional sulfuric acid hydrolysis were compared. The thermal stability of enzyme processed BCNC was almost two fold higher than sulfuric acid processed ones. Further, the activation energy required for decomposition of enzyme processed BCNC was much higher than the other. Using this enzyme processed BCNC, Polyvinylalcohol (PVA) nanocomposite films were prepared and characterized. Incorporation of these nanocrystals in polymer matrix resulted in a remarkable improvement in the thermal stability as well as mechanical properties of nanocomposite films. These nanocomposites exhibited higher melting temperature (Tm) and enthalpy of melting (ΔHm) than those of pure PVA, suggesting that the addition of nanocrystals modified the thermal properties of PVA. The effective load transfer from polymer chains to the BCNC resulted in an improved tensile strength from 62.5 MPa to 128 MPa, by the addition of just 4 wt% of BCNC. Furthermore, the elastic modulus was found to increase from 2 GPa to 3.4 GPa. The BCNC obtained through cellulose treatment under controlled conditions were associated with several desirable properties and appear to be superior over the conventional methods of nanocrystals production. The enzymatic method followed in this study is expected to contribute the fabrication of high performance polymer nanocomposites in a much greener and innovative manner.

Authors+Show Affiliations

Food Engineering and Packaging, Defence Food Research Laboratory, Siddarthanagar, Mysore 570011, Karnataka, India. g.johnsy@gmail.comNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

20920524

Citation

George, Johnsy, et al. "Bacterial Cellulose Nanocrystals Exhibiting High Thermal Stability and Their Polymer Nanocomposites." International Journal of Biological Macromolecules, vol. 48, no. 1, 2011, pp. 50-7.
George J, Ramana KV, Bawa AS, et al. Bacterial cellulose nanocrystals exhibiting high thermal stability and their polymer nanocomposites. Int J Biol Macromol. 2011;48(1):50-7.
George, J., Ramana, K. V., Bawa, A. S., & Siddaramaiah, . (2011). Bacterial cellulose nanocrystals exhibiting high thermal stability and their polymer nanocomposites. International Journal of Biological Macromolecules, 48(1), 50-7. https://doi.org/10.1016/j.ijbiomac.2010.09.013
George J, et al. Bacterial Cellulose Nanocrystals Exhibiting High Thermal Stability and Their Polymer Nanocomposites. Int J Biol Macromol. 2011 Jan 1;48(1):50-7. PubMed PMID: 20920524.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Bacterial cellulose nanocrystals exhibiting high thermal stability and their polymer nanocomposites. AU - George,Johnsy, AU - Ramana,K V, AU - Bawa,A S, AU - Siddaramaiah,, Y1 - 2010/10/23/ PY - 2010/06/15/received PY - 2010/09/04/revised PY - 2010/09/24/accepted PY - 2010/10/6/entrez PY - 2010/10/6/pubmed PY - 2011/4/5/medline SP - 50 EP - 7 JF - International journal of biological macromolecules JO - Int J Biol Macromol VL - 48 IS - 1 N2 - Nanocrystals prepared from bacterial cellulose are considered as 'green nanomaterials' depending on their renewable nature and ease of production without the involvement of hazardous chemical treatments. In this investigation, a top down approach was followed for the preparation of bacterial cellulose nanocrystals (BCNC) using a commercially available cellulase enzyme so as to retain native properties of bacterial cellulose even in its nanodimensional form. The morphological and dimensional parameters of BCNC were studied using atomic force microscope (AFM) and transmission electron microscope (TEM). Thermal properties of BCNC produced using the novel enzyme treatment and conventional sulfuric acid hydrolysis were compared. The thermal stability of enzyme processed BCNC was almost two fold higher than sulfuric acid processed ones. Further, the activation energy required for decomposition of enzyme processed BCNC was much higher than the other. Using this enzyme processed BCNC, Polyvinylalcohol (PVA) nanocomposite films were prepared and characterized. Incorporation of these nanocrystals in polymer matrix resulted in a remarkable improvement in the thermal stability as well as mechanical properties of nanocomposite films. These nanocomposites exhibited higher melting temperature (Tm) and enthalpy of melting (ΔHm) than those of pure PVA, suggesting that the addition of nanocrystals modified the thermal properties of PVA. The effective load transfer from polymer chains to the BCNC resulted in an improved tensile strength from 62.5 MPa to 128 MPa, by the addition of just 4 wt% of BCNC. Furthermore, the elastic modulus was found to increase from 2 GPa to 3.4 GPa. The BCNC obtained through cellulose treatment under controlled conditions were associated with several desirable properties and appear to be superior over the conventional methods of nanocrystals production. The enzymatic method followed in this study is expected to contribute the fabrication of high performance polymer nanocomposites in a much greener and innovative manner. SN - 1879-0003 UR - https://www.unboundmedicine.com/medline/citation/20920524/Bacterial_cellulose_nanocrystals_exhibiting_high_thermal_stability_and_their_polymer_nanocomposites_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0141-8130(10)00293-X DB - PRIME DP - Unbound Medicine ER -