title: Nanoparticle-induced controlled biodegradation and its mechanism in poly(epsilon-caprolactone).
abstract: Poly(epsilon-caprolactone) (PCL)/layered silicate nanocomposites have been prepared via solution route. Two different organically modified nanoclays were used to compare the variation in properties based on organic modifications. The nanostructures, as observed from wide-angle X-ray diffraction and transmission electron microscopy, indicate intercalated and partially exfoliated hybrids depending on the nature of organic modification in nanoclay. The nanohybrids exhibit significant improvement in thermal and mechanical properties of the matrix as compared to neat polymer. The nanoclays act as nucleating agent for the crystallization of PCL. The biodegradability of pure PCL and its nanocomposites have been studied under controlled conditions in enzyme, pure microorganism (fungi), compost, Ganges water, and alkaline buffer solution. The rate of biodegradation of PCL has enhanced dramatically in nanohybrids and depends strongly on the media used. Scanning confocal, electron, and atomic force microscopes have used to demarcate the nature of biodegradation of pristine PCL and its nanocomposites. The change in biodegradation is rationalized in terms of the crystallization behavior and organic modification in nanoclays of the nanohybrids vis-a-vis the neat polymer. The extent of compatibility was measured quantitatively through the interaction parameter for two different nanoclays to compare and establish the reason for variation in their properties in nanohybrids. A biodegradation mechanism has been revealed for PCL and its nanocomposites through enzyme activity in varying pH environment.
authors.affiliation: School of Materials Science and Technology, Institute of Technology, Department of Zoology, Banaras Hindu University, Varanasi 221 005, India.
authors.forename: Narendra K
authors.initials: NK
authors.lastname: Singh
authors.forename: Biswapratim
authors.initials: B
authors.lastname: Das Purkayastha
authors.forename: Jagat K
authors.initials: JK
authors.lastname: Roy
authors.forename: Rathindra M
authors.initials: RM
authors.lastname: Banik
authors.forename: Madhu
authors.initials: M
authors.lastname: Yashpal
authors.forename: Gajendra
authors.initials: G
authors.lastname: Singh
authors.forename: Sudip
authors.initials: S
authors.lastname: Malik
authors.forename: Pralay
authors.initials: P
authors.lastname: Maiti
mesh_terms: D001232:Aspergillus fumigatus / Q000254:growth & development* / Q000378:metabolism; D001673:Biodegradation, Environmental; D053761:Nanocomposites; D053758:Nanoparticles; D011091:Polyesters / Q000737:chemistry / Q000378:metabolism*
chemical_list: D011091:Polyesters; C016240:polycaprolactone