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Mechanistic origins of multi-scale reinforcements in segmented polyurethane-clay nanocomposites

DSpace at IIT Bombay

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Title Mechanistic origins of multi-scale reinforcements in segmented polyurethane-clay nanocomposites
 
Creator RATH, SK
ASWAL, VK
SHARMA, C
JOSHI, K
PATRI, M
HARIKRISHNAN, G
KHAKHAR, DV
 
Subject Segmented polyurethane
Microphase separation
Constrained region
STRESS-STRAIN BEHAVIOR
GLASS-TRANSITION
SILICATE NANOCOMPOSITES
CHARACTERISTIC LENGTH
MORPHOLOGY
DEGRADATION
COPOLYMERS
SCATTERING
POLYMERS
RUBBER
 
Description The objective of the present work is to get insights into the mechanistic origin of the reinforcement effects of nanoclay on a segmented polybutadiene polyurethane-urea system. To this end, a convergent analysis of the hard domain morphology and conformational state of soft segment in the nanocomposites was carried out by using a combination of complementary characterization techniques, namely, Fourier transform infrared spectroscopy, small angle neutron scattering, transmission electron microscopy, modulated differential scanning calorimetry and dynamic mechanical analysis. Analysis of small angle neutron scattering data by a combination of Percus-Yevick hard sphere and Zernike-Ornstein model coupled with direct visualization of the dispersed hard domain morphology from transmission electron microscopy provided insight on clay induced changes in the hard domain morphology. A monotonic decrease in the domain size as well as the average interdomain distance was observed with increasing nanoclay content in the polymer matrix. Analysis of the carbonyl stretching region from FTIR showed increased degree of hydrogen bonding for the urethane carbonyl groups of the nanocomposites compared to the neat matrix. A combination of calorimetric and dynamic mechanical analysis revealed the existence of a constrained amorphous region; quantified to be approximate to 16% at the highest clay content experimented. The manifestation of these morphological and conformational changes on the nano-, micro- and macro scale reinforcements in the nanocomposites was investigated by mechanical properties at these length scales using nanoindentation, DMA and tensile testing, respectively. (C) 2014 Elsevier Ltd. All rights reserved.
 
Publisher ELSEVIER SCI LTD
 
Date 2014-12-28T16:33:15Z
2014-12-28T16:33:15Z
2014
 
Type Article
 
Identifier POLYMER, 55(20)5198-5210
0032-3861
1873-2291
http://dx.doi.org/10.1016/j.polymer.2014.08.035
http://dspace.library.iitb.ac.in/jspui/handle/100/16894
 
Language English