Water-responsive mechanically adaptive nanocomposites based on styrene-butadiene rubber and cellulose nanocrystals - processing matters

Annamalai, Pratheep K., Dagnon, Koffi L., Monemian, Seyedali, Foster, E. Johan, Rowan, Stuart J. and Weder, Christoph (2014) Water-responsive mechanically adaptive nanocomposites based on styrene-butadiene rubber and cellulose nanocrystals - processing matters. ACS Applied Materials and Interfaces, 6 2: 967-976. doi:10.1021/am404382x


Author Annamalai, Pratheep K.
Dagnon, Koffi L.
Monemian, Seyedali
Foster, E. Johan
Rowan, Stuart J.
Weder, Christoph
Title Water-responsive mechanically adaptive nanocomposites based on styrene-butadiene rubber and cellulose nanocrystals - processing matters
Journal name ACS Applied Materials and Interfaces   Check publisher's open access policy
ISSN 1944-8244
1944-8252
Publication date 2014-01-22
Year available 2013
Sub-type Article (original research)
DOI 10.1021/am404382x
Open Access Status
Volume 6
Issue 2
Start page 967
End page 976
Total pages 10
Place of publication Washington, DC, United States
Publisher American Chemical Society
Abstract Biomimetic, stimuli-responsive polymer nanocomposites based on a hydrophobic styrene-butadiene rubber (SBR) matrix and rigid, rod-like cellulose nanocrystals (CNCs) isolated from cotton were prepared by three different approaches, and their properties were studied and related to the composition, processing history, and exposure to water as a stimulus. The first processing approach involved mixing an aqueous SBR latex with aqueous CNC dispersions, and films were subsequently formed by solution-casting. The second method utilized the first protocol, but films were additionally compression-molded. The third method involved the formation of a CNC organogel via a solvent exchange with acetone, followed by infusing this gel, in which the CNCs form a percolating network with solutions of SBR in tetrahydrofuran. The thermomechanical properties of the materials were established by dynamic mechanical thermal analysis (DMTA). In the dry state, all nanocomposites show much higher tensile storage moduli, E′, than the neat SBR or the SBR latex. E′ increases with the CNC content and depends strongly on the processing method, which appears to influence the morphology of the SBR nanocomposites produced. The highest E′ values were observed for the solution cast samples involving an SBR latex, where E′ increased from 3 MPa for the neat SBR to ca. 740 MPa for the nanocomposite containing 20% v/v CNCs. Upon submersion in deionized water, a dramatic reduction of E′ was observed, for example from 740 to 5 MPa for the solution-cast nanocomposite containing 20% v/v CNCs. This change is interpreted as a disengagement of the percolating CNC network, on account of modest aqueous swelling and competitive hydrogen bonding of water molecules with the CNCs. It is shown that the method of preparation also influenced the swelling behavior and kinetics of modulus switching, consistent with different arrangements of the CNCs, which serve as channels for water absorption and transport within the hydrophobic SBR matrix.
Keyword Cellulose nanocrystals
Mechanically adaptive
Nanocomposites
Processing
Stimuli-responsive
Styrene-butadiene rubber
Water-responsive behavior
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes Published online: 30 December 2013.

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2014 Collection
Australian Institute for Bioengineering and Nanotechnology Publications
 
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