@article {310, title = {Stimuli-Responsive Cement-Reinforced Rubber}, journal = {ACS Applied Materials \& Interfaces}, volume = {6}, year = {2014}, month = {May-14-2014}, pages = {6962 - 6968}, abstract = {
Abstract Image

In this work, we report the successful development of a cement\–rubber reactive composite with reversible mechanical properties. Initially, the composite behaves like rubber containing inert filler, but when exposed to water, it increases in volume and reaches a stiffness that is intermediate between that of hydrogenated nitrile butadiene rubber (HNBR) and hydrated cement, while maintaining a relatively large ductility characteristic of rubber. After drying, the modulus increases even further up to 400 MPa. Wet/drying cycles prove that the elastic modulus can reversibly change between 150 and 400 MPa. Utilizing attenuated total reflection Fourier transform infrared spectroscopy), we demonstrate that the high pH produced by the hydration of cement triggers the hydrolysis of the rubber nitrile groups into carboxylate anions. Thus, the salt bridges, generated between the carboxylate anions of the elastomer and the cations of the filler, are responsible for the reversible variations in volume and elastic modulus of the composite as a consequence of environmental moisture exposure. These results reveal that cement nanoparticles can successfully be used to accomplish a twofold task: (a) achieve an original postpolymerization modification that allows one to work with carboxylate HNBR (HXNBR) not obtained by direct copolymerization of carboxylate monomers with butadiene, and (b) synthesize a stimuli-responsive polymeric composite. This new type of material, having an ideal behavior for sealing application, could be used as an alternative to cement for oil field zonal isolation applications.

}, issn = {1944-8244}, doi = {10.1021/am500774k}, author = {Musso, Simone and Robisson, Agathe and Sudeep Maheshwar and Franz-Josef Ulm} } @article {219, title = {Reactive elastomeric composites: When rubber meets cement}, journal = {Composites Science and Technology}, volume = {75}, year = {2013}, month = {Feb-11-2013}, pages = {77 - 83}, abstract = {

This paper describes a novel reactive composite material comprised of hydrogenated nitrile butadiene rubber (HNBR) compounded with slag cement. The composite initially looks and behaves like rubber, but when exposed to water it simultaneously swells and stiffens due to hydration of the cement component. The material eventually reaches a stiffness that is intermediate between that of HNBR and hydrated cement, while maintaining a relatively large ductility that is more characteristic of rubber. This behavior, which is ideal for sealing applications, differentiates this material from conventional swellable materials that become less stiff upon swelling. The development of this new type of material was motivated by the requirements of oilfield zonal isolation, where alternatives to cement are needed for some challenging sealing applications. A mechanism for the swelling and stiffening of the reactive composite is proposed: water diffuses into the HNBR matrix and is converted to bound water through hydration reactions with the cement, causing the effective solid filler content of the composite to increase. A model is proposed that treats the composite as a cellular solid with a continuous filler phase (hydrated cement). This model is able to reproduce the observed increase in the elastic modulus with time during exposure to water.

Elastic modulus ratio (current/initial) as a function of swelling, for HNBR ...

Kinetics of swelling of all three materials during approximately 1month of ...

Evolution of the elastic modulus of all three materials during approximately ...

Tensile stress{\textendash}strain curves for HNBR-cement (61{\textendash}39\% by volume, pre-exposure) ...

Schematic of the hydration process occurring inside the HNBR-cement material, ...

SEM images of HNBR-cement material before (left) and after (right) hydration. It ...

}, issn = {02663538}, doi = {10.1016/j.compscitech.2012.11.012}, author = {Robisson, Agathe and Sudeep Maheshwar and Musso, Simone and Jeffrey J. Thomas and Auzerais, Francois M. and Han, Dingzhi and Qu, Meng and Franz-Josef Ulm} }