Engineering applications of current thermoset shape memory polymers are limited by three critical issues: demanding fabrication conditions (from 70 to 300 °C temperatures for hours or days), lack of reprocessability or recyclability, and low recovery stress and energy output. To address these problems simultaneously, a new UV curable and vitrimer-based epoxy thermoset shape memory polymer (VSMP) has been synthesized. A 1.1 mm thick VSMP film can be readily cured at room temperature under UV-irradiation (61 mW cm−2) in just 80 s. It possesses 36.7 MPa tensile strength, 230 MPa compressive strength, and 3120 MPa modulus at room temperature. It still has a compressive strength of 187 MPa at 120 °C. The covalent adaptable network (CAN) imparts the VSMP with recyclability, as reflected by two effective recycling cycles (>60% recycling efficiency). In addition, the VSMP exhibits good shape memory properties for multiple shape recovery cycles. With 20% compression programming strain, up to 13.4 MPa stable recovery stress and 1.05 MJ m−3 energy output in the rubbery state are achieved. With good mechanical strength, thermal stability, recyclability, and excellent shape memory properties combined with in situ UV-curing capabilities, the new VSMP is a promising multifunctional thermoset for engineering applications.

Recyclable thermoset shape memory polymers with high stress and energy output via facile UV-curing

Lost circulation has been a serious problem while drilling that may lead to heavy financial costs in the form of lost rig time and lost mud fluid. In severe cases, it can lead to well blowout with serious environmental hazards and safety consequences. Despite extensive advances in the last couple of decades, lost circulation materials used today still have disadvantages such as damaging production zones, failing to seal large fractures or plugging drilling tools. Here, we propose a new class of smart expandable lost circulation material (LCM) to remotely control the expanding force and functionality of the injected LCM. Our smart LCM is made out of shape memory polymers that become activated by formation’s natural heat. Once activated, these particles can effectively seal fractures’ width without damaging pores in the production zone or plugging drilling tools. The activation temperature of the proposed LCM can be adjusted based on the formation’s temperature. We conducted a series of experiments to measure the sealing efficiency of these smart LCMs as a proof of concept study. Various slot disk sizes were used to mimic different size fractures in the formation. The API RP 13B-1 and 13B-2 have been followed as standard testing methods to evaluate this product.

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Smart lost circulation materials for productive zones

Analysis on integrity of cement sheath in the vertical section of wells during hydraulic fracturing

Study and Use of Geopolymer Mixtures for Oil and Gas Well Cementing Applications

Smart Lost Circulation Materials for Productive Zones

Smart expandable cement additive to achieve better wellbore integrity

The use of temperature-triggered polymers to seal cement voids and fractures in wells

The nonlinear free vibration of the viscoelastic solid and annular circular microplate is investigated. Nonlinear viscoelastic symmetric and asymmetric foundations are considered. Thermal loading is assumed as constant value. The nonlinear equations of the microplate are derived by Hamilton principle based on third order shear deformation theory (TSDT) and modified couple stress theory (MCST). The finite element methods (FEM) and Newton repeated algorithm are employed to obtain the nonlinear natural frequency. The obtained results are validated with the literatures. Then, the effects of various parameters such as, length scale parameter, outer radius to thickness ratio , maximum deflection to thickness ratio, softening and hardening nonlinear foundation, symmetric and asymmetric nonlinear viscoelastic foundations, different boundary conditions, structure and foundation damping are conducted. The obtained results are compared with several literature and a close agreement are observed between them. The results show that the symmetric and asymmetric nonlinear viscoelastic foundations affect more the nondimensional nonlinear frequency ratio. Reduction effect of temperature difference on MCST nondimensional nonlinear frequency ratio is higher than that of classical theory. The results can be applied micro and nanomachines and smart systems. • Nonlinear free vibration formulation of circular micro plates based on MCST is presented. • Third order shear deformation theory is employed for nonlinear free vibration of thick circular microplates. • Cubic nonlinear foundation effect on nonlinear free vibration is investigated. • Softening and hardening foundations are considered. • Temperature change effect on the nonlinear free vibration are explored. 

Third order nonlinear vibration of viscoelastic circular microplate based on softening and hardening nonlinear viscoelastic foundation under thermal loading

M. Moayeri

Papers

Smart expandable cement additive to achieve better wellbore integrity

The use of temperature-triggered polymers to seal cement voids and fractures in wells

Third order nonlinear vibration of viscoelastic circular microplate based on softening and hardening nonlinear viscoelastic foundation under thermal loading