ORS7-1339
Development of Low-Damping Nanocomposite Adhesives for High-Precision Resonators: The Role of Filler Loading and Network Stoichiometry
Topic
S7. Innovations in Polymeric Composites: From Design and Processing to Industrial Applications
When and Where
Sep 30, 2026
17:40 - 17:55
Room 107
Session Chairs
Jin Chul KIM
Presenter(s)
krishna Enni (ISRO Inertial Systems Unit)
Co-Author(s)
Abstract
This study addresses interfacial energy dissipation in Hemispherical Resonator Gyroscopes (HRGs), where maintaining an ultra-high mechanical Quality Factor (Q) is essential for use in high-precision, deep-space satellites. It introduces an interfacial engineering strategy to reduce molecular-level damping in a DGEBA epoxy resin by adding high-surface-area fumed silica nanoparticles (30 nm) and optimizing network crosslinking with a structured amine curative.
A dual-stage formulation strategy was developed to correlate nanostructure-matrix interactions and crosslink density with viscoelastic damping behavior. Fourier-Transform Infrared (FTIR) spectroscopy confirmed that a 5 wt% fumed silica loading facilitates optimal silanol-epoxy surface interactions and a uniform nanoscale dispersion without disrupting network propagation. Dynamic Mechanical Analysis (DMA) revealed that a precise 7.5 wt% hardener stoichiometry maximized crosslink density, thereby minimizing the loss tangent (tanδ <0.02) and reducing thermal modulus variation by 50% over the operating window. Exceeding this stoichiometric optimum resulted in plasticization, increasing segmental mobility and impairing modulus stability. Space-qualification outgassing assays following ASTM E-595 demonstrated excellent vacuum stability, with a Total Mass Loss (TML) of 0.49% and a Collected Volatile Condensable Material (CVCM) of 0.044%, both well below aerospace limits of 1.0% and 0.1%, respectively.
The optimized nanocomposite formulation was used to bond a resonator shell to a pickoff adapter. Resonant ring-down evaluations under high vacuum using a Laser Doppler Vibrometer (LDV) confirmed that the gyroscope's high-Q characteristics were preserved post-curing. This study underscores how precise control over interfacial fillers and thermoset crosslinking kinetics can address macroscopic mechanical damping challenges in extreme aerospace environments using industrially scalable polymer systems.
A dual-stage formulation strategy was developed to correlate nanostructure-matrix interactions and crosslink density with viscoelastic damping behavior. Fourier-Transform Infrared (FTIR) spectroscopy confirmed that a 5 wt% fumed silica loading facilitates optimal silanol-epoxy surface interactions and a uniform nanoscale dispersion without disrupting network propagation. Dynamic Mechanical Analysis (DMA) revealed that a precise 7.5 wt% hardener stoichiometry maximized crosslink density, thereby minimizing the loss tangent (tanδ <0.02) and reducing thermal modulus variation by 50% over the operating window. Exceeding this stoichiometric optimum resulted in plasticization, increasing segmental mobility and impairing modulus stability. Space-qualification outgassing assays following ASTM E-595 demonstrated excellent vacuum stability, with a Total Mass Loss (TML) of 0.49% and a Collected Volatile Condensable Material (CVCM) of 0.044%, both well below aerospace limits of 1.0% and 0.1%, respectively.
The optimized nanocomposite formulation was used to bond a resonator shell to a pickoff adapter. Resonant ring-down evaluations under high vacuum using a Laser Doppler Vibrometer (LDV) confirmed that the gyroscope's high-Q characteristics were preserved post-curing. This study underscores how precise control over interfacial fillers and thermoset crosslinking kinetics can address macroscopic mechanical damping challenges in extreme aerospace environments using industrially scalable polymer systems.
