Micromachines, 2025, 16(4), 384, doi.org/10.3390/mi16040384

Enhanced DMA Test Procedure to Measure Viscoelastic Properties of Epoxy-Based Molding Compound: Multiple Oscillatory Strain Amplitudes and Monotonic Loading

Sukrut Prashant Phansalkar¹, Roshith Mittakolu¹, Bongtae Han¹, and Taehwa Kim^2
1Department of Mechanical Engineering, University of Maryland, College Park, MD 20742, USA
²Hyundai Motors R&D Division, Hwaseong-si 18280, Gyeonggi-do, Republic of Korea

For more information about this article and related research, please contact Prof. Bongtae Han.

Abstract:

Dynamic mechanical analysis (DMA) is routinely practiced in the semiconductor industry to measure the viscoelastic properties of various thermosetting polymers. Modern commercial DMA test machines are highly-advanced systems which enable users to perform automatic testing and post-processing of the experimental data. When highly filled thermosets like epoxy-based molding compound (EMC) are tested, unique challenges are encountered during measurements due to the extremely large change in modulus over the testing temperature range. An advanced procedure is proposed to cope with these problems. The first part is the use of different oscillation strain amplitudes so that the variations in stress amplitudes across the testing domain remain consistent. The second part is the conducting of two monotonic tests at the lowest and highest temperatures to obtain the glassy modulus and equilibrium modulus, which can guide the master curve construction accurately. The results of the proposed procedure are presented. The relaxation modulus master curve is used to conduct a virtual testing to verify the accuracy of the generalized Maxwell model constants determined from the frequency data using the proposed procedure.

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