Determination of viscoelastic properties of thin pressure sensitive adhesive using dynamic mechanical analysis
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Determination of viscoelastic properties of thin pressure sensitive adhesive using dynamic mechanical analysis H. Jung1 · H. Song1 · M. Lee1 · Y. Kim1 · S. Youn2 · K. Lee2 · J. Shin2 · M. Kim2
Received: 9 October 2017 / Accepted: 11 February 2019 © Springer Nature B.V. 2019
Abstract This paper suggests a testing method to measure the frequency-domain viscoelastic properties of a micron-scale thickness adhesive. To test a thin adhesive below room temperature, a new double-shear tester is designed in this study. A thin pressure-sensitive adhesive (KGK-200A50) with the thickness of 50 µm is tested in the range of −5.5 ◦ C–16.4 ◦ C and 0.1 Hz–5 Hz. The measured storage and loss modulus are found to vary between 15 kPa– 226 kPa and 31 kPa–301 kPa, respectively, and over the full range of frequency and temperature investigated. A time–temperature superposition is applied to derive higher-frequency viscoelastic properties with the extended frequency range of 0.1 Hz–2000 Hz at 16.4 ◦ C. The experimental results are found to be overall in good agreement with other published results. Keywords Dynamic mechanical analysis · Pressure-sensitive adhesive · Time–temperature superposition · Thin adhesive · Viscoelastic property Nomenclature shift factor aT Bi Biot number C1 , C2 material constants in the Williams–Landel–Ferry model; see Eq. (9) Ecycle dissipated energy per cycle (J/m3 ) f frequency (Hz) complex shear modulus (Pa) G∗ storage shear modulus (Pa) G loss shear modulus (Pa) G h convective heat transfer coefficient (W/m2 /K) k thermal conductivity (W/m/K) L characteristic length (m)
B Y. Kim
[email protected]
1
Department of Mechanical Engineering, Korea University, Seongbuk-Ku, Seoul, 02841, Republic of Korea
2
Samsung Display Corporation, CAE Team, Tangjeong-Myeon, Asan, 31454, Republic of Korea
Mech Time-Depend Mater
T δ γ∗ τ∗ ω
temperature (K) phase rag (rad) complex shear strain complex shear stress (Pa) angular velocity (rad/s)
Abbreviation TTS time–temperature superposition
1 Introduction Adhesive bonding using thin pressure-sensitive adhesives are widely used in portable electronics such as a mobile phone due to space and weight constraints (Hayashida et al. 2015; Jang et al. 2014). The pressure-sensitive adhesive (an elastomeric adhesive with rubber component) exhibits viscoelastic behavior (Benedek 2014). Mechanical behaviors of such viscoelastic materials are generally characterized by frequency-domain viscoelastic properties (storage and loss modulus) or the time-domain viscoelastic property (relaxation modulus) (Lakes 2004). Determining the frequency-domain viscoelastic properties of thin pressuresensitive adhesives is necessary to evaluate the reliability of portable electronic devices under vibratory and dynamic loading. Several testing standards for determining frequency-domain viscoelastic properties are available (ASTM International 2011; International Organization for Standardization 2011; Deutsches Institut fur Normung 1990). However, these standards are suitable for testing millime
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