Noise and vibration damping

The subject of interfacial surface tensions was reviewed recently by Gaines (1972) and Wu (1974). 

By application of the time-temperature superposition principle, a decade of frequency can be shown to correspond to a 6 or TC shift in 7. Noting that the normal acoustical range goes from 20 to 20,000 Hz, or three decades, it can be seen that the equivalent temperature range is 18-20°C. We then conclude that a properly chosen homopolymer can Just damp all acoustical frequencies at a single use temperature. 

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Medical Ultrasound Micro-positioning and Micro-motors Piezoelectric Transformers Active Noise and Vibration Damping SUGGESTED READING References on Silicon Devices Problems for Chapter 6... 

Viscoelastic Interpenetrating Polymer Networks (IPNs) have potential utility in many noise and vibration damping applications. Interpenetrating Polymer Networks (IPN) are a new class of materials consisting of multi-component crosslinked polymer systems. IPNs are distinguished from their parent polymer materials by a general characteristic that crosslinking occurs exclusively in. 

Sperling and Thomas employed gradient IPNs to obtain a hard exterior, a soft interior, and a composition-graded intermediate zone. Such materials were useful for noise and vibration damping as explored in Section 8.8. Predecki swelled hydroxyethyl methacrylate monomer mixes into silicone rubber to produce materials having hydratable surfaces. Such materials could replace surface coatings in arteriovenous shunts. 

J. A. Grates, D. A. Thomas, E. C. Hickey, and L. H. Sperling, Noise and Vibration Damping with Latex Interpenetrating Polymer Networks, /. Appl Polym. Sci. 19(6), 1731 (1975). Latex IPNs for sound damping. Methacrylic/acrylic compositions. 

Personal comfort can be improved when using bonding techniques. Highly effective noise and vibration damping can be engineered into the products. Fig. 18 illustrates the difference in acoustic properties of elastic, plastic and elasto-plastic materials such as Sikaflex . 

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