Energy Absorption tan

Resonance peaks exist in the —20 to — 40°C ranges for CHDI-based TPUs, and some of the mixed chain extenders such as BDO H- CHDM (Fig. 9.7) show a double resonance peak in both the —20 to — 40 C and the 140-1 SOX regions. 

The existence of this double-resonance-peak phenomenon is particularly notable in the Terathane 2000 series with most of the types of chain extender investigated. In the low-temperature region a peak is always present and one is also seen to exist at higher temperatures, usually greater than 160 C exceptionally the Dianol 22 TPU possesses a resonance tan 6 that commences at 120 C. 

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