Y. Yang et al. / Polymer 52 (2011) 3745e3751
3751
Table 3
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4. Conclusion
Isocyanate-phenols derived from chiral and racemic tyrosine
were synthesized and then polymerized in the presence of trie-
thylamine as the catalyst, providing the corresponding optically
active and racemic polyurethanes (LPU, DPU and RPU) in high
yields. The LPU and DPU are a couple of enantimorphs, the optical
rotations of them are reached to þ124.5 ꢀ and ꢁ120 ꢀ, respectively.
The asymmetric force field in the chiral isocyanate-phenols induces
orderliness in new region. They possess a helical configuration and
higher degree of hydrogen bond compared to the RPU which pre-
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thermal stability of LPU and DPU provide further proofs of regular
secondary structure and more inter-chain interactions. Both of
them result in the reduction of infrared emissivity. The optically
active polyurethanes based on amino acid could be regarded as
a set of promising materials for stealthy technology and the
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Acknowledgments
The authors are grateful to the National Nature Science Foun-
dation of China (50873026,51077013), the Key Program for the
Scientific Research Guiding Found of Basic Scientific Research
Operation Expenditure, Southeast University (3207041102),
Program for Training of 333 High-Level Talent, Jiangsu Province of
China (BRA2010033) for financial support.
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