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- Öjelund, K, et al.
(författare)
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Synthesis, Structure and Properties of MelamineB pTHF-Urethane Supramolecular Compounds.
- 2003
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Ingår i: Macromolecular Chemistry and Physics. - : Wiley. - 1521-3935 .- 1022-1352. ; 204:1, s. 52-60
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Tidskriftsartikel (refereegranskat)abstract
- The properties of melamine based supramolecular compounds have been studied with rheological, thermal, mechanical, dielectric and scattering techniques and compared with similar covalently bonded materials. The complexes are based on a linear pTHF-diol ([bar M ]n = 1 000) connected via a diisocyanate with melamine. The results obtained show that, despite of the material's low molecular weight (< 2 000 g · mol-1), it has properties typical for high molar mass polymers. The material has a high modulus above the glass transition temperature, and shows behavior similar to a semi-crystalline material. This is attributed to the presence of the hydrogen bonds, in combination with phase separation giving rise to hard domain formation. In comparison with a covalently bonded and a low molecular weight material of similar composition, the supramolecular compounds have a higher and more temperature dependent viscosity. By exchanging parts of the pTHF with a low molecular weight diol, in our case hexane diol, the mechanical properties at room temperature could be modified to a stiffer but more brittle material.
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