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Influence of Poly(ε‐caprolactone) Molecular Weight and Coumarin Amount on Photo‐Responsive Polyurethane Properties
Author(s) -
Salgado Cástor,
Arrieta Marina P.,
Peponi Laura,
FernándezGarcía Marta,
López Daniel
Publication year - 2017
Publication title -
macromolecular materials and engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.913
H-Index - 96
eISSN - 1439-2054
pISSN - 1438-7492
DOI - 10.1002/mame.201600515
Subject(s) - polyurethane , diol , materials science , caprolactone , differential scanning calorimetry , thermogravimetric analysis , polymer , thermal stability , hexamethylene diisocyanate , polymer chemistry , polymerization , organic chemistry , composite material , chemistry , physics , thermodynamics
Photo‐reversible polyurethane (PU) coatings based on coumarin diol (CD) are obtained. Initially, pre‐polymers based on different amounts of coumarin (5, 15, and 25 mol%) and 1,6‐hexamethylene diisocyanate are prepared to obtain PUs with a large incorporation of CD and high molecular weight. The pre‐polymer is posterior reacted with poly(ε‐caprolactone) diol (PCL‐diol), either with molecular weightM ¯ n= 530 or 2000 g mol –1 . The thermal stabilities of the PUs are studied using thermogravimetric analysis. Polymers with a higher content of CD present higher stability. The thermal transitions and the mechanical response are analyzed using differential scanning calorimetry and strain‐stress tests, respectively. Moreover, the photo‐reversibility of CD‐based PUs is followed by UV absorption. In general, photo‐dimerization induces better mechanical properties of the final PUs. Materials obtained with short PCL‐diol (M ¯ n= 530 g mol –1 ) and the highest amount of CD present higher reversibility processes. Therefore, these polymers are promising for application as coating systems.