SHAPE MEMORY-SEGMENTED POLYURETHANES: DEPENDENCE OF BEHAVIOR ON NANOCELLULOSE ADDITION AND TESTING CONDITIONS

MARÍA LUJÁN AUAD; TARA RICHARDSON; MARISA HICKS; MIRNA A. MOSIEWICKI; MIRTA I. ARANGUREN; NORMA E. MARCOVICH

POLYMER INTERNATIONAL

JOHN WILEY & SONS LTD

Lugar: LOndres; Año: 2012 vol. 61 p. 321 - 327

0959-8103

The response of synthesized shape-memory segmented-polyurethanes (PU) was affected by addition of cellulose nanocrystals, as well as the different conditions selected to carry out the thermo-mechanical cyclic tests. The polyurethane was synthesized from a polyether glycol (PTMG), tolylene 2,4-diisocyanate (TDI) and 1,4-butanediol (BD) as chain extender. Nanocomposites were prepared by mixing a suspension of cellulose nanocrystals in N,N-dimethylformamide (DMF) with the thermoplastic PU dissolved in the same organic solvent. The thermal properties of the neat polyurethane and resulting composites were examined by differential scanning calorimetry (DSC). It was found that cellulose addition increases the PU soft segment melting and crystallization temperatures and the degree of crystallinity of this phase. Shape-memory behavior was studied using cyclic thermal-tensile tests. Both, neat PU and composites exhibited shape-memory properties, with fixity and recovery values that depended on heating temperature, imposed deformation, deformation rate and nanofiller addition.