Some New Concepts of Shape Memory Effect of Polymers

Polymers

Abbas Tcharkhtchi²  Sofiane Abdallah-Elhirtsi²  Kambiz Ebrahimi¹  Joseph Fitoussi²  Mohammadali Shirinbayan² 

[1] School of Engineering, University of Bradford, West Yorkshire BD7 1DP, UK; E-Mail:;Laboratoire PIMM, UMR 8006 CNRS, Arts et Métiers ParisTech, Paris 75013, France; E-Mails:

关键词: polymers;    shape memory effect;    properties memory effect;    polyurethane;   

DOI  :  10.3390/polym6041144

来源: mdpi

【 摘 要 】

In this study some new concepts regarding certain aspects related to shape memory polymers are presented. A blend of polylactic acid (PLA) (80%) and polybutylene succinate (PBS) (20%) was prepared first by extrusion, then by injection molding to obtain the samples. Tensile, stress-relaxation and recovery tests were performed on these samples at 70 °C. The results indicated that the blend can only regain 24% of its initial shape. It was shown that, this partial shape memory effect could be improved by successive cycles of shape memory tests. After a fourth cycle, the blend is able to regain 82% of its shape. These original results indicated that a polymer without (or with partial) shape memory effect may be transformed into a shape memory polymer without any chemical modification. In this work, we have also shown the relationship between shape memory and property memory effect. Mono and multi-frequency DMA (dynamic mechanical analyzer) tests on virgin and 100% recovered samples of polyurethane (PU) revealed that the polymer at the end of the shape memory tests regains 100% of its initial form without regaining some of its physical properties like glass transition temperature, tensile modulus, heat expansion coefficient and free volume fraction. Shape memory (with and without stress-relaxation) tests were performed on the samples in order to show the role of residual stresses during recovery tests. On the basis of the results we have tried to show the origin of the driving force responsible for shape memory effect.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.