ACS Appl Mater Interfaces. 2016 Jan 20;8(2):1371-80. doi: 10.1021/acsami.5b10246. Epub 2016 Jan 08.

Tunable Shape Memory Performances via Multilayer Assembly of Thermoplastic Polyurethane and Polycaprolactone.

ACS applied materials & interfaces

Yu Zheng, Renqiong Dong, Jiabin Shen, Shaoyun Guo

PMID: 26713358 DOI: 10.1021/acsami.5b10246

Abstract

Shape memory materials containing alternating layers of thermoplastic polyurethane (TPU) and polycaprolactone (PCL) were fabricated through layer-multiplying extrusion. As a type of special co-continuous morphology, the multilayer structure had stable and well-defined continuous layer spaces and could be controlled by changing the number of layers. Compared with conventional polymer blends, the multilayer-assembled system with the same compositions had higher shape-fixing and -recovery ratios that could be further improved by increasing the number of layers. By analyzing from a viscoelastic model, the deformation energy preserved in elastic TPU layers would be balanced by adjacent PCL layers through interfacial shearing effect so that each component in the multilayer structure was capable of endowing the maximum contribution to both of the shape-fixing and -recovery stages. Besides, the influence of the hardness of TPU layers and the morphology of PCL layers were respectively concerned as well. Results revealed that choosing low-hardness TPU or replacing neat PCL layers by TPU/PCL blend with co-continuous morphology were beneficial to achieving outstanding shape memory performances.

Keywords: co-continuous; interface; multilayer structure; polycaprolactone; polyurethane; shape memory polymer

Publication Types

• Journal Article
• Research Support, Non-U.S. Gov't