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C M Lee

Bio: C M Lee is an academic researcher from Nanyang Technological University. The author has contributed to research in topics: Glass transition & Shape-memory polymer. The author has an hindex of 1, co-authored 1 publications receiving 200 citations.

Papers
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Journal ArticleDOI
Bin Yang1, Weimin Huang1, Chuan Li1, C M Lee1, Li Li1 
TL;DR: In this paper, it was observed that polyurethane shape memory polymer (SMP) loses its shape fixing capability after being exposed in the air at room temperature for several days.
Abstract: It was observed that the polyurethane shape memory polymer (SMP) loses its shape fixing capability after being exposed in the air at room temperature for several days. A significant indication for this change is the continuous decrease of the glass transition temperature (Tg) of polyurethane. Accompanying the decrease of Tg, the uniaxial tensile behaviour also changes. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) tests were carried out to find the cause behind this phenomenon. Moisture was concluded as the main reason. A mathematical expression was obtained for the relationship between Tg and the moisture. Moreover, the polyurethane shape memory polymer can fully regain its original properties after being heated at temperatures above 180 °C, which is the melting temperature of this SMP.

221 citations


Cited by
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TL;DR: Shape-memory polymers as discussed by the authors are an emerging class of active polymers that can change their shape in a predefined way from shape A to shape B when exposed to an appropriate stimulus.

1,575 citations

Journal ArticleDOI
TL;DR: In this paper, a comprehensive review of shape-memory polymers (SMPs) and their derivatives, such as composites and compound structures, as well as their current applications are presented.

1,034 citations

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TL;DR: A brief review on the current progress in stimuli-responsive shape memory materials can be found in this article, where the focus is on twofold, namely newly observed ones, and novel applications with great potential at present and in near future.

864 citations

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TL;DR: In this review different concepts for the creation of multifunctionality are derived from the various polymer network architectures of thermally-induced SMP, such as nanocomposites, as well as one-component polymer systems, in which independent functions are integrated.
Abstract: The thermally-induced shape-memory effect (SME) is the capability of a material to change its shape in a predefined way in response to heat. In shape-memory polymers (SMP) this shape change is the entropy-driven recovery of a mechanical deformation, which was obtained before by application of external stress and was temporarily fixed by formation of physical crosslinks. The high technological significance of SMP becomes apparent in many established products (e.g., packaging materials, assembling devices, textiles, and membranes) and the broad SMP development activities in the field of biomedical as well as aerospace applications (e.g., medical devices or morphing structures for aerospace vehicles). Inspired by the complex and diverse requirements of these applications fundamental research is aiming at multifunctional SMP, in which SME is combined with additional functions and is proceeding rapidly. In this review different concepts for the creation of multifunctionality are derived from the various polymer network architectures of thermally-induced SMP. Multimaterial systems, such as nanocomposites, are described as well as one-component polymer systems, in which independent functions are integrated. Future challenges will be to transfer the concept of multifunctionality to other emerging shape-memory technologies like light-sensitive SMP, reversible shape changing effects or triple-shape polymers.

824 citations

Journal ArticleDOI
TL;DR: In this paper, shape memory polymers and their composites (SMPs and SMPCs) can respond to specific external stimulus and remember the original shape, and the stimulus methods are discussed to demonstrate the shape recovery effect.
Abstract: As a new class of smart materials, shape memory polymers and their composites (SMPs and SMPCs) can respond to specific external stimulus and remember the original shape. There are many types of stimulus methods to actuate the deformation of SMPs and SMPCs, of which the thermal- and electro-responsive components and structures are common. In this review, the general mechanism of SMPs and SMPCs are first introduced, the stimulus methods are then discussed to demonstrate the shape recovery effect, and finally, the applications of SMPs and SMPCs that are reinforced with fiber materials in aerospace are reviewed. SMPC hinges and booms are discussed in the part on components; the booms can be divided again into foldable SMPC truss booms, coilable SMPC truss booms and storable tubular extendible member (STEM) booms. In terms of SMPC structures, the solar array and deployable panel, reflector antenna and morphing wing are introduced in detail. Considering the factors of weight, recovery force and shock effect, SMPCs are expected to have great potential applications in aerospace.

810 citations