A Versatile Polymer Co-Network with Broadened Glass Transition Showing Adjustable Multiple-Shape Memory Effect

The glass transition temperatures of epoxy-based shape memory polymers (SMPs), which contain a flexibilizer at various contents of 0%, 5%, 10% and 15% respectively, are determined through DMA tests. The shape memory effect of such materials is investigated through shape recovery experiments. Experimental results show that the content of flexibilizer has much influence on the shape memory effect of epoxy-based SMP. A shape recovery equation is developed based on the results of shape recovery experiment. Numerical calculations show that the developed shape recovery equation well predicts the shape recovery behaviors of epoxy-based SMP.

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Alteration of Thermal Characteristics of Polymer for the Purpose of Creating a Two-Stage Shape Memory Polymer

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.93-94.304 ◽

2010 ◽

Vol 93-94 ◽

pp. 304-311

Author(s):

Hirohisa Tamagawa

Keyword(s):

Glass Transition ◽

Shape Memory ◽

Shape Memory Effect ◽

Memory Effect ◽

Soft Segment ◽

Shape Memory Polymer ◽

Thermal Characteristics ◽

Two Stage ◽

Dsc Measurements ◽

Two Distinct Temperatures

A polymer fabricated by mixing PU soft segment and epoxy bore the thermal characteristics of the melting temperature, Tm, of PU soft segment and the glass transition temperature, Tg, of epoxy. The polymer fabricated even exhibited the shape memory effect at the Tg and Tm. Based on this observation, it was speculated that simply mixing two polymers bearing totally different thermal characteristics each other could result in a two-stage SMP, which could exhibit the shape memory effect at the two distinct temperatures. However, it was actually observed that the two-stage SMP was not always successfully created by that method. But DSC measurements revealed that such an unsuccessfully fabricated SMP still bore the thermal characteristics of its ingredient polymers. Hence, the mixing of appropriate polymers still could result in a new two-stage SMP, and the method of two-polymer-mixing must be still an effective method for creating a two-stage SMP.

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Characteristics of Ti-Ni-Zr Thin Film Metallic Glasses Exhibiting a Shape Memory Effect after Crystallization

Materials Science Forum ◽

10.4028/www.scientific.net/msf.654-656.1066 ◽

2010 ◽

Vol 654-656 ◽

pp. 1066-1069

Author(s):

Junpei Sakurai ◽

Yuko Aono ◽

Yui Ishida ◽

Seiichi Hata

Keyword(s):

Thin Film ◽

Glass Transition ◽

Shape Memory ◽

Shape Memory Effect ◽

Memory Effect ◽

Metallic Glasses ◽

Martensitic Phase ◽

Before And After ◽

One Step ◽

Start Temperature

We investigated characteristics of Ti-Ni-Zr amorphous thin films before and after annealing, in order to search for novel Ti-Ni-Zr thin film metallic glasses (TFMGs) that exhibit a shape memory effect after crystallization. We found that the Ti42Ni47Zr11 TFMG exhibited a stable shape memory effect after crystallization. This alloy showed a glass transition with the glass transition and crystallization temperatures of 703 and 760 K, respectively. Moreover, this alloy showed a one-step martensitic phase transformation of B2 to B19', when annealed at 973 K for 3.6 ks. The martensitic phase start temperature and reverse martensitic phase start temperature were 296 and 352 K, respectively. In addition, this alloy showed a recovery strain of about 2.4%.

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Tensile Failure of 55-Nitinol Wire

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100113858 ◽

1975 ◽

Vol 33 ◽

pp. 46-47

Author(s):

F. I. Grace

Keyword(s):

Shape Memory ◽

Shape Memory Effect ◽

Memory Effect ◽

Stoichiometric Composition ◽

Tensile Failure ◽

Initial State ◽

Initial Shape ◽

Nitinol Wire ◽

Cscl Type ◽

Shear Transformation

An interest in NiTi alloys with near stoichiometric composition (55 NiTi) has intensified since they were found to exhibit a unique mechanical shape memory effect at the Naval Ordnance Laboratory some twelve years ago (thus refered to as NITINOL alloys). Since then, the microstructural mechanisms associated with the shape memory effect have been investigated and several interesting engineering applications have appeared.The shape memory effect implies that the alloy deformed from an initial shape will spontaneously return to that initial state upon heating. This behavior is reported to be related to a diffusionless shear transformation which takes place between similar but slightly different CsCl type structures.

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