A relative study of the effect of static and dynamic vulcanization upon shape memory nature of thermally actuated peroxide crosslinked polyolefinic blends

2020 ◽  
Author(s):  
Tuhin Chatterjee ◽  
Asit Baran Bhattacharya ◽  
Sanjay Pal ◽  
Kinsuk Naskar
Keyword(s):  
Shape Memory ◽  
Dynamic Vulcanization ◽  
Thermally Actuated

scholarly journals A Large-Deformation Theory for Thermally-Actuated Shape-Memory Polymers and its Application

2010 ◽  
Author(s):  
Shawn A. Chester ◽  
Vikas Srivastava ◽  
Claudio V. Di Leo ◽  
Lallit Anand
Keyword(s):  
Glass Transition ◽  
Shape Memory ◽  
Deformation Theory ◽  
Shape Recovery ◽  
Large Deformations ◽  
Shape Memory Polymers ◽  
The Body ◽  
Thermally Induced ◽  
Thermally Actuated ◽  
Common Shape

The most common shape-memory polymers are those in which the shape-recovery is thermally-induced. A body made from such a material may be subjected to large deformations at an elevated temperature above its glass transition temperature &Vthgr;g. Cooling the deformed body to a temperature below &Vthgr;g under active kinematical constraints fixes the deformed shape of the body. The original shape of the body may be recovered if the material is heated back to a temperature above &Vthgr;g without the kinematical constraints. This phenomenon is known as the shape-memory effect. If the shape recovery is partially constrained, the material exerts a recovery force and the phenomenon is known as constrained-recovery.

A Shape Memory Polymer with Improved Shape Recovery

2004 ◽  
Vol 855 ◽  
Author(s):  
Changdeng Liu ◽  
Patrick T. Mather
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Shape Memory ◽  
Shape Memory Polymer ◽  
Model Fit ◽  
Mechanical Reinforcement ◽  
Conducting Filler ◽  
Thermal Conducting ◽  
Thermally Actuated ◽  
Triggering Process

ABSTRACTThermally actuated shape memory polymers (SMPs) interest, both academically and industrially, due to their ability to memorize a permanent shape that is set during processing and a temporary shape that is later programmed by manipulation above a critical temperature, either Tg or Tm. However, the thermal triggering process for SMPs is usually retarded compared to that of shape memory alloys, because the thermal conductivity of polymers is much lower (<0.30 W/m.K). In the present study, we incorporated a highly thermal conducting filler into a shape memory matrix to increase its thermal conductivity and therefore, shorten the heat transfer progress. A mathematical was worked out that quantitatively relates the material's thermal conductivity with the heat transfer time, τ, also defined as a shape memory induction time. The model fit nicely with our experimental data. In addition, mechanical reinforcement was observed with the addition of this rigid thermal conducting filler.

The Effect of Laser Welds on the Thermomechanical Fatigue of NiTi Shape Memory Alloys

2014 ◽  
Author(s):  
B. Panton ◽  
Z. Zeng ◽  
Y. N. Zhou ◽  
M. I. Khan
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Base Metal ◽  
Dissimilar Materials ◽  
Thermomechanical Fatigue ◽  
Dissimilar Joints ◽  
Laser Welds ◽  
Thermally Actuated ◽  
Niti Wires ◽  
Niti Shape Memory Alloys

Welding and joining of NiTi based shape memory alloys (SMAs) is essential for their integration into an increasing variety of applications. The titanium elemental constituent significantly complicates joining, especially with dissimilar materials where brittle intermetallics are often formed. There have been a relatively small number of investigations of the welding of NiTi in similar and in dissimilar joints. Of these studies, a few have investigated the effect of similar welded joints on the pseudoelastic fatigue of NiTi. To the author’s knowledge there are no investigations on the effect of joining on the fatigue of thermally actuated NiTi. The current work investigates the physical, thermomechanical fatigue and shape memory properties of welded shape memory wires. The welded NiTi wires successfully achieved 86% of the base metal ultimate tensile strength. The cycle lives of the welded wires that underwent thermomechanical fatigue were significantly less than the base metal.

scholarly journals Fully Biobased Shape Memory Thermoplastic Vulcanizates from Poly(Lactic Acid) and Modified Natural Eucommia Ulmoides Gum with Co-Continuous Structure and Super Toughness

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2040 ◽  
Author(s):  
Yan Wang ◽  
Jinhui Liu ◽  
Lin Xia ◽  
Mei Shen ◽  
Liping Wei ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Shape Memory ◽  
Poly Lactic Acid ◽  
Eucommia Ulmoides ◽  
Dynamic Vulcanization ◽  
Continuous Structure ◽  
Continuous State ◽  
Thermoplastic Vulcanizates ◽  
Potential Applications ◽  
Eucommia Ulmoides Gum

Novel, fully biobased shape memory thermoplastic vulcanizates (TPVs) were prepared using two sustainable biopolymers, poly(lactic acid) (PLA), and modified natural Eucommia ulmoides gum (EUG-g-GMA), via a dynamic vulcanization technique. Simultaneously, in situ compatibilization was achieved in the TPVs to improve interfacial adhesion and the crosslinked modified Eucommia ulmoides gum (EUG) was in “netlike” continuous state in the PLA matrix to form “sea-sea” phase structure. The promoted interface and co-continuous structure played critical roles in enhancing shape memory capacity and toughness of the TPVs. The TPV with 40 wt % modified EUG displayed the highest toughness with an impact strength of 54.8 kJ/m2 and the most excellent shape memory performances with a shape fixity ratio (Rf) of 99.83% and a shape recovery ratio (Rr) of 93.74%. The prepared shape memory TPVs would open up great potential applications in biobased shape memory materials for smart medical devices.

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