In situ measurements of free volume during recovery process of a shape memory polymer

Polymer ◽  
2017 ◽  
Vol 109 ◽  
pp. 66-70 ◽  
Author(s):  
Nuria García-Huete ◽  
Eneko Axpe ◽  
José María Cuevas ◽  
David Mérida ◽  
José Manuel Laza ◽  
...  
Keyword(s):  
Shape Memory ◽  
Free Volume ◽  
Shape Memory Polymer ◽  
Recovery Process ◽  
In Situ Measurements

scholarly journals In Situ Generation of Green Hybrid Nanofibrillar Polymer-Polymer Composites—A Novel Approach to the Triple Shape Memory Polymer Formation

Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1900
Author(s):  
Ramin Hosseinnezhad ◽  
Iurii Vozniak ◽  
Fahmi Zaïri
Keyword(s):  
Polymer Blends ◽  
Shape Memory ◽  
Shape Memory Polymer ◽  
Cellulose Nanofibers ◽  
Polymeric Materials ◽  
Novel Approach ◽  
Phase Transition Temperatures ◽  
Triple Shape Memory

The paper discusses the possibility of using in situ generated hybrid polymer-polymer nanocomposites as polymeric materials with triple shape memory, which, unlike conventional polymer blends with triple shape memory, are characterized by fully separated phase transition temperatures and strongest bonding between the polymer blends phase interfaces which are critical to the shape fixing and recovery. This was demonstrated using the three-component system polylactide/polybutylene adipateterephthalate/cellulose nanofibers (PLA/PBAT/CNFs). The role of in situ generated PBAT nanofibers and CNFs in the formation of efficient physical crosslinks at PLA-PBAT, PLA-CNF and PBAT-CNF interfaces and the effect of CNFs on the PBAT fibrillation and crystallization processes were elucidated. The in situ generated composites showed drastically higher values of strain recovery ratios, strain fixity ratios, faster recovery rate and better mechanical properties compared to the blend.

Investigate of Electrical Conductivity of Shape-Memory Polymer Filled with Carbon Black

2008 ◽  
Vol 47-50 ◽  
pp. 714-717 ◽  
Author(s):  
Xin Lan ◽  
Jin Song Leng ◽  
Yan Ju Liu ◽  
Shan Yi Du
Keyword(s):  
Electrical Conductivity ◽  
Carbon Black ◽  
Shape Memory ◽  
Shape Recovery ◽  
Volume Fraction ◽  
Shape Memory Polymer ◽  
Recovery Process ◽  
Thermomechanical Properties ◽  
Electrically Conductive ◽  
New System

A new system of thermoset styrene-based shape-memory polymer (SMP) filled with carbon black (CB) is investigated. To realize the electroactive stimuli of SMP, the electrical conductivity of SMP filled with various amounts of CB is characterized. The percolation threshold of electrically conductive SMP filled with CB is about 3% (volume fraction of CB), which is much lower than many other electrically conductive polymers. When applying a voltage of 30V, the shape recovery process of SMP/CB(10 vol%) can be realized in about 100s. In addition, the thermomechanical properties are also characterized by differential scanning calorimetery (DSC).

In Situ Reversible Tuning from Pinned to Roll-Down Superhydrophobic States on a Thermal-Responsive Shape Memory Polymer by a Silver Nanowire Film

2020 ◽  
Vol 12 (11) ◽  
pp. 13464-13472 ◽  
Author(s):  
Chuanzong Li ◽  
Yunlong Jiao ◽  
Xiaodong Lv ◽  
Sizhu Wu ◽  
Chao Chen ◽  
...  
Keyword(s):  
Shape Memory ◽  
Shape Memory Polymer ◽  
Silver Nanowire

Shape Memory Polymer Based Reconfigurable Compliant Mechanisms: An Exploration

2009 ◽  
Author(s):  
Nilesh D. Mankame ◽  
Alan L. Browne ◽  
Anupam Saxena
Keyword(s):  
Shape Memory ◽  
High Temperatures ◽  
Compliant Mechanisms ◽  
Shape Memory Polymer ◽  
Shape Memory Polymers ◽  
Large Strains ◽  
Qualitative And Quantitative ◽  
Order Of Magnitude ◽  
Quantitative Changes

This paper explores the concept of reconfigurable compliant mechanisms. We define these to be fully or partially compliant mechanisms whose performance can be modified after they have been fabricated. Specifically, we are interested in the nature and extent of in situ reconfigurability in compliant mechanisms. In other words, we seek to understand the range of performance that can be achieved by these mechanisms without requiring significant reassembly. The material properties such as the storage modulus of a newly studied class of materials — shape memory polymers — vary by over an order of magnitude over a temperature range of 20 – 50 C. These polymers also allow the fixing of moderate to large strains (20 – 75%) experienced at high temperatures for extended periods of time, while retaining the ability to remember their original shape when reheated to the same high temperatures. These two properties make shape memory polymers a natural candidate for the fabrication of reconfigurable compliant mechanisms. We explore various means for introducing reconfigurability in compliant mechanisms, and from these, select a subset that is suitable for in situ reconfiguration. Quasi-static nonlinear finite element simulations are used to study the change in performance due to reconfiguration of four fully compliant mechanisms made of a shape memory polymer. Preliminary results indicate that noticeable qualitative and quantitative changes in performance can be achieved by these mechanisms.

Current-Dependent Kinetics of Self-Folding for Multi-Layer Polymers Using Local Resistive Heating

2018 ◽  
Author(s):  
Moataz Elsisy ◽  
Evan Poska ◽  
Mostafa Bedewy
Keyword(s):  
Temperature Gradient ◽  
Shape Memory ◽  
Material Flow ◽  
Shape Memory Polymer ◽  
Lightweight Structures ◽  
Local Material ◽  
Flow Heat ◽  
Origami Engineering ◽  
Kinetics Of

The purpose of this paper is to characterize the kinetics and direction of self-folding of pre-strained polystyrene (PSPS) and non-pre-strained styrene (NPS), which results from local shrinkage using a resistively heated ribbon in contact with the polymer sheet. A temperature gradient across the thickness of this shape memory polymer (SMP) sheet induces folding along the line of contact with the heating ribbon. Varying the electric current changes the degree of folding and extent of local material flow. This method can be used to create practical 3D structures. Sheets of PSPS and NPS were cut to 10 × 20 mm samples and their folding angles were plotted with respect to time, as obtained from in situ videography. In addition, the use of polyimide tape (Kapton) was investigated for controlling the direction of self-folding. Results show that folding happens on the opposite side of the sample with respect to the tape, regardless of which side the heating ribbon is on, or whether gravity is opposing the folding direction. Given the tunability of fold times and extent of local material flow, heat-assisted folding is a promising approach for manufacturing complex 3D lightweight structures by origami engineering.

scholarly journals On the Size Effect of Additives in Amorphous Shape Memory Polymers

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 327
Author(s):  
Elias M. Zirdehi ◽  
Hakan Dumlu ◽  
Gunther Eggeler ◽  
Fathollah Varnik
Keyword(s):  
Shape Memory ◽  
Shape Recovery ◽  
Shape Memory Polymer ◽  
Shape Memory Polymers ◽  
Recovery Process ◽  
Size Ratio ◽  
Additive Concentration ◽  
Effect Of Additives ◽  
Dynamics Simulations ◽  
Small Additive

Small additive molecules often enhance structural relaxation in polymers. We explore this effect in a thermoplastic shape memory polymer via molecular dynamics simulations. The additive-to-monomer size ratio is shown to play a key role here. While the effect of additive-concentration on the rate of shape recovery is found to be monotonic in the investigated range, a non-monotonic dependence on the size-ratio emerges at temperatures close to the glass transition. This work thus identifies the additives’ size to be a qualitatively novel parameter for controlling the recovery process in polymer-based shape memory materials.

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