scholarly journals Reprogrammable Permanent Shape Memory Materials Based on Reversibly Crosslinked Epoxy/PCL Blends

Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1568
Author(s):  
Iker Razquin ◽  
Alvaro Iregui ◽  
Lidia Orduna ◽  
Loli Martin ◽  
Alba González ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Glass Transition ◽  
Shape Memory ◽  
Curing Process ◽  
Scanning Calorimetry ◽  
Disulfide Exchange ◽  
Shape Memory Properties ◽  
Permanent Shape ◽  
Shape Memory Materials ◽  
Very High

Epoxy/Polycaprolactone (PCL) blends cured with a conventional diamine (4,4′-diaminodiphenylmethane, DDM) and with different amounts of a disulfide containing diamine (4, 4´-dithioaniline, DSS) were prepared through melting. The curing process was studied by FTIR and differential scanning calorimetry (DSC) and the mechanical behavior of the networks was studied by DMA. The shape memory properties and the recyclability of the materials were also analyzed. All blends showed a very high curing degree and temperature activated shape memory effect, related to the glass transition of the epoxy resin. The PCL plasticized the mixture, allowing tailoring of the epoxy glass transition. In addition, in the blends cured with DSS, as a consequence of the disulfide exchange reaction, the permanent shape could be erased and a new shape could be reprogrammed. Using this strategy, reprogrammable permanent shape memory materials were obtained.

The Two-Stage Curing Method for Shape-Memory Materials

2012 ◽  
Vol 476-478 ◽  
pp. 2227-2230
Author(s):  
He Sun ◽  
Yu Yan Liu ◽  
Hui Feng Tan ◽  
Chang Guo Wang
Keyword(s):  
Shape Memory ◽  
Memory Performance ◽  
Mechanical Analysis ◽  
Scanning Calorimetry ◽  
Two Stage ◽  
Memory Tests ◽  
Second Stage ◽  
Shape Memory Properties ◽  
Shape Memory Materials ◽  
Curing Method

In this paper, a various shape-memory materials had been prepared by two-stage curing method. The purpose of using this approach was to maintain the excellent shape memory properties and low glass transition temperature (Tg) of shape-memory materials after first stage curing, furthermore, improve the Tg and heat resistence effectively after second stage curing. Differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and fold-deploy shape memory tests were used to characterize the feasibility of two-stage curing, thermodynamics properties and shape memory performance of these polymers. DSC results showed that two different curing stages could be achieved successfully, DMA results suggested that heat resistance of materials had been improved after second curing stage, while the fold-deploy shape memory tests proved that the composites possessed excellent shape memory properties, it could be deformed into different shape and recovered its original shape fully within three minutes.

A novel shape memory polymer based on conetworks

e-Polymers ◽  
2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Zonghui Li ◽  
Yi Pan ◽  
Peng Zhang ◽  
Zhaohui Zheng ◽  
Xiaobin Ding ◽  
...  
Keyword(s):  
Glass Transition ◽  
Shape Memory ◽  
Shape Memory Polymer ◽  
Recovery Ratio ◽  
Modulus Ratio ◽  
Poly Ethylene Glycol ◽  
Shape Memory Properties ◽  
Shape Memory Effects ◽  
Shape Memory Materials ◽  
Poly Ethylene

AbstractA novel shape memory polymer based on conetworks (CNs) was synthesized. These conetworks consisting of poly(methyl methacrylate) and poly (ethylene glycol) diacrylates showed excellent shape-memory properties with a recovery ratio of nearly 100%. Moreover, different shape memory effects were discovered in different mediums due to their amphiphilic properties. In addition, a large storage modulus ratio above and below the glass transition temperature(Eratio), which probably means excellent shape memory effect, were obtained due to the designed CN structure whether crystallization existed or not. It is quite different from the traditional methods to achieve large Eratio values. The versatility of shapememory conetworks potentially provides us a new route to prepare shape memory materials.

scholarly journals Improved Processing and Properties for Polyphenylene Oxide Modified by Diallyl Orthophthalate Prepolymer

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2016
Author(s):  
Honghua Wang ◽  
Qilin Mei ◽  
Yujie Ding ◽  
Zhixiong Huang ◽  
Minxian Shi
Keyword(s):  
Differential Scanning Calorimetry ◽  
Thermal Properties ◽  
Phase Separation ◽  
Dilution Effect ◽  
Gradual Decrease ◽  
Gel Point ◽  
Dynamic Mode ◽  
Curing Process ◽  
Scanning Calorimetry ◽  
Polyphenylene Oxide

Diallyl orthophthalate (DAOP) prepolymer was investigated as a reactive plasticizer to improve the processability of thermoplastics. The rheology of blends of DAOP prepolymer initiated by 2,3-dimethyl-2,3-diphenylbutane (DMDPB) and polyphenylene oxide (PPO) was monitored during the curing process, and their thermal properties and morphology in separated phases were also studied. Differential scanning calorimetry (DSC) results showed that the cure degree of the reactively plasticized DAOP prepolymer was reduced with increasing PPO due to the dilution effect. The increasing amount of the DAOP prepolymer led to a gradual decrease in the viscosity of the blends and the rheology behavior was consistent with the chemical gelation of DAOP prepolymer in blends. This indicated that the addition of the DAOP prepolymer effectively improved processability. The phase separation occurring during curing of the blend and the transition from the static to dynamic mode significantly influences the development of the morphology of the blend corresponding to limited evolution of the conversion around the gel point.

Evaluation of glass transition in model cell lines using differential scanning calorimetry

Cytotherapy ◽  
2021 ◽  
Vol 23 (5) ◽  
pp. S173
Author(s):  
C. Jones ◽  
J. Heimfeld ◽  
B.J. Hawkins ◽  
R. Marcu
Keyword(s):  
Differential Scanning Calorimetry ◽  
Glass Transition ◽  
Cell Lines ◽  
Scanning Calorimetry ◽  
Model Cell

scholarly journals Thermal analysis: basic concept of differential scanning calorimetry and thermogravimetry for beginners

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Nurul Fatahah Asyqin Zainal ◽  
Jean Marc Saiter ◽  
Suhaila Idayu Abdul Halim ◽  
Romain Lucas ◽  
Chin Han Chan
Keyword(s):  
Thermal Analysis ◽  
Differential Scanning Calorimetry ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Commercial Application ◽  
Scanning Calorimetry ◽  
Teaching Activities ◽  
Sample Decomposition ◽  
Calibration Baseline

AbstractWe present an overview for the basic fundamental of thermal analysis, which is applicable for educational purposes, especially for lecturers at the universities, who may refer to the articles as the references to “teach” or to “lecture” to final year project students or young researchers who are working on their postgraduate projects. Description of basic instrumentation [i.e. differential scanning calorimetry (DSC) and thermogravimetry (TGA)] covers from what we should know about the instrument, calibration, baseline and samples’ signal. We also provide the step-by-step guides for the estimation of the glass transition temperature after DSC as well as examples and exercises are included, which are applicable for teaching activities. Glass transition temperature is an important property for commercial application of a polymeric material, e.g. packaging, automotive, etc. TGA is also highlighted where the analysis gives important thermal degradation information of a material to avoid sample decomposition during the DSC measurement. The step-by-step guides of the estimation of the activation energy after TGA based on Hoffman’s Arrhenius-like relationship are also provided.

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