scholarly journals The Effect of POSS Type on the Shape Memory Properties of Epoxy-Based Nanocomposites

Molecules ◽  
2020 ◽  
Vol 25 (18) ◽  
pp. 4203
Author(s):  
Avraham I. Bram ◽  
Irina Gouzman ◽  
Asaf Bolker ◽  
Noam Eliaz ◽  
Ronen Verker
Keyword(s):  
Transition Temperature ◽  
Shape Memory ◽  
Crosslinking Density ◽  
Mechanical Analysis ◽  
Thermomechanical Properties ◽  
Space Environment ◽  
Scanning Calorimetry ◽  
Space Applications ◽  
Curing Conditions ◽  
Oligomeric Silsesquioxane

Thermally activated shape memory polymers (SMPs) can memorize a temporary shape at low temperature and return to their permanent shape at higher temperature. These materials can be used for light and compact space deployment mechanisms. The control of transition temperature and thermomechanical properties of epoxy-based SMPs can be done using functionalized polyhedral oligomeric silsesquioxane (POSS) additives, which are also known to improve the durability to atomic oxygen in the space environment. In this study, the influence of varying amounts of two types of POSS added to epoxy-based SMPs on the shape memory effect (SME) were studied. The first type contained amine groups, whereas the second type contained epoxide groups. The curing conditions were defined using differential scanning calorimetry and glass transition temperature (Tg) measurements. Thermomechanical and SME properties were characterized using dynamic mechanical analysis. It was found that SMPs containing amine-based POSS show higher Tg, better shape fixity and faster recovery speed, while SMPs containing epoxide-based POSS have higher crosslinking density and show superior thermomechanical properties above Tg. This work demonstrates how the Tg and SME of SMPs can be controlled by the type and amount of POSS in an epoxy-based SMP nanocomposite for future space applications.

Effect of C12-14 Alcohols on the Thermomechanical Properties of Epoxy Shape-Memory Polymer

2014 ◽  
Vol 787 ◽  
pp. 275-280
Author(s):  
Li Min Zhao ◽  
Xue Feng ◽  
Xu Jun Mi ◽  
Yan Feng Li ◽  
Hao Feng Xie ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Shape Memory ◽  
Room Temperature ◽  
Aliphatic Alcohol ◽  
Shape Memory Polymer ◽  
Mechanical Analysis ◽  
Thermomechanical Properties ◽  
Epoxy System ◽  
Scanning Calorimetry ◽  
Epoxy Polymers

A critical parameter for a shape memory polymer (SMP) lies in its shape memory transition temperature. For an amorphous SMP polymer, it is highly desirable to develop methods to tailor its Tg, which corresponds to its shape memory transition temperature. Starting with an amine cured aromatic epoxy system, epoxy polymers were synthesized by introducing flexible aliphatic alcohol. The thermal and thermomechanical properties of these epoxy polymers were characterized by differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). All the crosslinked epoxy polymers with Tg’s above room temperature were found to possess shape memory properties.

scholarly journals Bio-Based Epoxy Shape-Memory Thermosets from Triglycidyl Phloroglucinol

Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 542 ◽  
Author(s):  
David Santiago ◽  
Dailyn Guzmán ◽  
Francesc Ferrando ◽  
Àngels Serra ◽  
Silvia De la Flor
Keyword(s):  
Shape Memory ◽  
Shape Recovery ◽  
Memory Performance ◽  
Crosslinking Agent ◽  
Shape Memory Polymers ◽  
Crosslinking Density ◽  
Mechanical Analysis ◽  
Diglycidyl Ether ◽  
Partial Substitution ◽  
Scanning Calorimetry

A series of bio-based epoxy shape-memory thermosetting polymers were synthesized starting from a triglycidyl phloroglucinol (3EPOPh) and trimethylolpropane triglycidyl ether (TPTE) as epoxy monomers and a polyetheramine (JEF) as crosslinking agent. The evolution of the curing process was studied by differential scanning calorimetry (DSC) and the materials obtained were characterized by means of DSC, thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), stress-strain tests, and microindentation. Shape-memory properties were evaluated under free and totally constrained conditions. All results were compared with an industrial epoxy thermoset prepared from standard diglycidyl ether of Bisphenol A (DGEBA). Results revealed that materials prepared from 3EPOPh were more reactive and showed a tighter network with higher crosslinking density and glass transition temperatures than the prepared from DGEBA. The partial substitution of 3EPOPh by TPTE as epoxy comonomer caused an increase in the molecular mobility of the materials but without worsening the thermal stability. The shape-memory polymers (SMPs) prepared from 3EPOPh showed good mechanical properties as well as an excellent shape-memory performance. They showed almost complete shape-recovery and shape-fixation, fast shape-recovery rates, and recovery stress up to 7 MPa. The results obtained in this study allow us to conclude that the triglycidyl phloroglucinol derivative of eugenol is a safe and environmentally friendly alternative to DGEBA for preparing thermosetting shape-memory polymers.

scholarly journals The Influence of the Furan and Maleimide Stoichiometry on the Thermoreversible Diels–Alder Network Polymerization

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2522
Author(s):  
Ali Safaei ◽  
Seppe Terryn ◽  
Bram Vanderborght ◽  
Guy Van Assche ◽  
Joost Brancart
Keyword(s):  
Transition Temperature ◽  
Functional Groups ◽  
Polymer Networks ◽  
Viscoelastic Behavior ◽  
Mechanical Analysis ◽  
Thermomechanical Properties ◽  
Diels Alder ◽  
Stoichiometric Ratio ◽  
Self Healing ◽  
Scanning Calorimetry

In recent work, the thermoreversible Diels–Alder reaction between furan and maleimide functional groups has been studied extensively in the context of self-healing elastomers and thermosets. To elaborate the influence of the stoichiometric ratio between the maleimide and furan reactive groups on the thermomechanical properties and viscoelastic behavior of formed reversible covalent polymer networks, a series of Diels–Alder-based networks with different stoichiometric ratios was synthesized. Differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and dynamic rheology measurements were performed on the reversible polymer networks, to relate the reversible network structure to the material properties and reactivity. Such knowledge allows the design and optimization of the thermomechanical behavior of the reversible networks for intended applications. Lowering the maleimide-to-furan ratio creates a deficit of maleimide functional groups, resulting in a decrease in the crosslink density of the system, and a consequent decrease in the glass transition temperature, Young’s modulus, and gel transition temperature. The excess of unreacted furan in the system results in faster reaction and healing kinetics and a shift of the reaction equilibrium.

scholarly journals Influence of 1D and 2D Carbon Fillers and Their Functionalisation on Crystallisation and Thermomechanical Properties of Injection Moulded Nylon 6,6 Nanocomposites

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Fabiola Navarro-Pardo ◽  
Ana L. Martínez-Hernández ◽  
Victor M. Castaño ◽  
José L. Rivera-Armenta ◽  
Francisco J. Medellín-Rodríguez ◽  
...  
Keyword(s):  
Mechanical Analysis ◽  
Thermomechanical Properties ◽  
Reduced Form ◽  
Scanning Calorimetry ◽  
Graphene Nanocomposites ◽  
Moulding Process ◽  
Nylon 6,6 ◽  
Injection Moulding Process ◽  
The One ◽  
Carbon Fillers

Carbon nanotubes (CNTs) and graphene were used as reinforcing fillers in nylon 6,6 in order to obtain nanocomposites by using an injection moulding process. The two differently structured nanofillers were used in their pristine or reduced form, after oxidation treatment and after amino functionalisation. Three low nanofiller contents were employed. Crystallisation behaviour and perfection of nylon 6,6 crystals were determined by differential scanning calorimetry and wide angle X-ray diffraction, respectively. Crystallinity was slightly enhanced in most samples as the content of the nanofillers was increased. The dimensionality of the materials was found to provide different interfaces and therefore different features in the nylon 6,6 crystal growth resulting in improved crystal perfection. Dynamical, mechanical analysis showed the maximum increases provided by the two nanostructures correspond to the addition of 0.1 wt.% amino functionalised CNTs, enhancing in 30% the storage modulus and the incorporation of 0.5 wt.% of graphene oxide caused an increase of 44% in this property. The latter also provided better thermal stability when compared to pure nylon 6,6 under inert conditions. The superior properties of graphene nanocomposites were attributed to the larger surface area of the two-dimensional graphene compared to the one-dimensional CNTs.

Fabrication of a novel laser-processed NiTi shape memory microgripper with enhanced thermomechanical functionality

2012 ◽  
Vol 24 (8) ◽  
pp. 984-990 ◽  
Author(s):  
Matthew Daly ◽  
Andrew Pequegnat ◽  
Yunhong N Zhou ◽  
Mohammad I Khan
Keyword(s):  
Shape Memory ◽  
Processing Technique ◽  
Thermomechanical Properties ◽  
Nickel Titanium ◽  
Testing Methods ◽  
Scanning Calorimetry ◽  
Resistivity Measurements ◽  
Processed Material ◽  
Significant Research

The thermomechanical properties of nickel-titanium shape memory alloys have sparked significant research efforts seeking to exploit their exotic capabilities. Until recently, the performance capabilities of nickel-titanium devices have been inhibited by the retention of only one thermomechanical response. In this article, the application of a novel laser-processing technique is demonstrated to create a monolithic self-positioning nickel-titanium shape memory microgripper. Device actuation and gripping maneuvers were achieved by thermally activating processed material regions which possessed unique phase transformation onset temperatures and thermomechanical recovery characteristics. The existence of each thermomechanical material domain was confirmed through differential scanning calorimetry analysis. Independent thermomechanical recoveries of each embedded shape memory were captured using tensile testing methods. Deployment of each embedded shape memory was achieved using resistive heating, and in situ resistivity measurements were used to monitor progressive phase transformations.

Novel shape-memory polyurethane fibers for textile applications

2018 ◽  
Vol 89 (6) ◽  
pp. 1027-1037 ◽  
Author(s):  
Míriam Sáenz-Pérez ◽  
Tariq Bashir ◽  
José Manuel Laza ◽  
Jorge García-Barrasa ◽  
José Luis Vilas ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Shape Memory ◽  
Tensile Testing ◽  
Melt Spinning ◽  
Mechanical Analysis ◽  
Knitted Fabric ◽  
Scanning Calorimetry ◽  
Moisture Management ◽  
Potential Applications ◽  
Shape Memory Polyurethane

In this work, thermoresponsive shape-memory polyurethane (SMPU) fibers were produced by melt spinning from different SMPU pellets. Afterwards, the knitted fabric samples were prepared by the obtained fibers. Some of the SMPUs used were synthesized previously in our laboratory whereas a commercial one, named DIAPLEX MM4520, was also evaluated in order to carry out comparative studies. All the SMPUs were characterized by different techniques, such as thermogravimetric analysis, differential scanning calorimetry, dynamic mechanical analysis and tensile testing. Moreover, the shape-memory capabilities of the fabrics were measured by thermo-mechanical analysis. The obtained results show that the synthesized SMPUs could be attractive candidates for potential applications such as breathable fabrics or moisture-management textiles.

Thermal and Thermomechanical Properties of Poly(butylene succinate) Nanocomposites

2008 ◽  
Vol 8 (4) ◽  
pp. 1679-1689 ◽  
Author(s):  
Mamookho E. Makhatha ◽  
Suprakas Sinha Ray ◽  
Joseph Hato ◽  
Adriaan S. Luyt
Keyword(s):  
Thermal Stability ◽  
Tensile Modulus ◽  
Melting Behavior ◽  
Mechanical Analysis ◽  
Thermomechanical Properties ◽  
Scanning Calorimetry ◽  
Melt Mixing ◽  
Butylene Succinate ◽  
Modulated Differential Scanning Calorimetry ◽  
Thermal Stability Of

This article describes the thermal and thermomechanical properties of poly(butylene succinate) (PBS) and its nanocomposites. PBS nanocomposites with three different weight ratios of organically modified synthetic fluorine mica (OMSFM) have been prepared by melt-mixing in a batch mixer at 140 °C. The structure and morphology of the nanocomposites were characterized by X-ray diffraction (XRD) analyses and transmission electron microscopy (TEM) observations that reveal the homogeneous dispersion of the intercalated silicate layers into the PBS matrix. The thermal properties of pure PBS and the nanocomposite samples were studied by both conventional and temperature modulated differential scanning calorimetry (DSC) analyses, which show multiple melting behavior of the PBS matrix. The investigation of the thermomechanical properties was performed by dynamic mechanical analysis. Results reveal significant improvement in the storage modulus of neat PBS upon addition of OMSFM. The tensile modulus of neat PBS is also increased substantially with the addition of OMSFM, however, the strength at yield and elongation at break of neat PBS systematically decreases with the loading of OMSFM. The thermal stability of the nanocomposites compared to that of the pure polymer sample was examined under both pyrolytic and thermooxidative environments. It is shown that the thermal stability of PBS is increased moderately in the presence of 3 wt% of OMSFM, but there is no significant effect on further silicate loading in the oxidative environment. In the nitrogen environment, however, the thermal stability systematically decreases with increasing clay loading.

Thermomechanical Characterization of Bismuth Telluride Based Thermoelectric Materials

2001 ◽  
Vol 691 ◽  
Author(s):  
Witold Brostow ◽  
Kevin P. Menard ◽  
John B. White
Keyword(s):  
Bismuth Telluride ◽  
Van Der Waals ◽  
Mechanical Analysis ◽  
Thermomechanical Properties ◽  
Thermal Transitions ◽  
Scanning Calorimetry ◽  
Direction Parallel ◽  
Crystalline Polymers ◽  
Structural Metals ◽  
P Type

ABSTRACTThe thermoelectric properties of bismuth telluride based thermoelectric (TE) materials are well-characterized, but comparatively little has been published on the mechanical and thermomechanical properties of these materials. In this paper, we present the initial dynamic mechanical analysis (DMA) data for n-type and p-type bismuth telluride based TE materials. The materials' tan δ values, indicative of viscoelastic energy dissipation modes, approach that of glassy or crystalline polymers and are greater than ten times the tan delta of structural metals. TE samples measured perpendicular to the van der Waals planes have higher tan δ values. Thermal scans in the DMA compressive mode showed changes in mechanical properties versus temperature with clear hysteresis effects. These changes were correlated to differential scanning calorimetry (DSC) thermal transitions. The expected anisotropy was shown in flexural 3-point bending results for one n-type material that showed a storage modulus of 0.10 to 0.45 GPa in the direction parallel to the van der Waals planes and 0.07 to 0.2 GPa in the perpendicular direction.

Perfluoropolyether Modified Waterborne Shape Memory Polyurethaneurea Ionomers for Potential Medical Implant Application

2012 ◽  
Vol 499 ◽  
pp. 53-57
Author(s):  
Qun Xia Li ◽  
Zhong Yu Hou
Keyword(s):  
Molecular Structure ◽  
Differential Scanning Calorimetry ◽  
Transition Temperature ◽  
Shape Memory ◽  
Soft Segment ◽  
Cross Linking ◽  
Isophorone Diisocyanate ◽  
Scanning Calorimetry ◽  
Weight Percentage ◽  
Ft Ir

A series of cross-linked fluorinated waterborne shape memory polyurethaneurea (PUU) ionomers were synthesized from polycaprolactone diol, perfluoropolyether diol (PFPE), dimethylolproionic acid, isophorone diisocyanate, ethylenediamine (EDA) and diethylenetriamine (DETA). The effect of PFPE content in the soft segment and the degree of cross-linking on the molecular structure and the properties of for these PUU films was examined and studied. Differential scanning calorimetry showed that the transition temperature for these Tm type shape memory PUU could be facially tuned by PFPE weight percentage and EDA/DETA ratio in the range between 30°C to 50°C, in the vicinity of body temperature. The dependence of their properties on hydrogen-bonds evaluated by FT-IR was also discussed.

Study of a Cu-Al-Mn Shape Memory Alloy Produced by Plasma Melting Followed by Injection Molding

2014 ◽  
Vol 1611 ◽  
pp. 25-30
Author(s):  
Francisco Fernando Roberto Pereira ◽  
Maria Goretti Ferreira Coutinho ◽  
Bruno Moura Miranda ◽  
Carlos José de Araújo
Keyword(s):  
Injection Molding ◽  
Shape Memory ◽  
Shape Recovery ◽  
Permanent Deformation ◽  
Melting Process ◽  
Mechanical Analysis ◽  
Scanning Calorimetry ◽  
Dynamical Mechanical Analysis ◽  
Plasma Melting ◽  
New Applications

ABSTRACTShape Memory Alloys (SMA) are characterized by the capacity to recover a permanent deformation after being heated above a critical temperature called Final Austenite Temperature (Af). The Ni-Ti SMA are the most commercially used, however recent studies showed that the Cu-Al-Mn SMA present significant shape recovery and mechanical properties, showing a strong potential for developing new applications. In this context, the main goal of this work is to manufacture a Cu-Al-Mn SMA through a plasma melting process followed by injection molding of liquid metal and then characterize the samples, using the following techniques: Optical Microscopy (OM), Differential Scanning Calorimetry (DSC), Electrical Resistance as a function of Temperature (ERT) tests, Dynamical Mechanical Analysis (DMA) and Microhardness (MH).

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