scholarly journals Block Copolymers of Poly(ω-Pentadecalactone) in Segmented Polyurethanes: Novel Biodegradable Shape Memory Polyurethanes

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1928
Author(s):  
Katalin Czifrák ◽  
Csilla Lakatos ◽  
Marcell Árpád Kordován ◽  
Lajos Nagy ◽  
Lajos Daróczi ◽  
...  
Keyword(s):  
Shape Memory ◽  
Shape Recovery ◽  
Mechanical Analysis ◽  
Attenuated Total Reflectance ◽  
Dibutyltin Dilaurate ◽  
Scanning Calorimetry ◽  
Dynamical Mechanical Analysis ◽  
Good Shape ◽  
Segmented Polyurethanes ◽  
Shape Fixity

In this report, the synthesis of poly(ω-pentadecalactone) (PPDL) (co)polymers and their incorporation into polyurethanes (PUs) are reported. Optimal conditions for the ring-opening polymerization (ROP) of ω-pentadecalactone (PDL) using dibutyltin dilaurate catalyst were established. For the synthesis of linear and crosslinked PUs, 50 kDa poly(ε-caprolactone) (PCL) and 1,6-hexamethylenediisocyanate (HDI) were used. The obtained polyurethanes were characterized by Attenuated Total Reflectance Fourier-Transform Infrared spectroscopy (AT-FTIR), differential scanning calorimetry (DSC), and dynamical mechanical analysis (DMA). The DMA of the selected sample showed a rubbery plateau on the storage modulus versus temperature curve predicting shape memory behavior. Indeed, good shape memory performances were obtained with shape fixity (Rf) and shape recovery (Rr) ratios.

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).

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.

Pseudoelasticity of Cu-13.8Al-Ni Alloys Containing V and Nb

2008 ◽  
Vol 59 ◽  
pp. 101-107 ◽  
Author(s):  
Rodinei Medeiros Gomes ◽  
Ana Cris R. Veloso ◽  
V.T.L. Buono ◽  
Severino Jackson Guedes de Lima ◽  
Tadeu Antonio de Azevedo Melo
Keyword(s):  
Mechanical Properties ◽  
Shape Memory ◽  
Shape Recovery ◽  
Cold Water ◽  
Low Cost ◽  
Tensile Tests ◽  
Grain Refiner ◽  
Good Shape ◽  
Potential Applications ◽  
Superelastic Behavior

Polycrystalline copper-based shape memory alloys have been of particular interest in relation to Ni-Ti because of their low cost and good shape memory effect. Nevertheless the absence of a pronounced pseudoelasticity effect restricts the number of potential applications. In this work, the influence of Nb and V on the microstructure and the mechanical properties was investigated. Samples of Cu-13.8 Al-Ni containing V and Nb alloy were prepared by induction and solution treated at 850°C and then further quenched into cold water. The addition of Nb and V promotes the formation of precipitates which act as grain refiner and subsequently improve the mechanical properties. The tensile tests were performed at temperatures slightly inferior to Mf and superior to Af, to investigate the shape recovery and pseudoelasticity, respectively. Based on the analyses of the Cu-13,8Al-2Ni-1Nb (wt%) alloy was detected rupture strains greater than 14%, besides observation of the superelasticity of these alloys and quantification of this property by means of cycling, from 0 to strains between 1 and 7%. The studies performed on alloy Cu-13.8Al- 3,5Ni-1V (wt%) made it possible to determine rupture strains in the order of 3% and its superelastic behavior through cycling for deformations between 1 and 3%.

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.

Characristics of Shape Memory Composites Combined with Shape Memory Alloy and Shape Memory Polymer

2013 ◽  
Vol 705 ◽  
pp. 169-172
Author(s):  
Xue Feng ◽  
Li Min Zhao ◽  
Xu Jun Mi
Keyword(s):  
Shape Memory ◽  
Room Temperature ◽  
Shape Recovery ◽  
Volume Fraction ◽  
Shape Memory Polymer ◽  
Young Modulus ◽  
Thermomechanical Properties ◽  
The Matrix ◽  
Shape Memory Composites ◽  
Shape Fixity

In order to develop high functionality of shape memory materials, the shape memory composites combined with TiNi wire and shape memory epoxy were prepared, and the mechanical and thermomechanical properties were studied. The results showed the addition of TiNi wire increased the Young modulus and breaking strength both at room temperature and at elevated temperature. The composites maintained the rates of shape fixity and shape recovery close to 100%. The maximum recovery stress increased with increasing TiNi wire volume fraction, and obtained almost 3 times of the matrix by adding 1vol% TiNi wire.

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.

scholarly journals Determination of Shape Fixity and Shape Recovery Rate of Carbon Nanotube-filled Shape Memory Polymer Nanocomposites

2012 ◽  
Vol 41 ◽  
pp. 1641-1646 ◽  
Author(s):  
Shahrul Azam Abdullah ◽  
Aidah Jumahat ◽  
Nik Rosli Abdullah ◽  
Lars Frormann
Keyword(s):  
Carbon Nanotube ◽  
Shape Memory ◽  
Polymer Nanocomposites ◽  
Recovery Rate ◽  
Shape Recovery ◽  
Shape Memory Polymer ◽  
Shape Fixity

Actuation of Shape Memory Polymer by Resistive Heating of Carbon Nanopaper

2009 ◽  
Author(s):  
Haibao Lu ◽  
Yong Tang ◽  
Jihua Gou ◽  
Erin Chow ◽  
Jinsong Leng ◽  
...  
Keyword(s):  
Shape Memory ◽  
Shape Recovery ◽  
Carbon Nanofiber ◽  
Volume Fraction ◽  
Shape Memory Polymer ◽  
Mechanical Analysis ◽  
Thermomechanical Properties ◽  
Paper Sheet ◽  
Scanning Electron ◽  
Properties Of Composites

To electrically activate the shape recovery in a styrene-based shape-memory polymer (SMP) by coating with conductive carbon nanofiber paper has been demonstrated in this paper. Carbon nanofibers in the form of paper sheet in combination with SMP significantly improve the electrical and thermal conductivity of polymer, leading to the actuation of SMP/nanopaper composite (with 15% volume fraction of carbon nanopaper, dimension of 10.0 cm × 0.5 cm × 0.3 cm) can be carried out by applying 8.4 V voltage, with response time of 140 s. Therefore, electrical conductivity of 6.6 S/cm is obtained. This approach, although demonstrated in styrene-based polymer, is applicable to other type of SMP materials. Furthermore, the morphologies of carbon nanofiber in the form of paper is observed by scanning electron microscopy, and the thermomechanical properties of composites are measured and analyzed by dynamic mechanical analysis.

scholarly journals Shape Memory Epoxy Polymer (SMEP) Composite Mechanical Properties Enhanced by Introducing Graphene Oxide (GO) into the Matrix

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1107 ◽  
Author(s):  
Zhengwei Yu ◽  
Zhenqing Wang ◽  
Hao Li ◽  
Jianxin Teng ◽  
Lidan Xu
Keyword(s):  
Graphene Oxide ◽  
Shape Memory ◽  
Polymer Composites ◽  
Epoxy Polymer ◽  
Mechanical Performance ◽  
Memory Performance ◽  
Mechanical Analysis ◽  
Tensile Fracture ◽  
Good Shape ◽  
The Matrix

Shape memory epoxy polymer (SMEP) composite specimens with different graphene oxide (GO) contents were manufactured to study the effects of GO mass fractions on epoxy polymer composites. While ensuring the shape memory effect of SMEP, the addition of GO also remarkably strengthened the mechanical performance of the polymers. Analyses of the epoxy polymer composites’ thermal, mechanical, and shape memory performance were conducted through carrying out dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA), and static tensile, three-point bending, impact, and shape memory tests. Moreover, the tensile fracture, bending fracture, and impact fracture interfaces of epoxy resin composites were examined with scanning electron microscopy. The final test results indicated that when the GO content was 0.8 wt %, SMEP composites had good shape memory performance and optimum thermal and mechanical performance.

HEAT-TRIGGERED SHAPE MEMORY EFFECT OF PEROXIDE CROSS-LINKED ETHYLENE–METHACRYLIC ACID COPOLYMER/NITRILE–BUTADIENE RUBBER THERMOPLASTIC VULCANIZATES WITH SEA-ISLAND STRUCTURE

2021 ◽  
Author(s):  
Yingtao Sun ◽  
Jiahao Li ◽  
Kerui Liao ◽  
Jing Hua ◽  
Zhaobo Wang
Keyword(s):  
Shape Memory ◽  
Methacrylic Acid ◽  
Shape Recovery ◽  
Butadiene Rubber ◽  
X Ray Diffraction ◽  
Nitrile Butadiene Rubber ◽  
Acid Copolymer ◽  
Thermoplastic Vulcanizates ◽  
Switching Temperature ◽  
Shape Fixity

ABSTRACT Designing shape memory polymers (SMPs) based on thermoplastic vulcanizates (TPVs) is an essential research topic. An efficient SMP is designed with typical sea-island structured ethylene–methacrylic acid copolymer/nitrile–butadiene rubber (EMA/NBR) TPVs in which the heat-control switched phase performed by the EMA phase is related to the shape fixity ability. The results show that the heat-triggered SMPs exhibit surprising shape memory properties (shape fixity >95%, shape recovery >95%, and fast recovery speed <30 s at the switching temperature of 95 °C). Through X-ray diffraction characterization, it is seen that the shape fixity of TPVs is achieved mainly through ethylene crystallization. The switching temperature is largely determined by the melting temperature (98 °C) obtained by differential scanning calorimetery.

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