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.

scholarly journals Star-Shaped Crosslinker for Multifunctional Shape Memory Polyurethane

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 740 ◽  
Author(s):  
Xiuhuan Song ◽  
Hong Chi ◽  
Zibiao Li ◽  
Tianduo Li ◽  
FuKe Wang
Keyword(s):  
Shape Memory ◽  
Flame Retardant ◽  
Fire Resistance ◽  
Mechanical Performance ◽  
Tensile Tests ◽  
Mechanical Analysis ◽  
Good Shape ◽  
Thermosetting Polymers ◽  
High Flexibility ◽  
Shape Memory Polyurethane

Star-shaped cyclophosphazene (ACP) was employed as covalent crosslinker to form a rigid segment in polyurethanes network, to enhance the mechanical performance and to add extra flame retardant property. The effects of different ACP contents on the shape memory ability and fire resistance performance of polyurethane (PU) were studied. Tensile tests suggested high flexibility of the PUs with the maximum elongation-at-break of 161.59%. Dynamic mechanical analysis (DMA) indicated good shape recovery ratio of 72.58% after more than three repeated cycles. Under thermal treatment, the temporary shape could recover to its original state in 10 s. The peak heat release rate (pHRR), total heat released (THR) and temperature at pHRR (Tp) of flame-retardant shape memory polyurethane (FSPU) by micro-combustion calorimeter (MCC) was as low as 183.2 W/g, 21.4 KJ/g, 330.8 °C respectively, suggesting good inherent fire-resistant performance. As amine-containing crosslinkers are one of the most common building units in thermosetting polymers, we anticipate that our finding will have significant benefits beyond shape memory and fire-resistance.

scholarly journals Biocomposites from Rice Straw Nanofibers: Morphology, Thermal and Mechanical Properties

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2138 ◽  
Author(s):  
José Carlos Alcántara ◽  
Israel González ◽  
M. Mercè Pareta ◽  
Fabiola Vilaseca
Keyword(s):  
Rice Straw ◽  
Mechanical Performance ◽  
Cellulose Nanofibers ◽  
Nucleating Agent ◽  
Mechanical Analysis ◽  
Nanocomposite Films ◽  
Chemical Extraction ◽  
Poly Vinyl Alcohol ◽  
Scanning Calorimetry ◽  
The Matrix

Agricultural residues are major potential resources for biomass and for material production. In this work, rice straw residues were used to isolate cellulose nanofibers of different degree of oxidation. Firstly, bleached rice fibers were produced from the rice straw residues following chemical extraction and bleaching processes. Oxidation of rice fibers mediated by radical 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) at pH 10 was then applied to extract rice cellulose nanofibers, with diameters of 3–11 nm from morphological analysis. The strengthening capacity of rice nanofibers was tested by casting nanocomposite films with poly(vinyl alcohol) polymer. The same formulations with eucalyptus nanofibers were produced as comparison. Their thermal and mechanical performance was evaluated using thermogravimetry, differential scanning calorimetry, dynamic mechanical analysis and tensile testing. The glass transition of nanocomposites was shifted to higher temperatures with respect to the pure polymer by the addition of rice cellulose nanofibers. Rice nanofibers also acted as a nucleating agent for the polymer matrix. More flexible eucalyptus nanofibers did not show these two phenomena on the matrix. Instead, both types of nanofibers gave similar stiffening (as Young’s modulus) to the matrix reinforced up to 5 wt.%. The ultimate tensile strength of nanocomposite films revealed significant enhancing capacity for rice nanofibers, although this effect was somehow higher for eucalyptus nanofibers.

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.

Shape-Memory Properties of Radiopaque Micro-Composites from Amorphous Polyether Urethanes Designed for Medical Application

2009 ◽  
Vol 1190 ◽  
Author(s):  
Jing Cui ◽  
Karl Kratz ◽  
Andreas Lendlein
Keyword(s):  
Shape Memory ◽  
Polymer Composites ◽  
Medical Application ◽  
Tensile Tests ◽  
Barium Sulphate ◽  
Mechanical Analysis ◽  
Gravimetric Analysis ◽  
Micro Particles ◽  
Shape Memory Properties

AbstractBiocompatible shape-memory polymers are of high significance for application in medical devices or instruments for minimally invasive surgery. To follow the medical device placement or changes in shape of the device in vivo by imaging methods like X-ray techniques, radiopacity of the polymer is required. In this work, we explored the shape-memory properties of radiopaque polymer composites prepared by incorporation of barium sulphate micro-particles in a biomedical grade polyether urethane (PEU) by co-extrusion technique. The filler content was varied from 5 wt% to 40 wt%, which was confirmed by thermal gravimetric analysis (TGA) measurements, while the particle distribution was visualized by scanning electron microscopy (SEM). The thermal and mechanical properties of the composites were investigated by means of dynamic mechanical analysis at varied temperature (DMTA) and tensile tests. The shape-memory properties of PEU composites were quantified in cyclic, thermomechanical experiments. A significant increase in Young’s modulus and a decrease in elongation at break were observed for PEU composites with increasing content of BaSO4, while the DMTA results were not affected by incorporation of the fillers. All samples exhibited excellent shape-memory properties with shape fixity rates (Rf) above 98% and values for shape recovery rate (Rr) in the range of 81% to 93%. The maximum stress (σmax) obtained under constant strain recovery conditions increased from 0.6 MPa to 1.4 MPa with raising amount of BaSO4, while the corresponding temperature (Tσ,max) as well as the switching temperature (Tsw) determined under stress-free conditions remained constant for all polymer composites.

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.

scholarly journals Mechanical, Thermal, and Shape Memory Properties of Three-Dimensional Printing Biomass Composites

Polymers ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1234 ◽  
Author(s):  
Hongjie Bi ◽  
Min Xu ◽  
Gaoyuan Ye ◽  
Rui Guo ◽  
Liping Cai ◽  
...  
Keyword(s):  
Shape Memory ◽  
Wood Flour ◽  
Memory Performance ◽  
Thermoplastic Polyurethane ◽  
Tensile Elongation ◽  
Three Dimensional ◽  
Mechanical Analysis ◽  
Shape Memory Properties ◽  
Shape Memory Composites ◽  
Recovery Angle

In this study, a series of heat-induced shape memory composites was prepared by the hot-melt extrusion and three-dimensional (3D) printing of thermoplastic polyurethane (TPU) using wood flour (WF) with different contents of EPDM-g-MAH. The mechanical properties, microtopography, thermal property analysis, and heat-induced shape memory properties of the composites were examined. The results showed that, when the EPDM-g-MAH content was 4%, the tensile elongation and tensile strength of the composites reached the maximum value. The scanning electron microscopy and dynamic mechanical analysis results revealed a good interface bonding between TPU and WF when the EPDM-g-MAH content was 4%. The thermogravimetric analysis indicated that the thermal stability of TPU/WF composites was enhanced by the addition of 4% EPDM-g-MAH. Heat-induced shape memory test results showed that the shape memory performance of composites with 4% EPDM-g-MAH was better than that of unmodified-composites. The composites’ shape recovery performance at a temperature of 60 °C was higher than that of the composites at ambient temperature. It was also found that, when the filling angle of the specimen was 45°, the recovery angle of the composites was larger.

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.

scholarly journals Development of Trans-1,4-Polyisoprene Shape-Memory Polymer Composites Reinforced with Carbon Nanotubes Modified by Polydopamine

Polymers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 110
Author(s):  
Chuang Zhang ◽  
Long Li ◽  
Yuanhang Xin ◽  
Jiaqi You ◽  
Jing Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Thermal Stability ◽  
Shape Memory ◽  
Polymer Composites ◽  
Photoelectron Spectroscopy ◽  
Memory Performance ◽  
Shape Memory Polymer ◽  
Structure And Properties ◽  
X Ray

In this study, which was inspired by mussel-biomimetic bonding research, carbon nanotubes (CNTs) were interfacially modified with polydopamine (PDA) to prepare a novel nano-filler (CNTs@PDA). The structure and properties of the CNTs@PDA were studied using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). The CNTs and the CNTs@PDA were used as nanofillers and melt-blended into trans-1,4 polyisoprene (TPI) to create shape-memory polymer composites. The thermal stability, mechanical properties, and shape-memory properties of the TPI/CNTs and TPI/CNTs@PDA composites were systematically studied. The results demonstrate that these modifications enhanced the interfacial interaction, thermal stability, and mechanical properties of TPI/CNTs@PDA composites while maintaining shape-memory performance.

Influence of Radialization Dosage on Shape Memory Effect of Polystyrene Copolymer

2008 ◽  
Vol 47-50 ◽  
pp. 690-693 ◽  
Author(s):  
Da Wei Zhang ◽  
Jin Song Leng ◽  
Yan Ju Liu
Keyword(s):  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Smart Materials ◽  
Shape Recovery ◽  
Memory Performance ◽  
Shape Memory Polymer ◽  
Shape Memory Polymers ◽  
Mechanical Analysis ◽  
Styrene Copolymer

This paper is concerned about the synthesis of shape memory styrene copolymer and the investigation of the influence of radialization dosage on its shape memory effect. As one of novel actuators in smart materials, shape memory polymers (SMPs) have been investigated intensively. Styrene copolymer with proper cross-linking degree can exhibit shape memory effect (SME). In this paper, the influence of radialization on shape memory effect of styrene copolymer was investigated through altering the dosage of radialization. The radialization dosage of styrene copolymer was determined by changed radicalization time. The glass transition temperature (Tg) of styrene copolymerwas measured by Dynamic Mechanical Analysis (DMA). The shape memory performance of styrene copolymer with different radiated dosage was also evaluated. Results indicated that the shape memory polymer (SMP) was synthesized successfully. The Tg increased from 60°C to 65°C followed by increasing the radialization dosage. Moreover, the SMP experienced good SME and the largest reversible strain of the SMP reached as high as 150%. When heating above Tg+30°C (different copolymers performed different Tg), the shape recovery speed of the copolymers increased with increasing the radialization dosage. However, the recovery speed decreased with increasing the radialization dosage at the same temperature of 95°C.

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