scholarly journals High-Temperature-Induced Shape Memory Copolyimide

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3222
Author(s):  
Yucheng Zi ◽  
Dongxu Pei ◽  
Jianhua Wang ◽  
Shengli Qi ◽  
Guofeng Tian ◽  
...  
Keyword(s):  
High Temperature ◽  
Shape Memory ◽  
Shape Recovery ◽  
Memory Performance ◽  
Crosslinking Density ◽  
Polyimide Films ◽  
Film Properties ◽  
Chain Entanglement ◽  
Chain Mobility ◽  
The Relationship

A series of polyimide (PI) films with a high-temperature-induced shape memory effect and tunable properties were prepared via the facile random copolymerization of 4,4′-oxydianiline (ODA) with 4,4′-(hexafluoroisopropyl)diphthalic anhydride (6FDA) and 4,4′-oxydiphthalic anhydride (ODPA). The trigger temperature can be controlled from 294 to 326 °C by adjusting the ratio of monomers. The effects of monomer rigidity on the chain mobility, physical properties, and shape memory performance of as-prepared copolyimide were systematically investigated. The introduction of ODPA could enhance the mobility of PI macromolecular chains, which made chain entanglement more likely to occur and increased the physical crosslinking density, thereby improving the PI’s shape recovery up to 97%. Meanwhile, the existence of 6FDA enabled PI films to set quickly at low temperatures with a shape fixation of 98%. The shape memory cycling characteristics of the polyimide films are also studied, and the relationship between the PI chemical structure and the film properties are further discussed.

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.

Relationship Between Conductivities and Shape Memory Performance of FDM Composite Filaments

2017 ◽  
Author(s):  
Wenbo Liu ◽  
Nan Wu ◽  
Kishore Pochiraju
Keyword(s):  
Thermal Conductivity ◽  
Shape Memory ◽  
Shape Recovery ◽  
Fused Deposition Modeling ◽  
Filler Content ◽  
Memory Performance ◽  
Fused Deposition ◽  
Electrical Conductivities ◽  
Deposition Modeling ◽  
The Relationship

Silicon Carbide (SiC) and Carbon filled PLA Composite filaments made for use with Fused Deposition Modeling (FDM) were tested for their shape memory properties. Paper shows the relationship between the thermal and electrical conductivities of the filament and its shape recovery performance. The addition of SiC and graphite fillers accelerates the shape memory performance of PLA composites. Electrical conductivity of the filaments was characterized with I-V curves. Thermal conductivity measurements were performed, based on the ASTM D5470, on both FDM filaments and parts made with pure PLA and PLA composites. The results indicated that thermal conductivity increases with increasing SiC filler content. The conductivity increases correlate well with the reduction in the time to induce the shape recovery transition. This correlation enables control of shape transition timings in a part through the design of material composition.

The effect of phthalide cardo structure on the shape memory performance of high-temperature resistant epoxy resins

2018 ◽  
Vol 5 (11) ◽  
pp. 115702 ◽  
Author(s):  
Rong Ren ◽  
Zhaopeng Zhang ◽  
Xuhai Xiong ◽  
Lu Zhou ◽  
Xichao Guo ◽  
...  
Keyword(s):  
High Temperature ◽  
Shape Memory ◽  
Epoxy Resins ◽  
Memory Performance

A Study on Shape Memory Performance of Cu-Al-Ni-Be Alloy Single Crystal

2011 ◽  
Vol 287-290 ◽  
pp. 21-25
Author(s):  
Hua Ping Xu ◽  
Gao Feng Song ◽  
Xie Min Mao
Keyword(s):  
High Temperature ◽  
Temperature Gradient ◽  
Shape Memory Alloy ◽  
Single Crystal ◽  
Shape Memory ◽  
Directional Solidification ◽  
Memory Performance ◽  
Copper Base ◽  
Shape Memory Properties ◽  
Solidification Furnace

In this paper, single crystal of CuAlNiBe quaternary shape memory alloy was prepared in a high temperature gradient directional solidification furnace with a selective growing crystallizer. And its shape memory performance characters were systematically compared with other series copper base shape memory alloys. The results show that the single crystal of CuAlNiBe quaternary shape memory alloy has better shape memory properties.

Improved shape memory performance of star-shaped POSS-polylactide based polyurethanes (POSS-PLAUs)

RSC Advances ◽  
2015 ◽  
Vol 5 (109) ◽  
pp. 90209-90216 ◽  
Author(s):  
S. Y. Gu ◽  
X. F. Gao
Keyword(s):  
Shape Memory ◽  
Shape Recovery ◽  
Memory Performance ◽  
Shape Fixity

Star-shaped POSS-polylactide based polyurethanes with improved shape fixity ratios (above 99%) and shape recovery ratios (around 84%) are presented.

A STUDY ON FATIGUE DAMAGE OF SHAPE MEMORY ALLOY COMPOSITE USING NDE TECHNIQUE

2006 ◽  
Vol 20 (25n27) ◽  
pp. 3775-3780 ◽  
Author(s):  
YOUNG-CHUL PARK ◽  
JIN-KYUNG LEE ◽  
SANG-PILL LEE ◽  
GYU-CHANG LEE ◽  
JOON-HYUN LEE ◽  
...  
Keyword(s):  
High Temperature ◽  
Shape Memory Alloy ◽  
Crack Initiation ◽  
Crack Propagation ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Fatigue Damage ◽  
Shape Memory Composites ◽  
The Relationship

TiNi shape memory alloy was used to recover the shape of transformed objects using its shape memory effect. This shape memory effect plays an important role inside metal matrix composite. A composite using shape memory alloy has a large advantage that can control crack initiation and propagation, when compared with other composites due to the shape memory effect of shape memory alloy under high temperature. In this study, TiNi/Al6061 and TiNi/2024 shape memory composites were fabricated by the hot press method, and a fatigue test was performed to evaluate the fatigue damage for the shape memory composites under room temperature and high temperature. The relationship of the crack growth rate and the stress intensity factor for these shape memory composites were clarified at both temperature conditions. The delay effect of crack propagation due to shape memory alloy was also evaluated under high temperature. In addition, an acoustic emission technique was used to evaluate the crack initiation and the control of crack propagation by shape memory effect under fatigue test nondestructively. The relationship between AE parameter and the degree of fatigue damage of the shape memory composites was discussed.

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.

High-Temperature Shape Memory Effect of Ti-(Pt,Ir)

2007 ◽  
Vol 539-543 ◽  
pp. 3273-3278 ◽  
Author(s):  
Yoko Yamabe-Mitarai ◽  
Toru Hara ◽  
Seiji Miura ◽  
Hideki Hosoda
Keyword(s):  
Thermal Expansion ◽  
High Temperature ◽  
Shape Memory ◽  
Compression Test ◽  
Shape Recovery ◽  
The Other ◽  
Martensitic Transformation Temperature ◽  
Testing Methods ◽  
Thermal Expansion Measurement ◽  
Ternary Compounds

Shape recovery and superelasticity of Ti-50at%Pt and Ti-50at%(Pt, Ir), whose martensitic transformation temperature are above 1273 K, were investigated by thermal expansion measurement in dilatometer and loading-unloading compression test. The shape recovery was found in all compounds in at least one of the testing methods. The highest shape recovery, about 4% was found in Ti-25Pt-25Ir using loading-unloading compression test. On the other hand, superelasticity was found in only ternary compounds. Larger superelasticity was observed in ternary compounds with higher Ir contents. Potential of Ti-50Pt and Ti-50(Pt, Ir) as high-temperature shape memory alloys is discussed.

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