scholarly journals Development of Thermo-Responsive Polycaprolactone–Polydimethylsiloxane Shrinkable Nanofibre Mesh

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1427
Author(s):  
Chia-Hsuan Hsieh ◽  
Nur Adila Mohd Razali ◽  
Wei-Chih Lin ◽  
Zhi-Wei Yu ◽  
Dwita Istiqomah ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Shape Memory ◽  
Biomedical Applications ◽  
Memory Performance ◽  
Shape Memory Polymer ◽  
Electrospinning Process ◽  
Degree Of Crystallinity ◽  
Thermal And Mechanical Properties ◽  
Thermally Activated ◽  
Shape Fixity

A thermally activated shape memory polymer based on the mixture of polycaprolactone (PCL) and polydimethylsiloxane (PDMS) was fabricated into the nanofibre mesh using the electrospinning process. The added percentages of the PDMS segment in the PCL-based polymer influenced the mechanical properties. Polycaprolactone serves as a switching segment to adjust the melting temperature of the shape memory electro-spun PCL–PDMS scaffolds to our body temperature at around 37 °C. Three electro-spun PCL–PDMS copolymer nanofibre samples, including PCL6–PDMS4, PCL7–PDMS3 and PCL8–PDMS2, were characterised to study the thermal and mechanical properties along with the shape memory responses. The results from the experiment showed that the PCL switching segment ratio determines the crystallinity of the copolymer nanofibres, where a higher PCL ratio results in a higher degree of crystallinity. In contrast, the results showed that the mechanical properties of the copolymer samples decreased with the PCL composition ratio. After five thermomechanical cycles, the fabricated copolymer nanofibres exhibited excellent shape memory properties with 98% shape fixity and above 100% recovery ratio. Moreover, biological experiments were applied to evaluate the biocompatibility of the fabricated PCL–PDMS nanofibre mesh. Owing to the thermally activated shape memory performance, the electro-spun PCL–PDMS fibrous mesh has a high potential for biomedical applications such as medical shrinkable tubing and wire.

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.

Effect of Sidegroup on Mechanical Properties of Acrylate Networks for Biomedical Applications

2008 ◽  
Author(s):  
David Safranski ◽  
Ken Gall
Keyword(s):  
Mechanical Properties ◽  
Shape Memory ◽  
Biomedical Applications ◽  
Shape Memory Polymer ◽  
Shape Memory Polymers ◽  
Structure Property ◽  
Know How ◽  
Structure Property Relationships ◽  
Chain Stiffness ◽  
Recovery Strain

The purpose of this study was to understand how the side group dictates thermo-mechanical properties of shape-memory acrylate networks, specifically strain to failure and toughness. A useful parameter in assessing shape memory polymers is the strain to failure because it is critical to know how much recovery strain the material can experience. To understand how the structure is related to mechanical properties, such as strain to failure, materials of differing chain stiffness ratio, C∞, were compared at varying percentages of crosslinker. While the chemical and thermal properties of acrylate networks have been discussed in much detail, methods of toughening networks by the precise choice of certain acrylates have not been thoroughly examined. In order for these networks to be of practical use as biomedical devices, such as minimally invasive shape memory polymer stents, detailed structure-property relationships must be established.

Study on Shape-Memory Mechanism and Properties of NR/TPI Blends

2013 ◽  
Vol 467 ◽  
pp. 146-151 ◽  
Author(s):  
Guang Yi Lin ◽  
Shu Ming Liu ◽  
Fang Chen Dong
Keyword(s):  
Mechanical Properties ◽  
Shape Memory ◽  
Memory Performance ◽  
Dynamic Mechanical Properties ◽  
Memory Mechanism ◽  
Static Mechanical ◽  
Addition Level ◽  
Shape Fixity ◽  
Static Mechanical Properties

Crystalline grains of TPI distribute in NR/TPI blends in the role of physical crosslinking points and make up for deficiencies of the NR/TPI blending system. The flexibility and strength have been enhanced significantly by increasing the the addition level of TPI. The NR/TPI vulcanizates containing 30% of TPI were found to show the recovery rate of 99.4%, while the shape fixity was close to 100%. The study indicated that the recovery rates of NR/TPI vulcanizates depended to a large extent on the addition level of TPI. The influence of the addition level of TPI on the micro-structure of NR/TPI blends was investigated. In addition, the effects of TPI content on static mechanical properties, dynamic mechanical properties, shape-memory performance and cure characteristics of NR/TPI blends were also discussed.

Effects of ionic liquid types on the tribological, mechanical, and thermal properties of ionic liquid modified graphene/polyimide shape memory composites

2021 ◽  
pp. 095400832199676
Author(s):  
Yuting Ouyang ◽  
Qiu Zhang ◽  
Xiukun Liu ◽  
Ruan Hong ◽  
Xu Xu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Ionic Liquid ◽  
Composite Materials ◽  
Shape Memory ◽  
Recovery Rate ◽  
Shape Recovery ◽  
Graphene Nanosheets ◽  
Mechanical And Thermal Properties ◽  
Thermal And Mechanical Properties ◽  
Modified Graphene

Different ionic liquid modified graphene nanosheets (IG) were induced into polyimide (PI) to improve the tribological, thermal, and mechanical properties of shape memory IG/PI composites. The results demonstrated that when using 1-aminoethyl-3-methylimidazole bromide to modify graphene nanosheets (IG-1), the laser-driven shape recovery rate of IG-1/PI composites (IGPI-1) reached 73.02%, which was 49.36% higher than that of pure PI. In addition, the IGPI-1 composite materials reached the maximum shape recovery rate within 15 s. Additionally, under dry sliding, the addition of IG can significantly improve the tribological properties of composite materials. IGPI-1 exhibited the best self-lubricating properties. Compared with pure PI, the friction coefficient (0.19) and wear rate (2.62 × 10–5) mm3/Nm) were reduced by 44.1% and 24.2%, respectively, and the T10% of IGPI-1 increased by 32.2°C. The Tg of IGPI-1 reached 256.5°C, which was 8.4°C higher than that of pure PI. In addition, the tensile strength and modulus of IGPI-1 reached 82.3 MPa and 1.18 GPa, which were significantly increased by 33.6% and 29.8%, respectively, compared with pure PI. We hope that this work will be helpful for the preparation of shape memory materials with excellent tribological, thermal, and mechanical properties.

Light Activated Shape Memory Polymer Characterization—Part II

2011 ◽  
Vol 78 (6) ◽  
Author(s):  
Richard V. Beblo ◽  
Lisa Mauck Weiland
Keyword(s):  
Shape Memory ◽  
Thickness Distribution ◽  
Glassy State ◽  
Shape Memory Polymer ◽  
Chemical Kinetic ◽  
Chemical Kinetic Model ◽  
Polymer Characterization ◽  
Thermally Activated ◽  
Rubbery State ◽  
Consistent Method

Presented are the experimental results of two light activated shape memory polymer (LASMP) formulations. The optical stimulus used to activate the materials is detailed including a mapping of the spatial optical intensity at the surface of the sample. From this, results of energy calculations are presented including the amount of energy available for transitioning from the glassy state to the rubbery state and from the rubbery state to the glassy state, highlighting one of the major advantages of LASMP as requiring less energy to transition than thermally activated shape memory polymers. The mechano-optical experimental setup and procedure is detailed and provides a consistent method for evaluating this relatively new class of shape memory polymer. A chemical kinetic model is used to predict both the theoretical glassy state modulus, as only the sample averaged modulus is experimentally attainable, as well as the through thickness distribution of Young’s modulus. The experimental and model results for these second generation LASMP formulations are then compared with earlier LASMP generations (detailed previously in Beblo and Mauck Weiland, 2009, “Light Activated Shape Memory Polymer Characterization,” ASME J. Appl. Mech., 76, pp. 8) and typical thermally activated shape memory polymer.

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