Thermally Induced Self Healing of Thermosetting Resins and Matrices in Smart Composites

Author(s):  
Frank R. Jones ◽  
Wenting Zhang ◽  
Simon A. Hayes
Author(s):  
Sithara Gopinath ◽  
Suresh Mathew ◽  
P. Radhakrishnan Nair

2021 ◽  
Author(s):  
Zonghui Huang ◽  
Jianfeng Ban ◽  
Lulu Pan ◽  
Shuqing Cai ◽  
Junqiu Liao

Star-shape memory polyurethanes that combine thermally responsive and self-healing properties.


RSC Advances ◽  
2016 ◽  
Vol 6 (61) ◽  
pp. 56183-56192 ◽  
Author(s):  
Jun Chen ◽  
Xiaoyu Ma ◽  
Qiuchen Dong ◽  
Donghui Song ◽  
Derek Hargrove ◽  
...  

Almost 100% self-healing extent recovery performance was observed in thermal-induced bovine serum albumin hydrogel with external heating. Good biocompatibility and biodegradability of this materials were also demonstrated.


2020 ◽  
Vol 26 (S2) ◽  
pp. 1636-1640
Author(s):  
Jun Chen ◽  
Gyeonghee Ryu ◽  
Jamie Warner

AbstractStructural imperfections of 2D crystals such as point vacancies and grain boundaries (GBs) have considerable impacts on their chemical-physical properties. Here we study the atomic structure and dynamics of defects and GBs in monolayer Pd2Se3 using annular dark field scanning transmission electron microscopy (ADF-STEM). The Pd2Se3 monolayers are reproducibly created by thermally induced phase transformation of few-layered PdSe2 films in an in-situ heating holder in the TEM to promote Se loss. Diverse point vacancies, one-dimensional (1D) defects, GBs and defect ring complexes are directly observed in monolayer Pd2Se3, which show a series of dynamics triggered by electron beam. High mobility of vacancies leads to self-healing of point vacancies by migration to the edge and subsequent edge etching under the beam. Specific defects are stabilized by Se–Se bonds, which shift in a staggered way to buffer strain, forming a wave-like 1D defect. Bond rotations are also observed and play an important role in defect and GB dynamics in Pd2Se3 during vacancy production. The GBs form in a meandering pathway and migrate by a sequence of Se–Se bond rotations without large scale vacancy formation. In the GB corners and tilted GBs, other highly symmetric vacancy defects also occur to adapt to the orientation change. These results give atomic level insights into the defects and GBs in Pd2Se3 2D monolayers.


SPIN ◽  
2013 ◽  
Vol 03 (03) ◽  
pp. 1340005 ◽  
Author(s):  
MICHAEL MELZER ◽  
ALEXANDER KOPYLOV ◽  
DENYS MAKAROV ◽  
OLIVER G. SCHMIDT

Stretchable magneto-resistive sensing elements have been introduced lately as a novel component providing magnetic functionality to stretchable consumer electronics involving smart skin or medical diagnostic applications. While spin valves already revealed high stretchability and reliability, GMR multilayers still lack mechanical compliance and production yield. Here, we report on two crucial improvements in fabrication of GMR multilayers to address these limiting issues. On the one hand, we increase the stretchability of wrinkled magnetic nanomembranes on free-standing elastomer membranes by photolithographically structuring them into a meander pattern. The meander can be regarded as a 2D spring, which can accommodate tensile strains in addition to the apparent wrinkling. On the other hand, we highlight a self-healing effect of GMR multilayers, which occurs due to a thermally induced pre-strain in the elastic support. This causes the soft membrane to contract after the GMR elements are prepared on top and closes cracks often induced during fabrication. Relying on this feature we are able to restore the full GMR performance, even if the magneto-sensitive element initially appeared to be without electrical contact before contraction of the free-standing soft membrane.


Polymers ◽  
2017 ◽  
Vol 9 (12) ◽  
pp. 333 ◽  
Author(s):  
Liang Fang ◽  
Jiamei Chen ◽  
Yuting Zou ◽  
Zhongzi Xu ◽  
Chunhua Lu

2018 ◽  
Vol 7 (4.13) ◽  
pp. 129 ◽  
Author(s):  
Danish Mahmood Baitab ◽  
Dayang Laila Abang Haji Abdul Majid ◽  
Ermira Junita Abdullah ◽  
Mohd Faisal Abdul Hamid

Metallic structures, in various industrial fields such as transport and aerospace, are mostly replaced by composite structures having less weight and good strength. There is also a need of intensification of the operational dynamic environment with high durability requirements. So a smart composite structure is required that can manifest its functions according to environmental changes. One method of producing smart composite structures is to embed shape memory alloys in composite structures. Shape memory alloys (SMAs) have significant mechanical and thermodynamic properties and are available in very small diameters less than 0.2mm. These SMAs are embedded into composites for obtaining smart composites having tunable properties, active abilities, damping capacity and self-healing properties. Shape memory alloys are available in different shapes as wires, sheets, foils, strips, etc. For smart composites, mostly SMA embedded are in wire shape. Different techniques are used for embedding SMA wires in composites. SMA wires can be embedded between layers of laminates of composites, or embedded directly as reinforcement in matrix and can be woven into fabrics and used as a reinforcement. This paper reviews the different techniques of embedding SMA wires in composite structures, their pros and cons and their applications.  


Author(s):  
C. S. Giggins ◽  
J. K. Tien ◽  
B. H. Kear ◽  
F. S. Pettit

The performance of most oxidation resistant alloys and coatings is markedly improved if the oxide scale strongly adheres to the substrate surface. Consequently, in order to develop alloys and coatings with improved oxidation resistance, it has become necessary to determine the conditions that lead to spallation of oxides from the surfaces of alloys. In what follows, the morphological features of nonadherent Al2O3, and the substrate surfaces from which the Al2O3 has spalled, are presented and related to oxide spallation.The Al2O3, scales were developed by oxidizing Fe-25Cr-4Al (w/o) and Ni-rich Ni3 (Al,Ta) alloys in air at 1200°C. These scales spalled from their substrates upon cooling as a result of thermally induced stresses. The scales and the alloy substrate surfaces were then examined by scanning and replication electron microscopy.The Al2O3, scales from the Fe-Cr-Al contained filamentary protrusions at the oxide-gas interface, Fig. 1(a). In addition, nodules of oxide have been developed such that cavities were formed between the oxide and the substrate, Fig. 1(a).


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