scholarly journals Polymer nanocomposite-enabled high-performance triboelectric nanogenerator with self-healing capability

RSC Advances ◽  
2018 ◽  
Vol 8 (54) ◽  
pp. 30661-30668 ◽  
Author(s):  
Huidan Niu ◽  
Xinyu Du ◽  
Shuyu Zhao ◽  
Zuqing Yuan ◽  
Xiuling Zhang ◽  
...  
Keyword(s):  
High Performance ◽  
Healing Process ◽  
Polymer Nanocomposite ◽  
The Self ◽  
Triboelectric Nanogenerator ◽  
Self Healing

The self-healing process and the primary characteristics showing the performance of the self-healed triboelectric nanogenerator.

scholarly journals Microencapsulated healing agents for an elevated-temperature cured epoxy: Influence of viscosity on healing efficiency

2021 ◽  
pp. 096739112110453
Author(s):  
Habibah Ghazali ◽  
Lin Ye ◽  
Amie N Amir
Keyword(s):  
Fracture Toughness ◽  
Elevated Temperature ◽  
High Performance ◽  
Healing Process ◽  
Polymer Network ◽  
Diglycidyl Ether ◽  
The Self ◽  
Effect Of Temperature ◽  
Mode I ◽  
Self Healing

Among many applications, elevated-temperature cured epoxy resins are widely used for high-performance applications especially for structural adhesive and as a matrix for structural composites. This is due to their superior chemical and mechanical properties. The thermosetting nature of epoxy produces a highly cross-linked polymer network during the curing process where the resulting material exhibited excellent properties. However, due to this cross-linked molecular structure, epoxies are also known to be brittle, and once a crack initiated in the material, it is difficult to arrest the crack propagation. Earlier research found that the inclusion of encapsulated healing agents is able to introduce self-healing ability to the room-temperature cured epoxies. The current study investigated the self-healing behaviour of an elevated-temperature cured epoxy, which incorporated the dual-capsule system loaded with diglycidyl-ether of bisphenol-A (DGEBA) resin and mercaptan. The microcapsules were prepared by the in-situ polymerisation method while the fracture toughness and the self-healing capability of the tapered-double-cantilever-beam (TDCB) epoxy specimens were measured under Mode-I fracture toughness testing. We investigated the effect of temperature on viscosity of the healing agents and how these values influence the formation of uniform healing on the fracture surfaces. It was found that incorporation of the dual-capsule self-healing system onto an elevated-temperature cured epoxy slightly changed the fracture toughness of the epoxy as indicated by the Mode-I testing. In the case of thermal healing at 70°C, the self-healing epoxy exhibited a recovery of up to 111% of its original fracture toughness, where a uniform spreading of the healant was observed. The excellent healing behaviour is attributed to the lower viscosity of the healant at higher temperature and the higher glass transition temperature ( Tg) of the produced healant film. The DSC analysis confirmed that the healing process was not contributed by the post-curing of the host epoxy.

scholarly journals Application of GGBFS and Bentonite to Auto-Healing Cracks of Cement Paste

2018 ◽  
Vol 1 (1) ◽  
pp. 38 ◽  
Author(s):  
J J Ekaputri ◽  
M S Anam ◽  
Y Luan ◽  
C Fujiyama ◽  
N Chijiwa ◽  
...  
Keyword(s):  
Cement Paste ◽  
Surface Crack ◽  
Crack Width ◽  
Healing Process ◽  
Crack Depth ◽  
The Self ◽  
External Loading ◽  
Self Healing ◽  
Carbonation Reaction ◽  
Granulated Blast Furnace Slag

Cracks are caused by many factors. Shrinkage and external loading are the most common reason. It becomes a problem when the ingression of aggressive and harmful substance penetrates to the concrete gap. This problem reduces the durability of the structures. It is well known that self – healing of cracks significantly improves the durability of the concrete structure. This paper presents self-healing cracks of cement paste containing bentonite associated with ground granulated blast furnace slag. The self-healing properties were evaluated with four parameters: crack width on the surface, crack depth, tensile strength recovery, and flexural recovery. In combination with microscopic observation, a healing process over time is also performed. The results show that bentonite improves the healing properties, in terms of surface crack width and crack depth. On the other hand, GGBFS could also improve the healing process, in terms of crack depth, direst tensile recovery, and flexural stiffness recovery. Carbonation reaction is believed as the main mechanism, which contributes the self-healing process as well as the continuous hydration progress.

scholarly journals Effect of crack pattern on the self-healing capability in traditional, HPC and UHPFRC concretes measured by water and chloride permeability

2019 ◽  
Vol 289 ◽  
pp. 01006 ◽  
Author(s):  
Alberto Negrini ◽  
Marta Roig-Flores ◽  
Eduardo J. Mezquida-Alcaraz ◽  
Liberato Ferrara ◽  
Pedro Serna
Keyword(s):  
Reinforced Concrete ◽  
Water Permeability ◽  
High Performance ◽  
Water Immersion ◽  
Crack Pattern ◽  
The Self ◽  
Reinforced Concrete Beams ◽  
Multiple Cracks ◽  
Self Healing ◽  
High Performance Fibre

Concrete has a natural self-healing capability to seal small cracks, named autogenous healing, which is mainly produced by continuing hydration and carbonation. This capability is very limited and is activated only when in direct contact with water. High Performance Fibre-Reinforced Concrete and Engineered Cementitious Composites have been reported to heal cracks for low damage levels, due to their crack pattern with multiple cracks and high cement contents. While their superior self-healing behaviour compared to traditional concrete types is frequently assumed, this study aims to have a direct comparison to move a step forward in durability quantification. Reinforced concrete beams made of traditional, high-performance and ultra-high-performance fibre-reinforced concretes were prepared, sized 150×100×750 mm3. These beams were pre-cracked in flexion up to fixed strain levels in the tensioned zone to allow the analysis of the effect of the different cracking patterns on the self-healing capability. Afterwards, water permeability tests were performed before and after healing under water immersion. A modification of the water permeability test was also explored using chlorides to evaluate the potential protection of this healing in chloride-rich environments. The results show the superior durability and self-healing performance of UHPFRC elements.

The effect of nanoparticles on the self-healing capacity of high performance concrete

2019 ◽  
pp. 43-67 ◽  
Author(s):  
J.L. García Calvo ◽  
G. Pérez ◽  
P. Carballosa ◽  
E. Erkizia ◽  
J.J. Gaitero ◽  
...  
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
The Self ◽  
Self Healing

The effects of textile reinforcements on the protective properties of self-healing polymers intended for safety gloves

2020 ◽  
Vol 90 (17-18) ◽  
pp. 1974-1986
Author(s):  
Emilia Irzmańska ◽  
Anna Bacciarelli-Ulacha ◽  
Agnieszka Adamus-Włodarczyk ◽  
Anna Strąkowska
Keyword(s):  
Healing Process ◽  
Polymeric Composite ◽  
Polymeric Materials ◽  
Economic Loss ◽  
The Self ◽  
Raw Material ◽  
Protective Equipment ◽  
Self Healing ◽  
Hybrid Molecules ◽  
The Impact

In the environment where glove material is exposed to harmful chemicals, hazards related to faster penetration of dangerous substances into the glove interior may cause microdamage. One of the solutions to overcome this problem is to use the self-healing polymeric materials that can minimize economic loss and accidents in the workplace. The current work aims to present the impact of different types of textile reinforcement on the effectiveness and efficiency of the self-healing process of methyl vinyl silicone rubber containing hybrid molecules with an inorganic silsesquioxane intended for use on all-rubber gloves. Three knitted fabrics with a similar structure and differentiated raw material composition were selected: polyamide, cotton–polyamide, and cotton. Evaluation of the self-healing process of the elastomeric composite to personal protective equipment was performed. For this purpose the assessment of the surface morphology of materials has been performed before and after the self-healing process. The implementation of knitted fabric into the polymeric composite in the tested samples allowed us to obtain the best results in all tests. The studied composite samples exhibited an increased resistance to three types of damage: penetration, abrasion and puncture. The samples also underwent the self-healing processes and regeneration after a proper conditioning period. Thus, the obtained results confirmed the possibility of using tested elastomeric composites in the construction of protective gloves and showed an effectivity of the self-healing process for the long-term usage of that protective equipment.

Molecular dynamics simulation insight into the temperature dependence and healing mechanism of an intrinsic self-healing polyurethane elastomer

2020 ◽  
Vol 22 (31) ◽  
pp. 17620-17631
Author(s):  
Xianling Chen ◽  
Jing Zhu ◽  
Yanlong Luo ◽  
Jun Chen ◽  
Xiaofeng Ma ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Hydrogen Bonds ◽  
Molecular Diffusion ◽  
Healing Process ◽  
The Self ◽  
Dynamics Simulation ◽  
Polyurethane Elastomer ◽  
Self Healing ◽  
Insight Into

The changes in the type and number of hydrogen bonds as well as the microscopic behavior of molecular diffusion in the self-healing process of polyurethane are revealed.

scholarly journals The Self-Healing Performance of Carbon-Based Nanomaterials Modified Asphalt Binders Based on Molecular Dynamics Simulations

2021 ◽  
Vol 7 ◽  
Author(s):  
Yan Gong ◽  
Jian Xu ◽  
Er-hu Yan ◽  
Jun-hua Cai
Keyword(s):  
Healing Process ◽  
Asphalt Binder ◽  
Mean Square Displacement ◽  
The Self ◽  
Asphalt Binders ◽  
Self Healing ◽  
Modified Asphalt ◽  
Healing Efficiency ◽  
Carbon Based Nanomaterials ◽  
Carbon Based

In this study, the molecular dynamics simulation was used to explore the effects of carbon-based nanomaterials as binder modifiers on self-healing capability of asphalt binder and to investigate the microscopic self-healing process of modified asphalt binders under different temperature. An asphalt average molecular structure model of PEN70 asphalt binder was constructed firstly. Further, three kinds of carbon-based nanomaterials were added at three different percentages ranging from 0.5 to 1.5% to the base binder to study their effects on the self-healing capability, including two carbon nanotubes (CNT1 and CNT2) and graphene nanoflakes. Combining with the three-dimensional (3D) microcrack model to simulate the asphalt self-healing process, the density analysis, relative concentration analysis along OZ direction, and mean square displacement analysis were performed to investigate the temperature sensitive self-healing characters. Results showed that the additions of CNTs were effective in enhancing the self-healing efficiency of the plain asphalt binder. By adding 0.5% CNT1 and 0.5% CNT2, about 652% and 230% of the mean square displacement of plain asphalt binder were enhanced at the optimal temperatures. However, the use of graphene nanoflakes as an asphalt modifier did not provide any noticeable changes on the self-healing efficiency. It can be found that the self-healing capability of the asphalt was closely related to the temperature. For base asphalt, the self-healing effect became especially high at the phase transition temperature range, while, for the modified asphalt, the enhancement of the self-healing capability at the low phase transition temperature (15°C) became negligible. In general, the optimal healing temperature range of the CNTs modified asphalt binders is determined as 45–55°C and the optimal dosage of the CNTs is about 0.5% over the total weight of the asphalt binder. Considering the effect of carbon-based nanomaterials on the self-healing properties, the recommended carbon-based nanomaterials modifier is CNT1 with the aspect ratio of 1.81.

scholarly journals A Self-Healing Coating with UV-Shielding Property

Coatings ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 421 ◽  
Author(s):  
Lei Peng ◽  
Musong Lin ◽  
Sheng Zhang ◽  
Li Li ◽  
Qiang Fu ◽  
...  
Keyword(s):  
Moisture Absorption ◽  
Healing Process ◽  
Ultra Violet ◽  
The Self ◽  
Self Healing ◽  
Soft Substrate ◽  
Water Contact ◽  
Uv Shielding ◽  
Host Guest Complex ◽  
Healing Property

A self-healing coating with UV-shielding property was prepared in this paper. The self-healing property was based on the inclusion between a host (β-CD-TiO2) and a guest HEMA-Ad). After inclusion of the host and guest, the host–guest complex (HEMA-Ad/β-CD-TiO2) was polymerized with other reactive monomers (HEMA and BA) to obtain the final coating. The coating had good hydrophobicity (water contact angle >90°, moisture absorption rate <2%) and excellent UV-shielding performance (ultra-violet protect factor >90%), and could be firmly bonded to a soft substrate. In addition, the coating had good self-healing property, which means that cracks in the material can recover many times after being damaged and that the UV-shielding ability can be fully restored with the self-healing process.

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