Improvement of Mechanical Properties and Self-Healing Efficiency by Ex-Situ Incorporation of TiO2 Nanoparticles to a Waterborne Poly(urethane-urea)

Mapping Intimacies ◽

10.20944/preprints201907.0017.v1 ◽

2019 ◽

Author(s):

Iñigo Díez-García ◽

Arantxa Eceiza ◽

Agnieszka Tercjak

Keyword(s):

Mechanical Properties ◽

Tio2 Nanoparticles ◽

Polymer Matrix ◽

Research Work ◽

Nanocomposite Films ◽

Ex Situ ◽

Self Healing ◽

Force Microscopy ◽

Healing Efficiency ◽

Conductive Properties

This research work was focused on the incorporation of TiO2 nanoparticles into synthesized solvent-free waterborne poly(urethane-urea) based on hydrophilic poly(ethylene oxide) (PU0) in order to improve both mechanical properties and self-healing effectiveness of polymer matrix. The incorporation of TiO2 nanoparticles resulted in a successful enhancement of mechanical properties of nanocomposite films if compare to PU0. Simultaneously, obtained nanocomposite films did not only maintain the self-healing ability of PU0 film, measured by means of mechanical properties after successive cutting/recovery cycles, but also showed higher self-healing efficiency than the PU0 film. Moreover, well-dispersed TiO2 nanoparticles, visualized by atomic force microscopy (AFM), kept their electrical conductive properties when embedded in the PU0 matrix, as was confirmed by electrostatic force microscopy (EFM). This research work described a simple and industrially appealing way to control the dispersion of commercially available TiO2 nanoparticles in waterborne poly(urethane-urea) for the designing of inorganic/organic hybrid nanocomposites with enhanced mechanical properties and self-healing efficiency in which TiO2 nanoparticles preserved their conductive properties within the polymer matrix.

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Improvement of Mechanical Properties and Self-Healing Efficiency by Ex-Situ Incorporation of TiO2 Nanoparticles to a Waterborne Poly(Urethane-Urea)

Polymers ◽

10.3390/polym11071209 ◽

2019 ◽

Vol 11 (7) ◽

pp. 1209 ◽

Cited By ~ 1

Author(s):

Iñigo Díez-García ◽

Arantxa Eceiza ◽

Agnieszka Tercjak

Keyword(s):

Mechanical Properties ◽

Tio2 Nanoparticles ◽

Polymer Matrix ◽

Research Work ◽

Nanocomposite Films ◽

Ex Situ ◽

Self Healing ◽

Force Microscopy ◽

Healing Efficiency ◽

Conductive Properties

This research work was focused on the incorporation of TiO2 nanoparticles into synthesized solvent-free waterborne poly(urethane-urea) (WPUU) based on hydrophilic poly(ethylene oxide) (PU0) in order to improve both the mechanical properties and self-healing effectiveness of a polymer matrix. The incorporation of TiO2 nanoparticles resulted in a successful enhancement of the mechanical properties of nanocomposite films when compared to PU0. Simultaneously, the obtained nanocomposite films did not only maintain the self-healing ability of the PU0 film, measured by means of mechanical properties after successive cutting/recovery cycles, but they also showed a higher self-healing efficiency than the PU0 film. Moreover, the well-dispersed TiO2 nanoparticles, visualized by atomic force microscopy (AFM), kept their conductive properties when embedded in the PU0 matrix, as was confirmed by electrostatic force microscopy (EFM). This research work described a simple and industrially appealing way to control the dispersion of commercially available TiO2 nanoparticles in waterborne poly(urethane-urea) for the designing of inorganic/organic hybrid nanocomposites with enhanced mechanical properties and self-healing efficiency, in which TiO2 nanoparticles preserved their conductive properties within the polymer matrix.

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Study of Electrospun Poly\acrylonitrile (PAN) and PAN/CNT Composite Nanofibrous Webs

Research Journal of Textile and Apparel ◽

10.1108/rjta-19-01-2015-b004 ◽

2015 ◽

Vol 19 (1) ◽

pp. 36-45 ◽

Cited By ~ 3

Author(s):

M. K. Sinha ◽

B. R. Das ◽

A. Srivastava ◽

A. K. Saxena

Keyword(s):

Mechanical Properties ◽

Polymer Matrix ◽

Specific Conductivity ◽

Research Work ◽

Fibre Diameter ◽

Nonwoven Fabric ◽

Coating Process ◽

Carbon Nano Tube ◽

Conductive Properties ◽

Poly Acrylonitrile

The electrospinng of PAN and PAN/CNT composite webs is carried out with the commercially available Nanospider machine. The webs are spun under similar processes and coated on Polypropylene spun bonded nonwoven fabric. This research work reports on the influence of multi-walled carbon nano tube (MWCNT) on the morphology, tensile properties, conductivity, thermal, chemical and crystalline structure of PAN and PAN/CNT composite nanofibrous webs. The morphological developments are explained on the basis of nanofibre diameter and web density as depicted by FESEM images. An addition of CNT greatly affects the morphology of webs, increases fibre diameter, decreases web density and leads to a roughened web surface. The mechanical properties of PAN /CNT composite webs are also found to be influenced by CNT concentration. The addition of MWCNT to PAN enhances the conductive properties of webs. The specific conductivity of PAN/CNT composite webs is found to be in order of 10-6 S/cm, which falls in the semiconducting regime and follows Ohm's law of conductivity. The TGA plots confirmed that the PAN/CNT composite web is more thermally stable than the PAN web. The presence of CNT in the polymer matrix is evidenced by D and G band, indicating a successful electrospun coating process.

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Recyclable Self-Healing Polyurethane Cross-Linked by Alkyl Diselenide with Enhanced Mechanical Properties

Polymers ◽

10.3390/polym11050773 ◽

2019 ◽

Vol 11 (5) ◽

pp. 773 ◽

Cited By ~ 3

Author(s):

Yuqing Qian ◽

Xiaowei An ◽

Xiaofei Huang ◽

Xiangqiang Pan ◽

Jian Zhu ◽

...

Keyword(s):

Mechanical Properties ◽

Room Temperature ◽

Amide Bond ◽

Self Healing ◽

Healing Efficiency ◽

Polyurethane Networks ◽

Combined Action ◽

Cross Linker ◽

Dynamic Structures ◽

External Interventions

Dynamic structures containing polymers can behave as thermosets at room temperature while maintaining good mechanical properties, showing good reprocessability, repairability, and recyclability. In this work, alkyl diselenide is effectively used as a dynamic cross-linker for the design of self-healing poly(urea–urethane) elastomers, which show quantitative healing efficiency at room temperature, without the need for any catalysts or external interventions. Due to the combined action of the urea bond and amide bond, the material has better mechanical properties. We also compared the self-healing effect of alkyl diselenide-based polyurethanes and alkyl disulfide-based polyurethanes. The alkyl diselenide has been incorporated into polyurethane networks using a para-substituted amine diphenyl alkyl diselenide. The resulting materials not only exhibit faster self-healing properties than the corresponding disulfide-based materials, but also show the ability to be processed at temperatures as low as 60 °C.

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Numerical Studies of the Effects of Water Capsules on Self-Healing Efficiency and Mechanical Properties in Cementitious Materials

Advances in Materials Science and Engineering ◽

10.1155/2016/8271214 ◽

2016 ◽

Vol 2016 ◽

pp. 1-10 ◽

Cited By ~ 1

Author(s):

Haoliang Huang ◽

Guang Ye

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Elastic Modulus ◽

Cementitious Materials ◽

Self Healing ◽

Negative Effects ◽

Numerical Studies ◽

Healing Efficiency ◽

The Impact ◽

Positive Effect

In this research, self-healing due to further hydration of unhydrated cement particles is taken as an example for investigating the effects of capsules on the self-healing efficiency and mechanical properties of cementitious materials. The efficiency of supply of water by using capsules as a function of capsule dosages and sizes was determined numerically. By knowing the amount of water supplied via capsules, the efficiency of self-healing due to further hydration of unhydrated cement was quantified. In addition, the impact of capsules on mechanical properties was investigated numerically. The amount of released water increases with the dosage of capsules at different slops as the size of capsules varies. Concerning the best efficiency of self-healing, the optimizing size of capsules is 6.5 mm for capsule dosages of 3%, 5%, and 7%, respectively. Both elastic modulus and tensile strength of cementitious materials decrease with the increase of capsule. The decreasing tendency of tensile strength is larger than that of elastic modulus. However, it was found that the increase of positive effect (the capacity of inducing self-healing) of capsules is larger than that of negative effects (decreasing mechanical properties) when the dosage of capsules increases.

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Dynamic Mussel-Inspired Chitin Nanocomposite Hydrogels for Wearable Strain Sensors

Polymers ◽

10.3390/polym12061416 ◽

2020 ◽

Vol 12 (6) ◽

pp. 1416 ◽

Cited By ~ 3

Author(s):

Pejman Heidarian ◽

Abbas Z. Kouzani ◽

Akif Kaynak ◽

Ali Zolfagharian ◽

Hossein Yousefi

Keyword(s):

Mechanical Properties ◽

Polyacrylic Acid ◽

Strain Sensors ◽

Self Healing ◽

Network Stability ◽

Ferric Ions ◽

Trade Off ◽

Nanocomposite Hydrogels ◽

Healing Efficiency ◽

Hydrogel Network

It is an ongoing challenge to fabricate an electroconductive and tough hydrogel with autonomous self-healing and self-recovery (SELF) for wearable strain sensors. Current electroconductive hydrogels often show a trade-off between static crosslinks for mechanical strength and dynamic crosslinks for SELF properties. In this work, a facile procedure was developed to synthesize a dynamic electroconductive hydrogel with excellent SELF and mechanical properties from starch/polyacrylic acid (St/PAA) by simply loading ferric ions (Fe3+) and tannic acid-coated chitin nanofibers (TA-ChNFs) into the hydrogel network. Based on our findings, the highest toughness was observed for the 1 wt.% TA-ChNF-reinforced hydrogel (1.43 MJ/m3), which is 10.5-fold higher than the unreinforced counterpart. Moreover, the 1 wt.% TA-ChNF-reinforced hydrogel showed the highest resistance against crack propagation and a 96.5% healing efficiency after 40 min. Therefore, it was chosen as the optimized hydrogel to pursue the remaining experiments. Due to its unique SELF performance, network stability, superior mechanical, and self-adhesiveness properties, this hydrogel demonstrates potential for applications in self-wearable strain sensors.

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Adaptable Eu-containing polymeric films with dynamic control of mechanical properties in response to moisture

Soft Matter ◽

10.1039/c9sm02440a ◽

2020 ◽

Vol 16 (9) ◽

pp. 2276-2284 ◽

Cited By ~ 7

Author(s):

Zichao Wei ◽

Srinivas Thanneeru ◽

Elena Margaret Rodriguez ◽

Gengsheng Weng ◽

Jie He

Keyword(s):

Mechanical Properties ◽

Optical Properties ◽

Polymer Films ◽

Dynamic Control ◽

Polymeric Films ◽

Self Healing ◽

Healing Efficiency

Moisture that competes with dipicolylamine to bind Eu dynamically controls the mechanical and optical properties of polymer films, as well as their self-healing efficiency.

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Soluble Silicates as Additives for Self-Sealing and Self-Healing Concrete

MRS Proceedings ◽

10.1557/opl.2016.7 ◽

2016 ◽

Vol 1813 ◽

Author(s):

L. E. Rendon Diaz Miron ◽

M. E. Lara Magaña

Keyword(s):

Mechanical Properties ◽

Crack Formation ◽

Healing Process ◽

Self Healing ◽

Reaction Products ◽

Calcium Carbonate Precipitation ◽

Broad Perspective ◽

Healing Efficiency ◽

Tensile Forces ◽

Solubility Ratio

ABSTRACTTensile strength of concrete is limited and therefore is sensitive to crack formation. Steel reinforcement is added to bear the tensile forces; nonetheless, this does not completely omit crack formation. Repair of cracks in concrete is time-consuming and expensive. Self-sealing and self-healing of cracks upon appearance would therefore be a convenient property. We propose a mechanism to obtain self-repair of the concrete by adding soluble silicates (ASS) which will induce a self-sealing and self-healing process catalyzed by natural periods of wet and dry states of the concrete. Self-sealing approaches prevent the ingress of harsh chemical substances which may deteriorate the concrete matrix. This can be achieved by self-healing of concrete cracks (e.g. further cement hydration, calcium carbonate precipitation) and autonomous healing (e.g. further hydration of partially soluble silicates added as healing agents). The autogenous healing efficiency depends on the amount of deposited reaction products (ASS), its solubility (ratio of calcium to sodium silicate), the availability of water, and the crack width (restricted by adding microfibers). The self-sealing efficiency is generally evaluated by measuring the decrease in water permeability and air flow through the crack. The healing efficiency is usually evaluated by testing concrete´s regain in mechanical properties after crack formation; by reloading the cracked and autonomously healed specimen and comparing the obtained mechanical properties with the original ones. Self-sealing and self-healing of concrete gives a broad perspective and new possibilities to make future concrete structures more durable.

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Impact of Bio-Carrier Immobilized with Marine Bacteria on Self-Healing Performance of Cement-Based Materials

Materials ◽

10.3390/ma13184164 ◽

2020 ◽

Vol 13 (18) ◽

pp. 4164 ◽

Cited By ~ 1

Author(s):

Hayeon Kim ◽

Hyeongmin Son ◽

Joonho Seo ◽

H. K. Lee

Keyword(s):

Mechanical Properties ◽

Mercury Intrusion Porosimetry ◽

Tap Water ◽

Bottom Ash ◽

Self Healing ◽

Mixing Process ◽

Mercury Intrusion ◽

Healing Efficiency ◽

Cement Based Materials ◽

Healing Agent

The present study evaluated the self-healing efficiency and mechanical properties of mortar specimens incorporating a bio-carrier as a self-healing agent. The bio-carrier was produced by immobilizing ureolytic bacteria isolated from seawater in bottom ash, followed by surface coating with cement powder to prevent loss of nutrients during the mixing process. Five types of specimens were prepared with two methods of incorporating bacteria, and were water cured for 28 days. To investigate the healing ratio, the specimens with predefined cracks were treated by applying a wet–dry cycle in three different conditions, i.e., seawater, tap water, and air for 28 days. In addition, a compression test and a mercury intrusion porosimetry analysis of the specimens were performed to evaluate their physico-mechanical properties. The obtained results showed that the specimen incorporating the bio-carrier had higher compressive strength than the specimen incorporating vegetative cells. Furthermore, the highest healing ratio was observed in specimens incorporating the bio-carrier. This phenomenon could be ascribed by the enhanced bacterial viability by the bio-carrier.

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Mechanical Properties Assessment of Low-Content Capsule-Based Self-Healing Structural Composites

Applied Sciences ◽

10.3390/app10175739 ◽

2020 ◽

Vol 10 (17) ◽

pp. 5739

Author(s):

Xenia Tsilimigkra ◽

Dimitrios Bekas ◽

Maria Kosarli ◽

Stavros Tsantzalis ◽

Alkiviadis Paipetis ◽

...

Keyword(s):

Mechanical Properties ◽

Fracture Toughness ◽

Flexural Strength ◽

Mechanical Performance ◽

Urea Formaldehyde ◽

Healing Process ◽

Experimental Results ◽

Self Healing ◽

Healing Efficiency ◽

A Minor

Microcapsule-based carbon fiber reinforced composites were manufactured by wet layup, in order to assess their mechanical properties and determine their healing efficiency. Microcapsules at 10%wt. containing bisphenol-A epoxy, encapsulated in a urea formaldehyde (UF) shell, were employed with Scandium (III) Triflate (Sc (OTf)3) as the catalyst. The investigation was deployed with two main directions. The first monitored changes to the mechanical performance due to the presence of the healing agent within the composite. More precisely, a minor decrease in interlaminar fracture toughness (GIIC) (−14%), flexural strength (−12%) and modulus (−4%) compared to the reference material was reported. The second direction evaluated the healing efficiency. The experimental results showed significant recovery in fracture toughness up to 84% after the healing process, while flexural strength and modulus healing rates reached up to 14% and 23%, respectively. The Acoustic Emission technique was used to support the experimental results by the onsite monitoring.

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