scholarly journals Synthesis of calcium carbonate microcapsules as self-healing containers

RSC Advances ◽  
2019 ◽  
Vol 9 (41) ◽  
pp. 23666-23677 ◽  
Author(s):  
Nadeesha Maduwanthi Hettiarachchi ◽  
Rangika Thilan De Silva ◽  
M. M. M. G. Prasanga Gayanath Mantilaka ◽  
Pooria Pasbakhsh ◽  
K. M. Nalin De Silva ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Self Healing ◽  
Metal Coatings ◽  
Healing Agent

Healing agent, epoxy encapsulated calcium carbonate microcapsules were prepared using a facile method as a self-healing composite for protective metal coatings.

scholarly journals On the Applicability of a Precursor Derived from Organic Waste Streams for Bacteria-Based Self-Healing Concrete

2021 ◽  
Vol 7 ◽  
Author(s):  
Emanuele Rossi ◽  
Chris M. Vermeer ◽  
Renee Mors ◽  
Robbert Kleerebezem ◽  
Oguzhan Copuroglu ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Service Life ◽  
Circular Economy ◽  
Organic Waste ◽  
Bacterial Activity ◽  
Self Healing ◽  
Waste Streams ◽  
Sealing Capacity ◽  
Crack Sealing ◽  
Healing Agent

Bacteria-based self-healing concrete has the ability to heal cracks due to the bacterial conversion of incorporated organic compounds into calcium carbonate. Precipitates seal the cracks, theoretically increasing the service life of constructions. The aim of this paper is to propose a precursor for bacteria-based self-healing concrete derived from organic waste streams, produced is in line with the circular economy principle and ideally more affordable than other substrates. To verify the applicability of the proposed healing agent, some fundamental requirements of the proposed system are studied, such as its influence on functional properties, crack sealing capacity and evidence of bacterial activity in concrete.

scholarly journals Bacillus Subtilis as Self-Healing Agent in Cement Mortar: The Effect of Curing Time and Amount of Calcium Lactate on Strength

2021 ◽  
Vol 40 (4) ◽  
pp. 889-897
Author(s):  
Sohail Muhammad ◽  
Humair Ahmed Siddiqui
Keyword(s):  
Compressive Strength ◽  
Bacillus Subtilis ◽  
Calcium Carbonate ◽  
Cement Mortar ◽  
Calcium Lactate ◽  
Self Healing ◽  
Curing Time ◽  
Healing Agent ◽  
Cause Of Failure ◽  
The Cost

Crack growth is a major cause of failure in structures that are made using cement and concrete. Healing of these cracks can increase the life span of structures. In the present study micro-organism based self-healing of structures is studied. A commonly occurring micro-organism bacterium called Bacillus Subtilis, is used in the manufacturing of cement mortar blocks as a self-healing agent for cement mortar blocks, with the use of Calcium Lactate as feed for bacteria. In the first step, colonies of Bacillus Subtilis were grown and added with calcium lactate to produce a solution. The solution was then kept for one week to observe the metabolic product of Bacillus Subtilis. It was found that the bacterial product was composed of CaCO3 and thus the bacteria is suitable to be used as self-healing agent. Self-healing cement mortar blocks were made by adding Bacteria and Calcium Lactate with usual ingredients of cement mortar, i.e. cement, sand and water. It was found that the bacteria were also effective in converting Calcium Lactate to Calcium Carbonate, when mixed in cement mortar blocks. It was observed that the pores of cement mortar blocks were filled by Calcium Carbonate and that cracks get healed by the deposition of Calcium Carbonate in the cracks. Cement mortar blocks, with and without healing agent, were made to compare the effect of curing time. The samples were tested after seven, fourteen and twenty-eight days to compare the effect of healing agent. All the samples with the healing agent showed a higher compressive strength in comparison with the samples that were made without healing agent. Different percentages of Calcium Lactate, ranging from 1-7% were also used to find the best composition for future use. It was found that the compressive strength was increasing up to 5% while above 5% the increase was marginal thus it is proposed that Calcium Lactate should be used in between 5-7 % to reduce the cost of self-healing cement in construction industry.

Mechanical responses of microencapsulated self-healing cementitious composites under compressive loading based on a micromechanical damage-healing model

2021 ◽  
pp. 105678952110112
Author(s):  
Kaihang Han ◽  
Jiann-Wen Woody Ju ◽  
Yinghui Zhu ◽  
Hao Zhang ◽  
Tien-Shu Chang ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Compressive Strength ◽  
Micromechanical Model ◽  
Cementitious Composites ◽  
Self Healing ◽  
Damage Degree ◽  
Healing Efficiency ◽  
The Matrix ◽  
Healing Agent ◽  
Damage Healing

The cementitious composites with microencapsulated healing agents have become a class of hotspots in the field of construction materials, and they have very broad application prospects and research values. The in-depth study on multi-scale mechanical behaviors of microencapsulated self-healing cementitious composites is critical to quantitatively account for the mechanical response during the damage-healing process. This paper proposes a three-dimensional evolutionary micromechanical model to quantitatively explain the self-healing effects of microencapsulated healing agents on the damage induced by microcracks. By virtue of the proposed 3 D micromechanical model, the evolutionary domains of microcrack growth (DMG) and corresponding compliances of the initial, extended and repaired phases are obtained. Moreover, the elaborate studies are conducted to inspect the effects of various system parameters involving the healing efficiency, fracture toughness and preloading-induced damage degrees on the compliances and stress-strain relations. The results indicate that relatively significant healing efficiency, preloading-induced damage degree and the fracture toughness of polymerized healing agent with the matrix will lead to a higher compressive strength and stiffness. However, the specimen will break owing to the nucleated microcracks rather than the repaired kinked microcracks. Further, excessive higher values of healing efficiency, preloading-induced damage degree and the fracture toughness of polymerized healing agent with the matrix will not affect the compressive strength of the cementitious composites. Therefore, a stronger matrix is required. To achieve the desired healing effects, the specific parameters of both the matrix and microcapsules should be selected prudently.

Numerical investigation into effect of self-healing composite microcapsules thickness and diameter on their failure strength

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Raj Kumar Pittala ◽  
Satish Ben B. ◽  
Syam Kumar Chokka ◽  
Niranjan Prasad
Keyword(s):  
Matrix Composite ◽  
Polymer Matrix ◽  
Shell Thickness ◽  
Polymer Matrix Composite ◽  
Thickness Effect ◽  
Failure Strength ◽  
Self Healing ◽  
Content Type ◽  
Reinforced Polymer ◽  
Healing Agent

Purpose Microcapsule-embedded autonomic healing materials have the ability to repair microcracks when they come into contact with the crack by releasing the healing agent. The microcapsules with specific shape and thickness effect in releasing healing agent to the cracked surfaces. Thus, the purpose of this paper is to know the load bearing capacity of the self-healing microcapsules and the stresses developed in the material. Design/methodology/approach In the present study, self-healing microcapsule is modelled and integrated with the polymer matrix composite. The aim of the present study is to investigate failure criteria of Poly (methyl methacrylate) microcapsules by varying the shell thickness, capsule diameter and loading conditions. The strength of the capsule is evaluated by keeping the shell thickness as constant and varying the capsule diameter. Uniformly distributed pressure loads were applied on the capsule-reinforced polymer matrix composite to assess the failure strength of capsules and composite. Findings It is observed from the results that the load required to break the capsules is increasing with the increase in capsule diameter. The failure strength of microcapsule with 100 µm diameter and 5 µm thickness is observed as 255 MPa. For an applied load range of 40–160 N/mm2 on the capsules embedded composite, the maximum stress developed in the capsules is observed as 308 MPa. Originality/value Failure strengths of microcapsules and stresses developed in the microcapsule-reinforced polymer composites were evaluated.

scholarly journals Reversible Assembly of Terpyridine Incorporated Norbornene-Based Polymer via a Ring-Opening Metathesis Polymerization and Its Self-Healing Property

Polymers ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1173 ◽  
Author(s):  
Jookyeong Lee ◽  
Hwi Moon ◽  
Keewook Paeng ◽  
Changsik Song
Keyword(s):  
Ring Opening ◽  
Transition Metal Ions ◽  
Self Healing ◽  
Ring Opening Metathesis Polymerization ◽  
Metathesis Polymerization ◽  
Ligand Interactions ◽  
Healing Agent ◽  
Healing Property ◽  
External Stimuli ◽  
Metal Ligand

We induced a terpyridine moiety into a norbornene-based polymer to demonstrate its self-healing property, without an external stimulus, such as light, heat, or healing agent, using metal–ligand interactions. We synthesized terpyridine incorporated norbornene-based polymers using a ring-opening metathesis polymerization. The sol state of diluted polymer solutions was converted into supramolecular assembled gels, through the addition of transition metal ions (Ni2+, Co2+, Fe2+, and Zn2+). In particular, a supramolecular complex gel with Zn2+, which is a metal with a lower binding affinity, demonstrated fast self-healing properties, without any additional external stimuli, and its mechanical properties were completely recovered.

Microencapsulation of UV-Curable Self-healing Agent for Smart Anticorrosive Coating

2014 ◽  
Vol 27 (5) ◽  
pp. 607-615 ◽  
Author(s):  
Dong Zhao ◽  
Mo-zhen Wang ◽  
Qi-chao Wu ◽  
Xiao Zhou ◽  
Xue-wu Ge
Keyword(s):  
Self Healing ◽  
Uv Curable ◽  
Anticorrosive Coating ◽  
Healing Agent

scholarly journals Self-Healing Biogeopolymers Using Biochar-Immobilized Spores of Pure- and Co-Cultures of Bacteria

2020 ◽  
Author(s):  
Jadin Zam S. Doctolero ◽  
Arnel B. Beltran ◽  
Marigold O. Uba ◽  
April Anne S. Tigue ◽  
Michael Angelo B. Promentilla
Keyword(s):  
Image Analysis ◽  
Crack Width ◽  
Ultrasonic Pulse ◽  
Self Healing ◽  
Weak Effect ◽  
Bacterial Cultures ◽  
Healing Agent ◽  
Optimum Response ◽  
Maximum Crack ◽  
Cultured Bacteria

A sustainable solution for crack maintenance in geopolymers is necessary if they are to be the future of modern green construction. This study thus aimed to develop self-healing biogeopolymers that could potentially rival bioconcrete. First, a suitable healing agent was selected from Bacillus subtilis, B. sphaericus, and B. megaterium by directly adding their spores in the geopolymers and subsequently exposing them to a large amount of nutrients for 14 days. SEM-EDX analysis revealed the formation of biominerals for B. subtilis and B. sphaericus. Next, the effect of biochar-immobilization and co-culturing (B. sphaericus and B. thuringiensis) on the healing efficiencies of the geopolymers were tested and optimized by measuring their ultrasonic pulse velocities weekly over a 28-day healing period. The results show that using co-cultured bacteria significantly improved the observed efficiencies, while biochar-immobilization had a weak effect but yielded an optimum response between 0.3-0.4 g/mL. The maximum crack width sealed was 0.65 mm. Through SEM-EDX and FTIR analyses, the biominerals precipitated in the cracks were identified to be mainly CaCO3. Furthermore, image analysis of the XCT scans of some of the healed geopolymers confirmed that their pulse velocities were indeed improving due to the filling of their internal spaces with biominerals. With that, there is potential in developing self-healing biogeopolymers using biochar-immobilized spores of bacterial cultures.

scholarly journals Bioprecipitation of calcium carbonate by Bacillus subtilis and its potential to self-healing in cement-based materials

2020 ◽  
Vol 18 (5) ◽  
Author(s):  
Héctor Ferral Pérez ◽  
Mónica Galicia García
Keyword(s):  
Bacillus Subtilis ◽  
Calcium Carbonate ◽  
Building Materials ◽  
Soil Stabilization ◽  
Amorphous Material ◽  
Crystallinity Index ◽  
Self Healing ◽  
Semi Solid ◽  
A Minor ◽  
Novel Applications

In recent years, biological mineralization has been implemented as a viable option for the elaboration of new building materials, protection and repair of concrete by self-healing, soil stabilization, carbon dioxide capture, and drug delivery. Biogenic mineralization of calcium carbonate (CaCO3) induced by bacterial metabolism has been proposed as an effective method. The objective of the present study was to characterize the bioprecipitation of CaCO3 crystals by Bacillus subtilis in a semi-solid system. The results show that CaCO3 crystals were produced by day 3 of incubation. The prevalent crystalline polymorph was calcite, and in a minor proportion, vaterite. The presence of amorphous material was also detected (amorphous CaCO3 (ACC)). Finally, the crystallinity index was 81.1%. This biogenic calcium carbonate does not decrease pH and does not yield chloride formation. Contrary, it increases pH values up to 10, which constitutes and advantage for implementations at reinforced concrete. Novel applications for biogenic calcium carbonate derived from Bacillus subtilis addressing self-healing, biocementation processes, and biorestoration of monuments are presented.  

Self-healing organic coatings based on microcapsules – A patent-based review

2021 ◽  
Vol 04 ◽  
Author(s):  
Diego Moreira Schlemper ◽  
Sérgio Henrique Pezzin
Keyword(s):  
Corrosion Protection ◽  
State Of The Art ◽  
Review Article ◽  
The State ◽  
Organic Coatings ◽  
Self Healing ◽  
Future Challenges ◽  
The Matrix ◽  
Healing Agent

: Self-healing coatings are intended to increase long-term durability and reliability and can be enabled by the presence of microcapsules containing a self-healing agent capable of interacting with the matrix and regenerating the system. This review article provides an overview of the state-of-the-art, focusing on the patents published in the field of microcapsule-based self-healing organic coatings, since the early 2000’s. A discussion about coatings for corrosion protection and the different self-healing approaches and mechanisms are also addressed, as well as future challenges and expectations for this kind of coatings.

Sign in / Sign up

Export Citation Format

Share Document