Development of self-healing polymers via amine–epoxy chemistry: I. Properties of healing agent carriers and the modelling of a two-part self-healing system

2014 ◽  
Vol 23 (6) ◽  
pp. 065003 ◽  
Author(s):  
He Zhang ◽  
Jinglei Yang
Keyword(s):  
Self Healing ◽  
Healing System ◽  
Healing Agent

Fatigue response of a solid state self-healing resin

2020 ◽  
pp. 096739112095509
Author(s):  
Mohd Suzeren Md Jamil ◽  
Noor Nabilah Muhamad ◽  
Wan Naqiuddin Wan Zulrushdi
Keyword(s):  
Fatigue Life ◽  
Solid State ◽  
Fatigue Behavior ◽  
Fatigue Cracks ◽  
Healing Process ◽  
Fatigue Tests ◽  
Self Healing ◽  
Healing System ◽  
Healing Agent ◽  
Modified Epoxy

The present work verified the capability of a solid state self-healing system for retarding or arresting fatigue cracks in epoxy materials subjected to cyclic loading at room temperature. A solid state self-healing material is demonstrated using a thermosetting epoxy polymer which was modified by incorporating a linear thermoplastic polydiglycidyl ether bisphenol-A (PDGEBA) as a healing agent. The stress-controlled constant amplitude (CA) tensile fatigue behavior at stress ratio, R = 0.1 and frequency 10 Hz for both the neat and the modified epoxy was investigated. Fatigue life and residual strength degradation were continuously monitored during the fatigue tests. The modified epoxy fatigue life was shown to be increased by ∼50% after healing periods. The fatigue-healing process was proven through the surface and cross-section resin morphology analyses using microscopy optic and scanning electron microscope (SEM). On the whole, the solid state self-healing system has proven to be very effective in obstructing fatigue crack propagation, effectively improved the self-healing polymeric material to achieve higher endurance limits.

Microscopic Tests on Evaluation of Self-Healing Efficiency in Cementitious Materials with a Novel Self-Healing System

2020 ◽  
Vol 996 ◽  
pp. 104-109 ◽  
Author(s):  
Zhen Hong Yang ◽  
Xian Feng Wang ◽  
Ning Xu Han ◽  
Feng Xing
Keyword(s):  
Joint Action ◽  
Cementitious Materials ◽  
Cementitious Material ◽  
Self Healing ◽  
Test Results ◽  
Expansive Agent ◽  
Healing System ◽  
Healing Efficiency ◽  
Healing Agent

In this study, Na2CO3 solution as a self-healing agent was impregnated in LWA for autonomic self-healing on cracked cementitious material. The results showed that under the joint action of expansive agent, crystalline additive, phosphate and carbonate, the crack area showed a high self-healing efficiency (close to 70%) after curing in the still water 28d. SEM-EDS test results showed that in addition to ettringite and C-S-H/C-A-S-H, there was also a large amount of CaCO3 crystal in the depths of the crack.

scholarly journals Dual Monitoring of Cracking and Healing in Self-healing Coatings using Microcapsules Loaded with Two Fluorescent Dyes

2019 ◽  
Author(s):  
Young Kyu Song ◽  
Tae Hee Lee ◽  
Jin Chul Kim ◽  
Kyu Cheol Lee ◽  
Sang Ho Lee ◽  
...  
Keyword(s):  
Solid State ◽  
Fluorescent Dyes ◽  
Urea Formaldehyde ◽  
Uv Curing ◽  
Coating System ◽  
Self Healing ◽  
Matrix Resin ◽  
Healing System ◽  
Fluorescence Color ◽  
Healing Agent

We report the development of an extrinsic self-healing coating system that shows no fluorescence from the intact coating, yellowish fluorescence in cracked regions, and greenish fluorescence in healed regions, thus allowing the separate monitoring of cracking and healing of coatings. This fluorescence monitoring self-healing system consisted of a top coating, an epoxy matrix resin containing mixed dye-loaded in single microcapsule. The dye-loaded microcapsules consisted of a poly(urea-formaldehyde) shell encapsulating a healing agent containing MAT-PDMS and styrene, a photo-initiator and a mixture of two dyes, one that fluoresces only in the solid state (DCM) and a second that fluoresces dramatically increased in the solid than solution state (4-TPAE). A mixture of the healing agent, photo-initiator and the two dyes was yellow due to fluorescence from DCM. On UV curing of this mixture, however, the color changed from yellow to green and the fluorescence intensity increased due to fluorescence from 4-TPAE in the solid state. When a self-healing coating embedded with microcapsules containing the DCM/4-TPAE dye mixture was scratched, the damaged region exhibited a yellowish color that changed to green after healing. Thus, the self-healing system reported here allows the separate monitoring of cracking and healing based on changes in fluorescence color.

scholarly journals Dual Monitoring of Cracking and Healing in Self-healing Coatings Using Microcapsules Loaded with Two Fluorescent Dyes

Molecules ◽  
2019 ◽  
Vol 24 (9) ◽  
pp. 1679 ◽  
Author(s):  
Young Kyu Song ◽  
Tae Hee Lee ◽  
Jin Chul Kim ◽  
Kyu Cheol Lee ◽  
Sang-Ho Lee ◽  
...  
Keyword(s):  
Solid State ◽  
Fluorescent Dyes ◽  
Urea Formaldehyde ◽  
Uv Curing ◽  
Coating System ◽  
Self Healing ◽  
Matrix Resin ◽  
Healing System ◽  
Fluorescence Color ◽  
Healing Agent

We report the development of an extrinsic, self-healing coating system that shows no fluorescence from intact coating, yellowish fluorescence in cracked regions, and greenish fluorescence in healed regions, thus allowing separate monitoring of cracking and healing of coatings. This fluorescence-monitoring self-healing system consisted of a top coating and an epoxy matrix resin containing mixed dye loaded in a single microcapsule. The dye-loaded microcapsules consisted of a poly(urea-formaldehyde) shell encapsulating a healing agent containing methacryloxypropyl-terminated polydimethylsiloxane (MAT-PDMS), styrene, a photo-initiator, and a mixture of two dyes: one that fluoresced only in the solid state (DCM) and a second that fluoresced dramatically in the solid than in the solution state (4-TPAE). A mixture of the healing agent, photo-initiator, and the two dyes was yellow due to fluorescence from DCM. On UV curing of this mixture, however, the color changed from yellow to green, and the fluorescence intensity increased due to fluorescence from 4-TPAE in the solid state. When a self-healing coating embedded with microcapsules containing the DCM/4-TPAE dye mixture was scratched, the damaged region exhibited a yellowish color that changed to green after healing. Thus, the self-healing system reported here allows separate monitoring of cracking and healing based on changes in fluorescence color.

scholarly journals Pressurized vascular systems for self-healing materials

2011 ◽  
Vol 9 (70) ◽  
pp. 1020-1028 ◽  
Author(s):  
A. R. Hamilton ◽  
N. R. Sottos ◽  
S. R. White
Keyword(s):  
Fracture Toughness ◽  
Vascular System ◽  
Damage Zone ◽  
Capillary Forces ◽  
Self Healing ◽  
Vascular Networks ◽  
Healing System ◽  
Healing Efficiency ◽  
Healing Agent ◽  
Reactive Fluids

An emerging strategy for creating self-healing materials relies on embedded vascular networks of microchannels to transport reactive fluids to regions of damage. Here we investigate the use of active pumping for the pressurized delivery of a two-part healing system, allowing a small vascular system to deliver large volumes of healing agent. Different pumping strategies are explored to improve the mixing and subsequent polymerization of healing agents in the damage zone. Significant improvements in the number of healing cycles and in the overall healing efficiency are achieved compared with prior passive schemes that use only capillary forces for the delivery of healing agents. At the same time, the volume of the vascular system required to achieve this superior healing performance is significantly reduced. In the best case, nearly full recovery of fracture toughness is attained throughout 15 cycles of damage and healing, with a vascular network constituting just 0.1 vol% of the specimen.

Study on Self-Healing Concrete with Pre-Embedded Healing Agent

2011 ◽  
Vol 250-253 ◽  
pp. 405-408 ◽  
Author(s):  
Ming Zhang ◽  
Feng Xing ◽  
Hong Zhi Cui ◽  
Han Lu
Keyword(s):  
Civil Engineering ◽  
The Self ◽  
Self Healing ◽  
Research Focus ◽  
Technical Problems ◽  
Healing System ◽  
Healing Agent ◽  
Smart Concrete

Self-healing concrete is a kind of smart concrete, and becoming one of research focus both in material and civil engineering field, in the paper, main self-healing methods concluded and partial technical problems of the self-healing facing, aim to these problems designed a kind of novel self-healing system, and experimental analyzed mechanism of self-healing.

scholarly journals Effect of a Healing Agent on the Curing Reaction Kinetics and Its Mechanism in a Self-Healing System

2018 ◽  
Vol 8 (11) ◽  
pp. 2241 ◽  
Author(s):  
Xianfeng Wang ◽  
Ming Zhang ◽  
Feng Xing ◽  
Ningxu Han
Keyword(s):  
Reaction Kinetics ◽  
Epoxy Resin ◽  
Reaction Order ◽  
Glycidyl Ether ◽  
Self Healing ◽  
Curing Reaction ◽  
Healing System ◽  
Mass Fractions ◽  
Healing Agent ◽  
Butyl Glycidyl Ether

Self-healing cementitious composites have been developed by using microcapsules. In this study, the effect of the healing agent on the crosslinking and curing reaction kinetics was analyzed. The effect of the diluent n-butyl glycidyl ether (BGE) on the reaction was investigated for five fractions, namely 10.0%, 12.5%, 15.0%, 17.5%, and 20.0% mass fractions to epoxy resin. The Kissinger and Crane equations were used to obtain the activation energy and reaction order with different mass fractions of diluent, as well as the kinetic parameters of the curing reaction. The optimal fraction of BGE was determined as 17.5%. Likewise, the effect of the curing agent MC120D on the reaction kinetics was investigated for 10%, 20%, 30%, 40%, and 50% mass fractions to the diluted epoxy resin. The optimal fraction was determined as 20%. The mechanism of the curing reaction with the healing agent was investigated. The infrared spectra of the cured products of 20% MC120D with BGE/E51 (0.0%, 12.5%, 15.0%, 20.0%, 100%) were analyzed. It is shown that not only the epoxy resin E-51 was cured, but also that the BGE was involved in the cross-linking reaction of the epoxy resin E-51 with MC120D.

A MICROCAPSULE TECHNOLOGY BASED SELF-HEALING SYSTEM FOR CONCRETE STRUCTURES

2013 ◽  
Vol 07 (03) ◽  
pp. 1350014 ◽  
Author(s):  
BIQIN DONG ◽  
NINGXU HAN ◽  
MING ZHANG ◽  
XIANFENG WANG ◽  
HONGZHI CUI ◽  
...  
Keyword(s):  
Urea Formaldehyde ◽  
Concrete Structures ◽  
The Self ◽  
Polymerization Reaction ◽  
Formaldehyde Resin ◽  
Self Healing ◽  
Cementitious Composite ◽  
Healing System ◽  
Healing Efficiency ◽  
Healing Agent

In the study, a novel microcapsule technology based self-healing system for concrete structures has been developed. Through situ-polymerization reaction, the microcapsule is formed by urea formaldehyde resin to pack the epoxy material, which is applied to cementitious composite to achieve self-healing effect. The experimental results revealed that the self-healing efficiency of the composite can be accessed from the recovery of the permeability and strength for the cracked cementitious specimens as the healing agent in the microcapsule acting on the cracks directly. Scanning electronic microscope (SEM/EDX) results show that the epoxy resin is released along with the cracking of the cementitious composite and prevent from cracks continued growth. Further studies show that the self-healing efficiency is affected by the pre-loading of composite, particle size of microcapsule, aging duration of healing agent and so on.

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