Synthesis of Self-Healing Thermosetting Resin Based Capsules and their Related Complexities

2015 ◽  
Vol 1119 ◽  
pp. 428-432 ◽  
Author(s):  
Ikbal Choudhury ◽  
Sudipta Halder ◽  
Abhinav Mathur ◽  
Writuparna Nath ◽  
Aniruddha Phukan
Keyword(s):  
Emulsion Polymerization ◽  
Process Parameters ◽  
Urea Formaldehyde ◽  
Solvent Evaporation ◽  
Preparation Process ◽  
Self Healing ◽  
Thermosetting Resin ◽  
Shell Wall ◽  
Bioinspired Materials ◽  
The Difference

Microencapsulation forms an integral part in synthesizing bioinspired materials. This paper focuses on elaborating the problems faced in encapsulation of DGEBA microcapsules in PMMA and urea formaldehyde shell wall. The preparation process and the process parameters affecting the microcapsule property are discussed. The difference between the microcapsules prepared using emulsion polymerization and that by solvent evaporation has been discussed. The size, shape and morphology of the microcapsules was characterized using FESEM technique. It was observed that the agglomeration of the microcapsules can be prevented by changing the concentration of the emulsifier. However, in case of urea formaldehyde encapsulation chunks of pre-polymer resulted in agglomeration of the nanosized capsules even if higher concentration of emulsifier was implemented.

scholarly journals Synthesis of Urea Formaldehyde microcapsules containing linseed oil for self-healing coating

2016 ◽  
Vol 19 (4) ◽  
pp. 50-57
Author(s):  
Ha Thi Thai La ◽  
Tinh Dinh Cong Vo
Keyword(s):  
Emulsion Polymerization ◽  
Sodium Dodecyl Sulphate ◽  
Linseed Oil ◽  
Urea Formaldehyde ◽  
Sodium Dodecyl ◽  
Agitation Rate ◽  
Self Healing ◽  
The Core ◽  
Average Size

Microcapsules had Urea Formaldehyde (UF) shell and linseed oil core were investigated manufacture. Synthesis UF shell of Microcapsules was experimented by emulsion polymerization and pH was only adjusted once by mixer of Resorcinol / Amoni Clorua. Content of Urea and emulsifiler Sodium Dodecyl Sulphate, pH, agitation rate were investigated. This research shows that the linseed oil (core) is disintegrated at 1,500 rpm in pH = 5.5 with 1.2% (w/w) Sodium Dodecyl Sulphate. In addition, the combination of Urea used in order to create the shell about 40% (w/w) linseed oil and Formaldehyde are suitable. The microcapsules products have the average size less 100 μm. Besides that, the content of the linseed oil in the core is about 87% (w/w)take the advantage to use in self-healing coating.

scholarly journals Healing Efficiency of CNTs-Modified-UF Microcapsules That Provide Higher Electrical Conductivity and EMI Shielding Properties

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2753
Author(s):  
Maria Kosarli ◽  
Anastasia Polymerou ◽  
Georgios Foteinidis ◽  
Christos Vazouras ◽  
Alkiviadis S. Paipetis
Keyword(s):  
Thermal Stability ◽  
Electrical Conductivity ◽  
Electrical Properties ◽  
Electromagnetic Interference ◽  
Urea Formaldehyde ◽  
Conductive Network ◽  
Self Healing ◽  
Shell Wall ◽  
Healing Efficiency ◽  
Emi Se

In this study, the effect of the addition of multi-walled carbon nanotubes (MWCNTs), at three percentages, into the urea-formaldehyde (UF) shell-wall of microcapsules on the healing efficiency is reported. The modified shell-wall created a conductive network in semi-conductive epoxies, which led to an improvement of the electromagnetic interference shielding effectiveness (EMI SE); utilizing the excellent electrical properties of the CNTs. The microcapsule’s mean diameter and shell wall were examined via scanning electron microscopy (SEM). Thermal stability was evaluated via thermogravimetric analysis (TGA). The healing efficiency was assessed in terms of fracture toughness, while the electrical properties were measured using impedance spectroscopy. The measurements of the EMI SE were carried out in the frequency range of 7–9 GHz. The derived results indicated that the incorporation of the CNTs resulted in a decrease in the mean size of the microcapsules, while the thermal stability remained unchanged. In particular, the introduction of 0.5% w/v CNTs did not affect the healing efficiency, while it increased the initial mechanical properties of the epoxy after the incorporation of the self-healing system by 27%. At the same time, it led to the formation of a conductive network, providing electrical conductivity to the epoxies. The experimental results showed that the SE increased on average 5 dB or more after introducing conductive microcapsules.

scholarly journals Influence of the SolubleInsoluble Ratios of Cyclodextrins Polymers on the Viscoelastic Properties of Injectable ChitosanBased Hydrogels for Biomedical Application

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 214 ◽  
Author(s):  
Carla Palomino-Durand ◽  
Marco Lopez ◽  
Frédéric Cazaux ◽  
Bernard Martel ◽  
Nicolas Blanchemain ◽  
...  
Keyword(s):  
Viscoelastic Properties ◽  
Biomedical Applications ◽  
Structural Integrity ◽  
Biomedical Application ◽  
Water Soluble ◽  
Self Healing ◽  
Indirect Contact ◽  
Polyelectrolyte Complexes ◽  
Anionic Polymers ◽  
The Difference

Injectable pre-formed physical hydrogels provide many advantages for biomedical applications. Polyelectrolyte complexes (PEC) formed between cationic chitosan (CHT) and anionic polymers of cyclodextrin (PCD) render a hydrogel of great interest. Given the difference between water-soluble (PCDs) and water-insoluble PCD (PCDi) in the extension of polymerization, the present study aims to explore their impact on the formation and properties of CHT/PCD hydrogel obtained from the variable ratios of PCDi and PCDs in the formulation. Hydrogels CHT/PCDi/PCDs at weight ratios of 3:0:3, 3:1.5:1.5, and 3:3:0 were elaborated in a double–syringe system. The chemical composition, microstructure, viscoelastic properties, injectability, and structural integrity of the hydrogels were investigated. The cytotoxicity of the hydrogel was also evaluated by indirect contact with pre-osteoblast cells. Despite having similar shear–thinning and self-healing behaviors, the three hydrogels showed a marked difference in their rheological characteristics, injectability, structural stability, etc., depending on their PCDi and PCDs contents. Among the three, all the best above-mentioned properties, in addition to a high cytocompatibility, were found in the hydrogel 3:1.5:1.5. For the first time, we gained a deeper understanding of the role of the PCDi/PCDs in the injectable pre-formed hydrogels (CHT/PCDi/PCDs), which could be further fine-tuned to enhance their performance in biomedical applications.

scholarly journals Effect of Urea-Formaldehyde (UF) with Waterborne Emulsion Microcapsules on Properties of Waterborne Acrylic Coatings Based on Coating Process for American Lime

2020 ◽  
Vol 10 (18) ◽  
pp. 6341 ◽  
Author(s):  
Xiaoxing Yan ◽  
Wenting Zhao ◽  
Xingyu Qian
Keyword(s):  
Urea Formaldehyde ◽  
Paint Film ◽  
Coating Process ◽  
Self Healing ◽  
Waterborne Coatings ◽  
Aging Resistance ◽  
Acrylic Coatings ◽  
Waterborne Emulsion ◽  
The Impact ◽  
Good Coating

The purpose of this paper is to explore the effect of urea-formaldehyde (UF) with waterborne emulsion microcapsules on the optical, mechanical and aging resistance properties of waterborne coatings from the perspective of coating process. In this paper, the microcapsules were prepared with UF resin as the wall materials and waterborne emulsion as the core materials. Based on the coating process, the optical, mechanical and aging resistance properties of the waterborne acrylic coatings with microcapsules for American lime were tested. The good coating process is three layers of primer, two layers of topcoat, and adding microcapsules into primer. The results showed that the coating process had little effect on the color difference of the paint film with microcapsules, the gloss of the paint film prepared by the good coating process was basically not changed, and the mechanical properties of the paint film were good. At this time, the hardness grade of the paint film was 3H, the adhesion was grade 0, the impact resistance was 110.0 N·cm−2, and the elongation at break was 29.7%. The microcapsules added to the primer had better liquid resistance than those added to the topcoat. The paint film had good stability and aging resistance, and could inhibit the generation of microcracks to a certain extent. The paint film prepared by the good coating process had better comprehensive performance. This work provides a technical reference for self-healing of the waterborne coatings on American lime.

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