Microencapsulation of Mercaptan Using Polycaprolactone as Shell Material Toward Self-Healing Coating Applications

Abstract

Polymer materials incorporating microencapsulated self-healing agents have a wide range of application from paint coating, anti-corrosion coatings to automotive and construction materials. In this research, microcapsules containing reactive mercaptan compound for use in self healing polymers were successfully fabricated via the oil-in-water emulsion method. We employed for the first time the UV-initiated thiol-ene reaction between an alkene-functionalized polycaprolactone and a tetrathiol compound to form the microcapsule shell. To synthesize microcapsules, the tetrathiol was used in large excess, thus maintaining inside the microcapsules as the core material. The obtained microcapsules were analyzed by Fourier Transform infrared microscopy, optical microscopy, scanning electron microscopy (SEM) and laser diffraction particle size analysis. The core was extracted by Soxhlet extraction and analyzed by 1H NMR and FTIR spectroscopy.

Electrosprayed PMMA microcapsules containing green soybean oil-based acrylated epoxy and a thiol: a novel resin for smart self-healing coatings

“…In-situ polymerization Dual capsules: (1) Diglycidyl tetrahydro-ophthalate (2) PETMP [24] 50 µm a 100 µm a -Self-healing composite Dual capsules: (1)Epoxy prepolymer (EC 157) (2) PETMP [25] 10-35 µm 5-45 µm -Self-healing composite Solvent Evaporation PETMP [26] 160 µm a -Self-healing composite epoxy resin (diglycidyl ether of bisphenol A) [32] 575 µm a -Self-healing composite Dual capsules: (33) (1) epoxy resin (DGEBPA) (2) PETMP [33] 364 µm a 334 µm a 3-6 µm Self-healing composite Budesonide and Epigallocatechin gallate (EGCG) [27] 165 nm to 1.2 µm -Coating of drug Paclitaxel [28] 600 nm-6 µm 300 nm Smart Drug Release Folic acid [29] 4.5 µm (max) -Food industry Whey protein [30] 56. The feasibility and kinetics crosslinking reaction between the healing agent and curing agent were studied by mixing AESO and TMPMP.…”

“…Ahangaran et al used PMMA as shell material for encapsulation of a mercaptan and an epoxy with low viscosity (0.50-0.60 Pa • s) by solvent evaporation method [25]. Truong et al reported microencapsulation of a reactive mercaptan compound using solvent evaporation method, they employed UV rays to initiate thiol-ene reaction to form the microcapsule's shell [26].…”