Characterizations on Microencapsulated Sunflower Oil as Self-Healing Agent Using <i>In Situ</i> Polymerization Method

Abstract

This paper emphasizes the characterization on the microencapsulation of sunflower oil as self-healing agent. In-situ polymerization method mainly implicates in the microencapsulation process. The analysation of microencapsulated sunflower oil via prominent characterization of yield of microcapsules, microcapsules characteristics and Fourier Transmission Infa-Red Spectroscopy (FTIR). The prime optimization used was reaction time of microencapsulation process in the ranges of 2, 3 and 4 h. The higher reaction time of microencapsulation process resulted in a higher yield of microcapsules. The yield of microcapsules increases from 46 to 53% respectively by the increasing of reaction time from 2 to 4 h. The surface morphology study associating the diameter of microcapsules measured to analyse the prepared microcapsules. It was indicated that microcapsules were round in shape with smooth micro-surfaces. It was discovered that the diameter of microcapsules during microencapsulation process after 4 h reaction time was in average of 70.53 μm. This size was measured before filtering the microcapsules with solvent and dried in vacuum oven. Apparently, after filtering and drying stage, the diameter of microcapsules specifically identified under Field Emission Scanning Electron Microscopy (FESEM) showing the size of 2.33 μm may be due to the removing the suspended oil surrounded the microcapsules. Sunflower oil as core content and UF as shell of microcapsules demonstrated the proven chemical properties on characterization by FTIR with the stretching peak of 1537.99 - 1538.90 cm-1 (-H in-CH2), 1235.49 - 1238.77 cm-1 (C-O-C Vibrations at Ester) and 1017.65 - 1034.11 cm-1 (C-OH Stretching Vibrations). It was showed that sunflower oil can be considered as an alternative nature resource for self-healing agent in microencapsulation process. The characterization of microencapsulated sunflower oil using in-situ polymerization method showed that sunflower oil was viable healant to be encapsulated and incorporated in metal coating.

The Mechanical Integrity of Self-Healing Coating Embedded with Microencapsulated Vegetable Oil

“…The embedment of microencapsulated vegetable oil into coating system were proven able to perform self-healing mechanism to heal crack on the coating surface [2,[12][13][14][15][16]. Waste sunflower oil as the self-healing agent were already discovered by author [17] and this paper continued the study and emphasis the mechanical integrity analysis on the coating system to determine the improvement on the mechanical strength. Mechanical integrity analysis on coating system embedded with vegetable oil as the self-healing agent will show that nature sources able to bring future growth of green material to the next level of success and contribute to the progression of coating industries.…”

“…All the chemicals were used without any further purification. Microencapsulation of waste sunflower oil were via in-situ polymerization method [15][16][17][18]. The procedure starts with addition of 100 mL of deionized (DI) water and 10 mL of 5 wt.% of EMA in 250 ml beaker.…”

“…The coating matrix was dried, cured for 7 days and scratched with blade reaching the coating substrate. The self-healing on scratch was evaluated under Scanning Electron Microscope (SEM) (Hitachi S-3400N) [15][16][17][18]. The mechanical integrity of coating system developed with epoxy and microencapsulated waste sunflower oil were conducted by two different mechanical testing; bending test and Vickers test.…”