Three-Dimensional Nano-Morphology of Carbon Nanotube/Epoxy Filled Poly(methyl methacrylate) Microcapsules

M Galip Icduygu,Youssef K Hamidi,Meltem Asilturk,M Cengiz Altan,M Akif Yalcinkaya

doi:10.3390/ma12091387

M Galip Icduygu, Youssef K Hamidi + Show 3 more

Open Access

https://doi.org/10.3390/ma12091387

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Abstract

The three-dimensional nano-morphology of poly(methyl methacrylate; PMMA) microcapsules filled with carbon nanotubes (CNTs) and epoxy resin were investigated by various microscopy methods, including a novel, laser scanning confocal microscopy (LSCM) method. Initially, PMMA microcapsules containing various amounts of CNTs were synthesized by a solvent evaporation method. Scanning electron microscopy analysis showed that pore-free, smooth-surface microcapsules formed with various types of core-shell morphologies. The average size of CNT/epoxy/PMMA microcapsules was shown to decrease from ~52 μm to ~15 μm when mixing speed during synthesis increased from 300 rpm to 1000 rpm. In general, the presence of CNTs resulted in slightly larger microcapsules and higher variations in size. Moreover, three-dimensional scans obtained from confocal microscopy revealed that higher CNT content increased the occurrence and size of CNT aggregates inside the microcapsules. Entrapped submicron air bubbles were also observed inside most microcapsules, particularly within those with higher CNT content.

Highlights

Microencapsulation is a process by which droplets or small particles, often referred to as the core, are enclosed within a shell to produce micro-scale capsules [1,2,3]
In order to ensure that the fabricated PMMA microcapsules contain both epoxy and carbon nanotubes (CNTs), FTIR
Increasing CNT content was observed to increase increase the heat resistance-index. These results show that the fabricated PMMA microcapsules the heat resistance-index. These results show that the fabricated PMMA microcapsules contained both contained both epoxy and CNTs, corroborating Thermogravimetric analysis (TGA) and FTIR findings

Summary

Introduction

Microencapsulation is a process by which droplets or small particles, often referred to as the core, are enclosed within a shell to produce micro-scale capsules [1,2,3]. Microencapsulation was first introduced in the 1950s to produce carbonless copy paper from gelatin and gum arabic, which has been used commercially for many decades [4]. Interest in the microencapsulation technology has developed beyond printing, such that microcapsules are used in a large number of applications, ranging from cosmetics and food additives to chemicals [5,6] and pharmaceuticals [7,8]. Several microencapsulation techniques have been developed to effectively encapsulate a spectrum of material in gas, liquid, and solid phases. The resulting microcapsules exhibit various sizes (10–1000 μm in diameter) and shapes (ranging from simple spherical to irregular shells) [5,6,7,8,9,10]

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