Synthesis of isocyanate microcapsules and micromechanical behavior improvement of microcapsule shells by oxygen plasma treated carbon nanotubes

Abstract

In this study, we present the novel isocyanate microcapsule preparation of poly(urea-formaldehyde) (PUF) embedded with oxygen plasma treated carbon nanotubes (OPCNTs) to improve the micromechanical behavior of microcapsule shells significantly. Isophorone diisocyanate was encapsulated by PUF through in situ polymerization. PUF, PUF with ultrasonically treated CNTs, and PUF with oxygen plasma treated CNTs (OPCNTs) microcapsules were characterized via field emission-scanning electron microscopy, 3D optical microscopy, fluorescence microscopy, laser diffraction analysis, thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy and nanoindentation tests. As a result, OPCNTs modified by hydroxyl, carboxyl, and carbonyl groups, easily forming hydrogen bonds with water, could be highly dispersed in the shells of microcapsules during the thermosetting process. The particle size distributions of the microcapsules range from 10 to 200 mm with different reaction parameters. Although the CNT mass content of the OPCNTs microcapsules, as measured via TGA, is relatively small, the nanoindentation test indicated that the OPCNTs enhance the hardness and the Young's modulus of the microcapsule shells.

Dynamic postpolymerization of 3D‐printed photopolymer nanocomposites: Effect of cellulose nanocrystal and postcure temperature

“…Moreover, the reaction between CNC and MA molecules can also facilitate postpolymerization to obtain a high R max within a short time period and at low temperature . However, R max increased at 0.5% CNC and decreased at 1–4% CNC; this can be attributed to the different CNC particle size, which resulted from CNC aggregation in the MA matrix and resulted in different reaction parameters . With increasing postcure temperature, R max decreased due to the enhanced concentration of initiating macroradicals, which were resulted from thermal decomposition of the residual photoinitiator, furthermore, the existence of CNC in the polymerized nanocomposites hindered the polymerization of MA molecules resulting in decrease of R max [Fig.…”

Multilayer composite microcapsules synthesized by Pickering emulsion templates and their application in self-healing coating

“…Nevertheless, when the wrapped core material comes to be liquid isophorone diisocyanate (IPDI), the capsulation technology is severely restricted, because IPDI is a highly reactive healing reagent for one-component catalyst-free selfhealing system. [28][29][30] However, numerous hardships, including insufficient IPDI loading capability and efficiency, undesirable shape and inner/outer shell morphology of capsule, difficulty of being facilely synthesised in large quantity, etc., still remain to be solved. Yang et al 28 made the first successful attempt of IPDI encapsulation via interfacial polymerization of polyurethane (PU), and there were three other literatures that had reported the IPDI encapsulation in microcapsule till now.…”

Synthesis and properties of microencapsulated phase change material with a urea–formaldehyde resin shell and paraffin wax core

“…Moreover, it was found that the decomposition temperature of Micro‐P6 has exceeded its ambient temperature when be used in the field of cementing and buildings. Besides, the thermal stability of Micro‐P6 sample could be further improved by some modified materials, such as single and multiwalled carbon nanotubes, nanosilica, and Al 2 O 3 …”