Preparation and Characterization of Silicone Liquid Core/Polymer Shell Microcapsules via Internal Phase Separation

Abstract

Microcapsules with a silicone liquid core surrounded by a polymeric shell were synthesised through the controlled phase separation. The dispersed silicone phase consisted of the shell polymer PMMA, a good solvent for the PMMA (dichloromethane, DCM) and a poor solvent (methylhydrosiloxane dimethylsiloxane) for the PMMA. The morphology of the PMMA microcapsules was investigated by ATR‐FTIR and by optical microscopy. Microcapsules were prepared with different emulsifiers and different concentrations of acetone and PMMA in the oil phase. The thermal stability of the PMMA microcapsule and the content of the silicone oil core were assessed by TGA. 1H‐NMR spectroscopy and an extraction method were also used to determine the content of the silicone liquid core in the microcapsules.

New Polyurethane/Docosane Microcapsules as Phase‐Change Materials for Thermal Energy Storage

“…So, FT‐IR spectrum of the microencapsulated n ‐docosane by PU shell shows a series of strong absorption bands that correspond to both the PCM core and shell components of the microcapsules. There is no evidence of hydroxyl groups (OH) in the region of 3300 cm −1 from the emulsifier,19 which means it does not remain in the obtained microcapsules.…”

Preparation of silica/epoxy hybrid polymers as sealing layers on ceramic coatings and their stability study upon thermal treatment

“…However, their corresponding Si contents are quite different. With the incorporation of silicone compounds in the hybrids, the phase separation and aggregation of congenial species become more and more serious, resulting in the formation of some big powders enriched Si compounds which may blocking some internal defects and thus the restriction of more Si reaching the boundary areas adjacent to the substrate, this may be the reason that the hybrid containing 20% silica contained very low Si in these areas compared to that of the hybrid containing 15% silica in Figure [also refer Figure S3 (Supporting Information), the line scanning based on cross‐sectional images of samples for (a) 15% and (b) 20%]. The hybrid sealants containing silica at around 10–15% can infiltrate deeper sealing depth for the ceramic coatings which provide much more effective protection to the carbon steel upon heating.…”

Controlled release in hard to access places by poly(methyl methacrylate) microcapsules triggered by gamma irradiation

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“…Poly(methyl methacrylate) (PMMA) has been used widely as a shell material for encapsulating liquid compounds . PMMA is brittle and hard below the glass transition temperature (T g ), but it becomes soft and flexible at higher temperatures.…”