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

Abstract

Gamma irradiation was investigated as a triggering stimulus for the activation of poly(methyl methacrylate) (PMMA) microcapsules. PMMA was exposed to varying doses of irradiation and analyzed by differential scanning calorimetry, size‐exclusion chromatography, and nuclear magnetic resonance. It was found that the glass transition temperature (Tg) of the polymer decreases at low irradiation doses. Additionally, Tg can be physically adjusted by adding a plasticizer, and both kinds of microcapsules were successfully prepared with non‐plasticized and plasticized PMMA shell. Finally, impermeable microcapsules were shown to become permeable after irradiation and release an encapsulated cross‐linker, which enables the remotely controlled formation of polydimethylsiloxanes in traditionally unavailable places. Therefore, the activation method has significant implications for industrial application. Copyright © 2015 John Wiley & Sons, Ltd.

Synthesis of PMMA Nanoparticles Loaded with Geopropolis Extract from the Brazilian Stingless Bee Melipona quadrifasciata Lepeletier, 1836 by Miniemulsion Polymerization

“…These results are consistent with the spectra obtained by Kostrzewska et al for PMMA. [ 57 ] The spectrum for PMMA obtained in the formulation containing 10% of propolis shows only one additional peak that can be attributed to propolis, with a chemical displacement of 1.573 ppm. However, due to the low intensity, it is believed that this signal can be attributed to the R 3 ‐CH groups.…”

Synthesis of inositol‐based star polymers through low ppm ATRP methods

“…In the 1 H NMR spectrum (Fig. ) of Ino‐(PDEGMA 51 ‐ b ‐PMMA 30 ‐Br) 6 star block copolymer (Table , entry 7), the chemical shifts, 0.55–1.38, 1.40–2.15, and 3.51–3.90 ppm, are primarily attributable to the –CH 3 (α′), –CH 2 – (β′), and –OCH 3 (f) of PMMA units, denoting the inherence of PMMA segments …”

“…7) of Ino-(PDEGMA 51 -b-PMMA 30 -Br) 6 star block copolymer (Table 1, entry 7), the chemical shifts, 0.55-1.38, 1.40-2.15, and 3.51-3.90 ppm, are primarily attributable to the -CH 3 (α 0 ), -CH 2 -(β 0 ), and -OCH 3 (f) of PMMA units, denoting the inherence of PMMA segments. [34,36,[105][106][107][108] Arm length of vitamin B 8 -based star polymers…”

Magnetically activated microcapsules as controlled release carriers for a liquid PDMS cross-linker

“…Magnetic microcapsule reactivity was investigated by means of rheology. The microcapsules were mixed with the PDMS premix with a mass ratio 1:10, which was shown previously to be the suitable ratio to obtain a strong low-loss tangent (Tanδ < 0.1 @ 1 Hz) network [27]. The PDMS premix consisted of the vinyl-terminated poly(dimethylsiloxane) DMS-V31 with 50 ppm of a platinum catalyst.…”