Encapsulation of organomodified montmorillonite with PMMA via in situ SR&NI ATRP in miniemulsion

Abstract

Encapsulation of organomodified montmorillonite within poly (methyl methacrylate) via in situ atom transfer radical polymerization with simultaneous reverse and normal initiation system (SR&NI ATRP) was successfully performed. Miniemulsion polymerization technique has been employed for its abundant advantages to encapsulate inorganic materials. Successful SR&NI ATRP was carried out using 4,4′-dinonyl-2,2′-bipyridine (dNbPy) as a hydrophobic ligand and cetyltrimethylammonium bromide (CTAB) as an effective cationic surfactant at high temperatures. Homogeneous distribution of droplets and particles with sizes in the range of around 170 nm was evaluated by dynamic light scattering (DLS) analysis. Final monomer conversion and molecular weight were determined by gravimetry and size exclusion chromatography (SEC) respectively. By increasing nanoclay content, conversion and molecular weight of nanocomposites decreased. Meanwhile, an increase in PDI values was also observed. X-ray diffraction (XRD) analysis results display organoclay layers disordered and delaminated in the polymer matrix. Thermal stability improvement of all the nanocomposites in comparison with the neat polymer was revealed by thermogravimetric analysis (TGA). Homogeneous distribution of spherical particles with sizes in the range of 170 nm was demonstrated by scanning electron microscopy (SEM) images. These results are complied with the DLS results. Transmission electron microscopy (TEM) image display a dispersion of partially exfoliated clay stacks in the matrix of PMNM 2.

Spherical mesoporous silica nanoparticles/tailor-made polystyrene nanocomposites by in situ reverse atom transfer radical polymerization

“…MCM 41 nanoparticles as an impurity can increase chain transfer and termination reactions of propagat ing radicals, and therefore broadens molecular weight distribution of the resultant polymers [39,40]. Color change of reaction media during polymerization (from light green to light brown) is convenient evidence of ATRP equilibrium establishment [10,41,42]. Increasing PDI values from 1.41 to 2.07 and decreas ing of molecular weights and also conversion depends on the nature of MCM 41 nanoparticles.…”

INTRODUCTION OF A DOUBLE BOND CONTAINING MODIFIER ON THE SURFACE OF MCM-41 NANOPARTICLES: APPLICATION FOR SR&NI ATRP OF STYRENE

“…In overall, SR&NI technique opens a practical synthetic path to synthesize tailor-made polymers with various compositions and architectures. 34,35 General procedure for synthesis of well-de¯ned polystyrene chains via SR&NI ATRP in the presence of modi¯ed MCM-41 nanoparticles is illustrated in Scheme 2.…”

Encapsulation of Tandem Organic Luminescence Solar Concentrator With Optically Transparent Triple Layers of SiO2/Epoxy/SiO2

“…Because of its extremely fast curing time at room temperature and ultra-low water-oxygen permeability as well as strong UV absorption, UV-cured epoxy has been widely selected as a base material for encapsulating organic optoelectronic devices, such as organic light emitting devices (OLEDs) and organic solar cells (OSCs) [33]- [36]. In addition, UV-cured epoxy has extensively been used for bonding building materials, such as the transparent safety glass windows, due to its ultra-high transparency (exceeding 80%), strong glutinosity and long lifetime.…”