SR&amp;NI Atom Transfer Radical Random Copolymerization of Styrene and Methyl Methacrylate: Incorporation of Diatomite Platelets

Khezrollah Khezri,Hassan Alijani,Yousef Fazli

doi:10.17344/acsi.2018.4331

Abstract

Mesoporous diatomite platelets were employed to prepare various random poly (styrene-co-methyl methacrylate)/diatomite composites by in situ simultaneous reverse and normal initiation technique for atom transfer radical random copolymerization (SR&NI ATRP) technique. Nitrogen adsorption/desorption isotherm, SEM and TEM were employed for evaluating some inherent properties of the pristine diatomite platelets. Conversion and molecular weight determinations were carried out using GC and SEC respectively. Addition of 3 wt% diatomite platelets leads to increase of conversion from 76 to 92%. Molecular weight of poly (styrene-co-methyl methacrylate) chains increases from 12893 to 14907 g mol-1 by addition of 3 wt% mesoporous diatomite; however, polydispersity index values increases from 1.18 to 1.44. Copolymers composition was evaluated using 1H NMR spectroscopy. Increasing thermal stability of the nanocomposites is demonstrated by TGA. Differential scanning calorimetry shows an increase in glass transition temperature from 67.6 to 73.4 °C by adding 3 wt% of mesoporous diatomite platelets.

Highlights

During the last decades, polymer based nanocomposites have attracted much attention in the industrial and academia.[1,2] Addition of low volume of nano-filler in the polymer matrix results in considerable improvements in several properties.[2,3] Nanocomposites as a novel class of materials present unique features that are not shared by traditional composites
Nanocomposites can be categorized into three main types depending on the number of nanometer regimes of the dispersed filler(s); a) three dimensions are in the order of nanometers such as spherical silica nanoparticles. b) two dimensions are in the nanometer scale such as nanotubes or whiskers
In situ SR&NI atom transfer radical polymerization (ATRP) of styrene and methyl methacrylate in the presence of 3 wt% of mesoporous diatomite platelets leads to increment of conversion and molecular weight from 76 to 92% and 12893 to 14907 g mol–1 respectively

Summary

Introduction

Polymer based nanocomposites have attracted much attention in the industrial and academia.[1,2] Addition of low volume of nano-filler in the polymer matrix results in considerable improvements in several properties (such as thermal and mechanical properties).[2,3] Nanocomposites as a novel class of materials present unique features that are not shared by traditional composites. Nanocomposites can simultaneously present useful properties of organic phase (e.g., flexibility, ductility, and processability) and nano-inorganic phase (e.g., rigidity and thermal stability).[4,5] Nanocomposites can be categorized into three main types depending on the number of nanometer regimes of the dispersed filler(s); a) three dimensions are in the order of nanometers such as spherical silica nanoparticles. C) one dimension in the nanometer range such as clay platelets.[6,7] Melt intercalation, solution blending, and in situ polymerization are three famous pathways to prepare polymer nanocomposites that the latter consists of polymerization of monomer(s) in the presence of nano-fillers.[8,9] Nanocomposites can simultaneously present useful properties of organic phase (e.g., flexibility, ductility, and processability) and nano-inorganic phase (e.g., rigidity and thermal stability).[4,5] Nanocomposites can be categorized into three main types depending on the number of nanometer regimes of the dispersed filler(s); a) three dimensions are in the order of nanometers such as spherical silica nanoparticles. b) two dimensions are in the nanometer scale such as nanotubes or whiskers.

Methods

Results

Conclusion