Preparation of new copolymer (polystyrene/TMSPM grafted on DDA-fractionated algerian montmorillonite) hybrid organoclay by radical copolymerization: structural study, thermal stability and hydrophobicity area

Abstract

Polystyrene/organo-Algerian montmorillonite hybrid material was prepared by radical copolymerization of styrene monomer in the presence of the double organic modified clay. Before copolymerization process, the local (Algerian) montmorillonite was sodified, fractionated (<\u20092 µm), intercaled with dodecylamine (DDA) salts and grafted by trimethoxysilylpropylmethacrylate (TMSPM). The copolymerization has occurred onto methacrylate ported by grafted silane. X-ray fluorescence results showed a successful homoionization and insersion of DDA salts onto montmorillonite. CHN microanalysis revealed the evolution of the carbon ratio during modification of MMT by DDA, grafting and copolymerization reactions. The characterization (XRD) revealed that DDA salts were intercaled onto montmorillonite galleries and part of the copolymerization was occurred in interlayer spaces of clay (intercalated structure) by increasing d001 from 12.69 Å for homoionisated clay to 15.33 Å for intercalated clay and to 23.08 Å for hybrid material. Fourier transform infrared (FTIR) spectra mainly confirmed the presence of DDA salts, the grafting of TMSPM and polystyrene polymer and increasing of hydrophobicity of clay during modifications process (intercalation, grafting and copolymerization). Thermogravimetic analysis (TGA) showed that the grafted clay sample have higher thermal stability than intercalated sodic montmorillonite. TGA revealed also that the thermal stability of prepared hybrid organoclay is greatly higher than pur polystyrene polymer (45 °C higher) and that hydrophobicityhybrid organoclay > hydrophobicitygrafted clay > hydrophobicity intercalated clay > hydrophobicityfractinated sodic clay. The copolymer was recovered by hydrofluoric acid attack, analyzed by FTIR and compared to hybrid organoclay FTIR spectra.