سال انتشار: ۱۳۸۷

محل انتشار: دومین کنگره بین المللی علوم و فناوری نانو

تعداد صفحات: ۲

نویسنده(ها):

M Abbasian – Payame Noor University of Tabriz, Tabriz-Iran
M Jaymand –
S Esmaeily Shoja – Islamic Azad University, Bonab branch, Bonab-Iran
M Adeli – Khorram Abad University, Khorram Abad –Iran

چکیده:

Syndiotactic polystyrene (s-PS) has received considerable attention because it is regarded as a new low-cost engineering polymer with various desirable properties, such as high melting temperature (270 °C), fast crystallization rate, low dielectric constant, low permeability to gases, and good chemical resistance. Nanoscaled polymer/clay hybrids, called nanocomposites, are superior to conventional microcomposites in strength, stiffness, flame retardancy, and barrier properties. The main advantage of nanocomposites, however, is that the enhanced mechanical properties can be obtained with only a small amount of clay because of the large contact area between the polymer and the clay. In addition, the layered structure of clay with a high aspect ratio provides outstanding barrier properties that could not appear in polymer composite filled with glass fiber [1,2]. Nanocomposites have been synthesized by various methods, including solution intercalation, in situ polymerization, or melt intercalation, for many polymeric systems ranging from thermoplastic polymers to thermosetting ones. Among the preparation methods, melt intercalation is considered to be the most promising approach for the fabrication of nanocomposites because of its versatility, its compatibility with polymer-processing equipment, and its environmental friendliness because of the absence of any solvent. The microstructure of synthesized polymer/clay nanocomposites can be classified into two groups according to the dispersed state of clay layers in the matrix polymer: intercalated structures or exfoliated structures.The present work is design to synthesizes sPS then, sPS-graft copolymers by utilizing the ATRP of methacrylates monomers (e.g., MMA) or atactic polystyrene from α-phenyl chloroacetylated sPS macroinitiator. The partially alpha-phenyl chloroacetylated syndiotactic polystyrene macroinitiator was prepared from the acid-catalyzed halogenation reaction of syndiotactic polystyrene, which was synthesized in a heterogeneous process with α-phenyl chloroacetyl chloride and anhydrous aluminum chloride in carbon disulfide via Friedel–Crafts acylation reaction [3,4]. Modified syndiotactic polystyrene (MMA- s-PS)/montmorillonite nanocomposites was synthesized under static melt-intercalation conditions in the absence of high shear rates or solvents. Upon nanocomposite formation, s-PS exhibited an improvement in the thermal stability in comparison with neat s-PS, and the -crystal form of s-PS became dominant. The crystallizability and thermal properties of these nanocomposites were determined by differential scanning calorimetry (DSC) analysis and thermogravimetric analysis (TGA).