Nitroxide mediated radical polymerization of styrene from poly(ethylene terephthalate) and its polymer/montmorillonite nanocomposite

In this study, for the first time, a novel strategy for the synthesis of graft copolymers using polystyrene (PSt) monomer from surface modification of poly(ethylene terephthalate) PET through surface-initiated nitroxide-mediated radical polymerization was performed. For this purpose, the PET surface was first aminated by ۱,۳-diamino propane, which was used as an amination agent. Second, phenyl chloro acetylation of PET was prepared by coupling amino and hydroxyl groups with α-phenyl chloro acetyl chloride. Afterward, ۲,۲,۶,۶-tetramethyl-۱-piperidinyloxy (TEMPO) was synthesized, then ۱-hydroxy-۲,۲,۶,۶-tetramethylpiperidine (TEMPO–OH) was obtained by reduction of TEMPO with sodium ascorbate and coupled with chloroacetylated PET to obtain PET-TEMPO macroinitiator. Furthermore, the (St) monomer was grafted onto the PET surfaces through the “grafting from” technique. The obtained macroinitiator for living radical polymerization was heated in the adjacency of (St) monomer to obtain the graft copolymer (PET-g-PSt) onto the PET surfaces. Finally, PET-g-PSt/MMt nanocomposite was synthesized by the solution intercalation method. The surface combination, morphology, and thermal properties of the modified PET films were proved using various characterization methods such as transform infrared spectroscopy (FT-IR), ۱H nuclear magnetic resonance (۱H NMR), differential scanning calorimetry (DSC), thermogravimetric analysis, X-ray photoelectron spectroscopy, and termination electron microscopy (TEM).

Keywords:

Nitroxide-Mediated Radical Polymerization (NMRP) , TEMPO , Poly (ethylene terephthalate) (PET) , Surface-initiated Polymerization , graft copolymer