Adnan Kurt

Thermal Degradation and Synthesis of Block Copolymers of Styrene and n-Butyl Methacrylate by Atom Transfer Radical Polymerization

Abstract Poly(n-butyl methacrylate) (PnBMA)-b-polystyrene (PS) (diblock), PnBMA-b-PS, and PnBMA-b-PS-b-PnBMA (triblock copolymers) were synthesized by atom transfer radical polymerization (ATRP), using PnBMA and PnBMA-b-PS with C-Br-end-group as macroinitiators. The diblock and triblock copolymers were characterized by 1H-NMR, FT-IR spectroscopy, and differential scanning calorimetry (DSC). The molecular weight and molecular weight distributions were obtained by gel permeation chromatography (GPC). Polymerization was controlled up to a molecular weight of 46,200, and the polydispersity index was 1.33. The experimental results showed that the polymerization was controlled/living. The thermal degradation behavior of the block copolymers was studied using thermogravimetry (TG) and a single line vacuum system consisting of a degradation tube with a condenser for product collection and a liquid nitrogen trap (−196°C). The block copolymers were heated from ambient temperature to 500°C. The products of degradation were collected at two different fractions, which are cold ring fraction (CRF) and volatile liquid fraction (VLF) trapped at −196°C. All the fractions of diblock and triblock copolymers were investigated by means of IR, 1H-NMR, and GC-MS. In this study, n-butyl methacrylate and styrene are given as major products of degradation. On the other hand, the most important minor products are benzene, ethyl benzene, ethyl methacrylate, and toluene.

Characterization and Synthesis of Three‐Armed Copolymers of Phenoxycarbonylmethyl Methacrylate and Ethyl Methacrylate Via Atom Transfer Radical Polymerization

1,3,5‐(2′‐Bromo‐2′‐methylpropionato)benzene was used as a three‐functional initiator in the synthesis of three‐armed star polymer of phenoxycarbonylmethyl methacrylate (PCMMA) and its copolymers with ethylmethacrylate (EMA) via the atom transfer radical polymerization (ATRP) with a Cu(I)Br/2,2′‐bipyridine catalitic system at 90°C. The homo‐ and copolymers were characterized by FT‐IR, 1H and 13C NMR techniques. The compositions of the copolymers were calculated from 1H‐NMR spectra. The diblock copolymer of poly(PCMMA‐b‐EMA) synthesized using poly(PCMMA) macroinitiator and Cu(I)Br/bpy catalitic system showed an inefficient polymerization of ethylmethacrylate with low molecular weight and higher polydispersity. The molecular weight and molecular weight distribution were obtained by Gel Permeation Chromatography (GPC). For this copolymerization system, their monomer reactivity ratios were obtained by using both Kelen‐Tüdös and Fineman‐Ross equations. The thermal behavior of three‐armed poly(PCMMA) and its copolymers were studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Three‐armed poly(PCMMA) heated to 270°C was characterized by GPC.

Synthesis and Characterization of Coumarin Derived Copolymers

Mevcut calismada, kumarin turevli yeni bir monomer olan 3-benzoil kumarin-7-il-metakrilat (BKMA) monomerinin metil metakrilat (MMA) ile farkli bilesimlerde bir seri kopolimeri hazirlandi. Bu amacla serbest radikal polimerizasyon yontemi kullanildi. Spektral karakterizasyonlar FTIR ve 1 H-NMR teknikleri ile basarildi. Kopolimer sistemlerinin bilesimleri 1 H-NMR spektrumlarindan belirlendi. DSC analizinden kopolimer bilesimindeki BKMA orani %23 seviyesine dustugunde camsi gecis sicakliginda 179 o C’den 165 o C’ye bir azalis goruldu. Poli(BKMA) homopolimeri ve %54 BKMA bilesimli kopolimerin TGA analizinde her iki polimer icin baslangic bozunma sicakliklari sirasiyla 321 o C ve 311 o C olarak kaydedildi.