ELSEVIER zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Polymer Degwda~ion and Sfahi1rt.v 60 (1998) 317-320 8 1998 Elsevier Science Limited. All rights reserved Printed in Northern Ireland zyxwvutsrqp PII: SO141-3910(97)00085-2 0141.3910/98/$19.00 Investigation of the thermal degradation and stability of copolymers of 2-acrylamido-2- methylpropanesulphonic acid and methyl methacrylate zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJ Y. A. Aggour zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLK Mansoura University, Faculty of Science, Chemistry Department, Demiatta, Egypt (Received 3 January 1997; accepted 17 March 1997) Copolymers of 2-acrylamido-2-methylpropanesulphonic acid (AMPS) and methyl methacrylate (MMA) were prepared. Thermal behaviour was studied by TG and DTG methods. Incorporation of more comonomer units, at various compositions, results in a copolymer more stable than the AMPS homopolymer. Decomposition of the copolymers involves the formation of anhydrides, the majority of which involve six-membered cyclic anhydride rings. Further heating results in the formation of a highly aromatic char at the higher temperatures. The apparent activation energies of decomposition of the homo- and copolymers were established. 0 1998 Elsevier Science Limited. All rights reserved 1 INTRODUCTION Many copolymers involving methyl methacrylate (MMA) as one of the monomer pair have been studied. The degradation behaviour varies greatly according to the nature of the comonomer.1-3 Ion- containing polymers are of great academic and industrial interest. The introduction of ionic groups into polymeric materials alters the polymer morphology, and consequently the physical and chemical properties.h6 Recently, 2-acrylamido-2-methylpropanesul- phonic acid (AMPS) was used successfully in pre- paration of ionic hydrogels and polymer complexes. 7,8 Copolymers of AMPS with acryla- mide and 2-(dimethylamino) ethyl acrylate have been studied in detail.9T’0 Continuing work to pre- pare and characterize ion-containing polymers of AMPS and MMA is described in this paper, in which thermal stability and degradation of such polymers is discussed. 2 EXPERIMENTAL 2.1 Materials AMPS (Merck) was recrystallized from methanol. MMA (BDH Chemicals Ltd) was degassed and 317 twice distilled on a vacuum line, dried over CaH2 and kept below - 18°C. Potassium persulphate (BDH Ltd) was recrystallized from deionized water and stored in a vacuum desiccator. 2.2 Preparation of polymers and copolymers The homopolymers and copolymers were prepared using R&08 as the initiator (3 mol%) and pure water as the solvent. Four different compositions of the copolymers with 50, 33, 25 and 20mol% of AMPS units were prepared. Polymerizations were carried out at 60°C for 8 h. The polymers were precipitated into ethanol, filtered off and dried under vacuum. 2.3 Infrared spectroscopy Infrared (IR) spectra were recorded on a JASCO FT/IR spectrometer. Polymers were examined as KBr discs. 2.4 Thermal methods of analysis 2.4.1 Thermogravimetry Thermogravimetry (TG) measurements were made using a DuPont 950 thermobalance. Samples (10 mg) were heated at 10°C mini in a flowing nitrogen atmosphere (70 ml mini) in a boat-shaped