Thermal degradation of methyl. methacrylate polymers functionalized by phosphorus-containing molecules - I. TGA/FT-IR experiments on polymers with the monomeric formula CH2C(CH3)C(O)OCHRP(O)(OC2H5)(2) (R=H, (CH2)(4)CH3, C6H5Br, C10H7)

The thermal behaviour of methyl methacrylate polymers (PMMA) prepared from phosphorus-containing monomers: CH2C(CH3)C(O)OCHRP(O)(OC2H5)(2) (R=H, (CH2)(4)CH3, C6H5BT, C10H7) was investigated by thermal gravimetric analysis (TGA) coupled with on-line FT-IR analysis of evolved gases. Four homopolymers and two MMA/functionalized-MMA copolymers were studied. They exhibited a thermal behaviour largely different from that encountered for PMMA. Particularly, the results revealed a major and common degradation stage near 300 degreesC leading to diethyl phosphite HPO(OC2H5)(2) or diethyl phosphonate RPO(OC2H5)(2), aldehyde RCHO, CO, CO2 and ethylene C2H4. Functicanalization introduces high temperature degradation stages (above 750 degreesC) and weak points in the polymeric chain leading to a complete cracking of the polymer as no monomer molecules were found during the degradation, in contrast to PMMA. A first evaluation of the fire retardation properties of the polymers was performed by determining the limiting oxygen index (LOI). (C) 2000 Elsevier Science Ltd. All rights reserved.