ABSTRACT:The reaction of poly(allyl azide) (PAA; number-average molecular weight ϭ 1800 g/mol) with N-phenyl maleimide, 4,4Ј-bis(maleimidodiphenyl) ether, 4,4Ј-(bismaleimidodiphenyl) sulfone, and 1,6-bismaleimido hexane is described in this article. As indicated by Fourier transform infrared studies, the azido group reacted with the highly electron-deficient olefinic bond of N-phenyl maleimide or bismaleimides in a 3 ϩ 2 cycloaddition reaction under mild reaction conditions. The curing of PAA with bismaleimides (10 -30 phr) was monitored with differential scanning calorimetry. In freshly prepared samples of PAA and bismaleimides, a broad exothermic transition was observed in the temperature range of 150 -280°C and could be attributed to the loss of N 2 from PAA and the curing of bismaleimides. The heat of the exothermic reaction (⌬H) depended on the structure and composition and was in the range of 800 -1413 J/g. Isothermal heating in an air oven at 40°C (2 days) followed by 60°C (5-6 days) resulted in the conversion of a sticky, viscous liquid into an elastic, nonsticky material. No significant difference in the ⌬H values of uncured and cured samples was observed, and this indicated the reaction of fewer azido groups with the bismaleimides (dipolarophiles). In the thermogravimetry traces, a mass loss was indicated in the temperature range of 130 -280°C due to the loss of nitrogen from the azido group.

ABSTRACT:The article describes the preparation of cast copolymer sheets of methyl methacrylate with varying mole fractions of N-(p-methoxyphenyl) itaconimide/ N-(2-methoxy-5-chlorophenyl) itaconimide/N-(3-methoxy-5-chlorophenyl) itaconimide monomers by bulk copolymerization using azobisisobutyronitrile as an initiator. The effect of incorporation of varying mole fractions of N-arylsubstituted itaconimides in poly(methyl methacrylate) (PMMA) backbone on the thermal, optical and physicomechanical properties of cast acrylic sheets were evaluated. The glass transition temperature and the thermal stability increased with increasing amounts of itaconimides in the polymer backbone. An increase in tensile strength, flexural strength, and storage modulus was also observed. The impact strength decreased marginally upon incorporation of imides into the polymer backbone. A slight decrease in the transparency and a significant increase (4-50%) in the haze was observed. The chemical resistance of PMMA remains unaffected by copolymerization.

We report synthesis of potential initiators1a-Br,2a-Br, and3a-Br for the ATRP ofN-phenylitaconimide and MMA. We find (i) good agreement between experimentally determined and calculatedKATRPvalues (ii)3a-Br performs better than the commercially available initiator.

ABSTRACT:The article describes the synthesis and characterization of N- (4-methoxy-3-chlorophenyl) itaconimide (MCPI) and N- (2-methoxy-5-chlorophenyl) itaconimide (OMCPI) obtained by reacting itaconic anhydride with 4-methoxy-3-chloroanisidine and 2-methoxy-5-chloroanisidine, respectively. Structural and thermal characterization of MCPI and OMCPI monomers was done by using 1 H NMR, FTIR, and differential scanning calorimetry (DSC). Copolymerization of MCPI or OMCPI with methyl methacrylate (MMA) in solution was carried out at 60°C using AIBN as an initiator and THF as solvent. Feed compositions having varying mole fractions of MCPI and OMCPI ranging from 0.1 to 0.5 were taken to prepare copolymers. Copolymerizations were terminated at low percentage conversion. Structural characterization of copolymers was done by FTIR, 1 H NMR, and elemental analysis and percent nitrogen content was used to calculate the copolymer composition. The monomer reactivity ratios for MMA-MCPI copolymers were found to be r 1 (MMA) ϭ 0.32 Ϯ 0.03 and r 2 (MCPI) ϭ 1.54 Ϯ 0.05 and that for MMA-OMCPI copolymers were r 1 (MMA) ϭ 0.15 Ϯ 0.02 and r 2 (OMCPI) ϭ 1.23 Ϯ 0.18. The intrinsic viscosity [] of the copolymers decreased with increasing mole fraction of MCPI/or OMCPI. The glass transition temperature as determined from DSC scans was found to increase with increasing amounts of OMPCI in copolymers. A significant improvement in the char yield as determined by thermogravimetry was observed upon copolymerization.

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