Fundamental investigations of the free radical copolymerization and terpolymerization of maleic anhydride, norbornene, and norbornene tert-butyl ester: In-situ mid-infrared spectroscopic analysis

Various synthetic factors that affect the molecular weight, yield, and comp osition of maleic anhydride (MAH), norbornene (Nb), and tert-butyl 5-norbor nene-2-carboxylate (Nb-TBE) terpolymers were investigated. Real-time monito ring via in-situ FTIR spectroscopy of co- and terpolymerizations of MAH wit h N-b and N-b-TBE was utilized to evaluate the observed rates of varying Nb /NTb-TBE monomer feed ratios. Pseudo-first-order kinetic analysis indicated that the observed rate of reaction (Ie L,) was a strong function of the Nb /Nb-TBE ratio with a maximum of 6.68 < 10(-5) s(-1) for a 50/0/50 Nb/NTh-TB E/MAH monomer ratio and a minimum of 1.13 x 10(-5) s(-1) for a 0/50/50 Nb/N Tb-TBE/MA-H ratio. In addition, polymer yields were also observed to be a f unction of the Nb/Nb-TBE ratio and also decreased with increasing Nb-TBE. S ampling of an Nb/NTb-TBE/MAH (25/25/50 mole ratio) terpolymerization and su bsequent analysis using H-1 NMR indicated that the relative rate of N-b inc orporation is approximately 1.7 times faster than Nb-TBE incorporation. Als o, the observed rate constant of 4.42 x 10(-5) s(-1) calculated using H-1 N MR agreed favorably with the k(obs) determined via in-situ FTIR (3.83 x 10( -5) s(-1)). Terpolymerizations in excess Nb-TBE and in the absence of solve nt resulted in relatively high molecular weight materials (M > 20 000) and provided a potential avenue for control of the Nb/N-b-TBE incorporation int o the resulting materials.