HYDROGEN-BONDS OF POLY[(N-ALKYL METHACRYLATE)-CO-(METHACRYLIC ACID)]SIN DILUTE-SOLUTIONS

The nature of the association of poly[(n-alkyl methacrylate)-co-(metha crylic acid)]'s (poly(RMA-co-MAA)'s) in dilute chloroform solutions wa s investigated by Fourier transform infrared (FT-IR) spectroscopy and the solution viscosity. The proportions (P-free) of free carboxyls inc reased with the length of the alkyl groups in RMA's and with the decre asing MAA composition. From the relationships between P-free and the e ffective concentration (C-eff) of carboxyls attached to the polymer ch ain, it was shown that the major substituent effects of the alkyl grou ps on the hydrogen bonds in the copolymers are the extension of the po lymer chain and the steric effect on the association between carboxyls and ester groups. Also, from the features of the shrinkage of the pol ymer chains accompanied with the intrachain association of carboxyls i t was suggested that the hydrogen bonds in the copolymers are formed c hiefly between neighboring sites along the chain.