Refractive index increments of di‐n‐alkylitaconate polymers and copolymers

Refractive index increments of 11 poly(di‐n‐alkylitaconate) polymers were determined systematically in seven organic solvents, expected to be suitable for light scattering and other solution property measurements. Of 13 solvents tried, poly(dimethylitaconate) was soluble only in 6, however higher members of the polymer series exhibit better solubility. The measured dn/dc values in butanone and ethyl‐and amylacetate are practically independent of an increase of the number of carbon atoms in the ester substituents of the monomer, however a decrease of the values for solvents with higher refractive indices can be observed. For statistical poly(styrene‐co‐di‐n‐alkylitaconate) samples the additive character of dn/dc in butanone and toluene was observed and verified from copolymer compositions determined by UV and elemental analysis.