Abstract
High molecular weight o-cresol resins and the acetylated resins (Ac-oCR) were prepared. The dilute solution properties of Ac-oCR were determined to elucidate the nature of high molecular weight phenolic resins. The intrinsic viscosity [η] of Ac-oCR was determined in THF (good solvent) and THF/cyclohexane mixed solvent (θ-solvent). The exponent in MHS Eq. for Ac-oCR was 0.43 in THF and 0.28 in θ-solvent, respectively. Each value was much smaller than that for polystyrene. However, the values of expansion factor αη3= [η] / [η] θ for Ac-oCR in THF were equal to that for polystyrene in toluene, indicating that Ac-oCR showed the excluded volume effect and behaved like a linear polymer in good solvent.
On the other hand, the molecular weight dependence of mean-square radius of gyration <S2> for Ac-oCR agreed with that for polystyrene in both good and θ-solvent. The values of <S2>0/Xw were constant for higher molecular weight Ac-oCR samples with xw >500. This means that Ac-oCR behaves like a Gaussian chain, which is an ideal chain for linear polymer. We concluded that Ac-oCR with higher molecular weight showed linear polymeric properties such as polystyrene in solution.
