The kinetics of isothermal anionic homopolymerization of ss-myrcene (MYR) and 4-methylstyrene (4MS) in cyclohexane, initiated by n-butyllithium was studied at different temperatures (55, 63, and 71 degrees C). The kinetic information obtained from the homopolymerizations was used to estimate the parameters of the Eyring equation, Delta H-double dagger= 84080 J/mol and Delta S-double dagger= -21.9 J/mol center dot K for the MYR, and Delta H-double dagger= 51250 J/mol and Delta S-double dagger= -116.8 J/mol center dot K for the 4MS, to calculate the apparent propagation coefficients kpapp as a function of temperature. Finally, the parameters obtained for the Eyring equation were validated by applying them in a mathematical model representing the kinetics of nonisothermal (quasi-adiabatic) polymerization experiments of MYR and 4MS. (c) 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019