Benson-Buss's group additivity method for estimating thermodynamical parameters for low molecular compounds has been extended to polymers. Both the heat and entropy of polymerization for head-to-tail or tail-to-head structure may be expressed as follows

△Hgg = △Hf0 (polymer structure unit) - △Hf0 (monomer)

△Sgg = S0 (polymer structure unit) - S0 (monomer).In general

the empirical expressions mentioned above have several advantages

they are simple

intuitive

having definite physical meaning and do not need of in-troducing any other empirical parameter. The heat andentropy of polymerization for 28 typical polymers have been estimated.