Interdiffusion of polymers with glassy bulk

Mechanical properties developing at the contact zone of two samples of linear amorphous polymers with vitrified bulk have been employed to analyze the process of segmental diffusion of reptating chains across polymer–polymer interfaces. The diffusion coefficients (D) of this process have been estimated for polymers with different chain architecture and investigated with respect to healing temperature (T). It has been shown that logD ∼ 1/T at \( T < T_{\text{g}}^{\text{bulk}} \) (\( T_{\text{g}}^{\text{bulk}} \) is the glass transition temperature of the polymer bulk), which implies that the process of segmental diffusion under healing conditions investigated is a thermally activated Arrhenius-like process describing as D = D ₀ exp[−E _a/(RT)], where D ₀ and E _a are the activation energy and the pre-exponential factor, respectively. It has been found that logD ₀ ∼ E _a, which points to the validity of the so-called kinetic compensation effect for the interdiffusion process at the contact zones of polymers with glassy bulk when an increase in E _a is “compensated” by the corresponding increase in D ₀.