A Novel Kinetic Analysis of Crystallization of Polypropylene (PP) in Dynamically-vulcanized PP/Ethylene-propylene-diene Rubber (EPDM) Blends Using an In-situ Measurement Technique

Abstract

The effects of cooling medium temperatures and plastic/rubber ratios on solidification and crystallization kinetics of dynamically-vulcanized polypropylene/ethylene-propylene-diene rubber (PP/EPDM) blends were investigated with the aid of an in-situ measurement technique. The cooling medium temperature heavily influenced the solidification kinetics primarily due to a combination of latent heat liberated from the molten polymer and the heat transferred away via the metallic wall during the cooling period. Interestingly, the parameter C in three-parameter model was not only affected by the material properties, but also by the cooling condition, different from the previous literature. The crystallization kinetics analysis indicated that the effect of EPDM in the blends consisted of both nucleation-promoting effect (low EPDM loading) and steric effect (higher EPDM loading). The present kinetic analysis may be helpful to further studies on improving the product performances for industrial applications.

Filler network structure and crystallization behavior of polyvinylidene fluoride/graphene nanoplatelet composites using SEM, DSC, rheological, and in situ measurement approach

“…Table ), suggesting that FPM is more acceptable for the PVDF/GNP composites. More importantly, the values of the parameter C in both TPM and FPM decreased gradually with the increase of GNP content, indicating that the thermal conduction ability was remarkably improved due to the formation of thermal conductive network structure, which is also in agreement with the discussion earlier (cf. Table ).…”

“…In order to better understand the relationship between thermal properties and internal structure, we applied the nonlinear parametric fitting technique, and a normalized temperature θ was defined as follows: where T , T 0 , and T w are the time‐dependent melt temperature, initial melt temperature, and cooling medium temperature, respectively. In our previous studies, a three‐parameter model (TPM) was raised to nonlinearly fit the cooling curves of crystalline polymers (PE, PP), and can be written in the following form: where y = θ and x = ln t , respectively. On this basis, we, in this study, suggest a FPM as below: …”

“…Table ). Therefore, the nonlinear curve fitting coupled with the in situ temperature measurement could be a useful tool to evaluate the formation of thermal conductive network structure in polymer composites, which can also be utilized for forecasting the minimum time of mold cooling stage during industrial processing operations (eg, injection molding).…”