Papers by Author: Gisèle Boiteux

Abstract: The blending of semi-crystalline polymer, poly (vinylidene fluoride), (PVDF) and uncross-linked elastomer epoxidized natural rubber with 50 mol% epoxide (ENR-50) blends were prepared in an internal mixer by melt mixing process. Dynamic mechanical analysis (DMA) and dielectric analysis (DEA) of PVDF/ENR-50 blends were investigated. It was found that the pure PVDF showed higher storage modulus than that of the pure ENR-50 and storage modulus of the PVDF/ENR blends decrease with increasing ENR-50 content. Furthermore, PVDF showed two relaxation peaks correspond to α_a-relaxation and α_c-relaxation, while ENR-50 showed only a single relaxation that is related to α-relaxation or glass transition temperature (T_g). Two relaxation peaks were observed in the PVDF/ENR-50 blends due to phase separation. However, the maximum peak of relaxation shifted toward to higher and lower temperature compared with the pure components which indicates the partial miscible blends. Moreover, at high temperature, the neat polymer and blends showed a sharp increase of loss factor (ε) that correspond to conductivity and/or Maxwell-Wagner-Sillar (MWS) process.

Abstract: Thermoplastic elastomer based on poly (vinylidene fluoride) (PVDF) and epoxidized natural rubber (ENR) blends at 50/50 by weight with different type of ENR (i.e., ENR with 25 and 50 mol% epoxide which are called as ENR-25 and ENR-50, respectively) has been prepared by melt blending method. Difference content of epoxide groups in ENR molecules on dynamic mechanical properties, dielectric properties and morphological properties of blends were investigated. The morphology reveals the co-continuous phase structure of PVDF and ENR phases. Furthermore, ENR-50/PVDF blend showed finer grain morphology and the glass transition (T_g) of the rubber phase was shifted to lower temperature. The structure of the blends correlated well with permittivity (ε) in dielectric properties with the permittivity of PVDF/ENR-50 higher than that of PVDF/ENR-25.