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Utilization of Ionic Liquids (IL) as suitable candidate for nanofiller modification is of considerable interest in the current scenario owing to its peculiar properties. In the present study reduced graphene oxide (rGO) is modified with varying amount of IL to improve the dispersability and interaction with fluoroelastomer (FKM) matrix. The surface modification of rGO using IL, its dispersion and incorporation into the FKM matrix was confirmed by FTIR, Raman, XRD, and AFM surface roughness analysis. The prepared nanocomposites achieved better static and dynamic mechanical properties by the addition of 2 phr of IL to rGO. Moreover the nanocomposites showed an increase in glass transition temperature from DSC (−18.82 for FIL 0 to −14 for FIL 2) analysis that supports the enhanced interaction between FKM and modified filler. Dynamic mechanical analysis of the nanocomposites proved the reinforcing ability and the effectiveness of ILrGO to enhance the properties as a whole. The dielectric study of the nanocomposites showed improved AC conductivity, dielectric constant value (60 with 2 phr of IL content) and a decrease in dielectric heating coefficient value with increase in ILrGO content. These property combinations make the nanocomposites a multifunctional material.

A novel kind of fluoroelastomer nanocomposites based on tube-like halloysite clay mineral were successfully prepared using a bis-phenol curing system, which resulted in prominent improvements in mechanical and dynamic mechanical properties and in the elevation as high as 30 K of the thermal decomposition temperature. Wide-angle X-ray scattering and transmission electron microscopy techniques were employed to assess the morphology developed in the nanocomposites, while stress strain diagrams were used to evaluate the mechanical properties. These nanocomposites were further characterized by moving die rheometer, dynamic mechanical properties and thermo-gravimetric analysis. Structure-properties relationship and the improvement of the mechanical, dynamic mechanical and thermal properties of fluoroelastomers are reported in the present study. Increasing amount of the filler reduced the curing efficiency of the bis-phenol curing system, which was evident from the rheometric and physical properties of the resulting composites. A sort of filler–filler interaction was perceived during the strain sweep analysis of the composites. The polymer–filler interaction was reflected in the improved mechanical and thermal properties which were the consequence of proper dispersion of the nanotubes in the polymer matrix; whereas the intercalation of macromolecular chains into the nanotubes was not reflected in the X-ray diffraction analysis.

Tetrafluoroethylene–propylene elastomers containing from 41 to 53 mol% tetrafluoroethylene were prepared by emulsion copolymerization in batch operation, initiated by a redox system with tert-butylperoxybenzoate. Alternating copolymers in a wide range of monomer compositions were obtained. The composition curve has one azeotropic point at 46.7 mol% tetrafluoroethylene. The reactivity ratio calculated from NMR and elemental analysis was found to be rTFE=0.014 and rP=0.18. Highly alternating structures of the copolymers synthesized were proved. Copolymer compositions calculated from NMR spectra correspond to those obtained by elemental analysis. The thermal properties were measured by DSC and TGA and discussed in connection with the copolymer structure.

An experimental investigation was carried out to explore the possibility of using crystalline vinylidene fluoride copolymers as reinforcing agents for fluorosilicone elastomers. To achieve a fine dispersion of the fluoropolymer in the fluoroelastomer matrix, and to develop a strong adhesion between the two polymer phases, a compatibilisation procedure was used involving the pre-grafting of multi-functional free-radical crosslinking agents on the fluoropolymer chains before being blended with the fluorosilicone gum. Mixtures of Triallyl isocyanurate and Diallyl phthalate were found to be particularly useful for this purpose using γ -radiation to promote grafting reactions, which were enhanced by the addition of a small amount of benzoyl peroxide paste in the subsequent melt blending operation. The efficacy of this procedure was confirmed by differential scanning calorimetry and dynamic mechanical tests, showing a reduction in the degree of crystallinity and a depression of the melting point of the fluoropolymer phase and a small increase in glass transition temperature of the fluoroelastomer matrix. The peroxide cured blends exhibited large improvements in mechanical properties, both at room temperature and at 140 °C, and in large reductions in solvent absorption.

Stress relaxation measurements have been used to study network changes taking place during postcuring of Viton GF fluoroelastomer vulcanizates. The same technique was used to study network changes during the initial stages of heat-ageing of postcured vulcanizates. In both non-postcured and postcured vulcanizates, it was found that stable additional crosslinks were formed in air and nitrogen environments. Thus, postcuring, which leads to the formation of new crosslinks, is a pre-requisite for full crosslink development in Viton GF fluoroelastomer.