文摘
The study of curing mechanism and the related kinetics in montmorillonite/vinyl-terminated polysiloxane nanocomposites was carried out. Commercially unmodified montmorillonite, as well as two different types of organically modified products, under the trade names: Nanofil 116, Cloisite 20A and Cloisite 30B, respectively, was used as the reinforcing nanofillers. The vulcanization reaction was followed by isothermal and non-isothermal differential scanning calorimetry analysis. The Cloisite 20A/PDMS systems showed increased reaction rate at the early stages of cross-linking, followed by a retardation of the rate and extension of curing time, with respect to the pure PDMS. On the other hand, Cloisite 30B decreases the curing rate of PDMS during the whole process, whereas a significant increase in this parameter was recorded in the case of unmodified clay/PDMS nanocomposites. This diversity of the effect of various types of fillers was attributed to physicochemical interactions between the cross-linking system and organoclay particles mainly due to their surface chemistry. In an attempt to further evaluate the obtained results, it was found that the autocatalytic model shows good fitting with the experimental data.