Influence of Fe‐MMT on crosslinking and thermal degradation in silicone rubber/clay nanocomposites

Abstract

In this article, silicone rubber (SR)/clay nanocomposites were synthesized by a melt‐intercalation process using synthetic Fe‐montmorillonite (Fe‐MMT) and natural Na‐MMT which were modified by cetyltrimethyl ammonium bromide (CTAB). This study has been designed to determine if the presence of structural iron in the matrix can result in radical trapping and then enhance thermal stability, affect the crosslinking degree and elongation. The SR/clay nanocomposites were characterized by X‐ray diffraction (XRD) patterns and transmission electron microscopy (TEM). Exfoliated and intercalated nanocomposites were obtained. Thermo gravimetric analysis (TGA) and mechanical performance were applied to test the properties of the SR/clay nanocomposites. The presence of iron significantly increased the onset temperature of thermal degradation in SR/Fe‐MMT nanocomposites. The thermal stability, gel fraction and mechanical property of SR/Fe‐MMT were different from the SR/Na‐MMT nanocomposites. So the iron not only in thermal degradation but in the vulcanization process acted as an antioxidant and radicals trap. Copyright © 2006 John Wiley & Sons, Ltd.

Flame Retardant and Smoke Suppressant of Fe‐Organophilic Montmorillonite in Polyvinyl Chloride Nanocomposites

“…14,15 And the Fe-MMT and Na-MMT were modified by CTAB. The PVC, additives and desired amounts of Na-OMT and Fe-OMT were premixed, then extruded at 165 ℃ using a twin-screw extruder (TE-35, Jiangsu, China) at a rotating speed of 60 r/min for 10 min.…”

The role of the trivalent metal in an LDH: Synthesis, characterization and fire properties of thermally stable PMMA/LDH systems

“…The presence of iron as a substitutional impurity in MMT has been shown to lead to radical trapping reactions and a reduction in the PHRR at low amounts of clay [23]. Kong et al have recently reported on a synthetic iron-containing MMT analog and found that the iron has a significant effect on the degradation and fire properties [24].…”

The effect of layered silicates on the crosslinking reaction of silanol‐terminated polysiloxane

“…Decrease in gel fraction (GF) with increasing clay content was observed by Kong et al [21], in silicone rubber nanocomposites reinforced with Fe-MMT and Na-MMT, modified with cetylthimethyl ammonium bromide. The decrease in GF values was due to the additives of clay having the action of blocking free radicals during the formation of the network structure.…”

“…Silanol-terminated PDMS, grade DMS-S35 (Gelest) of molecular weight 49,000 g mol 21 , was the silicone base elastomer used in this work. The vulcanization reaction system consisted of 10 phr tetrapropoxysilane (TPOS, Aldrich) as a crosslinker and 0.1 phr dibutyl tin dilaurate (Aldrich) as catalyst.…”

“…Temperature modulated differential scanning calorimetry (TMDSC) method, also called Alternating DSC (ADSC), in which temperature modulation is superimposed on the constant heating rate of a conventional DSC, was used for the study of PDMS vulcanization. Measurements were performed at a heating rate 5 C min 21 , the temperature amplitude was 60.4 C, with time period of 48 s and temperature range of the experiments 2150 to 20 C. Samples of $10 mg were accurately weighed in an analytical balance and encapsulated in aluminum pans. Samples from the vulcanizing mixture were placed in the DSC cell, which was cooled to 2150 C, and then heated.…”