D₂‐m‐carborane‐siloxanes. III. Preparation and properties of trifluoropropyl‐modified polymers

Abstract

Linear D2‐m‐carborane‐siloxanes with one, two, and three trifluoropropyl moieties per repeat unit were prepared by the condensation reaction between bisureidosilanes and carborane disilanol. Molecular weights between 100,000 and 220,000 were obtained. Compared to fluorosilicones, the trifluoropropyl‐modified carborane‐siloxanes exhibited greater thermal and oxidative stability and in certain cases comparable solvent resistance. The swelling index for carborane‐siloxane elastomers decreased with increasing trifluoropropyl content, although this fluorocarbon moiety did compromise the thermal stability of the carborane system.

Improvement in oil resistance of room temperature-vulcanized polysiloxane rubber via blending with self-synthetic fluorosilicone

“…As a whole, at the same immersion time, DM and DV of different samples decreased with an increase in the VFS oil content. As reported previously, 35,43 the introduction of -CH 2 CH 2 CF 3 could well improve the oil resistance of materials. Actually, the oil resistance of the polysiloxane rubber was improved by the incorporation of VFS oil.…”

Effects of CH2CH2CF3 on properties of RTV polysiloxane rubber: Processability, thermal stability, and oil/solvent resistance

“…The apparent shear‐thinning character of the mixed gums with higher VFS‐oil content could be observed in Figure (A), while the temperature‐sensitive character was exhibited in Figure (B). As shown in Scheme , there was about 30 mol % (29.1 mol % calculated by H NMR) of F unit in the VFS‐oil, and the CH 2 CH 2 CF 3 is so large that it exerted an increasing steric‐hindrance effect, which hampered the motion of the VFS‐oil chain . Besides, the CH 2 CH 2 CF 3 is a polar group due to the presence of fluorine, so the force of interaction between the CH 2 CH 2 CF 3 group and the SiOH group on the SiO 2 particles' surface was higher than that between PDMS chain and SiO 2 .…”

Carborane–Siloxanes: Synthesis and Properties. New Possibilities for Structure Control

“…One of the methods is based on the synthesis of silanol derivatives of carboranes 1,7-[(HO)Me 2 Si] 2 C 2 B 10 H 10 which react further with compounds of a general formula SiR 2 L 2 , where R = amino, carbamate or ureido groups and L = NMe 2 or an amide group (Scheme 1) [45][46][47][48]. Thus, the reaction of bis(ureido)silanes results in linear polymers with the molecular masses over 250000.…”