Preparation and Characterization of Carborane Modified Liquid Fluoroelastomers and the investigation of their properties

Abstract

The preparation of liquid fluoroelastomers that are liquid with excellent mechanical properties remains a challenge. Here, we show a very straightforward method to produce liquid fluoroelastomers by introducing carborane. Carborane-terminated liquid fluoropolymer was synthesized by Steglich reaction of carboxyl-terminated liquid fluoropolymer and 1,7-bis (hydroxy)-carborane. The product is brown, viscous at room temperature and in the semi-solid state. On this basis, HDI Trimer was used as a curing agent to cure liquid fluoroelastomer. Thermogravimetric analysis of the cured products was carried out. The carbon residue rate of the cured product increased from 35% to 58% of the cured product. The results show that the addition of carborane structure can effectively improve the carbon residue rate of liquid fluoroelastomer. The tensile strength, elongation and shore hardness of the cured product were also examined, and the results show that the tensile strength of carborane modified liquid fluorine increased by 463% compared with that before modification, but the elongation at break was reduced by 42%, which was mainly due to the introduction of rigid structure of carborane. At the same time, the solvent resistance test results show that the introduction of carborane structure has little effect on the aviation kerosene resistance and organic solvent resistance of fluororubber, but it can improve its alkali resistance.

Microwave-Assisted Oxidative Degradation of Poly(vinylidene fluoride-co-hexafluoropropylene) Copolymers: Preparation, Characterization, and Reaction Mechanism

“…Our research team has been extensively studied the mechanisms of degradation of LTCFs made with CH-assisted oxidative degradation. It was found that Zaitsev’s rule was mostly followed, and Hofmann’s rule was partially followed during the dehydrofluorination of the P(VDF-HFP) copolymer. , However, more practical and theoretical research is needed to determine if the degradation mechanism still holds under the novel volumetric heating circumstances of MW.…”

Thermal-Oxidation-Resistant Poly(Carborane-Silane) for Protective Coatings Under Harsh Environments

“…Carborane and its derivatives are highly sought after due to their 3D-aromatic structure and have been investigated to improve the heat stability of organic polymers. Carborane is soluble in commonly used organic solvents and can be easily introduced into polymer systems such as polyester, , polysiloxane, , polyamides/polyimides, − polyphosphazenes, − heteroelement-substituted polymers, , and so on. − Among the polymers discussed above, polysiloxane stands out because the introduction of carborane segments substantially improves its heat resistance. The addition of carborane segments significantly improved the modified polymers’ thermal resistance.…”