Synthesis and characterization of thermosetting polyacetylene‐terminated silicone resins

Abstract

ABSTRACTA novel polyacetylene‐terminated silicone (PTS) resins possessing low curing temperature and high heat resistance has been prepared by Grignard reaction using m‐diacetylenylbenzene (DEB), 1,3,5‐triacetylenylbenzene(TEB), and dichlorosilane as original materials. The reaction of the functional groups was characterized by in situ Fourier transform infrared spectrometer. The experimental results indicated that Si─H and C≡CH bonds are almost exclusively involved in the crosslinking reaction, while ─C≡C─ bonds only partially react. Further, Si─H and C≡CH bonds can participate in the curing reaction at relatively low temperatures, but ─C≡C─ bonds require higher temperature, indicating the higher activity of Si─H and C≡CH bonds than ─C≡C─ bonds. As determined by differential scanning calorimetry, PTS resins have low peak exothermic temperature at 184.5 °C, which is lower than MSP resin (~ 210 °C); in addition, rheological test showed that PTS resins have a very wide processing window from 40 to 163.3 °C, indicating that the PTS resins have excellent processability with a low curing temperature and wide processing window. What is more, TGA results of thermal‐cured PTS resins revealed that Td5 (5% weight loss temperature) of PTS‐H10 reached the highest of 684.4 °C. Compared with PTS‐H0 resin, there is an increase of 124.2 °C and the remarkably increased heat resistance correlated with a higher m‐DEB input ratio. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48783.