Synthesis and characterization of thermosetting polyacetylene‐terminated silicone resins

A 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 T d5 (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.