Benzocyclobutene-functionalized hyperbranched polysiloxane for low-k materials with good thermostability

ABSTRACT

Although hyperbranched polysiloxanes have been extensively studied, they have limited practical applications because of their low glass transition temperatures. In this study, we synthesized benzocyclobutene-functionalized hyperbranched polysiloxane (HB-BCB) via the Piers-Rubinsztajn reaction. The synthesized material was cured and crosslinking occurred at temperatures greater than 200 °C, forming a low-k thermoset resin with high thermostability. The structure of the resin was characterized using nuclear magnetic resonance (NMR) spectroscopy, viz. ¹H NMR and ¹³C NMR spectroscopy. ²⁹Si NMR spectroscopy was used to calculate the degree of branching. Differential scanning calorimetry, dynamic mechanical analysis, and thermogravimetric analysis revealed that the cured resin possesses good high-temperature mechanical properties and exhibits a high thermal decomposition temperature (T_d5 = 512 °C). In addition, the cured resin has a low dielectric constant (k = 2.70 at 1 MHz) and low dissipation factor (2.13 × 10⁻³ at 1 MHz). Thus, the prepared resin can function as a low-k material with excellent high-temperature performance. These findings indicate that the performance of crosslinked siloxane is significantly attributed to the introduction of BCB groups and the formation of the highly crosslinked structure.

KEYWORDS:

• Benzocyclobutene
• hyperbranched polysiloxane
• low dielectric constant material
• thermosets

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was financially supported by the Natural Science Foundation of Shanghai (18ZR1402400), the National Natural Science Foundation of China (NSFC No. 5187030110).