Preparation, polymerization and properties of an adamantyl‐based benzoxazine

Abstract

A novel adamantyl‐based benzoxazine (AD‐Bz) was successfully synthesized with 1,3‐bis(4‐aniline)‐adamantane (AD) derived from 1‐adamantanol and acetanilide through the Friedel–Crafts alkylation reaction. The chemical structure, curing behavior and curing kinetics of AD‐Bz were characterized by Fourier transform infrared spectroscopy, NMR spectroscopy (1H NMR and 13C NMR) and DSC, respectively. The results indicated that the activation energies (Ea) of AD‐Bz were 106.3 kJ mol−1 (Kissinger–Akahira–Sunose method) and 109.5 kJ mol−1 (Ozawa method), which are significantly lower than that of the benzoxazine derived from salicylaldehyde and 4,4′‐diamine diphenylmethane (P‐ddm). Furthermore, the thermal properties, dielectric properties and flammability properties of poly(AD‐Bz) were explored with dynamic mechanical analysis, an Agilent impedance analyzer and TGA. It was found that poly(AD‐Bz) exhibited higher heat‐resistant properties (Tg = 253.4 °C), higher thermal stability (Td,10% = 401 °C) and lower dielectric constant (εr = 3.16, 10 MHz) compared with poly(P‐ddm), favoring its application as a candidate for interlayer materials in ultra‐large‐scale integrated circuit and aerospace materials. © 2022 Society of Industrial Chemistry.

Synthesis and characterization of novel main‐chain benzoxazines containing cycloaliphatic and aliphatic structures and their thermal and dielectric properties

“…The E' vs. temperature curves (a) and tan δ vs. temperature curves (b) of P(BPA-AD/dd1) main . [Color figure can be viewed at wileyonlinelibrary.com] of 253.4 C), 19 the main-chain polybenzoxazine (P(BPA-AD) main ) exhibited a higher T g due to its higher crosslinking density. Notably, P(BPA-AD 0.5) main , P(BPA-AD 0.25) main and P(BPA-dd1) main presented two temperature peaks in the loss factor (tan δ) vs. temperature curves.…”

“…Generally, there are three main methods for the reduction of the dielectric constants of benzoxazine resins: the first method is the introduction of fluorine atoms, 14,15 Si O bonds, 16 aliphatic rings/chains 2,17 and other low-polarity or bulk chemical structures into the three-dimensional network of polybenzoxazine through molecular design to obtain new structural benzoxazines with excellent dielectric properties. [18][19][20][21] For instance, Velez-Herrera et al synthesized highly fluorinated mainchain benzoxazine resins from highly fluorinated diamines, highly fluorinated bisphenol A, and formaldehyde. It was shown that the dielectric constant and dielectric loss of the fluorinated polybenzoxazine reached 2.2 and 0.008 @ 1 GHz, respectively, 15 which was attributed to the less polarizability and larger free volume of C-F bonds compared with C-H bonds.…”

“…Similarly, our previous research suggested that polybenzoxazine with adamantane structure exhibited high heat resistance with a T g of 253.4 C and low dielectric constants (3.27-3.16) in a frequency range 1-10 MHz. 19 Moreover, benzoxazines containing aliphatic chains, such as cashew phenol, 23,24 Priamine 1074, 25,26 and other raw materials containing a large number of aliphatic chains, 27,28 were used to toughen and lower the dielectric constant of polybenzoxazine. Kuo et al successfully prepared benzoxazines and bismaleimides with Priamine 1074 (C36 diamine).…”

Preparation of polybenzoxazine/resorcinarene composites with low dielectric constants

“…14 Li et al introduced crown ether into bisphenol A type polyimide, which effectively reduced the dielectric constant. 15 Yonekawa et al copolymerized p-tert-butylcalix [8]alkene glycidyl ether with benzoxazine to form a dense cross-linking network, which reduced the dielectric constant from 3.6 to 2.9 at 1 GHz. 16 The curing temperature of conventional benzoxazine is relatively high, which may have some impact on the practical applications of PBZ.…”

“…Low‐polarity groups, such as fluorinated groups 4 and siloxane, 5 are introduced to decrease the molar polarizability of the polymers. The free volume of PBZ could be increased by incorporating steric hindrance groups, for instance, tert‐butyl 6,7 and adamantane, 8 thereby decreasing the polarized molecular density of PBZ. Yuan et al prepared a PBZ containing bulky tert‐butyl groups and low‐polarity siloxane chain to improve the thermal stability and low‐dielectric properties 9 .…”