A Novel Acetylene-Functional/Silicon-Containing Benzoxazine Resin: Preparation, Curing Kinetics and Thermal Properties

Abstract

Benzoxazine resin has been paid more attention in the fields of aviation, electronics, automobiles and new energy industries because of its excellent comprehensive performance. Further application is limited, however, by shortcomings such as high brittleness and high curing temperature. Furthermore, higher thermal stability is imperiously demanded in special areas. Incorporating both an acetylene group and silicon into the benzoxazine monomer is a promising possible solution to improve the curing processability, thermal properties and toughness of benzoxazine. In this paper, an acetylene-functional/silicon-containing benzoxazine monomer was prepared by two-step synthesis, and acetylene-functional benzoxazine was also prepared as a comparison. FTIR and 1H NMR confirmed the molecular structure of acetylene-functional/silicon-containing benzoxazine. Differential scanning calorimetry (DSC) analysis showed that the initial and peak degradation temperatures of acetylene-functional/silicon-containing benzoxazine were decreased by 21 °C and 18 °C compared with acetylene-functional benzoxazine, respectively. The apparent activation energy of the curing reaction of acetylene-functional/silicon-containing benzoxazine was 83.1 kJ/mol, which was slightly lower than acetylene-functional benzoxazine (84.7 kJ/mol). TGA results showed that the acetylene-functional/silicon-containing benzoxazine had a higher thermal stability than acetylene-functional benzoxazine. The temperatures of 5% weight loss of acetylene-functional/silicon-containing benzoxazine were 380 °C in nitrogen and 485 °C in air, and the char yield at 1000 °C was 80% in nitrogen and 21% in air, respectively. The results of mechanical properties showed that the impact strength of acetylene-functional/silicon-containing benzoxazine was higher than acetylene-functional benzoxazine by 35.4%. The tensile and flexural strengths of acetylene-functional/silicon-containing benzoxazine were slightly higher than that of acetylene-functional benzoxazine.

Synthesis of a novel boron‐containing hyperbranched benzoxazine and its flame‐retardant properties in copolymer with epoxy resin

“…Kobzar et al prepared a new type of crosslinked polybenzoxazine centered on 1,4‐tetrafluorobenzene with low water absorption (0.5%) and high crosslinking degree (98.5%) and exhibits excellent dielectric properties with frequency stability 18 . To improve benzoxazine's curing process performance, thermal performance, and toughness, acetylene functional group/silicon‐containing benzoxazine monomer was synthesized by a two‐step method 19 …”

“…18 To improve benzoxazine's curing process performance, thermal performance, and toughness, acetylene functional group/silicon-containing benzoxazine monomer was synthesized by a two-step method. 19 Hyperbranched polymer (HP) is a kind of dendritic supramolecular polymer with a unique structure, which has defects in molecular structure and wider molecular weight distribution compared with traditional dendrimers. However, hyperbranched polymers can be synthesized in a single step by the one-pot method.…”

Hybrids from silazane and allyl‐containing benzoxazine for low‐curing temperature and high‐flame retardance

“…The char yield of PBS increases (from 25.57% to 66.11%) with the gains of weight percent of silazane, but it is barely growing when the weight percent of silazane is more prominent than 80%. The char yield of PBS is nearly as high as acetylene‐functional benzoxazine 38–40 . All of the above results reveal that the cured PBS resin has excellent thermal stability.…”

Synthesis of an alkynyl‐ and allyla‐ terminated modifiers and its thermal and mechanical properties in copolymer with epoxy resin

“…The targeted MNEM was prepared following the procedure described in Scheme 1, and the molecular structure of MNEM was analyzed by FTIR and 1 H‐NMR. From the FTIR spectrum depicted in Figure 1, there are two absorption bands at 3276 and 2108 cm −1 ascribed to the vibration of ≡C‐H and C ≡ C for alkynyl group, respectively 28 . The band at 932 cm −1 is attributed to the –C=C in allyl group.…”

“…From the FTIR spectrum depicted in Figure 1, there are two absorption bands at 3276 and 2108 cm À1 ascribed to the vibration of ≡C-H and C ≡ C for alkynyl group, respectively. 28 The band at 932 cm À1 is attributed to the -C=C in allyl group. Meanwhile, for the TFBAM monomer, the absorption peak of aldehyde group for AM at 1690 cm À1 disappeared and new peak related to the Schiff base was found at 1628 cm À1 , which was produced from the reaction of AM and TEA.…”