Structurally diverse benzoxazines: synthesis, polymerization, and thermal stability

Abstract

Bisphenol-A is converted to indane bisphenol and spirobiindane bisphenol. The compounds bisphenol-A benzoxazine (BAB), indane bisphenol benzoxazine (IBPB), and spirobiindane bisphenol benzoxazine (SBIB) are prepared by condensing the respective bisphenols with paraformaldehyde and aniline. The structural characterization of the synthesized materials is done by using FTIR, 1 H, and 13 C NMR. Curing behavior of these benzoxazines and glass transition temperature for polybenzoxazines are studied using differential scanning calorimeter (DSC). The curing exotherm of these benzoxazines is much influenced by the nature of the aromatic unit present in the chosen bisphenol. Compared to the aromatic nucleus in BAB, the indane nucleus present in IBPB shifts the cure exotherm to lower temperatures, whereas the biindane moiety present in SBIB shifts the same to high temperatures. These benzoxazines are thermally cured both at the onset and at the peak maximum of the curing exotherm. The thermal stability of these cured materials is investigated using thermogravimetry. The nature of the aromatic nucleus present in the bisphenol and the temperature at which the curing is done decide the glass transition temperature and thermal stability of the polybenzoxazine.

Indane‐based bismaleimide and cloisite 15a nanoclay blends: Kinetics of thermal curing and degradation of particulate nanocomposites

“…The endset of degradation temperature increases nearly 34, 38, 59, 66, and 62°C by the incorporation of 1, 3, 5, 7, and 9% cloisite 15a into BMII, respectively. The similar effect on onset, endset of degradation temperature was also noted by the incorporation of nanoparticles in other bismaleimides investigated. Different loading levels of cloisite 15a nanoparticles in BMIX decrease the onset temperature and increase the endset temperature of polyBMIX system.…”

“…The DTG curves of thermally cured pure BMII and its cloisite 15a nanocomposites show two degradation maximum temperatures which overlap each other indicating that the second degradation starts before the completion of the first degradation. The authors investigated the thermal properties of thermally cured structurally different bismaleimides . All the investigated materials show two overlapping degradations.…”

Bis(isomaleimide) and diphenol blends: Non-isothermal degradation kinetics and TG-FTIR studies

“…The synthetic procedures for the preparation of 5-hydroxy-3-(4-hydroxyphenyl)-1,1,3-trimethyl indane (IBP), 6,6 0 -dihydroxy-3,3,3 0 ,3 0 -tetramethyl-1,1 0 -spirobiindane (SBI) and 4,4 0 -dihydroxy benzophenone were already presented in detail in the previous work. [14][15][16] Preparation of bis(isomaleimide) (VS) of 4,4 0 -methylene dianiline A solution of 1.05 mole of 4,4 0 -methylene dianiline in methylene chloride was slowly added to a solution of 2.0 mole of maleic anhydride in the same solvent. After stirring at ambient temperature for 1 h, the formed bis(maleamic acid) ( Figure 1) was separated by filtration, washed with methylene chloride to remove excess diamine and dried in an air oven.…”

“…The synthetic procedures for the preparation of 5-hydroxy-3-(4-hydroxyphenyl)-1,1,3-trimethyl indane (IBP), 6,6′-dihydroxy-3,3,3′,3′-tetramethyl-1,1′-spirobiindane (SBI) and 4,4′-dihydroxy benzophenone were already presented in detail in the previous work. 14 –16…”

Silane‐functional benzoxazine: synthesis, polymerization kinetics and thermal stability

“…The superb molecular design flexibility of the benzoxazine monomers allows the properties of the polymerized materials to be tailored in a wide range for the specific requirements of individual applications. Good thermal, chemical, electrical, mechanical and physical properties make them attractive alternatives for existing applications . Additional new applications can be developed by utilizing unique properties of polybenzoxazines that have not been often observed in other well‐known polymers.…”