Preparation And Properties Of Benzoxazine Based On2-allyl Phenol/4,4’-Diaminodiphenyl Ether

The bis(4-(8-allyl-2H-benzo[e][1,3]oxazin-3(4H)-yl)phenyl)ether (oAP-dde), wassynthesized from o-allylphenol,4,4′-diaminodiphenyl ether (DDE), and formaldehyde via asolution method. The chemical structure of oAP-dde was confirmed by Fourier transforminfrared (FTIR) spectroscopy, nuclear magnetic resonance (1H and13C NMR) spectroscopy,and elemental analysis.The thermally activated polymerization behaviors of oAP-dde were investigated by FTIR,solid-state13C NMR, and differential scanning calorimetry (DSC). FTIR spectra show that theintensities of the peaks related to the oxazine ring, such as CH2, C–O–C and C–N–C, decreasegradually and some of the absorption peaks disappear in the polymerization reaction. At thesame time, the intensities of the peaks related to the allyl also decrease. It is indicated thatboth oxazine ring and allyl are involved in the polymerization. But only one exothermic peakis shown on the DSC curves, and the polymerization peak temperature is264°C and theexothermic heat is266.7J/g. The dynamic mechanical properties of the correspondingpolybenzoxazine (PoAP-dde) were determined by dynamic mechanical analysis (DMA). Theresults show that the glass transition temperature is143°C, and the storage modulus ofPoAP-dde at25°C is about3.02GPa. Thermal degradation behaviors of PoAP-dde werestudied by thermogravimetry (TG), differential thermal analysis, and FTIR, and the resultsshow that the char yield is35.7%at800°C in nitrogen.The isomerization reaction of oAP-dde catalyzed by RhCl(PPh3)3/Et3SiH catalytic systemyielded a propenyl-containing benzoxazine (oPP-dde). The chemical structure of oPP-ddewas confirmed by Fourier transform infrared (FTIR) spectroscopy and nuclear magneticresonance (1H and13C NMR) spectroscopy. The thermally activated polymerization behaviorsof oPP-dde were investigated by FTIR and DSC. On the DSC curves, the onset andmaximum polymerization temperatures of oPP-dde are lower than those of oAP-dde, but thetemperature range covered by the DSC exothermic peak broadens. The dynamic mechanical properties and thermal degradation behavior of the corresponding polybenzoxazine(PoPP-dde) were studied by DMA and TG. The rsults show that the glass transitiontemperature is154°C, and the storage modulus of PoAP-dde at25°C is about2.05GPa. Thethermal stability of PoPP-dde is slightly higher than that of PoAP-dde.Hydrosilylation of oAP-dde with1,1,3,3-tetramethyldisiloxane (TMDS) catalyzed bychlorotris(triphenylphosphine)rhodium(I) yield a benzoxazine-containing polysiloxane(PTMDS-PP-dde). The chemical structure of PTMDS-PP-dde was confirmed by FTIRspectroscopy and1H and13C NMR spectroscopy. The thermally activated polymerizationbehaviors were investigated by FTIR and DSC. The DSC curve shows that thepolymerization peak temperature is265°C and the exothermic heat is266.7J/g, indicating thatthe peak temperature is close to that of oAP-dde and the exothermic heat is lower than that ofoAP-dde. The dynamic mechanical properties of the crosslinked polymer(CR-PTMDS-PP-dde) were studied by DMA. The rsults show that the storage modulus ofCR-PTMDS-PP-dde at25°C is about1.49GPa and the glass transition temperature is91°C,which are lower than those of PoAP-dde and PoPP-dde.