Synthesis and characterizations of a latent polyhedral oligomeric silsequioxane‐containing catalyst and its application in polybenzoxazine resin

In this article, a novel latent curing agent, octa(paratoluenesulfonic acid ammomium salt) (OPAAS) polyhedral oligomeric silsequioxane was synthesized and used in modifying the polybenzoxazine/2,2′‐(1,3‐phenylene)‐bis(4,5‐dihydro‐oxazoles) (PBO) (PBZ/PBO) resin. The liberated octa(aminophenyl) silsesquioxane and paratoluenesulfonic acid can catalyze the ring‐opening reaction of benzoxazine (BZ) resin. The initial curing temperature (T_i), peak curing temperature (T_p) and the Enthalpy of the curing temperature had significantly decreased with respect to pristine BZ/PBO resin. When the OPAAS amount was 3 wt %, the peak curing temperature decreased from 233.7 to 218.2°C. Also, PBZ/PBO/OPAAS composites exhibited better storage modulus than pure PBZ/PBO resin. Meanwhile, PBZ/PBO/OPAAS composites are more thermally stable than PBZ/PBO resin. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Curing behavior of 4,4′‐diamonodiphenyl methane‐based benzoxazine oligomers/bisoxazoline copolymers and the properties of their cured resins

1,3‐Phenylene bisoxazoline is synthesized and characterized. The optimal synthetic conditions for yield (92%) are as follows: reaction temperature = 115°C; ratio (mol) of ethanolamine to 1,3‐dicyanobenzene = 2.5 : 1; ratio (mol) of zinc acetate to 1,3‐dicyanobenzene = 0.055; reaction time = 6 h. 4,4′‐diamonodiphenyl methane‐based benzoxazine and its oligomers (Oligo‐Da) are synthesized and characterized. The curing behavior and properties of the Oligo‐Da/1,3‐PBO copolymer resins are investigated. It was found that the cure induction time and cure time of the molten mixture from Oligo‐Da/1,3‐PBO could be reduced, compared with that from Oligo‐Ba/1,3‐PBO, especially above 175°C. The reason lies in that the bisphenol generated in ring opening of Ba has more steric hindrance than the phenol generated in ring opening of Da because of isopropyl group. Thus, the Mannich bridge structure in the Da polymer is relatively much easier to form between the ortho positions of phenolic hydroxyl groups than that in the Ba polymer. Curing temperature of Oligo‐Da/1,3‐PBO could be lowered with triphenylphosphite as a catalyst. SEM results confirm that 1,3‐PBO could toughen Oligo‐Da system when the mol ratio of 1,3‐PBO and Oligo‐Da is ≤1 because of the formation of ether–amide bonds. However, a brittle fracture surface is observed because of too higher crosslinking density of the cured resin, when the mol ratio of 1,3‐PBO and Oligo‐Da is >1. The cured resin from Oligo‐Da/1,3‐PBO has superior heat resistance, electrical insulation, and water resistance than that from Oligo‐Ba/1,3‐PBO. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1359–1366, 2006     

Curing kinetics,thermal, and adhesive properties of acetylene‐terminated benzoxazine

The acetylene‐terminated benzoxazine monomer (BB‐apa) has been synthesized using 2,2‐bis(4‐hydroxyphenyl)butane, 3‐aminophenylacetylene, and paraformaldehyde. The structure of the monomer was characterized by FTIR spectroscopy and ¹H NMR spectra, which indicated that the reactive oxazine ring and acetenyl groups existed in molecular structure of BB‐apa. The polymerization behavior was monitored by FTIR and non‐isothermal differential scanning calorimetry (DSC), which showed that the BB‐apa had completely cured with multiple polymerization mechanisms according to oxazine ring‐opening and ethynyl addition polymerization. The curing kinetics results revealed that the introduction of ethynyl groups can accelerate the ring‐opening polymerization of benzoxazine, leading to a lower curing temperature and apparent activation energy. Moreover, the thermoset derived from the BB‐apa exhibits higher thermal stability and lap shear strength (at 350 °C) with the glass transition temperature of 353 °C compared with the traditional benzoxazine polymer without ethynyl groups (BB‐a). © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44547.     

Synthesis and properties of a novel bio‐based benzoxazine resin with excellent low‐temperature curing ability

A novel bio‐based benzoxazine resin (diphenolic acid/furfurylamine benzoxazine resin, PDPA‐F‐Boz) was prepared by using bio‐based diphenolic acid, furfurylamine and paraformaldehyde as raw materials. The structure of DPA‐F‐Boz monomer was characterized by Fourier transform infrared spectroscopy, ¹H NMR and ¹³C NMR, and then its curing reaction and the thermal stability of the cured PDPA‐F‐Boz were analyzed. Compared with the traditional fossil‐based benzoxazine (bisphenol A/aniline benzoxazine, BPA‐A‐Boz) and the bio‐based benzoxazine (diphenolic acid/aniline benzoxazine, DPA‐A‐Boz), DPA‐F‐Boz monomer showed the lowest curing temperature, and PDPA‐F‐Boz had the highest residual char ratio at 800 °C and the lowest degradation rate at the peak temperature. Meanwhile, the total heat release, peak heat release rate and heat release capacity of PDPA‐F‐Boz were much lower than those of PBPA‐A‐Boz and PDPA‐A‐Boz. Thus, PDPA‐F‐Boz showed excellent low‐temperature curing ability and thermal stability. © 2019 Society of Chemical Industry     

Preparation,characterization, and polymerization of novel maleimidobenzoxazine containing carboxylic moiety and its cocuring behaviors with epoxy resin

A novel benzoxazine containing maleimide and carboxylic moieties, 1‐[3‐(4‐carboxylphenyl)‐3,4‐dihydro‐2H‐benzo[e][1,3]‐oxazin‐6‐yl]maleimide (Mal‐Bz‐Co), was synthesized and the structure was identified by ¹H‐NMR and FTIR. Mal‐Bz‐Co exhibited good solubility in common organic solvents. The cure behavior of Mal‐Bz‐Co and cocure behavior of Mal‐Bz‐Co with o‐cresol formaldehyde epoxy resin were investigated by differential scanning calorimetry. Results indicated that Mal‐Bz‐Co showed a single curing exothermic peak at about 238.3°C. However, the maximum curing temperature (T_p) decreased to 146.1°C when Mal‐Bz‐Co cocured with o‐cresol formaldehyde epoxy resin in the molar ratio of 1 : 1. The T_p was about 92°C lower than that of Mal‐Bz‐Co. Thermogravimetric analysis showed that high‐decomposition temperature and char yield were observed for the cured resins of Mal‐Bz‐Co and Mal‐Bz‐Co/o‐CFER. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis and characterization of a novel acetylene‐ and maleimide‐terminated benzoxazine and its high‐performance thermosets

A novel acetylene‐ and maleimide‐terminated benzoxazine, 3‐(3‐ethynylphenyl)‐3,4‐dihydro‐2H‐6‐(N‐maleimido)‐1,3‐benzoxazine (MBZ‐apa), was successfully synthesized with N‐(4‐hydroxyphenyl)maleimide, paraformaldehyde, and 3‐aminophenylacetylene. The structure of the benzoxazine is confirmed by FTIR and ¹H‐NMR spectroscopies. MBZ‐apa is easily dissolved in common organic solvents. Differential scanning calorimetry (DSC) was used to study thermal cross‐linking behavior of MBZ‐apa. The DSC curve shows only a single exothermic peak due to the oxazine ring‐opening polymerization and the polymerization of the acetylene and maleimide groups occurring simultaneously in the same temperature range. Dynamic mechanical analyses (DMA) reveals that the novel polybenzoxazine exhibits high glass‐transition temperature (T_g) (ca. 348°C). The storage modulus arrives at 4.5 GPa in the range of room temperature to 330°C. The polybenzoxazine exhibits good thermal stability as evidenced by thermogravimetric analysis (TGA). Pyrolysis‐gas chromatography/mass spectrometry (Pyrolysis‐GC/MS) was employed to characterize the polybenzoxazine. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Preparation of nanocomposites of thermosetting resin from benzoxazine and bisoxazoline with montmorillonite

The thermosetting resin from 2,2′‐(1,3‐phenylene)‐bis(4,5‐dihydro‐oxazoles) (PBO) and bis(3‐phenyl‐3,4‐dihydro‐2H‐1,3‐benzoxazine)isopropane (BZ) was prepared, and it was found that the thermal property of the final resin was affected greatly by the content of PBO. The nanocomposite from the thermosetting resin from BZ and PBO (molar ratio of PBO to BZ, 0.8 : 1) (PBZ–PBO) and organically modified montmorillonite (OMMT) was prepared by melt method. Differential scanning calorimetry showed that on the introduction of OMMT, the onset curing temperature of the copolymerization of BZ and PBO decreased. The X‐ray diffractometer and transmission electron micrograph characterization of the dispersion of OMMT in the PBZ–PBO matrix suggested that exfoliation structure of OMMT was achieved. Dynamic mechanical analyses indicated that the nanocomposites exhibited much higher T_g values than the PBZ–PBO resin and pristine polybenzoxazine, and storage modulus of the nanocomposites was maintained up to higher temperature with the increasing OMMT content. Dynamic thermogravimetric analysis showed that the dispersion of clay nanolayers in the PBZ–PBO copolymer gave better thermal stability. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4741–4747, 2006     

Synthesis and characterization of 2‐oxazoline‐benzoxazine compound and its polymer

A novel 2‐oxazoline‐benzoxazine (POB) was synthesized with 2‐(hydroxylphenyl)‐2‐oxazoline, 1,3,5‐triphenylhexahydro‐1,3,5‐triazine and paraformaldehyde. The chemical structure of the monomer was confirmed by FTIR, ¹H‐NMR, ¹³C‐NMR, and MS. The curing behavior of the monomer was studied by DSC and FTIR, and the ring opening reaction of the monomer was found to occur from 187.5°C. The results of DMA and TGA demonstrated that the thermal properties of polymer for POB monomer (P‐m) are better than polymer for POB precursor (P‐p), because that the oligomer in benzoxazine precursor decreased the perfection of the polymer's network structure; it was also found that the thermal properties of P‐m and P‐p are much better than the common polybenzoxazine and the composite material of benzoxazine and 2‐oxazoline. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci , 2008.     

Synthesis and curing behavior of a novel benzoxazine‐based bisphthalonitrile monomer

A novel bisphthalonitrile containing benzoxazine units (BZ‐BPH) was synthesized via a solventless method from 4,4′‐dihydroxybiphenyl, paraformaldehyde, and 4‐aminophenoxylphthalonitrile. The chemical structure of BZ‐BPH was confirmed by ¹H‐NMR and ¹³C‐NMR analyses. The curing behavior was investigated with DSC, FTIR, TGA, and rheology techniques. The monomer manifested a two‐stage thermal polymerization pattern. The first stage was attributed to the ring‐opening polymerization of benzoxazine moiety, and the second to the polymerization of phthalonitriles. Study about the effect of the catalysts including 4,4′‐diaminodiphenylsulfone and FeCl₃ on the polymerization of BZ‐BPH was performed, and the result indicated that the addition of these agents could increase the curing rate and lower the curing temperature. Additionally, the cured product showed excellent thermal and thermo‐oxidative stability, the high char yield was 76.0% by weight at 800°C in nitrogen atmosphere and 81.2% by weight at 600°C in air, and temperature at 5% weight loss (T_5%) in nitrogen and air was 477.9°C and 481.7°C, respectively. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis,cationic polymerization and curing reaction with epoxy resin of 3,9‐di(p‐methoxybenzyl)‐1,5,7,11‐tetra‐oxaspiro(5,5)undecane

A new spiro ortho carbonate, 3,9‐di(p‐methoxybenzyl)‐1,5,7,11‐tetra‐oxaspiro(5,5)undecane was prepared by the reaction of 2‐methoxybenzyl‐1,3‐propanediol with di(n‐butyl)tin oxide, following with carbon disulfide. Its cationic polymerization was carried out in dichloromethane using BF₃‐OEt₂ as catalyst. The [¹H], [¹³C]NMR and IR data as well as elementary analysis of the polymers obtained indicated that it underwent double ring‐opening polymerization. The polymerization mechanism is discussed. The curing reaction of bisphenol A type epoxy resin in the presence of the monomer and a curing agent was investigated. DSC measurements were used to follow the curing process. In the case of boron trifluoride‐o‐phenylenediamine (BF₃‐OPDA) as curing agent, two peaks were found on the DSC curves, one of which was attributed to the polymerization of the epoxy group, and the other to the copolymerization of the monomer with the isolated epoxy groups or homopolymerization. However, when BF₃‐H₂NEt was used as curing agent, only one peak was present. IR measurement of the modified epoxy resin with various weight ratios of epoxy resin/monomer was performed in the presence of BF₃‐H₂NEt as curing agent. The results demonstrate that the conversion of epoxy group increases as the content of monomer increases. The curing process and the structure of the epoxy resin network are discussed. © 2000 Society of Chemical Industry     

New type of phenolic resin—The curing reaction of bisphenol A based benzoxazine with bisoxazoline and the properties of the cured resin. III. The cure reactivity of benzoxazine with a latent curing agent

The curing reaction of a bisphenol A based benzoxazine [2,2‐bis(3,4‐dihydro‐3‐phenyl‐1,3‐benzoxazine) propane (Ba)] and bisoxazoline with a latent curing agent and the properties of the cured resins were investigated. With a latent curing agent, the ring‐opening reaction of the benzoxazine ring occurred more rapidly, and then the phenolic hydroxyl group generated by the ring‐opening reaction of the benzoxazine ring also reacted with the oxazoline ring more rapidly. The cure time of molten resins from Ba and bisoxazoline with a latent curing agent was reduced, and the cure temperature was lowered, in comparison with those of resins from Ba and bisoxazoline without a latent curing agent. The melt viscosity of molten resins from Ba and bisoxazoline with a latent curing agent was kept around 50 Pa s at 80°C even after 30 min, and molten resins from Ba and bisoxazoline with a latent curing agent showed good thermal stability below 80°C. However, above 170°C, the curing reaction of Ba with bisoxazoline with a latent curing agent proceeded rapidly. Cured resins from Ba and bisoxazoline with a latent curing agent showed good heat resistance, flame resistance, mechanical properties, and electrical insulation in comparison with cured resins from Ba and bisoxazoline without a latent curing agent. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Curing of diglycidyl ether of bisphenol‐A epoxy resin using a poly(aryl ether ketone) bearing pendant carboxyl groups as macromolecular curing agent

BACKGROUND: Reactive thermoplastics have received increasing attention in the field of epoxy resin toughening. This paper presents the first report of using a novel polyaryletherketone bearing one pendant carboxyl group per repeat unit to cure the diglycidyl ether of bisphenol‐A epoxy resin (DGEBA). The curing reactions of DGEBA/PEK‐L mixtures of various molar ratios and with different catalysts were investigated by means of dynamic differential scanning calorimetry and Fourier transform infrared (FTIR) spectroscopy methods. RESULTS: FTIR results for the DGEBA/PEK‐L system before curing and after curing at 135 °C for different times demonstrated that the carboxyl groups of PEK‐L were indeed involved in the curing reaction to form a crosslinked network, as evidenced by the marked decreased peak intensities of the carboxyl group at 1705 cm^?1 and the epoxy group at 915 cm^?1 as well as the newly emerged strong absorptions of ester bonds at 1721 cm^?1 and hydroxyl groups at 3447 cm^?1. Curing kinetic analysis showed that the value of the activation energy (E_a) was the highest at the beginning of curing, followed by a decrease with increasing conversion (α), which was attributed to the autocatalytic effect of hydroxyls generated in the curing reaction. CONCLUSION: The pendant carboxyl groups in PEK‐L can react with epoxy groups of DGEBA during thermal curing, and covalently participate in the crosslinking network. PEK‐L is thus expected to significantly improve the fracture toughness of DGEBA epoxy resin. Copyright © 2009 Society of Chemical Industry     

Synthesis,characterization, and polymerization of a novel benzoxazine based on diethyltoluenediamine

A novel aromatic diamine‐based benzoxazine monomer (PDETDA) was successfully prepared from diethyltoluenediamine (DETDA), phenol, and paraformaldehyde through a simple one‐step solvent‐less method. The structure of PDETDA was confirmed by FTIR, ¹H NMR, and ¹³C NMR. The curing behavior of PDETDA was studied by DSC, FTIR, and rheological measurement. The results showed that the alkyl substituents on the benzene ring in DETDA not only facilitated the synthesis of PDETDA by effectively hindering the formation of triazine network, but also endowed PDETDA with the advantage of low viscosity (1 Pa s at 90°C). However, steric hindrance of the substituents made PDETDA difficult to form a crosslinked network through ring‐opening polymerization, and therefore only oligomers and noncrosslinked polymers were obtained. The curing kinetics of PDETDA was studied by nonisothermal DSC, and the results revealed that the curing of PDETDA displayed autocatalytic characteristic. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41920.     

New thermosetting resin from bisphenol A‐based benzoxazine and bisoxazoline

Bisphenol A‐based benzoxazine was prepared from bisphenol A, formaline, and aniline. Curing reaction of bisphenol A‐based benzoxazine with bisoxazoline and the properties of the cured resin were investigated. Consequently, using triphenylphosphite as a catalyst, for the first time the ring‐opening reaction of benzoxazine ring occurred at 170°C, and then the phenolic hydroxyl group generated by the ring‐opening reaction of the benzoxazine ring reacted with the oxazoline ring at 200°C. The melt viscosity of the molding compound was kept 0.1–1 Pa · s at 140°C even after 1.5 h, and increased rapidly at 180°C. It was realized that the molding compound showed good flowability below 140°C, curing reaction proceeded above 180°C rapidly. The cured resin from bisphenol A‐based benzoxazine and bisoxazoline showed good heat resistance, water resistance, electrical insulation, and mechanical properties, compared with the cured resin from bisphenol A‐type novolac and bisoxazoline. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1551–1558, 1999     

Preparation and cure behavior of organoclay‐modified allyl‐functional benzoxazine resin and the properties of their nanocomposites

A new type of polybenzoxazine‐clay nanocomposites were prepared by the in‐situ polymerization of allyl‐functional benzoxazine monomer, bis(3‐allyl‐3,4‐dihydro‐2H‐1,3‐benzoxazinyl)isopropane (B‐ala), in the presence of two different types of organoclay, allyldimethylstearylammonium‐montmorillonite and propyldimethylstearylammonium‐montmorillonite. The organoclays were mixed with molten B‐ala, followed by pouring into glass mold and then gradual curing up to 250°C. DSC and IR were used to follow the cure behavior of B‐ala in the presence of organoclay, indicating that organoclays catalyzed the ring opening of cyclic benzoxazine structure. The XRD of the nanocomposites showed featureless patterns, suggesting the exfoliation of the organoclay into the matrix. The viscoelastic properties of the hybrids showed that the glass transition temperatures (T_g) of the nanocomposites shifted to lower temperature in the presence of small amount of organoclay, but T_g started to increase with the increase of the organoclay content. This result suggests that, in the presence of organoclay, the curing reaction of ally and benzoxazine occurred in a different way, resulting in a different network structure. However, the presence of dispersed layered silicates into the matrix enhanced the thermal stability over the neat thermoset resin. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers     

Thermally activated polymerization behavior of bisphenol‐S/methylamine‐based benzoxazine

A bifunctional benzoxazine monomer, 6,6′‐bis(3‐methyl‐3,4‐dihydro‐2H‐benzo[e] [1,3]oxazinyl) sulfone (BS‐m), was synthesized from bisphenol‐S, methylamine, and formaldehyde via a solution method. The chemical structure of BS‐m was characterized with ¹H and ¹³C‐nuclear magnetic resonance (NMR) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, and elemental analysis. The ring‐opening polymerization reaction of BS‐m monomer was studied by FTIR, ¹³C solid‐state NMR, and differential scanning calorimetry. With the polymerization reaction proceeding, the intensities of the FTIR absorption peaks of CH₂, C? O? C, and C? N? C of the oxazine ring decreased gradually, and some of these absorption peaks disappeared. The shapes and intensities of the absorption peaks associated with benzene ring, sulfone group, and aromatic C? S bond changed in various ways. The changes in the solid‐state ¹³C‐NMR pattern, including chemical shifts, intensity of resonances, and line‐width, were observed from the spectra of BS‐m and the corresponding polybenzoxazine. The melting process of BS‐m overlapped with the beginning of the ring‐opening polymerization reaction. The polymerization kinetic parameters were evaluated for nonisothermal and isothermal polymerization of BS‐m. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Flexible polybenzoxazine thermosets containing pendent aliphatic chains

The rich chemistry of polybenzoxazines allows a wide range of molecular structure design by using appropriate starting materials. A new class of polybenzoxazines has been developed from benzoxazine monomers containing pendent long aliphatic chains. The monomers have been synthesized by the reaction of phenol or bisphenol A with two different long‐chain aliphatic amines. The chemical structure of the monomers was confirmed by ¹H nuclear magnetic resonance and Fourier transform infrared spectroscopy. The polymerization behavior of the monomers studied by differential scanning calorimetry shows exothermic peaks due to the ring‐opening polymerization of benzoxazine monomers centered at 247–255 °C. Dynamic mechanical analysis indicated that the glass transition temperatures T_g were in the range 81–92 °C. The thermal stability of the polymers was also examined by thermogravimetric analysis, demonstrating that the weight loss temperatures decreased in comparison with that of traditional polybenzoxazine. Copyright © 2011 Society of Chemical Industry     

Studies on new type of phenolic resin (IX) curing reaction of bisphenol A‐based benzoxazine with bisoxazoline and the properties of the cured resin. II. Cure reactivity of benzoxazine

Bisphenol A‐based benzoxazine that contained oligomers (oligo‐Ba) was prepared from bisphenol A, formaline, and aniline. Curing reaction of oligo‐Ba with bisoxazoline and the properties of the cured resin were investigated. Consequently, the ring‐opening reaction of benzoxazine ring occurred, and then the phenolic hydoroxyl group generated by the ring‐opening reaction of benzoxazine ring reacted with oxazoline ring. It was found that the cure induction time and cure time of the molten mixture from oligo‐Ba and bisoxazoline could be reduced and also the cure temperature could be lowered, compared with those from bisphenol A‐based benzoxazine, which contained no oligomers (Ba), and bisoxazoline. The melt viscosity of the molten mixture from oligo‐Ba and bisoxazoline was kept 0.1–10 [Pas] at 140°C even after 40 min, the molten mixture from oligo‐Ba and bisoxazoline showed good flowability below 140°C as well as that from Ba and bisoxazoline. However, above 160°C the curing reaction of oligo‐Ba with bisoxazoline proceeded more rapidly than that of Ba with bisoxazoline. The cured resin from oligo‐Ba and bisoxazoline showed good heat resistance and water resistance, compared with the cured resin from Ba and bisoxazoline. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 79: 2331–2339, 2001     

Hybridization of aqueous PU/epoxy resin via a dual self‐curing process

Amino‐terminated and carboxyl‐containing polyurethane (PU) is prepared by an isocyanate‐terminated PU prepolymer process. Carboxyl‐containing epoxy resin is obtained from a half‐esterification of epoxy resin with maleic anhydride. These two aqueous resins are obtained after neutralization with triethylamine and dispersion into water phase, respectively. A latent curing agent (TMPTA‐AZ) is prepared by a Michael addition of aziridine with trimethylolpropane triacrylate (TMPTA). A self‐curing system of PU/epoxy hybrid is obtained from a blending of these two aqueous resins with latent curing agent. PU/epoxy hybrid is derived from two self‐curing reactions on drying. The first curing for hybridization between PU amino groups with oxirane groups of epoxy resin is via a ring‐opening reaction and the secondary curing takes place on carboxyl groups of PU/epoxy hybrid with aziridine of TMPTA‐AZ. The final properties of these dual self‐cured PU/epoxy hybrids are reported. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

含双DOPO的双酚A-单苯并(口恶)嗪合成、表征及其与环氧树脂共聚物的阻燃性能

以含双DOPO-双酚A、苯胺和多聚甲醛为原料,合成了含双DOPO的双酚A-单苯并(口恶)嗪(1DD)。采用红外、核磁(氢谱核磁和碳谱核磁)等分析手段对1DD的化学结构进行了表征;采用DSC对1DD的固化特性进行研究,使用TG分析了所得聚苯并(口恶)嗪的热稳定性。再将1DD与环氧树脂以0.5/1的质量比进行共混,按照一定的程序进行升温固化,得到共聚物P1DD-ER。采用UL94垂直燃烧实验、极限氧指数仪(LOI)测试了共聚物的阻燃性能。结果表明:含双DOPO的双酚A-单苯并(口恶)嗪树脂的起始熔点约为185℃,在222℃处有一个很明显的放热峰。固化后的树脂从348℃开始分解,在463℃分解速率达到最快,在800℃时的残碳率为35.78%。制备的苯并(口恶)嗪可以用作环氧树脂的固化剂,且其共聚物具有很好的阻燃性能,LOI可以达到37,UL94等级为V-0。