二烯丙基双酚A改性双马来酰亚胺三嗪树脂的固化工艺及性能

以烯丙基化合物改性的方法制得了改性双马来酰亚胺三嗪(BT)树脂,研究了改性BT树脂体系的固化动力学,求得表观活化能为45.9 kJ/mol,反应级数为0.842,确定了固化工艺,并采用力学性能分析和动态热机械分析等手段对树脂浇铸体的性能进行了研究.结果表明,对于烯丙基化合物改性BT树脂体系,二烯丙基双酚A具有改善双马来...     

Flame‐retardant materials based on phosphorus‐containing polyhedral oligomeric silsesquioxane and bismaleimide/diallylbisphenol a with improved thermal resistance and dielectric properties

Polyhedral oligomeric silsesquioxane containing 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DP) was used to flame‐retard 4,4′‐bismaleimidophenyl methane (BDM)/2,2′‐dially bisphenol A (DBA) resins, and the integrated properties of the resins were investigated. The fire resistance of BDM/DBA resins containing DP was analyzed by limiting oxygen index (LOI) and vertical burning (UL94) tests. The results show that DP increased the LOI of the resins from 25.3 to 38.5%. The BDM/DBA resins were evaluated to have a UL‐94 V‐1 rating, which did not satisfy the high standards of industry. On the other hand, BDM/DBA containing DP achieved a UL‐94 V‐0 rating. The thermal stability and char formation were studied by thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy. TGA and scanning electron microscopy–energy‐dispersive X‐ray spectrometry measurements demonstrated that the DP resulted in an increase in the char yield and the formation of the thermally stable carbonaceous char. The results of Raman spectroscopy showed that the DP enhanced the graphitization degree of the resin during combustion. Moreover, the modified BDM/DBA resins exhibited improved dielectric properties. Specifically, the dielectric constant and loss at 1 MHz of the BDM/DBA/15% DP resin were 3.11 and 0.008, respectively, only about 93 and 73% of those of the BDM/DBA resin. All of the investigations showed that DP was an effective additive for developing high‐performance resins with attractive flame‐retardant and dielectric properties. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41545.     

High‐performance hyperbranched poly(phenylene oxide) modified bismaleimide resin with high thermal stability,low dielectric constant and loss

High‐performance hyperbranched poly(phenylene oxide)‐modified bismaleimide resin with high thermal stability, low dielectric constant, and loss was developed, which is made up of hyperbranched poly(phenylene oxide) (HBPPO), 4,4′‐bismaleimidodiphenylmethane (BDM), and o, o′‐diallylbisphenol A (DBA). The curing reactivity, morphology, and performance of BDM/DBA/HBPPO resin were systemically investigated, and similar investigations for BDM/DBA resin were also carried out for comparison. Results show that BDM/DBA/HBPPO and BDM/DBA resins have similar curing mechanism, but the former can be cured at lower temperature than the later; in addition, cured BDM/DBA/HBPPO resin with suitable HBPPO content has better thermal stability and dielectric properties (lower dielectric constant and loss) than BDM/DBA resin. The difference in macroproperties between BDM/DBA/HBPPO and BDM/DBA resins results from the different chemical structures and morphologies of their crosslinking networks. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Curing behavior and dielectric properties of hyperbranched poly(phenylene oxide)/cyanate ester resins

A novel hyperbranched poly(phenylene oxide) (HBPPO) modified 2,2′‐bis(4‐cyanatophenyl) isopropylidene (BCE) resin system with significantly reduced curing temperature and outstanding dielectric properties was developed, and the effect of the content of HBPPO on the curing behavior and dielectric properties as well as their origins was thoroughly investigated. Results show that BCE/HBPPO has significantly lower curing temperature than BCE owing to the different curing mechanisms between the two systems, the difference also brings different crosslinked networks and thus dielectric properties. The dielectric properties are frequency and temperature dependence, which are closely related with the content of HBPPO in the BCE/HBPPO system. BCE/2.5 HBPPO and BCE/5 HBPPO resins have lower dielectric constant than BCE resin over the whole frequency range tested, while BCE/10 HBPPO resin exhibits higher dielectric constant than BCE resin in the low frequency range (<10⁴ Hz) at 200°C. At 150°C or higher temperature, the dielectric loss at the frequency lower than 10² Hz becomes sensitive to the content of HBPPO. These phenomena can be attributed to the molecular relaxation. Two relaxation processes (α‐ and β‐relaxation processes) are observed. The β‐relaxation process shifts toward higher frequency with the increase of temperature because of the polymer structure and chain flexibility; the α‐relaxation process appears at high temperature resulting from the chain‐mobility effects. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Preparation and properties of high‐performance polysilsesquioxanes/bismaleimide‐triazine hybrids

A novel kind of high‐performance hybrids (coded as POSS‐NH₂/BT) with significantly decreased curing temperature, lowered dielectric constant and loss, and improved thermal resistance were developed, which were prepared by copolymerizing bismaleimide with cage octa(aminopropylsilsesquioxane) (POSS‐NH₂) to produce POSS‐containing maleimide, and then co‐reacted with 2,2′‐bis(4‐cyanatophenyl) isopropylidene. The curing behavior and typical properties of cured POSS‐NH₂/BT were systematically investigated. Results show that POSS‐NH₂/BT hybrids have lower curing temperatures than BT resin because of the additional reactions between  OCN and amine groups. Compared with BT resin, all hybrids show improved dielectric properties. Specifically, hybrids have slightly decreased dielectric constants and similar dependence of dielectric constant on frequency over the whole frequency from 10 to 10⁶ Hz; more interestingly, the dielectric loss of hybrids is only 25% of that of BT resin at the frequency lower than 10⁵ Hz, whereas all hybrids and BT resin have almost equal dielectric loss when the frequency is higher than 10⁵ Hz. In addition, POSS‐NH₂/BT hybrids also show good thermal and thermo‐oxidative stability compared with BT resin. All these differences in macroproperties are attributed to the difference in chemical structure between POSS‐NH₂/BT hybrids and BT resin. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Catalytic effect of 2,2′‐diallyl bisphenol A on thermal curing of cyanate esters

Cyanate esters are a class of thermal resistant polymers widely used as thermal resistant and electrical insulating materials for electric devices and structural composite applications. In this article, the effect of 2,2′‐diallyl bisphenol A (DBA) on catalyzing the thermal curing of cyanate ester resins was studied. The curing behavior, thermal resistance, and thermal mechanical properties of these DBA catalyzed cyanate ester resins were characterized. The results show that DBA is especially suitable for catalyzing the polymerization of the novolac cyanate ester resin (HF‐5), as it acts as both the curing catalyst through depressing the exothermic peak temperature (T_exo) by nearly 100°C and the toughening agent of the novolac cyanate ester resin by slightly reducing the elastic modulus at the glassy state. The thermogravimetric analysis and dynamic mechanical thermal analysis show that the 5 wt % DBA‐catalyzed novolac cyanate ester resin exhibits good thermal resistance with T_d⁵ of 410°C and the char yield at 900°C of 58% and can retain its mechanical strength up to 250°C. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1775–1786, 2006     

二烯丙基双酚A催化改性酚醛型氰酸酯树脂的催化固化

研究了二烯丙基双酚A（DBA）催化改性酚醛型氰酸酯树脂（cy-5）,通过差示扫描量热法（DSC）、热重分析（TG）、冲击性能和动态热机械分析（DMA）测试,分析了改性树脂的热性能和力学性能。研究表明：DBA对cy-5有催化和增韧的双重作用,当DBA的添加量为5%（质量分数）时,催化效果最为明显,含10% DBA的改性树脂固化物的冲击强度达到7.41 kJ/m2,改性树脂固化物的玻璃化转变温度（Tg）和储能模量（E'）均有所降低,但幅度不大。     

Allylated novolac/4,4′‐bismaleimidodiphenylmethane resin containing polyhedral oligomeric silsesquioxane: Preparation,morphology and thermal stability

Allylated novolac/4,4′‐bismaleimidodiphenylmethane resin (AN/BDM) had been modified with well‐defined inorganic building blocks‐polyhedral oligomeric silsesquioxane (POSS). Octamaleimidophenyl polyhedral silsesquioxane (OMPS) was used as the cocuring reagent of the AN/BDM resin to prepare POSS‐modified AN/BDM resin, and POSS content was between 0 and 17.8 wt %. The curing reaction of the POSS‐modified AN/BDM resin was monitored by means of Fourier transform infrared spectroscopy (FTIR), and the results revealed that maleimide groups on OMPS molecule could undergothe curing reaction between allyl groups and maleimide groups. Therefore, the crosslinked network containing POSS was formed. Scanning electron microscopy (SEM) and X‐ray diffraction (XRD) were employed to study the morphology of the cured POSS‐modified AN/BDM resins. The homogeneous dispersion of POSS cages in AN/BDM matrices was evidenced. Thermogravimetric analysis (TGA) indicated that incorporation of POSS into AN/BDM crosslinked network led to enhanced thermal stability. The improved thermal stability could be ascribed to higher crosslink density and inorganic nature of POSS. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3903–3908, 2007     

Fluorinated bismaleimide resin with good processability,high toughness,and outstanding dielectric properties

In this study, novel fluorinated bismaleimide (BMI) resins were prepared by the copolymerization of 2,2′‐bis[4‐(4‐maleimidephenoxy)phenyl]hexafluoropropane (6FBMP) and diallyl hexafluorobisphenol A (6FDABPA) to enhance their dielectric properties. The dielectric properties of the resins were investigated in the frequency range 7–18 GHz through a cavity method. Through the incorporation of a hexafluoroisopropyl group with the polymer chain, the dielectric constant (ε) was effectively decreased because of the small dipole and the low polarizability of the carbon‐fluorine (C? F) bonds. The 6FBMP/6FDABPA resin possessed excellent dielectric properties, with ε being 2.88 and the dielectric loss being 0.009 at 10 GHz and 25°C. In comparison with the 4,4′‐bismaleimidodiphenylmethane (BDM)/2,2′‐diallyl bisphenol A (DABPA) resin, the glass‐transition temperature (T_g) of 6FBMP/6FDABPA decreased. The flexible ether group in the long chain of 6FBMP was considered to disrupt chain packing and cause a decreased crosslinking density and a lower T_g. 6FBMP/6FDABPA showed a similar thermal decomposition temperature and good thermal properties like the BDM/DABPA resin, whereas the impact strength of the 6FBMP/6FDABPA resin was almost 1.6 times higher than that of the BDM/DABPA resin. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42791.     

Flame retardancy and dielectric properties of dicyclopentadiene‐based benzoxazine cured with a phosphorus‐containing phenolic resin

A dicyclopentadiene‐based benzoxazine (DCPDBZ) was prepared and separately copolymerized with melamine–phenol formaldehyde novolac or phosphorus‐containing phenolic resin (phosphorus‐containing diphenol) at various molar ratios. Their curing behaviors were characterized by differential scanning calorimetry. The electrical properties of the cured resins were studied with a dielectric analyzer. The glass‐transition temperatures were measured by dynamic mechanical analysis. The thermal stability and flame retardancy were determined by thermogravimetric analysis and a UL‐94 vertical test. These data were compared with those of bisphenol A benzoxazine and 4,4′‐biphenol benzoxazine systems. The effects of the diphenol structure and cured composition on the dielectric properties, moisture resistance, glass‐transition temperature, thermal stability, and flame retardancy are discussed. The DCPDBZ copolymerized with phosphorus‐containing novolac exhibited better dielectric properties, moisture resistance, and flame retardancy than those of the melamine‐modified system. The flame retardancy of the cured benzoxazine/phosphorus‐containing phenolic resins increased with increasing phosphorus content. The results indicate that the bisphenol A and 4,4′‐biphenol systems with a phosphorus content of about 0.6% and the dicyclopentadiene system with a phosphorus content of about 0.8% could achieve a flame‐retardancy rating of UL‐94 V‐0. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Dielectric and thermal properties of polymer network based on bismaleimide resin and cyanate ester containing dicyclopentadiene or dipentene. III

A series of bismaleimide‐triazine (BT) resins were prepared from commercial bismaleimide (DDMBMI) and 2,6‐dimethylphenol‐dicyclopentadiene dicyanate ester (DCPDCY) or 2,6‐dimethylphenol‐dipentene dicyanate ester (DPCY). The thermal properties of cured BT resins containing DCPD or DP were studied using a dielectric analyzer (DEA), dynamic mechanical analyzer (DMA), and thermal gravimetric analyzer (TGA). These data were compared with that of DDMBMI cured with bisphenol A dicyanate ester (BADCY). The cured DDMBMI/DCPDCY or DDMBMI/DPCY exhibits a lower dielectric constant, dissipation factor, and moisture absorption than those of DDMBMI/BADCY. The effects of blend composition on the glass transition temperatures and thermal stability are discussed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1942–1951, 2007     

Synthesis of epoxy‐functionalized hyperbranched poly(phenylene oxide) and its modification of cyanate ester resin

High curing temperature is the key drawback of present heat resistant thermosetting resins. A novel epoxy‐functionalized hyperbranched poly(phenylene oxide), coded as eHBPPO, was synthesized, and used to modify 2,2′‐bis (4‐cyanatophenyl) isopropylidene (CE). Compared with CE, CE/eHBPPO system has significantly decreased curing temperature owing to the different curing mechanism. Based on this results, cured CE/eHBPPO resins without postcuring process, and cured CE resin postcured at 230°C were prepared, their dynamic mechanical and dielectric properties were systematically investigated. Results show that cured CE/eHBPPO resins not only have excellent stability in dielectric properties over a wide frequency range (1–10⁹Hz), but also show attractively lower dielectric constant and loss than CE resin. In addition, cured CE/eHBPPO resins also have high glass transition temperature and storage moduli in glassy state. These attractive integrated performance of CE/eHBPPO suggest a new method to develop high performance resins. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis and properties of trifluoromethyl groups containing epoxy resins cured with amine for low Dk materials

The study synthesized a trifluoromethyl (CF₃) groups with a modified epoxy resin, diglycidyl ether of bisphenol F (DGEBF), using environmental friendly methods. The epoxy resin was cured with 4,4′‐diaminodiphenyl‐methane (DDM). For comparison, this study also investigated curing of commercially available diglycidyl ether of bisphenol A (DGEBA) with the same curing agent by varying the ratios of DGEBF. The structure and physical properties of the epoxy resins were characterized to investigate the effect of injecting fluorinated groups into epoxy resin structures. Regarding the thermal behaviors of the specimens, the glass transition temperatures (T_g) of 50–160°C and the thermal decomposition temperatures of 200–350 °C at 5% weight loss (T_d5%) in nitrogen decreased as amount of DGEBF increased. The different ratios of cured epoxy resins showed reduced dielectric constants (D_k) (2.03–3.80 at 1 MHz) that were lower than those of pure DGEBA epoxy resins. Reduced dielectric constant is related to high electrronegativity and large free volume of fluorine atoms. In the presence of hydrophobic CF₃ groups, the epoxy resins exhibited low moisture absorption and higher contact angles. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Preparation and characterization of soluble bismaleimide‐triazine resins based on asymmetric bismaleimide

A series of bismaleimide‐triazine resins (EBT) were prepared from 2‐(4′‐maleimido)phenyl‐2‐(4′‐maleimidophenoxyl)phenylbutane (EBA‐BMI) and 2,2‐bis(4‐cyanatophenyl)propane (BADCy). The resins show attractive processability with good solubility in low boiling point solvents and wide processing temperature windows. Introduction of diallylbisphenol A (DBA) can decrease the curing temperature of EBT resins that the curing exothermic peak temperature shifted from 291 to 237 °C as the content of DBA increased from 0 to 20%. The curing condition influenced the thermal properties of the cured EBT resins. The glass transition temperature increased as the curing temperature and curing time increased. The cured EBT resins show high glass transition temperature up to 352 °C, high thermal stability with 5% weight loss temperature over 405 °C, low coefficient of thermal expansion about 45 to 52 ppm/°C, and high storage modulus up to 2.6 GPa at 250 °C. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44519.     

A simple imide compound as a curing agent for epoxy resin. I. Synthesis and properties

A simple imide compound, 4‐amino‐phthalimide (APH), was synthesized as a curing agent for epoxy resin. APH was prepared from the hydration of 4‐nitro‐phthalimide, which was prepared from the nitration of phthalimide. The chemical structure of APH was verified by IR and ¹H‐NMR spectra. The thermal properties and dielectric constant (ε) of a phosphorus‐containing novolac epoxy resin cured by APH were determined and compared with those of epoxy resins cured by either 4,4′‐diamino diphenyl methane (DDM) or 4,4′‐diamino diphenyl sulfone (DDS). The results indicate that the epoxy resin cured by APH showed better thermal stability and a lower ε than the polymer cured by either DDM or DDS. This was due to the introduction of the imide group of APH into the polymer structure. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

烯丙基双酚A改性双马来酰亚胺-三嗪树脂的热性能

以4,4′-二苯甲烷双马来酰亚胺、双酚A型氰酸酯和2,2-二烯丙基双酚A为基本原料制备了改性双马来酰亚胺-三嗪（BT）树脂。系统地研究了2,2-二烯丙基双酚A对BT树脂固化动力学、BT树脂的溶解性能和BT树脂固化物的热性能的影响。研究结果表明：烯丙基双酚A有效地降低了BT树脂的固化反应温度并提高了BT树脂的溶解性能。当烯丙基双酚A的加入量为20%（质量分数）时,BT树脂的固化反应峰值降至233.1 ℃;并且,其固化物的玻璃化转变温度仍然达到239.4 ℃,5%热失重温度为372.9 ℃,显示了良好的耐热性能。     

Rheological study of crosslinking and gelation in bismaleimide/cyanate ester interpenetrating polymer network

In searching for high performance polymer resins that have a combination of low dielectric constant and loss, high temperature resistance, ease of being processed, and other desirable properties, an interpenetrating polymer network (IPN) based on cyanate ester (CE) and 2,2′‐diallylbisphenol A (DBA) modified bismaleimide resin (BMI) was prepared via prepolymerization followed by thermal curing. This work discusses the use of multiple waveform rheological technique to investigate the crosslinking and gelation behavior of this resin system at various temperatures. The gel point can be accurately determined from a single experiment using this technique. At the point of gelation, both the storage modulus (G′) and loss modulus (G″) of the IPN follow a similar power law equation with oscillation frequency used in the rheological measurement. Both the relaxation exponent n, a viscoelastic parameter related to the cluster size of the gel, and gel strength S, related to the mobility of the crosslinked chain segments, were determined via a curve fitting method. Both n and S were found to be temperature dependent in this BMI/DBA–CE IPN system. The apparent activation energy of gelation or curing reaction was found to be approximately 47.6 kJ/mol. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2437–2445, 2001     

Synthesis of functionalized GO for improving the dielectric properties of bismaleimide-triazine resin

A type of functionalized graphene oxide (GO), named GO-POSS-BPA, was synthesized by nucleophilic substitution reaction with chloropropyl polyhedral oligomeric silsesquioxanes (POSS) and bisphenol A (BPA). Subsequently, the GO-POSS-BPA was added into bismaleimide-triazine (BT) resin to improve dielectric properties of bismaleimide-triazine resin. The structure of GO-POSS-BPA was characterized by Fourier-transform infrared spectra (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and transmission electron microscopic (TEM). The effects of GO-POSS-BPA on the dielectric, mechanical, thermal and water resistant properties of BT resin were investigated systematically. The results show that, GO-POSS-BPA decreased the dielectric constant and dielectric loss of BT resin over the testing frequency from 10 to 50 MHz, also enhanced the stability of dielectric constant. Meanwhile, the appropriate content of GO-POSS-BPA can enhance the impact and flexural strengths of BT resin to a certain extent. In addition, GO-POSS-BPA can also enhance the thermal stability and moisture resistance of BT resin.     

Curing behavior and thermal mechanical properties of cyanate ester blends

Cyanate esters are a class of important thermally resistant polymers. To tailor their processability and thermomechanical properties, a series of cyanate ester blends based on a trifunctional novolac cyanate ester (HF‐5), a difunctional bisphenol E cyanate ester (HF‐9), and a reactive catalyst [2,2′‐diallyl bisphenol A (DBA)] were formulated. The effect of the blend composition on the rheology and curing behavior of these cyanate ester blends and the corresponding thermal and mechanical properties of the cured cyanate ester blends was studied. The results showed that HF‐5 contributed to good mechanical property retention at high temperatures because of its trifunctionality, whereas HF‐9 imparted processability by reducing the viscosity and extending the pot life of the formulated cyanate ester blends at the processing temperature. On the basis of the results, an optimal cyanate ester blend suitable for resin transfer molding was determined: the HF‐5/HF‐9/DBA weight ratio of 80 : 15 : 5 exhibited good processability and thermomechanical properties. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4284–4290, 2006