Preparation and properties of high performance phthalide‐containing bismaleimide modified epoxy matrices

A series of intercrosslinked networks formed by diglycidyl ether of bisphenol A epoxy resin (DGEBA) and novel bismaleimide containing phthalide cardo structure (BMIPP), with 4,4′‐diamino diphenyl sulfone (DDS) as hardener, have been investigated in detail. The curing behavior, thermal, mechanical and physical properties and compatibility of the blends were characterized using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), notched Izod impact test, scanning electron microscopy (SEM) and water absorption test. DSC investigations showed that the exothermic transition temperature (T_p) of the blend systems shifted slightly to the higher temperature with increasing BMIPP content and there appeared a shoulder on the high‐temperature side of the exothermic peak when BMIPP content was above 15 wt %. TGA and DMA results indicated that the introduction of BMIPP into epoxy resin improved the thermal stability and the storage modulus (G′) in the glassy region while glass transition temperature (T_g) decreased. Compared with the unmodified epoxy resin, there was a moderate increase in the fracture toughness for modified resins and the blend containing 5 wt % of BMIPP had the maximum of impact strength. SEM suggested the formation of homogeneous networks and rougher fracture surface with an increase in BMIPP content. In addition, the equilibrium water uptake of the modified resins was reduced as BMIPP content increased. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Phosphonate‐containing bismaleimide resins. II. Preparation and characteristics of reactive blends of phosphonate‐containing bismaleimide and epoxy

Two kinds of phosphonate‐containing bismaleimide (BMI) monomers, phenyl‐(4,4′‐bismaleimidophenyl) phosphonate and ethyl‐(4,4′‐bismaleimido‐phenyl) phosphonate, were synthesized and added through blending to two epoxy systems for the study of their applications as reactive flame retardants. The thermal behaviors of the BMI monomers in both kinds of epoxy systems, bisphenol and phenol–novolac, were similar. An increase in the BMI contents increased the storage modulus and glass‐transition temperature but slightly reduced the mechanical strength of the epoxy blends. The pyrolysis models of both BMI blends in the two epoxy systems were quite alike. Although the initial pyrolysis temperatures of all the blending systems gradually decreased as the phosphorous content increased, the flame retardancy of all the phosphonate‐containing epoxy systems was promoted significantly by increasing contents of BMI. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2375–2386, 2004     

双马改性酚醛树脂的耐热性及热分解动力学研究

采用二笨甲烷型双马来酰亚胺对酚醛树脂进行改性,制备出一种耐热性良好的改性酚醛树脂.采用热重分析法研究了双马来酰亚胺改性酚醛树脂的热分解动力学,并用Kissinger法、Ozawa法、Crane法计算其热分解动力学参数.结果表明,改性树脂的平均表观活化能为376.144kJ/mol,反应级数为0.940,其热分解分为3个...     

Intermolecular force and thermal properties of the sulfonyl epoxy blends cured with DGEBA epoxy

The sulfonyl epoxy monomer (SEP) was synthesized and further to blend with the diglycidyl ether of bisphenol A (DGEBA). The glass transition temperature (T_g) of the SEP/DGEBA blended materials increased from 103.7 to 163.8°C. The cross‐linking density and polymer chain self‐association intra‐molecular action affected more than that the polymer–polymer intermolecular action (hydrogen bonding) in the SEP blended with the DGEBA materials. The excess stabilization energy in the overall stabilization was only 0.00145% (14.5 ppm), which indicated that the polymer‐polymer intermolecular action was weak. The thermal degradation of the SEP segments could form various sulfate derivatives at lower temperature and analyzed by the TGA/GC/Mass. The sulfate derivatives could generate the thermal stable chars, which provided the “shielding effect” and antioxidation property. Additionally, these chars could also improve the protective effect and inhibit the thermal‐oxidation decomposition under the air atmosphere. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis and properties of brominate bismaleimide monomers

Brominated bismaleimides were prepared by reacting 3(4)‐maleimidobenzoylchloride with various bisphenols, using chloroform as solvent and triethylamine as acid acceptor. These monomers were characterized by elemental analysis, infrared (IR), and proton nuclear resonance (¹H‐NMR) spectroscopy. Thermal properties of monomers were accomplished by differential scanning calorimetry (DSC) and dynamic thermogravimetric analysis (ATG). The properties of these compounds were compared with those of monomers derived from bisphenol A and bisphenol A chlorinated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3881–3885, 2006     

苯并(噁)嗪和双马来酰亚胺共混树脂性能的研究

将苯并噁嗪(BOZ)和双马来酰亚胺树脂(BMI)按照不同的配比进行共混固化,制备了浇铸体和玻璃纤维增强的层压板。测试结果表明,BOZ和BMI共混的树脂浇铸体线性收缩率为0.85%~0.93%,小于BMI的1.3%略高于BOZ的0.73%。浇铸体和层压板的弯曲强度均随着BOZ含量的增加而上升,并且层压板吸水率还具有不断降低的趋势;其电气绝缘性能较佳。同时该共混树脂体系具有较好的耐热性,其Tg最高达到257℃比单纯BOZ的Tg提高了近50℃。DSC结果表明BOZ/BMI树脂体系的固化反应相对二者各自固化反应向低温移动,使体系中的BMI在相对较低的温度就固化完全。     

Preparation and thermal properties of hybrid nanocomposites of poly(methyl methacrylate)/octavinyl polyhedral oligomeric silsesquioxane blends

A series of poly(methyl methacrylate) (PMMA)/octavinyl polyhedral oligomeric silsesquioxane (POSS) blends were prepared by the solution‐blending method and characterized with Fourier transform infrared, X‐ray diffraction, transmission electron microscopy, differential scanning calorimetry, and thermogravimetric analysis techniques. The glass‐transition temperature (T_g) of the PMMA–POSS blends showed a tendency of first increasing and then decreasing with an increase in the POSS content. The maximum T_g reached 137.2°C when 0.84 mol % POSS was blended into the hybrid system, which was 28.2°C higher than that of the mother PMMA. The X‐ray diffraction patterns, transmission electron microscopy micrographs, and Fourier transform infrared spectra were employed to investigate the structure–property relationship of these hybrid nanocomposites and the T_g enhancement mechanism. The results showed that at a relatively low POSS content, POSS as an inert diluent decreased the interaction between the dipolar carbonyl groups of the homopolymer molecular chains. However, a new stronger dipole–dipole interaction between the POSS and the carbonyl of PMMA species formed at the same time, and a hindrance effect of nanosize POSS on the motion of the PMMA molecular chain may have played the main role in the T_g increase of the hybrid nanocomposites. At relatively high POSS concentrations, the strong dipole–dipole interactions that formed between the POSS and carbonyl groups of the PMMA gradually decreased because of the strong aggregation of POSS. This may be the main reason for the resultant T_g decrease in these hybrid nanocomposites. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Rheological and thermal properties of polypropylene blends based in a low molecular weight EVA

Blends of polypropylene (PP) and poly(ethylene-co-vinyl acetate) (EVA) having a PP/EVA viscosity ratio of 240 were prepared by melt mixing. EVA concentration varies from 2 to 26 wt%. All blends display two-phase structure with quasi-spherical EVA domains evenly distributed in the PP matrix. The diameter of the domains increases with EVA concentration from about 0.4 to 6 μm. Each component crystallizes separately. The melting temperature of PP phase is no noticeably affected by the presence of EVA while the crystallization one gradually increases by 4°C. The dynamic moduli of the blends are well predicted by the emulsion model of Palierne, revealing that the system PP/EVA has a very small interfacial tension. The thermal degradation behavior of the blends, determined by thermogravimetry, shows that the deacylation process in EVA is not affected by the presence of PP while the beginning of the degradation process of PP is increased by up to 20°C due to the presence of EVA. This effect goes along with an increment in the maximum degradation rate of PP.     

Thermal properties of new bismaleimide resins containing hydrogen silsesquioxane and diallyl bisphenol A

Bismaleimide (BMI) resins modified with hydrogen silsesquioxane (HSQ) and diallyl bisphenol A (DABPA) (BMI‐HSQ‐DABPA resins) were prepared. DSC, FTIR, and TGA were used to characterize the curing behaviors, structures, and thermal properties of the BMI‐HSQ‐DABPA resins, respectively. The results showed that the glass transition temperatures and thermal stabilities of the cured BMI‐HSQ‐DABPA resins increased with the rise of the contents of HSQ. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

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     

Preparation and thermal properties of novel phthalonitrile oligomer containing biphenyl ethernitrile/bisphthalonitrile blends

A kind of novel n = 2 phthalonitrile oligomer containing biphenyl ethernitrile (2PEN‐BPh) had been firstly synthesized from 2,6‐dichlorobenzonitrile, 4,4′‐biphenol and 4‐nitrophthalonitrile via solution reaction, and the 2PEN‐BPh was characterized by FTIR, ¹H‐NMR spectra which exhibited that cyano groups and ethernitrile linkages existed in the backbone of 2PEN‐BPh. The 2PEN‐BPh oligomer was blended with bisphthalonitrile monomer, the curing reaction behaviors of the blends were studied by FTIR, DSC, and rheological analysis. The thermal and thermo‐oxidative stabilities of the 2PEN‐BPh/BPh polymers were investigated by TGA, and the results showed that the completely cured polymers could achieve char yields up to 78% at 800°C in nitrogen, above 11% at 800°C in air. The whole research indicated that the 2PEN‐BPh/BPh blends could efficiently improve the processability of BPh monomer without scarifying other desirable high temperature properties. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Effect of addition of oligobetapinene on morphology,thermal and gas permeation properties in blends with HDPE

Binary blends of high density polyethylene (HDPE) and oligobetapinene (OBP) were prepared by melt mixing. The morphology, thermal and permeability properties of compression molded and slow cooled films are reported. Applying the first‐derivative procedure on differential scanning calorimetry (DSC) traces, we have detected the temperature of glass transition (T_g) of HDPE as a large peak centered from ?125 to ?100°C. In the blends, we observed that the OBP molecules were able to resolve the transition into two components. The lower one was ascribed to the γ‐transition of HDPE, and the upper one was attributed to its T_g. The OBP molecules also formed another transition at a higher temperature. The blends were composed at least of three distinct phases, likely composed of amorphous HDPE with some amount of OBP molecules, amorphous OBP with some polyolefin and crystalline HDPE. The scanning electron microscopy (SEM) investigations revealed segregation of the components. The permeation to CO₂ of plain HDPE and 90/10 blends was similar, but at higher concentrations of oligomer, the value was slightly higher than that of neat HDPE. The decrease of overall crystallinity was counterbalanced by the presence of an OBP rich phase in the blend and could explain the slight increase in permeability of the film blends. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 315–320, 2004     

改性双马树脂/碳纤维复合材料体系耐湿热性能研究

对5428/T700复合材料的吸湿率、不同吸湿条件下的玻璃化转变温度及高温湿态力学性能进行了研究。结果表明,5428/T700体系具有较低的吸湿率,经70℃去离子水水煮72 h,吸湿率为0.5%,饱和吸湿率(水煮360 h)为0.8%。而且随着复合材料吸湿量的增加,其Tg下降缓慢;5428/T700复合材料在干态170℃下的弯曲性能和层间剪切性能保持率在70%以上,在湿态150℃下的弯曲性能和层间剪切性能保持率在50%以上;5428/T700复合材料在湿态150℃下的开孔压缩强度保持率在80%以上。     

二元胺型苯并噁嗪/双马来酰亚胺共混树脂及其玻璃布增强的层压板

苯并噁嗪(BZ)和双马来酰亚胺(BMI)按照不同的配比进行共混固化。用FTIR、DSC、凝胶化时间、DMA、TGA、万能电子拉力机分别研究了BZ/BMI共混体系的固化行为以及BZ/BMI固化树脂的热性能和剪切强度等。结果表明BZ和BMI除了发生均聚反应,还发生苯并噁嗪开环生成的酚羟基和双马来酰亚胺的双键生成醚键的反应。BZ和BMI共混后,固化温度比各自的固化温度都低。BMI的加入提高了共混树脂的热性能,BZ/BMI固化树脂的T_g达289℃,T_d5达387℃,T_d10达422℃,800℃的残炭率达55.3%。另外,BMI的加入提高了BZ/BMI固化树脂的剪切强度,当BMI的含量为60％时,BZ/BMI固化树脂的剪切强度为12.44 MPa。进一步,制备了玻璃布增强的BZ/BMI层压板,并对其力学性能和断面形貌进行了研究。结果表明,当BMI用量为40%时,BZ/BMI层压板的拉伸强度、弯曲强度、冲击强度分别达394 MPa、490 MPa、160 kJ·m^-2。     

Nitrile functionalized benzoxazine/bismaleimide blends and their glass cloth reinforced laminates

A novel high‐performance resin blend composed of nitrile functionalized benzoxazine (CNBZ) and bismaleimide (4,4′‐bismaleimidodiphenyl methane) (BMI) was prepared via solvent method. Its curing behaviors, thermal properties, and mechanical properties were studied by differential scanning calorimetry (DSC), fourier transform infrared spectroscopy (FTIR), dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA), and universal testing machine, respectively. The results showed that the addition reaction between phenolic hydroxyl group and the double bond occurred except for the homopolymerization of CNBZ and BMI. When BMI content was more than 40%, the cured CNBZ/BMI blends exhibited higher glass transition temperatures (T_gs) than CNBZ and BMI homopolymers, which reached up to 334°C. Meanwhile, when BMI content was 40%, the tensile strength, flexural strength, and shearing strength reached up to 69, 235, and 12.9 MPa, respectively, which exhibited the comparable mechanical properties with BT resin. Furthermore, the glass cloth (GF) reinforced laminates based on these blends were prepared. The results showed that when BMI content was 40%, their tensile strength, flexural strength, and impact strength reached up to 334 MPa, 593 MPa, and 145 KJ m^?2, respectively. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41072.     

Synthesis of bismaleimide resin containing the poly(ethylene glycol) side chain: Curing behavior and thermal properties

Two maleimido end‐capped poly(ethylene glycol) (m‐PEG) of different molecular weights were synthesized and blended at various proportions with bismaleimide resin (4,4′‐bismaleimido diphenylmethane) (BDM). The curing behavior and the thermal properties of the m‐PEG/BDM blends were studied and presented here. It was found that the addition of m‐PEG enhanced the processability of the BDM resin significantly. The processing window of the BDM resin was increased from approximately 20 to 80°C. The addition of m‐PEG modified resins, however, resulted not only in the reduction in the thermal stability of the blended BDM resin but also elevation of the coefficients of thermal expansion. The changes in thermal/mechanical properties of the blends were found to be proportional to the amounts of m‐PEG incorporated. It was observed that the curing behavior, and thermal and mechanical properties, of the blends were independent of the molecular weight of the PEG segment. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2935–2945, 2002     

Synthesis and cure of liquid crystalline diallyl modifiers for bismaleimide resin

Three kinds of liquid crystalline aromatic azomethine modifiers were synthesized with high yield, and the modification of bismaleimide resin (BMI) with them was studied by scanning electron microscope, polarizing optical microscope, thermogravimetric analyzer, differential scanning calorimetry, and rheolometry. Blends cured at the temperature of liquid crystalline phase were found to have oriented liquid crystal‐rich phase and improved mechanical properties. The addition of o,o′‐diallyl bisphenol A in the blends of BMI decreases thermal properties but shows little effect on phase structures. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4366–4371, 2006     

新型含硼苯并噁嗪的合成及其与环氧树脂共混热性能

以乙醇胺、硼酸为原料合成硼酸乙醇胺酯（BAE）,再用所得硼酸乙醇胺酯与多聚甲醛、苯酚反应,合成含硼苯并噁嗪（BAE-BOZ）。将所得BAE-BOZ高温固化,BAE-BOZ和环氧树脂E-51按照不同的质量比进行熔融共混,并经高温固化。采用FT-IR,¹H NMR 和¹³C NMR等分析了BAE-BOZ的化学结构,证明了产物为目标产物;采用DSC对BAE-BOZ的固化特性进行研究;采用TG 分析了含硼乙醇胺型苯并噁嗪poly（BAE-BOZ）和BAE-BOZ/E-51共聚物的热稳定性。结果表明：BAE-BOZ在218℃出现了固化峰;BAE-BOZ的硼含量达到8.67%,在N₂条件下,poly（BAE-BOZ）的热分解温度为302℃,在426℃时热分解速率最快,800℃的残炭率为58.08%,与未经硼改性的乙醇胺型苯并噁嗪（E-BOZ）相比,热分解温度提高40℃,残炭率提高了16.28%;BAE-BOZ/E-51共聚物的热分解温度达到343℃,热性能得到进一步提高。     

Preparation,intermolecular motion,and thermal properties of thiodiphenyl epoxy

The thiodiphenyl epoxy (THEP) was prepared by the 4,4′‐thiodiphenol (THDOL) and the epichlorohydrin (ECH) without using any NaOH or KOH catalysts. The THEP possessed weak hydrogen bonding in the cured THEP/DGEBA system. The intermolecular motion parameters k and q were 0.26 and ?168.5, respectively, which determined by the Gordon‐Taylor and Kwei equations. The soft sulfide linkage (? S? ) of the THEP degraded at lower temperature than cured DGEBA material, and further to form various thermal stable sulfate derivative chars. The char yields increased from 11.43 to 25.94 wt % and from 0.65 to 1.04 wt % in the nitrogen and air, respectively. Introduction of the THEP into the DGEBA could provide the antioxidation thermal property and improve the thermal stability of the DGEBA epoxy in the air. In the air atmosphere, the activation energies of the second thermal degradation were increased from 66.67 to 103.42 kJ/mol. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparation and properties of halogen‐free flame‐retarded phthalonitrile–epoxy blends

Halogen‐free flame‐retarded blends composed of 2,2‐bis[4‐(3,4‐dicyanophenoxy) phenyl] propane (BAPh) and epoxy resin E‐44 (EP) were successfully prepared with 4,4′‐diaminodiphenyl sulfone as a curing additive. The structure of the copolymers was characterized by Fourier transform infrared spectroscopy, which showed that epoxy groups, a phthalocyanine ring, and a triazine ring existed. The limiting oxygen index values were over 30, and the UL‐94 rating reached V‐0 for the 20 : 80 (w/w) BAPh/EP copolymers. Differential scanning calorimetry and dynamic rheological analysis were employed to study the curing reaction behaviors of the phthalonitrile/epoxy blends. Also, the gelation time was shortened to 3 min when the prepolymerization temperature was 190°C. Thermogravimetric analysis showed that the thermal decomposition of the phthalonitrile/epoxy copolymers significantly improved with increasing BAPh content. The flexible strength of the 20:80 copolymers reached 149.5 MPa, which enhanced by 40 MPa compared to pure EP. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012