三氟甲磺酸金属盐对苯并恶嗪固化及性能影响

采用示差扫描量热法(DSC)、原位红外分析(FT-IR)、X射线光电子能谱(XPS)和热失重法(TGA)研究了三氟甲磺酸金属(铝、镱、镧)盐对双酚A-苯胺型苯并恶嗪树脂固化反应和耐热性能的影响。结果表明,加入三氟甲磺酸金属盐后,苯并恶嗪树脂的固化温度明显降低,但其固化反应活化能却有一定程度的提高。苯并恶嗪可在较低温度下开环,形成苯胺对位Mannich桥、酚羟基邻位Mannich桥、苯胺对位亚甲基桥和酚羟基邻位亚甲基桥4种结构。此外,添加了催化剂的固化产物由于少量C=N键端基存在导致了其分解温度降低。但由于亚甲基桥连接2个苯环,在热降解过程中容易形成较为致密的炭层,最终导致固化产物的残炭量有所提升。     

氯化镧对苯并嗯嗪热稳定性的影响及机理研究

采用溶液法将氯化镧加入3种不同结构的苯并嗯嗪中,制备了浇注体,对固化产物进行了热失重测试和红外光谱分析,并对热降解逸出气体进行了红外光谱分析.结果表明,氯化镧的加入使得苯并嗯嗪的热稳定性和残炭率有很大提高.加入氯化镧的苯并嗯嗪固化物中形成了较多苯胺对位连接的Mannich桥结构,推迟了苯胺结构的降解,从而提高了苯并嗯嗪的热稳定性.     

氯化镧对苯并噁嗪热稳定性的影响及机理研究

采用溶液法将氯化镧加入3种不同结构的苯并噁嗪中,制备了浇注体,对固化产物进行了热失重测试和红外光谱分析,并对热降解逸出气体进行了红外光谱分析。结果表明,氯化镧的加入使得苯并噁嗪的热稳定性和残炭率有很大提高。加入氯化镧的苯并噁嗪固化物中形成了较多苯胺对位连接的Mannich桥结构,推迟了苯胺结构的降解,从而提高了苯并噁嗪的热稳定性。     

取代基电子效应对聚苯并噁嗪热稳定性影响研究

以苯酚/苯胺型苯并噁嗪和苯酚/4,4'–二苯甲烷二胺型苯并噁嗪为参照对象,通过DSC、TGA和TGA-FTIR联用测试,研究了酚羟基对位连有不同电子效应的取代基时,苯并噁嗪中间体开环聚合及其聚合物热稳定性的变化。结果表明,酚羟基对位氯原子的取代降低了苯并噁嗪中间体开环聚合的温度,而甲基的取代使苯并噁嗪中间体开环聚合的温度升高;由于氯原子的吸电子效应导致聚苯并噁嗪Mannich(曼尼希)桥上的C—N和C—C键被削弱,使得其热稳定性下降;甲基的取代使聚苯并噁嗪的交联密度下降,因而也降低了其热稳定性。     

取代苯胺对含烯丙基的苯并恶嗪的性能影响

以甲基苯胺和苯胺与多聚甲醛、烯丙基双酚A合成了含烯丙基的苯并恶嗪(BA),采用红外及核磁氢谱对其结构进行了表征。其与单官能度苯并恶嗪(PAF)在溶液中共混并加热固化。通过DSC,TGA及DMA对BA及共混物、固化物的热性能进行了研究。结果表明,BA固化峰值温度>250℃,与PAF共混后固化温度下降,且随PAF加入量的增加而下降。共混后固化后热稳定性较好,其中含间位取代苯胺的烯丙基苯并恶嗪与PAF共混树脂的热稳定和弯曲强度最高,热失重5%和10%时的温度分别为308℃、384℃,玻璃化转变温度为171℃,弯曲强度24 MPa。     

氢氧化镁改性苯并噁嗪树脂的热性能

本文应用示差量热扫描法(DSC)、动态热机械分析(DMA)和热失重(TGA)对氢氧化镁改性苯并噁嗪树脂的固化行为和热性能进行了研究。结果表明,氢氧化镁的加入对苯并噁嗪树脂的固化反应基本没有影响。DMA测试结果表明,氢氧化镁的加入使聚苯并噁嗪体系的玻璃化转变温度略微有所增高,室温下的储能模量略有增加。TGA测试结果表明,氢氧化镁的加入使聚苯并噁嗪体系的热稳定性提高,起始分解温度和800℃残重均有所提高。     

苯并恶嗪/环氧树脂/酸酐三元体系固化反应研究

采用重结晶双酚A-苯胺型苯并恶嗪(BA-a)、双酚A型环氧树脂(BPA-E)与聚苯乙烯马来酸酐(EF40)进行共聚反应。通过示差扫描量热分析和红外光谱测试对苯并恶嗪/酸酐、环氧树脂/酸酐二元体系及苯并恶嗪/环氧树脂/酸酐三元体系的固化行为及各阶段固化物结构进行了研究。结果表明:酸酐与苯并恶嗪、环氧树脂均发生反应,分别生成不同类型的酯键结构。在三元体系中,酸酐与环氧树脂首先反应,形成醇酯键;其次,苯并噁恶嗪自聚,聚苯并恶嗪中的酚羟基与少量酸酐、环氧树脂反应,生成酚酯键、羧酸或醚式结构,同时新生成的羧酸结构可促进苯并恶嗪开环聚合。     

微波固相法合成苯并恶嗪及其共混树脂的性能

邻位二烷基取代苯胺与苯酚和多聚甲醛经100 W微波辐照20 min反应得到了5种苯并恶嗪单体,将其中邻位为甲基和乙基取代的苯胺型苯并恶嗪与双酚A型苯并恶嗪(BAF)共混,采用红外光谱(FT-IR)、核磁共振氢谱(1H-NMR)、示差扫描量热仪(DSC)、动态机械分析(DMA)、热失重分析仪(TGA)、粘度仪和介电阻抗仪研究了共混树脂的粘温性、热性能及介电性能。结果表明,邻二甲基苯胺型苯并恶嗪(2m6m-BZ)与BAF以物质的量比3∶7共混的体系100～250℃下粘度<500 mPa.s,其固化后热性能接近固化后的纯BAF树脂,且介电常数<3.9,介电损耗低于0.003 5,优于其它共混树脂。     

酸性催化剂对苯并恶嗪三元共混体系固化的影响

采用DSC和FT-IR对双酚A-苯胺型苯并恶嗪/双环戊二烯型环氧树脂/聚苯乙烯马来酸酐三元共混体系在己二酸、间苯二酚、对甲苯磺酸和三氯化铁酸性催化剂作用下的固化行为,固化机理及固化物结构作了研究。结果表明,在几种酸性催化剂体系中环氧/酸酐共聚反应与苯并恶嗪自聚反应几乎同时发生,温度升高后,发生聚苯并恶嗪与环氧或酸酐的共聚反应,及其与环氧/酸酐共聚反应的竞争反应。在催化剂作用下竞争反应产生不同的结果,最终得到不同结构的固化产物。使用对甲苯磺酸作为催化剂,酸性较强,有利于聚苯并恶嗪与酸酐的共聚反应,产物中含有较多羧基。     

苯并噁嗪定向固化及热稳定性研究

以苯胺、苯酚和多聚甲醛为原料,采用无溶剂法合成了BZ(苯并噁嗪)预聚体;然后将BZ预聚体进行一般固化和定向固化,并着重探讨了不同固化方式对固化产物[即PBZ(聚苯并噁嗪)]热稳定性的影响。研究结果表明:固化温度和固化方式对PBZ的热稳定性影响较大。180℃一般固化的聚合物之热稳定性相对最高,其热失重5%时的对应温度为291℃;160℃定向固化的聚合物之热稳定性相对最高,其热失重5%时的对应温度为341℃;对同样的BZ预聚体而言,160℃定向固化的聚合物之热稳定性优于180℃一般固化的聚合物。     

Synthesis,thermal polymerization,and properties of benzoxazine resins containing fluorenyl moiety

Three difunctional fluorene‐based benzoxazine compounds were synthesized via Mannich condensation and were characterized by proton nuclear magnetic resonance spectroscopy (¹H NMR), Fourier transform infrared spectroscopy (FTIR), and elementary analysis (EA). The polymerization of benzoxazine monomers were investigated with differential scanning calorimeter (DSC) method. Thermal properties of the polybenzoxazines were studied by thermogravimetric analysis (TGA) and DSC. Water absorption of the polybenzoxazines was tested. Contact angle measurement was employed to characterize the surface property of materials. The glass transition temperatures (T_gs) and thermal stability were improved significantly in comparison with bisphenol‐A‐based analogue because of the incorporation of rigid fluorenyl group. The fluorenyl‐based polybenzoxazines showed hydrophobic characteristics, which was ascribed to the low polarity of fluorenyl and pi–pi stacking interaction of fluorenyl on the surface. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers     

稀土金属樟脑磺酸盐的制备和表征

合成了3种稀土金属(镧、钕和铈)樟脑磺酸盐,并用红外光谱(FTIR)和热重(TGA)分析进行了表征.TGA研究表明,所合成的3种盐分别含有7.72、6.26和5.93个结晶水.研究了其无水化合物的热稳定性,结果表明,樟脑磺酸铈的热稳定性较弱,樟脑磺酸镧和樟脑磺酸钕的热稳定性较强.并分析了空气气氛下各种盐的最终分解产物.     

过渡金属氧化物对苯并恶嗪热稳定性影响研究

将过渡金属氧化物TiO2、MnO2、CuO、Cu2O、ZnO、ZrO2以及Y2O3、CeO2、Sm2O3、Gd2O3分别添加到苯酚/4,4'-二苯甲烷二胺型苯并恶嗪(BB)中间体中,制备了过渡金属氧化物/BB固化物,通过FTIR、TGA和DMA分析研究了过渡金属氧化物对苯并恶嗪热稳定性的影响。结果表明,这些氧化物的添加不改变BB固化物的化学结构;除ZnO外,其他氧化物均使BB的热稳定性和800℃残炭率降低,这是由于过渡金属氧化物与BB中N原子间配位作用的形成削弱了C—N键,使其更易断裂。     

Energetic Salts of 5‐(5‐Azido‐1H‐1,2,4‐triazol‐3‐yl)tetrazole

Several metal and nitrogen‐rich salts of the recently presented 5‐(5‐azido‐1H‐1,2,4‐triazol‐3‐yl)tetrazole (AzTT), including silver ( 1 ), copper(I) ( 2 ), potassium ( 3 ), cesium ( 4 ), copper(II) ( 7 ), ammonium ( 8 ), and guanidinium ( 9 ), as well as the respective double‐salts of 3 , 4 , 8 and 9 , were prepared and well characterized by IR and multinuclear (¹H, ¹³C, ¹⁴N) NMR spectroscopy, DSC, mass spectrometry, elemental analysis and one ( 4 ) additionally by single‐crystal X‐ray diffraction. The sensitivities towards impact, friction and electrostatic discharge were determined according to BAM standards, revealing most of the metal salts as highly sensitive and the nitrogen‐rich salts as insensitive. The metal salts were further tested for their ability of being primary explosives.     

1-氨基-1-肼基-2,2-二硝基乙烯碱金属盐的制备及对改性双基推进剂主组分热分解的催化作用

1-氨基-1-肼基-2,2-二硝基乙烯（AHDNE）与氢氧化钾或碳酸铯反应得到相应的碱金属盐AHDNE-K 和AHDNE-Cs。 通过元素分析和红外光谱对其进行结构表征;采用单晶X射线衍射分析法测定了AHDNE-K的单晶结构,DSC技术研究了两种金属盐对3种改性双基推进剂主组分HMX、RDX和NC/NG热分解的影响。结果表明,AHDNE-K对NC/NG有明显的催化效果,使分解温度降低了约24 ℃,能量增加了1 316 J·g^-1。     

Synthesis,curing behavior and thermal properties of fluorene-containing benzoxazines based on linear and branched butylamines

A series of fluorene-containing benzoxazine monomers based on linear and branched butylamines were successfully synthesized in high purity and good yield through a facile one-pot procedure by the reaction of 9,9-bis-(4-hydroxyphenyl)-fluorene with paraformaldehyde and isomeric butylamines. The chemical structures of the target monomers were characterized by Fourier transform infrared (FT-IR), Elemental analysis, ¹H and ¹³C nuclear magnetic resonance (NMR). The curing behavior of benzoxazine monomers was studied by differential scanning calorimetry (DSC) and FT-IR. The thermal properties of cured polybenzoxazines were measured by DSC and thermogravimetric analysis (TGA). The results reveal that the polarity of solvent and the basicity of butylamines produce clear effects on the synthesis of the butylamine-based benzoxazine monomers. Also, the basicity and steric effect of butylamines exhibit significant effects on the curing behavior of benzoxazine monomers and the thermal properties of their polymers. The glass transition temperature and thermal stability of branched butylamine-based polybenzoxazines are higher than those of the corresponding linear butylamine-based polybenzoxazine and traditional bisphenol A-based polybenzoxazines.     

The Synthesis and Characterization of Star Shaped Metal Complexes of Triazine Cored Schiff Bases: Their Thermal Decompositions and Magnetic Moment Values

Tripodal ligand III, 2,4,6-tris(4-hydroxybenzimino)-1,3,5-triazine, was synthesized by reacting melamine with 4-hydroxybenzaldehyde. (E)-4-Bromo-2-((2-bromoethylimino)-methyl)phenol VI was obtained by reaction of 5-bromo-2-hydroxybenzaldehyde and 2-bromoethanamine hydrochloride. Melamine cored tripodal Schiff base VII (H₃L) was synthesized by reacting III with VI. Tripodal metal complexes were obtained by reacting H₃L and transition metal salts. The complexes were characterized by elemental analyses, FT-IR, ¹H NMR and LC–MS spectroscopy, thermal analyses and magnetic measurements. Finally, metal ratios of the complexes were determined by atomic absorption spectroscopy. The complexes are square-planar low-spin (S = 1/2) Co(II), diamagnetic square-planar Ni(II), square-planar (S = 1/2) Cu(II) and diamagnetic tetrahedral Zn(II).     

Synthesis and characterization of bio-based benzoxazines derived from thymol

In the present study, bio-based benzoxazine resins were synthesized from bio-based phenolic compound; thymol, and three different amines; ethylamine, aniline and 1,6-diaminohexane, and paraformaldehyde by solvent-free condensation reaction. The chemical structures of bio-based benzoxazines; T-ea (thymol, ethylamine), T-a (thymol, aniline), and T-dh (thymol, 1,6-diaminohexane) were characterized by proton nuclear magnetic resonance spectroscopy, Fourier transform infrared (FTIR) spectroscopy, elemental analysis, and high-resolution mass spectrometry. The curing studies of T-ea, T-a, and T-dh bio-based benzoxazines were performed by stepwise thermal treatment at 150, 175, 200, 225, and 250 °C. The polymerization (ring-opening and crosslinking reactions) of T-ea, T-a, and T-dh bio-based benzoxazines was investigated by FTIR spectroscopy. Cure analysis was conducted using differential scanning calorimetry and the changes in thermal properties of the T-ea, T-a, and T-dh bio-based benzoxazine resins and their corresponding thermally crosslinked polybenzoxazines PT-ea, PT-a, and PT-dh were studied by thermogravimetric analyzer. The results indicated that all the thymol-based polybenzoxazines have shown enhanced thermal stability. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47371.     

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