酶催化聚酚及其衍生物的合成和热性能

利用聚酚和4-硝基邻苯二甲腈的亲核取代反应,将邻苯二甲腈单元引入到了聚酚中。傅里叶转变红外光谱(FT-IR)证实了其基本的结构单元,凝胶渗透色谱法(GPC)结果显示在聚酚衍生物的合成中可能发生了一些链段的断裂。利用差示扫描量热计(DSC)和热重分析(TGA)技术对聚酚及其衍生物进行了分析,热分析结果显示聚酚衍生物的热性能较聚酚有一定的提高,预固化试验揭示了分子结构中的氰基在羟基的存在下发生了自加速热聚合,从而对聚酚衍生物的热性能提高有较大贡献。     

含氧族元素过渡链的邻苯二甲腈衍生物的性能

合成了四种含氧族元素过渡链(醚键及硫醚键)的邻苯二甲腈衍生物,红外光谱(FT-IR)和核磁共振氢谱(1H-NMR)证实了它们的结构。氮气氛下的热重分析(TGA)和差示扫描量热分析(DSC)对四种单体的性能进行的表征结果显示,带有氨基的邻苯二甲腈衍生物在高温下出现了自加速热固化现象,不带氨基的邻苯二甲腈衍生物没有出现自加速热固化现象;含硫醚键的邻苯二甲腈衍生物热性能可以优于对应的含醚键衍生物。含硫醚键的邻苯二甲腈衍生物在空气氛中的TGA测试结果显示,由于未发生热氧化交联反应,但热氧化降解明显,其热性能反而更低。     

含聚硅氧烷链段邻苯二甲腈树脂的制备及性能

以端羟基聚二甲基硅氧烷和4-硝基邻苯二甲腈为原料,在强极性溶剂中进行亲核取代反应合成了含聚硅氧烷链段邻苯二甲腈树脂(SIPH),并利用氨基改性剂(AWL)与该树脂进行反应制备了改性含聚硅氧烷链段邻苯二甲腈树脂预聚物(SIPH-AL)。通过红外光谱和核磁共振表征了SIPH树脂的化学结构;采用差示扫描量热法、红外光谱法、热重分析和动态力学热分析表征了SIPH-AL的固化行为和固化物的耐热性。结果表明,SIPH-AL起始固化温度为207℃,其固化物在空气和氮气中失重5%的温度(T_d5)及1000℃质量保留率分别是453℃,29%和500℃,77%;石英纤维增强SIPH-AL复合材料室温和600℃时的弯曲强度分别为515.5 MPa和94.5 MPa,玻璃化转变温度(T_g)高于500℃。     

聚芳醚腈/双邻苯二甲腈树脂共混改性与性能研究

通过联苯型双邻苯二甲腈与聚芳醚腈熔融共混形成预聚物,经高温固化及后热处理制备了聚芳醚腈/双邻苯二甲腈共混体系,研究了其耐热性能、力学性能、形貌特征以及其微观结构与性能之间的关系。其共混体系固化物的弯曲强度,断裂弯曲应变等性能较纯双邻苯二甲腈树脂均有大幅度的提高,并且保持了纯双邻苯二甲腈树脂耐高温,高模量等优越性能。当聚芳醚腈的含量达到12%时,该体系的弯曲强度和断裂弯曲应变较纯双邻苯二甲腈固化物分别高了52.7%和61.6%,实现了热固性基体树脂的同时增韧增强而不降低耐热性的改性技术路线。     

含邻苯二甲腈侧基的聚酰胺的合成与热行为

合成了一种新型的含邻苯二甲腈基团的二胺4-（2,4-二氨基苯氧基）邻苯二甲腈（CNDA）,将它与苯甲酰氯和间苯二甲酰氯反应,分别合成了溶解性能良好的酰胺模型化合物（b-CNPA）和酰胺聚合物（m-CNPA）,并分别在265℃和275℃对它们进行热固化反应。热重分析（TGA）,差示扫描量热分析（DSC）和红外光谱（FT-...     

取代基位置对羟基[60]富勒烯吡咯烷衍生物空间结构的影响

为进一步认识羟基[60]富勒烯吡咯烷衍生物的空间结构,借助密度泛函考察了羟基取代位置和取代基数量对羟基[60]富勒烯吡咯烷衍生物空间结构的影响。结果显示,5种羟基[60]富勒烯吡咯烷衍生物的LUMO均集中在[60]富勒烯上,羟基出现在邻位时其衍生物的LUMO和HOMO能量差ΔE最小,而羟基在间位时其ΔE最大。吡咯烷键长和键角并不随羟基数量的增加而呈规律性的变化,但羟基取代基位置对吡咯烷键长和键角的影响由大到小的顺序是:对位、间位、邻位。     

新型间苯三酚基邻苯二甲腈及其聚合物的制备与表征

在DMSO为溶剂,无水碳酸钾存在的条件下,间苯三酚与4-硝基邻苯二甲腈发生亲核取代反应,首次合成出一种新型间苯三酚基邻苯二甲腈化合物,收率为85%。通过红外光谱图和核磁共振氢谱图分析证实了它的存在。该化合物可以发生本体加成聚合反应,生成高度交联的新型树脂材料。通过热重分析,该种树脂耐高温性能良好,有望作为一种耐高温材料在航空航天领域发挥重要作用。     

改性邻苯二甲腈树脂及复合材料体系研究进展

邻苯二甲腈树脂是一类新型的耐高温热固性树脂体系，为了改善其工艺性并满足严苛的环境性能需求，国内外针对邻苯二甲腈树脂体系开展了大量改性研究工作。着重从分子主链结构设计、固化方式及机理、树脂改性和复合材料改性等方面，介绍了改性邻苯二甲腈体系的研究进展，表明其具有优异的工艺性、耐候性和力学特性，展示出良好的应用前景。     

含苯并噁嗪-双邻苯二甲腈树脂及其复合材料的制备与性能

本工作通过以4-氨基苯氧基邻苯二甲腈,双酚A,甲醛为原料,二氧六环为溶剂,甲苯为脱水剂合成了含苯并噁嗪-双邻苯二甲腈,采用腈基二元胺为交联剂在160oC制备预聚物树脂,经丙酮溶解并分散碳纳米管再浸渍玻璃布获得预浸料,经热压成型后热处理制得玻璃纤维/碳纳米管/双邻苯二甲腈树脂复合材料,详细研究了树脂的合成及其固化反应.该类树脂及复合材料具有较好的力学性能,热稳定性能,碳纳米管的加入可以协同增强玻纤复合材料,同时改善其导电性,并赋予复合材料新的吸波特性。     

邻苯二甲腈树脂分子结构及性能调控工作进展

邻苯二甲腈树脂是一类具有耐高温及其他优异综合性能的热固性树脂,在国防、军工等使用环境苛刻的领域中有着广泛的应用需求.但苛刻的固化工艺严重制约了邻苯二甲腈树脂的应用发展.文中梳理了本研究团队对邻苯二甲腈树脂分子结构及高性能固化剂的设计思路和方法,总结了在拓宽树脂加工窗口、降低固化温度和缩短固化时间等改善树脂固化工艺方面的...     

Design of low temperature self-cured phthalonitrile-based polymers for advanced glass fiber composite laminates

Self-promoted copolymerization behavior and processability of phthalonitrile oligomer/phthalonitrile containing benzoxazine (Po/BA-ph) system were investigated by differential scanning calorimetry and dynamic rheological analysis. The results revealed that Po/BA-ph systems exhibited double-stage curing behaviors which corresponded to the ring-opening polymerization of benzoxazine rings and ring-formation polymerization of nitrile groups. Compared with Po, processability of Po/BA-ph blends was improved and could be tuned by varying BA-ph contents, processing temperature, and time. The structures of the copolymers were also characterized and discussed to further confirm the copolymerizing behaviors. Then Po/BA-ph copolymers were employed to prepare Po/BA-ph/glass fiber (GF) composite laminates, and their mechanical and thermal properties were investigated. Compared with those of Po/GF composites, the flexural strength and modulus of Po/BA-ph/GF composites were increased by 6.5 and 25 %, respectively. All of the Po/BA-ph/GF composite laminates were stable up to 430 °C in air. The systematic study of Po/BA-ph system could enrich the thermosetting resin/thermosetting resin systems in industrial applications. Meanwhile, the outstanding mechanical properties and thermal stabilities enable the Po/BA-ph/GF composite laminates to be further applied in the areas which require excellent mechanical properties and high temperature resistance.     

Porous materials prepared by heating derivatives from halloysite

Halloysite clay was subjected to serious treatment by trimethylsilylation and hydrochloric acid. The resulting derivatives were heated below 1473 Kin nitrogen or air to prepare thermally stable porous materials including larger pores than those in zeolite. The trimethylsilylated halloysite resulted in a thermally stable porous material, in an amorphous state, including extremely uniform pores of 1.7 nm. Another derivative also resulted in a thermally cable porous material but consisted of very heterogeneous pores. The thermal degradation behaviour of both derivatives is discussed in detail.     

Natural Zeolites Used as Surface Reaction for Phthalocyanine Synthesis

Natural zeolites were characterized in order to be studied as surface reaction for phthalocyanine synthesis. Nonsubstituted phthalocyanines have been synthesized starting from phthalonitrile in various nonaqueous solvents in the presence of two different zeolites of the clinoptilolite type. The zeolites are shown to be effective matrices for phthalonitrile cyclisation at relatively low temperatures (0-40°C). The presence of CaCO₃ in one of two natural mineral of zeolites suggested a low activity of the surface to promote the cyclization of phthalonitrile at low temperature. The influence of different solvents is not relevant for the heterogeneous reaction.     

新交联型二阶非线性光学环氧聚合物的合成与表征

合成了一种含丙烯酰基团的热交联型二阶非线性光学聚合物材料,以提高其电场极化产生的偶极取向的稳定性。二次谐波产生测量表明,热交联聚合物具有高的以向稳定性。     

超支化聚合物/环氧树脂体系的固化行为及性能

利用傅立叶变换红外光谱(FT-IR)法研究了脂肪族聚酯型超支化聚合物/环氧树脂/酸酐固化体系的固化反应,并研究了不同代数及含量超支化聚合物对固化产物力学性能的影响。结果表明,超支化聚合物的引入能促进体系中酸酐基团的开环并产生游离羧酸,从而对体系的固化反应产生促进作用。较低含量超支化聚合物的引入即能较好地改善固化产物的力学性能,其中第三代HBP含量为3%时,固化物的拉伸强度提高20.54%、冲击强度提高71.14%、断裂伸长率提高41.02%。     

Preparation and characterization of iron phthalocyanine polymer magnetic materials

A novel kind of polymer magnetic material iron phthalocyanine (FePc) was prepared via the polymerization of phthalonitrile with iron pentacarbonyl. The pre-polymerization was monitored by FTIR and UV–Vis spectra. Microwave dielectric properties of prepolymers were dependent on their chemical structures. The thermal properties of FePc polymer were evaluated by TGA, the initial decomposition temperature of completely cured polymer was about 420 °C and char yield at 800 °C was 63.56%. Controlling the pre-polymerization degree of phthalonitrile by the reaction time, the magnetic properties of cured polymer materials can be finely tuned. The saturation magnetization of cured polymer decreased from 2.48 to 0.42 emu/g, whereas the coercive force increased from 123.8 to 228.6 Oe. The microstructure of iron phthalocyanine polymer was characterized by scanning electron microscope and the typical layer structure morphology of phthalocyanine polymer was clearly observed.     

Overview on dislocation-point defect interaction: the brownian picture of dislocation motion

The interactions between dislocations (D) and point defects (PD) are one of the most important causes of mechanical damping in metals. In the past 40 years, many experimental results have been obtained and published, from which it appears that two fundamental behaviors can be observed when dislocations interact with motionless point defects: thermally activated behaviors and athermal behaviors. In this paper, it is shown that these two observed behaviors can be consistently explained by a “brownian picture” of the motion of dislocations interacting with PD distributed at different distances from the dislocation glide plane.     

Temperature-induced resistance transition behaviors of melamine sponge composites wrapped with different graphene oxide derivatives

Temperature-responsive resistance transition behaviors of the melamine sponges wrapped with different graphene oxide derivatives(i.e.nanoribbon,wide-ribbon and sheet)were investigated.Melamine sponge composites coated by three types of GO derivatives were prepared by a simple dip-coating approach.All these composites show good mechanical flexibility and reliability(almost unchanged compressive stress at 70％strain after 100 cycles),high hydrophobicity(water contact angle＞120°),excellent flame resistance(self-extinguishing)and structural stability even after burning,which was used to construct the resistance-based fire alarm/warning sensor.Notably,the different resistance response behaviors of such sensors are strongly dependent on the GO size and network formed on the MF skeleton surface.Typically,at a fixed high temperature of～350℃,the three fire alarm sensors show different response time(to trigger the alarm light)of 6.3,8.4 and 11.1 s for nanoribbon,wide-ribbon and sheet at the same concentration,respectively.The structural observation and chemical analysis demonstrated that the discrepancy of temperature-responsive resistance transition behaviors of various GO derivatives was strongly determined by their different thermal reduction degrees during the high-temperature or flame treating process.This work offers a design and development for construction of smart fire alarm device for potential fire prevention and safety applications.