含咪唑的自加速固化邻苯二甲腈化合物的性能研究

通过三步反应合成了一种含咪唑的邻苯二甲腈的模型化合物(BIPN),同时合成了一种不含咪唑的邻苯二甲腈的模型化合物(Biphenyl-PN)用于对比。通过热重分析(TGA)、紫外光谱、热处理前后的红外光谱(FT-IR)、核磁共振氢谱(1H-NMR)对比研究了这两种化合物的结构和性能,并初步研究了BIPN的固化机理。结果表明:BIPN具有自催化作用,其固化过程中有酞菁环和三嗪环生成,且主要结构为三嗪环。     

4,5-二氯邻苯二甲腈的合成

以4,5-二氯邻苯二甲酸为原料,经过乙酸酐脱水、甲酰胺亚胺化、氨水氨解、三氯氧磷脱水合成了4,5-二氯邻苯二甲腈。对反应步骤进行了简化,发现亚胺化后用一锅加的方法直接进行氨解合成4,5-二氯邻苯二甲酰胺,可提高产率。     

聚邻苯二甲腈树脂研究进展

介绍了聚邻苯二甲腈树脂(PN)的热聚合行为和机理,加工特性,综述了近年来在其热性能,力学性能,吸水性,导电性研究及树脂改性、应用开发方面的进展,并指出了该树脂未来的研究方向。     

邻二甲苯氨氧化制邻苯二甲腈的研究

以V-Cr-P-助活性组份SiO_2为催化剂,探讨了各种因素对反应结果的影响,提出了适宜的反应条件:常压,反应温度490℃,空气量4.8升/分,氨量2.8升/分,邻二甲苯浓度50克/米~3,邻苯二甲腈收率达75％左右(纯度为98％以上)。     

4-硝基邻苯二甲腈的合成研究

以邻苯二甲酸酐为原料经亚酰胺化,硝化、氨解后得到4－硝基邻苯二甲酰胺,再在N,N－二甲胺存在下用三氯氧磷脱水制得4－硝基邻苯二甲腈,反应条件温和,产品纯度高,总产率达到36％。     

氨氧化法合成邻苯二甲腈

气相氨氧化邻二甲苯合成邻苯二甲腈是目前最简单、最经济的合成工艺。作者针对邻二甲苯的特 点,研制出了选择性高、寿命长、氨与邻二甲苯物质的量之比较小的V—Cr-Mo-O催化剂。经在φ330mm流化床中试 生产结果证明:邻苯二甲腈收率可达60％以上,产品纯度≥99.0％,达到了国际先进水平。     

改性邻苯二甲腈酚醛树脂胶黏剂的研究

采用4-硝基邻苯二甲腈和线型酚醛树脂反应,制备出邻苯二甲腈酚醛树脂。采用改性树脂和增韧剂对邻苯二甲腈酚醛树脂进行改性,制备出改性邻苯二甲腈酚醛树脂胶黏剂。并借助IR、DSC、TG对合成树脂及胶黏剂进行表征。该胶黏剂可在200℃温度下固化,固化产物具有较高的耐热性能和粘接性能。     

4—叔丁基邻苯二甲腈的合成

以叔丁基苯为原料经溴化、氰基化合成4－叔丁基邻苯二甲腈，优化了反应条件。溴化45℃下反应4小时，收率74．6％。氰化反应摩尔比为溴化物：CuCN:PTC=1:2.9:0.05,反应温度165℃，反应时间4小时，收率60．9％。     

邻苯二甲腈醚化酚醛树脂的制备与性能

以碱为催化剂,通过酚醛树脂与4-硝基邻苯二甲腈之间的亲核取代反应,制备了邻苯二甲腈醚化酚醛树脂(BPN)并采用红外光谱,GPC,流变仪,DSC及TGA对其性能进行了研究。结果表明,BPN树脂加工窗口约为65℃,最小粘度约为300 mPa.s,具有优良的加工性能。BPN固化温度为175～350℃,固化反应峰值温度为290℃,说明该树脂通过酚羟基对邻苯二甲腈基团的催化热聚合反应,实现了含氰基树脂的单组分、较低温度的加成固化。BPN树脂在温和的后固化条件下(250℃/6 h)即可获得优良的热稳定性,其5%失重温度约为420℃,氮气氛围900℃残炭率约为72%。     

Phenol‐containing phthalonitrile polymers – synthesis,cure characteristics and laminate properties

Novolac–phthalonitrile polymers bearing a controlled concentration of phthalonitrile groups were synthesized by condensation of novolac with 4‐nitrophthalonitrile. The cure characteristics monitored by DSC and rheometry indicated acceleration of the cure reaction by the phenolic groups. Fourier transform infrared analysis of the cured products indicated that the cure mechanism was dependent on the extent of phthalonitrile substitution. In phenol‐rich systems, evidence was obtained for the phenol‐mediated reaction of nitrile groups resulting in the formation of isoindoline groups. The phthalonitrile‐rich system underwent crosslinking through formation of triazine and phthalocyanine groups. The phenol groups in the phthalonitrile backbone were conducive to building a stronger interphase in their carbon composites, resulting in better mechanical properties. This was corroborated by morphological studies by SEM. However, these groups were detrimental to the thermal stability of the cured resins. The polymers exhibited very high flame retardancy which improved further on increasing the degree of phthalonitrilation. Copyright © 2012 Society of Chemical Industry     

Effect of curing behaviors on the properties of poly(arylene ether nitrile) end-capped with phthalonitrile

Poly(arylene ether nitrile) (PEN) end-capped with phthalonitrile (PEN-n) was synthesized by incorporating phthalonitrile into the terminals of PEN. The as-prepared flexible PEN-n (after elevated temperature treatment) was characterized by infrared spectroscopy, nuclear magnetic resonance, gel permeation chromatography, and rheological measurements. In addition, the effects of curing behaviors on properties of PEN-n films were studied by thermal, dielectric and mechanical measurements. Differential scanning calorimetry analysis showed that glass transition temperature of PEN-n was improved from 176 to 232°C as the curing temperature and time increased. Thermal gravimetric analysis revealed that initial decomposition temperature of PEN-n cured at 320°C for 2 h was 570°C. Mechanical properties showed that tensile strength of PEN-n uncured and cured at 320°C for 3 h was 85 and 97 MPa, respectively. The dielectric properties showed that the dielectric constant of PEN-n film decreased from 4.0 to 3.1 as the curing time increased and dielectric loss of PEN-n was 0.01 at 100 kHz. This kind of PEN-n film may be used as a good candidate for high-performance polymeric materials. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

间苯二甲腈催化加氢工艺条件优化研究

通过均匀试验和单纯形优化法试验,得到了间苯二甲腈催化加氢的优化工艺条件：催化剂用量为间苯二甲腈质量的１２％,溶剂乙醇、液氨添加量与间苯二甲腈之比分别为４．１∶１（ｇ）、６．８∶１（ｍｏｌ）,反应压力４．５１ＭＰａ,反应温度１２６℃,反应时间５．３ｈ。最优工艺条件下间苯二甲胺的收率可达８３．７％,产品纯度稳定在９７％以上。     

7-(3,4-二氰基苯氧基)-4-甲基香豆素的合成

以间苯二酚和乙酰乙酸乙酯为原料,在浓硫酸的催化下合成7-羟基-4-甲基香豆素。以4-硝基邻苯二甲酰亚胺为原料,通过氨水催化开环,三氯氧磷脱水制得4-硝基邻苯二甲腈。得到的7-羟基-4-甲基香豆素和4-硝基邻苯二甲腈经过亲核取代反应得到7-(3,4-二氰基苯氧基)-4-甲基香豆素。考察了7-羟基-4-甲基香豆素和4-硝基邻苯二甲腈的投料比、缚酸剂用量、反应温度和反应时间对反应的影响,最优反应条件为:n(7-羟基-4-甲基香豆素)∶n(4-硝基邻苯二甲腈)∶n(无水碳酸钾)=1.4∶1.0∶1.5,反应温度30℃,反应时间14 h,收率为63.7%,并通过红外吸收光谱、核磁共振氢谱和高效液相色谱(色谱纯度为99.30%)对合成的化合物的结构进行了确证。在该条件下适当放大实验条件得到收率基本在83.1%,比文献报道收率68%要高。     

双酚A型双邻苯二甲腈/酚醛树脂共混体系研究

双酚A型双邻苯二甲腈(BAPh)与酚醛树脂(novolac)通过熔融共混形成了预聚物(BAPh/novolac),经后续热处理制备了BAPh/novolac固化物。通过DSC,FTIR,TGA及流变性能测试研究了该共混体系的固化反应特性,固化物的热稳定性和热氧化稳定性。结果表明:该共混体系可以在无外加固化剂的条件下进行固化反应,固化物的玻璃化转变温度(Tg)达241℃。其固化物在空气和N2气氛中的起始分解温度为380～449℃,且在氮气下800℃残炭率达71%,表现出良好的热稳定性和热氧稳定性。     

Preparation and properties of bisphenol A polyetherketoneketone based phthalonitrile resins

A promising high temperature phthalonitrile (PN) resin composed of a polyetherketoneketone (PEKK) core bridged by two bisphenol A linkers and end capped with PN groups is presented. This PEKK-PN resin was characterized via differential scanning calorimetry, thermogravimetric analysis, proton nuclear magnetic resonance spectroscopy, scanning electron microscopy, dynamic mechanical analysis, attenuated total reflection Fourier transform infrared, and rheometry. The PEKK-PN resin was evaluated with two different compositions containing 1) 70:30 PEKK-PN to bisphenol A PN (n = 0) and 2) pure PEKK-PN. The 70:30 PEKK-PN resin was mixed with bis[4-(3-aminophenoxy)phenyl]sulfone and exhibited a melt viscosity of 271 cP, much lower than the 657 cP viscosity of the pure PEKK-PN mixture. Void-free PEKK-PN polymers were easily prepared by degassing and curing up to 380°C, resulting in fully crosslinked networks exhibiting thermal stability above 500°C and a 75% char yield. Additionally, the cured PEKK-PN polymer samples displayed good mechanical integrity retaining 50% stiffness at 300°C. This combination of properties suggests these new PEKK-PN resins are excellent materials for high temperature thermosets in composite applications.     

Optimizing the thermal properties of fiber reinforced phthalonitrile composites

The development of lightweight composites with desirable thermo-mechanical properties is progressively increasing. Phthalonitrile (PN) based composites have shown great potential in this regard. However, the basic thermal properties of PN composites required for engineering design are not yet fully understood. In this work, we investigated the thermal stability, thermal expansion behavior and thermal conductivity of PN composites reinforced with carbon fiber (CF) and high silicon fiberglass (HSF) via combined experimental studies and numerical simulations. The results indicated that CF/PN performs better in thermostability than HSF/PN at temperatures below 500°C. Moreover, the incorporation of CF and HSF lowered the coefficient of thermal expansion (CTE) and thermal insulation of PN. At room temperature, the in-plane CTE of CF/PN and HSF/PN were 1.97E-6 and 9.24E-6°C⁻¹, respectively, while the out-plane thermal conductivities of CF/PN and HSF/PN were 0.65 and 0.34 W/(m K). It is worth noting that an excessively high fiber volume fraction would lead to poor thermal insulation and lightweight properties of the PN composites, while a low fiber volume fraction would result in poor stiffness and thermal dimensional stability. Determined via TOPSIS model, a fiber volume fraction range of 50%–60% was ideal for both composites with comprehensive optimal properties, respectively.     

Copolymerization modification: improving the processability and thermal properties of phthalonitrile resins with novel comonomers

Two novel tetrahydrophthalic anhydride end‐capped imide compounds (THAN and THBN) with high thermal stability were synthesized to promote the curing reaction of 1,3‐bis(3,4‐dicyanophenoxy)benzene (3BOCN), and to study the effects of comonomer structure on the curing behavior and thermal performance of phthalonitrile resins. The curing behaviors of THAN/3BOCN and THBN/3BOCN blends with various molar ratios were investigated using rheological analysis and differential scanning calorimetry, suggesting a wide processing window. Dynamic mechanical analysis and thermogravimetric analysis showed that the cured resins possessed high glass transition temperatures (> 500 °C), and superior thermal and long‐term thermo‐oxidative stabilities with weight retention of 95% ranging from about 544 to 558 °C in both nitrogen and air. All these results indicated that the processability and thermal properties of phthalonitrile resins could be improved further by modifying the structure of comonomer in this kind of curing system. © 2018 Society of Chemical Industry     

Chemically bonded iron carbonyl for magnetic composites based on phthalonitrile polymers

Dicarboxylic acid‐containing 1,3‐benzoxazine was synthesized and chemically bonded on iron carbonyl particles using a post‐coating method. Novel organic–inorganic hybrid magnetic composites were prepared via the interfacial reaction between magnetic phthalonitrile prepolymers and the benzoxazine functional coatings that chemically modified the iron carbonyl particles. The results showed that, compared with pure iron carbonyl particles, the modified particles could cure the phthalonitrile prepolymers efficiently and improve the interfacial compatibility of the functional composites. The magnetic composites with chemically modified particles exhibited stronger magnetism in comparison to composites containing bare particles: the saturation magnetization of the magnetic composites with equal concentration (5 wt%) of Fe(CO)₅ increased from 41.12 to 48.82 emu g^?1. Also, the magnetic composites obtained demonstrated excellent thermal stability up to 500 °C. Copyright © 2010 Society of Chemical Industry