自催化交联酞菁树脂的研究

【作者】 曾科；

【导师】 杨刚；

【作者基本信息】 四川大学 ， 材料学， 2006， 硕士

【摘要】 酞菁树脂(又称聚邻苯二甲腈树脂)是一类高性能的热固性树脂。它主要是由邻苯二甲腈化合物在高温下通过氰基的加成聚合而成。由于其优异的高温力学性能、热氧稳定性、化学稳定性、低燃性、低吸水性以及良好的加工性，酞菁树脂在航空航天、微电子等高技术领域具有广泛的应用前景。传统的酞菁树脂在固化过程中，通常需添加酚或胺类催化剂以加速酞菁的固化过程。由于催化剂大多是分子量相对较小的低分子化合物，难以避免催化剂(特别是芳香胺和酚类小分子)在高温下的挥发或分解，这往往会造成材料的缺陷。另外，催化剂的挥发，必将导致树脂加工性和固化反应性的变化，该变化给树脂带来更大地加工复杂性，对工程控制也提出了更高的要求，这必然将增加酞菁树脂的加工成本。针对这个问题，我们采用了一种“自催化固化方法”，即希望在无需外加催化剂的情况下，邻苯二甲腈化合物能借助自催化特性加速其自身的固化。为了实现这个目的，我们合成了一系列的邻苯二甲腈化合物，其分子结构中带有羟基或氨基。然后，借助傅立叶转变红外光谱技术(FT-IR)和核磁共振氢谱(~1H NMR)，对产物的结构进行充分地表征。产物的纯度，我们通过薄层色谱(TLC)对其进行表征。为了实现带羟基或氨基邻苯二甲腈化合物的大量合成，我们也是借助TLC方法跟踪反应进程，确定最佳的反应条件和后处理条件。通过4-硝基邻苯二甲腈在极性溶剂中的亲核取代反应，可以高产率地合成一系列带羟基或氨基的邻苯二甲腈化合物。然后，我们对这系列的邻苯二甲腈化合物的热行为进行了研究。通过示差扫描量热分析(DSC)和热重分析(TGA)的研究，表明带羟基或氨基的邻苯二甲腈化合物在高温下表现出明显地自加速聚合行为，具有自催化固化特性。这证实了借助“自催化固化方法”解决酞菁树脂工程可控问题的可能性。为了进一步深入理解分子结构与自催化特性的关系，我们又对比研究了邻苯二甲腈化合物的自催化固化行为。结果发现，羟基和氨基在邻苯二甲腈化合物中的位置确实对其固化行为有很大影响。另外，通过羟基和氨基在~1H NMR上化学位移差异的对比研究，我们发现，在自催化交联酞菁树脂体系中，羟基的酸性和氨基的碱性与其固化行为有密切关联。更多还原

【Abstract】 Phthalonitrile polymers are an important class of high-performance polymers. These polymers are derived by heating the phthalonitrile derivatives for an extended periods of time at elevated temperatures by addition curing reaction of cyano groups from phthalonitrile derivatives. Because of their outstanding thermal and thermal-oxidative stability, good mechanical properties, low flammability, water and chemical resistance, and easy processability, phthalonitrile polymers have found many applications in advanced technologies such as aerospace, marine, and microelectronics.The curing reaction was found to be readily promoted in the presence of a small amount of curing additives such as phenols and organic amines. Beacause of the high temperature required for resin processing, curing additives, aromatic amines or phenols generally of low molecular weight, tend to be volatile or decomposed, therefore casuing void problems. On the other hand, loss of curing additives from some volatility and thus a slowdown of cure have been observed, which can increase processing costs because greater care must be taken to insure that the right amount of curing agent is used.To solve the void and processing cost problem, we designed a "self-promoted curing method" , using phthalonitrile derivatives with self-promoted curing behavior to prepare the thermosets. We hope that the phthalonitrile derivatives can be thermally polymerized to a network polymer by self-promoted curing reaction without addition any other curing additives. To achieve this aim, an class of hydroxy or amino-containing phthalonitrile derivatives were synthesized. The structure of the phthalontrile derivatives was confirmed by Fourier transform infrared spectra (FT-IR) and nuclear magnetic resonance (~1HNMR). The product purity was characterized by TLC.With an aim to synthesize the phthalonitrile derivatives in large scale, a optimal synthesis procedure was determined by TLC monitorring of the reaction progress. Most of the phthalonitrile derivatives were synthesized in high yield by nucleophilic displacement of 4-nitrophthalonitrile and phenol compounds.The thermal behaviors of the phthalonitrile derivatives were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The thermal analysis results indicated that the hydroxy and amino-containing phthalonitrile derivatives showed a self-promoted curing behavior at high temperatures. This result comfim the possability that the "self-promoted curing method" offer a novel synthetic route to the phthalonitrile polymers, which can be used to solve the void and processing cost problem.The self-promoted curing behavior of the phthalonitrile derivatives was investigated in comparison for better understaning of the relationship between the molecular structure and the self-promoted curing characteristic. Thermal analysis performed on phthalonitrile derivatives revealed that positions of hydroxy or amino groups in molecule have much effect on the self-promoted curing behavior. It was also found that self-promoted curing reactivity has much association with the acidity of hydroxy or the basicity of amino groups in this phthalonitrile polymer system determined by chemical shift of hydroxy or amino group on the ~1H NMR spectrum.更多还原