球形聚苯并噁嗪树脂酸催化性能研究

苯并噁嗪预聚体在甲基硅油中经反相悬浮固化法得到球形聚苯并噁嗪树脂,再经磺化反应后制得聚苯并噁嗪树脂酸。通过催化冰醋酸与乙醇的酯化反应来考察该树脂酸的催化活性。结果表明:当V(甲基硅油)∶V(苯并噁嗪预聚体)=100∶6.0、固化温度为200℃左右时,可得到球形聚苯并噁嗪树脂。当磺化温度为45℃、反应时间为3 h和w(催化剂)=4.8%(相对于冰醋酸而言)时,则冰醋酸的转化率为73%;催化剂连续重复使用3次后,其转化率仍超过60%;经磺化再生后的催化剂,其催化活性基本上能完全恢复。     

苯并噁嗪改性研究进展

苯并噁嗪是一种类似于酚醛树脂结构的新型树脂,具有低黏度、低收缩率、低介电常数和良好的分子设计性等特点,同时又具有脆性、固化温度高和热稳定性不够高等缺点。从分子设计、共混改性和固化工艺三个角度阐述了苯并噁嗪的改性方法,并指出其今后的发展方向。     

非等温DSC研究聚苯并噁嗪/炭纤维复合材料的固化动力学

采用非等温差示扫描量热法（DSC）测试了不同升温速率下,聚苯并噁嗪及聚苯并噁嗪/炭纤维复合材料的固化过程.分析了不同升温速率下,两体系的特征固化温度、反应热及反应速率与温度的关系.Kissinger方程分析计算了聚苯并噁嗪及聚苯并噁嗪/炭纤维复合材料的固化反应表观活化能和反应级数.结果表明,炭纤维对聚苯并噁嗪固化具有催化作用,同时又有缓聚作用.浅析了炭纤维影响聚苯并噁嗪固化的原因。     

Structure and properties of amine‐hardened epoxy/benzoxazine hybrids: Effect of epoxy resin functionality

Bifunctional, trifunctional, and tetrafunctional epoxy resins (EP) were hardened with stoichiometric amount of 4,4′‐diaminodiphenyl methane in presence and absence of benzoxazine (BOX). The EP/BOX ratio of the hybrid systems was 100/0, 75/25, 50/50, and 25/75 wt %, respectively. Information on the structure of the hybrid systems was received from differential scanning calorimetry, dynamic‐mechanical thermal analysis, atomic force microscopy, and fractographic studies. The flexural and fracture mechanical properties of the EP/BOX hybrids were determined and compared to those of the reference EPs. The thermal degradation and fire resistance of the hybrids were also studied. It was found that the polymerized BOX was built in the network in from of nanoscale inclusions and acted as antiplasticizer. Incorporation of BOX enhanced the flexural modulus and strength and reduced the glass transition temperature of the parent EP. The fracture toughness and energy were practically not improved by hybridization with BOX. The charring and flame resistance were improved with increasing amount of BOX in the EP/BOX hybrids. The relative improvement in the latter was most prominent for the bifunctional EP/BOX systems. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

MA型苯并恶嗪树脂流变特性及其固化动力学

采用粘度测试和动态DSC分析研究了MA型苯并恶嗪树脂体系的流变特性及不同工艺条件下的固化反应过程。结果表明:95～115℃时,树脂体系粘度500 mPa.s的时间可达350 min;树脂体系的凝胶温度为185℃,固化温度为213℃,后处理温度为248℃;根据Arrhenius公式求得体系的表观反应活化能为87.5 kJ/mol;树脂体系的固化工艺为130℃/3 h+140℃/1 h+150℃/1 h+160℃/1 h+170℃/1 h+180℃/2 h+210℃/2 h,后处理工艺为250℃/2 h。     

开环聚合酚醛树脂基玻璃布层压板性能的研究

详细讨论了树脂组成、催化剂、纤维种类和层压板成型工艺等因素对开环聚合酚醛树脂基玻璃布层压板力学性能、耐热性和阻燃性的影响。     

Two novel halogen-free,phosphorus-free,and intrinsically flame-retardant benzoxazine thermosets containing electron-withdrawing bridge groups

Two novel furfurylamine type benzoxazine prepolymers are firstly synthesized from 4,4′-bishydroxydeoxybenzoin (BHDB) and 4,4′-dihydroxybenzophenone (DHBP). Both BHDB- and DHBP-based polybenzoxazines present accelerated curing behaviors, high glass transition temperatures, and very low heat release capacity values, resulting from the introduction of electron-withdrawing groups and furan rings. It is especially noteworthy that the flame retardancy of DHBP-based polybenzoxazine is classified as UL-94 V-1 grade, whereas that of BHDB-based polybenzoxazine is evaluated to be UL-94 V-2 grade. Hence, DHBP is considered as an alternative to BHDB for benzoxazine preparation because of its similar chemical structure, competitive price, high efficiency preparation, and outstanding flame resistance. Therefore, this work not only provides an economical and effective strategy for the preparation of halogen-free, phosphorus-free, and intrinsically flame-retardant benzoxazine resins but also provides important insight into the effects of electron-withdrawing bridge groups on the curing behavior and thermal and flame-retardant properties of benzoxazine resins.     

Dynamic mechanical and shape memory properties of copolymers based on o‐allylphenol type benzoxazines and diglycidyl ether of bisphenol‐A

Three benzoxazines based on o‐allylphenol and 1,6‐hexamethylenediamine (HDA) or 4,4′‐diaminodiphenyl methane (DDM) or 4,4′‐diaminodiphenyl ether (DDE) were respectively blended with diglycidyl ether of bisphenol‐A (DGEBA) in various weight ratios followed by thermal polymerization to prepare three series of benzoxazine/DGEBA copolymers. With increasing DGEBA content, the peak temperature of the exothermic peaks in the DSC curves shows a systematic increase for the three series of benzoxazine/DGEBA blends. Each copolymer shows a single glass transition temperature (T_g). As the content of DGEBA is increased, T_g reaches a minimum for the copolymer system based on HDA but a maximum for the two systems based on DDM and DDE. For the same benzoxazine/DGEBA weight ratio, copolymers based on DDM and DDE show high T_g values over those based on HDA. The three series of benzoxazine/DGEBA copolymers exhibit a one‐way dual shape memory effect based on T_g, and the shape memory properties of the copolymers under tensile deformation mode vary with the variation of both diamine bridge structure and DGEBA content. © 2018 Society of Chemical Industry     

苯并嗪树脂的研究进展

综合介绍了苯并口恶嗪树脂的合成、性能、改性和应用 ,并对其他双酚类苯并口恶嗪和萘并口恶嗪进行了概述。     

Synthesis and performance enhancement of novel polybenzoxazines with low surface free energy

A new siloxane‐imide‐containing benzoxazine, BZ‐A6, has been successfully synthesized. The thermal properties of the polybenzoxazine (PBZ) prepared from BZ‐A6 (PBZ‐A6) are superior to those of conventional PBZs lacking siloxane groups. The normally brittle PBZs are toughened significantly as a result of adding siloxane‐imide moieties. Moreover, the thermal and UV stabilities of the surface free energy of PBZ‐A6 are dramatically improved over the conventional bisphenol‐A‐type PBZ. Siloxane‐imide PBZs are more suitable for application as low‐surface‐free‐energy materials that are highly resistant to temperature and UV radiation. PBZ‐A6 may also be useful in weather‐resistant and self‐cleaning coating materials because of its low surface free energy and good thermal and UV resistance. Copyright © 2011 Society of Chemical Industry