苯并噁嗪树脂及其玻璃纤维增强复合材料的阻燃改性

应用聚磷酸铵(APP)对苯并噁嗪(BOZ)树脂及玻璃纤维(GF)/BOZ复合材料进行了阻燃改性,结合热分析和微观形貌分析等研究了材料的阻燃机制。结果表明:APP可以明显提高BOZ树脂的阻燃性能,随APP含量的提高,树脂体系的极限氧指数逐渐提高,添加量为3wt%时可使BOZ树脂的极限氧指数从基体的31.5%提高到34.5%,并达到UL 94V-0级。APP的加入使改性树脂体系的分解温度前移,玻璃化转变温度略有下降,改性树脂体系固化反应提前,反应过程变得缓和。APP的加入使GF/BOZ复合材料的阻燃性能进一步提高,10wt%GF/APP-BOZ复合材料的极限氧指数从GF/BOZ的51.0%提高到57.7%。微观形貌分析表明:APP的加入使APP-BOZ改性树脂及GF/APP-BOZ复合材料燃烧后生成更为致密的炭层,从而使材料的阻燃性能得到提高。     

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     

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     

苯并噁嗪酮环上N-甲基化研究

从两方面研究了苯并噁嗪酮环上N-甲基化反应:首先,研究了不同甲基化试剂对甲基化反应的影响,综合安全环保和成本等因素筛选得到碳酸二甲酯甲基化试剂。其次,研究了碳酸二甲酯作为甲基化试剂的反应温度等工艺条件。结果表明适宜反应温度为75℃。优化条件下,以碳酸二甲酯作为苯并噁嗪酮环上N甲基化的反应收率达到90%以上,产物纯度大于98%。     

反应介质对合成双酚A-苯胺型苯并噁嗪的影响

以多聚甲醛、苯胺和双酚A为原料,固定加料方式和反应温度等反应条件,改变溶剂种类和NaOH的用量,合成了双酚A-苯胺型苯并噁嗪树脂。采用1H NMR、凝胶化时间测试、DSC等方法对苯并噁嗪的结构、环化率和热固化行为进行了表征,研究了反应介质对苯并噁嗪合成反应的影响。实验结果表明,溶剂的介电常数越低或溶剂对原料双酚A或产物苯并噁嗪的溶解性越好,越有利于提高苯并噁嗪树脂的环化率和纯度;另外,随溶解多聚甲醛时所用NaOH用量的增加,苯并噁嗪的环化率、凝胶化时间和固化峰值温度都呈现先升高后降低的趋势,当NaOH质量分数(基于双酚A)为0.26%时,产物的环化率最高、凝胶化时间最长、固化峰值温度最高。     

Synthesis and characterization of a hybrid material based on a trimethoxysilane functionalized benzoxazine

A polybenzoxazine/polysiloxane hybrid has been prepared by sol–gel process and ring‐opening polymerization. For this purpose, first a functionalized benzoxazine was synthesized from bisphenol A, paraformaldehyde and 3‐(trimethoxysilyl) propylamine, with initial molar ratio 1 : 4 : 2, and 95% yield. The structure of the monomer was characterized by Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance. The sol–gel process and curing behavior have been studied by FTIR spectroscopy and differential scanning calorimetry. The dynamic mechanical thermal analysis of the hybrid material (Bz‐PSi) showed higher T_g and storage modulus respect to the conventional polybenzoxazine (Bz‐BA). Also, the thermogravimetric analysis revealed a better thermal stability. The high limiting oxygen index (LOI) values (about LOI = 32) confirmed similar effective flame retardance properties of the hybrid material respect to conventional benzoxazine. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

双马来酰亚胺改性苯并噁嗪树脂的力学性能及摩擦性能

苯并噁嗪(BOZ)树脂作为一种新型的热固性PF(酚醛树脂),具有诸多优异性能,但其韧性和耐磨性较差。以AE-BMI(含烯丙基醚的双马来酰亚胺预聚体)为改性剂制备AE-BMI/BOZ改性树脂,并对其力学性能和摩擦性能进行了研究。结果表明:适量的AE-BMI对BOZ树脂具有明显的增韧增强作用,并且其耐磨性也明显提高;当w(AE-BMI)=15%时,AE-BMI/BOZ改性体系的弯曲强度(125.53 MPa)和冲击强度(11.57 kJ/m2)分别比纯BOZ体系提高了57%和60%,并且其摩擦因数(0.27)和磨损率[18.50×10-6mm3/(N.m)]分别比纯BOZ体系降低了15.6%和50.6%。     

Use of allyl‐functional benzoxazine monomers as replacement for styrene in vinyl ester resins

New vinyl ester systems are prepared using allyl‐functional benzoxazine monomers, 3‐allyl‐6‐methyl‐3,4‐dihydro‐2H‐benzo[e][1,3]oxazine (pC‐ala) or bis(3‐allyl‐3,4‐dihydro‐2H‐benzo[e][1,3]oxazin‐6‐yl)methane (BF‐ala), as reactive diluents for vinyl ester resins derived from an epoxy resin, diglycidyl ether of bisphenol A, instead of using styrene. Different initiators are used to investigate the copolymerization of allyl function from pC‐ala with vinyl function from vinyl ester resin prepolymer. The temperature dependence of viscosity is studied to demonstrate the retention of processability of the new vinyl ester resins. Dynamic mechanical and thermogravimetric analyses are used to investigate the dynamic mechanical properties and thermal stability of the new resins. Copyright © 2012 Society of Chemical Industry     

Bismaleimides blend with a synthesised phosphorus-containing benzoxazine and its mechanical and tribological properties

ABSTRACT

The phosphorus-containing benzoxazine-bismaleimides (PBOZ-BMI) resin was fabricated by blending the synthesised phosphorus-contained benzoxazine monomer (PBOZ) with bismaleimides (BMI). The influence of PBOZ content on the mechanical and tribological properties of PBOZ-BMI resin was researched. The results showed that suitable addition of PBOZ can enhance the mechanical properties and decrease the frictional coefficient and wear rate of PBOZ-BMI resin to some extent. The improvement of mechanical properties of PBOZ-BMI can be attributed to the cross hydrogen bonding and network interpenetrating. The wear mechanism of the PBOZ-BMI resin was converted from fatigue wear to adhesive wear after the addition of PBOZ, observed from the wear surface of the materials by scanning electron microscopy (SEM). The enhancement of tribological properties is due to the high heat resistance of PBOZ, which can inhibit the adhesive wear during the wear effective.     

Investigation of polymerization of benzoxazines and thermal degradation characteristics of polybenzoxazines via direct pyrolysis mass spectrometry

Polymerization of benzoxazines and thermal degradation mechanisms of polybenzoxazines were investigated using the direct pyrolysis mass spectrometry (DP‐MS) technique. The benzoxazine structures were based on phenol and aniline and on bisphenol‐A and methylamine or aniline. Polymerizations of the benzoxazines were carried out by curing them at elevated temperatures without addition of initiator or catalyst. DP‐MS data showed the presence of chains generated by opposing polymerization reaction pathways indicating quite complex structures for the polybenzoxazines under investigation. Thermal decomposition of polybenzoxazines was started by the cleavage of methylamine or aniline linkages. It was determined that polybenzoxazines based on phenol were more stable than the corresponding bisphenol‐A‐based polybenzoxazines, while those based on methylamine were more stable than the corresponding polybenzoxazines incorporating aniline. Thus, it can be concluded that the presence of bulky groups decreased the extent of crosslinking which in return decreased the thermal stability. Copyright © 2012 Society of Chemical Industry