Polybenzoxazine-montmorillonite hybrid nanocomposites: synthesis and characterization
Polybenzoxazine-montmorillonite hybrid nanocomposites: synthesis and characterization
复制标题
DOI：
10.1016/s0032-3861(00)00064-1
复制
发表时间：
2000-06-01
期刊：
影响因子：
4.6
通讯作者：
Takeichi, T
中科院分区：
文献类型：
--
作者：
Agag, T;Takeichi, T
以有机改性蒙脱土（OMMT）为层状硅酸盐，以聚苯并恶嗪（B-a）为前驱体，制备了聚苯并恶嗪-粘土杂化纳米复合材料。采用正辛基、十二烷基和十八烷基氯化铵对蒙脱土进行表面处理，制备了有机蒙脱土。用IR和DSC研究了B-a在分散OMMT存在下的固化行为。DSC显示原始B-a的开环聚合开始于223 ℃。然而，在OMMT存在下，B-a的开环聚合在177-190 ℃开始，表明OMMT表面对开环聚合的催化作用。DSC和IR表明B-a的固化在230 ℃固化循环结束时完成。XRD分析表明，OMMT在聚苯并恶嗪基体中的分散性较好，表明OMMT的配位结构发生了破坏。从XRD图谱的OMMT的基础间距衍射的情况下表明，当表面用长链表面活性剂如十二烷基或硬脂基氯化铵预处理时，OMMT层在分子水平上的分散。然而，在OMMT的情况下，这是预处理与短链表面活性剂，如辛基氯化铵，聚苯并恶嗪到粘土画廊的插层发生有规律的茎层状结构。粘弹性测试结果表明，杂化材料的Tg高于纯树脂。此外，杂化材料的储能模量保持到较高的温度，表明通过OMMT实现的增强。等温和动态热重分析表明，纳米复合材料具有延迟的分解温度相比，原始聚苯并恶嗪表明增强的热稳定性。(C)2000爱思唯尔科技有限公司版权所有。
Polybenzoxazine-clay hybrid nanocomposites were prepared from a polybenzoxazine precursor (B-a) and organically modified-montmorillonite (OMMT) as a type of layered silicates. OMMTs were prepared by surface treatment of montmorillonite (MMT) by octyl, dodecyl or stearyl ammonium chloride. The curing behavior of B-a in the presence of dispersed OMMT was followed by IR and DSC. DSC showed that the onset of the ring opening polymerization of pristine B-a started at 223 degrees C. The ring opening polymerization of B-a in the presence of OMMT started at 177-190 degrees C, however, suggesting the catalytic effect of the OMMT surface on the ring opening polymerization. DSC and IR indicated that the curing of B-a was completed by the end of the 230 degrees C cure cycle. The dispersion of OMMT in the polybenzoxazine matrix was confirmed by XRD, which indicated the collapse of the registry of the OMMT. The absence of basal spacings diffractions of OMMTs from the XRD patterns suggests the dispersion of OMMT layers on the molecular level when the surface was pretreated with long chain surfactants like dodecyl or stearyl ammonium chloride. However, in case of OMMT, which was pretreated with short chain surfactants like octyl ammonium chloride, the intercalation of polybenzoxazine into the clay galleries occurred with a regularly stalked layered structure. Viscoelastic measurements showed that the T-gS of the hybrid materials were higher than that of the pristine resin. In addition, the storage modulii of the hybrid materials were maintained up to higher temperatures suggesting the reinforcement attained by OMMT. Isothermal and dynamic TGA showed that nanocomposites have delayed decomposition temperatures when compared with pristine polybenzoxazine indicating the enhancement in the thermal stability. (C) 2000 Elsevier Science Ltd. All rights reserved.