...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Polymer: The International Journal for the Science and Technology of Polymers >Cross-link inhomogeneity in phenolic resins at the initial stage of curing studied by H-1-pulse NMR spectroscopy and complementary SAXS/WAXS and SANS/WANS with a solvent-swelling technique
【24h】

Cross-link inhomogeneity in phenolic resins at the initial stage of curing studied by H-1-pulse NMR spectroscopy and complementary SAXS/WAXS and SANS/WANS with a solvent-swelling technique

机译：酚醛树脂在固化初期的交联不均匀性通过H-1脉冲NMR光谱和补充的SAXS / WAXS和SANS / WANS进行了溶剂溶胀技术研究

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The cross-link inhomogeneity of phenolic resins at the initial stage of curing in a temperature range of 110-130 degrees C was investigated through structural analysis of the network structure evolution mechanism using H-1-pulse nuclear magnetic resonance spectroscopy and complementary small- and wide-angle X-ray and neutron scattering methods. Two types of phenolic resins, PR06 and PR12, were prepared with stoichiometrically insufficient and sufficient amounts of cross-linker, respectively, via curing of a novolac-type phenolic resin oligomer with hexamethylenetetramine as the curing agent. Their network structures comprised three different structural domains because of the cross-link inhomogeneity: the high-cross-link-density domain (HXD), the low-cross-link-density domain (LXD), and the interface region between these domains. Percolation of the HXD occurred at the beginning of the curing. Intradomain reactions inside both HXD and LXD proceeded as the dominant reactions accompanying minor interdomain reactions between the HXDs, resulting in no significant change in the spatial location and size of the HXDs and LXDs. Intradomain reactions inside the LXD involved reactions with dangling chains, which would not affect the average mesh size of the domain significantly. These behaviors of the network structure evolution mechanism at the initial stage of the curing are a general feature of phenolic resins that does not depend on the amount of cross-linker. The difference between the amount of the cross-linker present in PR06 and PR12 was manifested as a difference in the degree of cross-linking in the percolated HXDs, i.e., the HXD of PR12 exhibited a tightly cross-linked, well-developed network structure since the beginning of the curing process; however, that of PR06 exhibited a loosely cross-linked network structure, with the degree of cross-linking increasing as the curing proceeded. (C) 2016 Elsevier Ltd. All rights reserved.
机译：通过使用H-1脉冲核磁共振波谱和互补的小和小分子网络对网络结构演化机理进行结构分析，研究了酚醛树脂在110-130℃温度范围内固化初期的交联不均匀性。广角X射线和中子散射方法。通过用六亚甲基四胺作为固化剂固化线型酚醛树脂型酚醛树脂低聚物，分别制备了化学计量上不足和足够量的交联剂的两种酚醛树脂PR06和PR12。由于交联不均匀，它们的网络结构包含三个不同的结构域：高交联密度域（HXD），低交联密度域（LXD）和这些域之间的接口区域。 HXD的渗滤发生在固化开始时。 HXD和LXD内部的域内反应都是主要反应，伴随着HXD之间较小的域间反应，因此HXD和LXD的空间位置和大小没有明显变化。 LXD内部的域内反应涉及带有悬链的反应，这不会显着影响域的平均网格大小。固化初期网络结构演化机制的这些行为是酚醛树脂的一个总体特征，它不依赖于交联剂的量。 PR06和PR12中存在的交联剂数量之间的差异表现为渗透的HXD中交联度的差异，即PR12的HXD表现出紧密交联，发达的网络结构自固化过程开始以来;然而，PR06的树脂表现出松散的交联网络结构，随着固化的进行，交联度增加。 （C）2016 Elsevier Ltd.保留所有权利。

著录项

相似文献

  • 外文文献
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号