• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Applied Polymer Science >Influence of lignin's pH on polyurethane flexible foam formation and how to control it
【24h】

Influence of lignin's pH on polyurethane flexible foam formation and how to control it

机译：木质素pH对聚氨酯柔性泡沫形成的影响及如何控制

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

Low pH of commercial lignins has a catastrophic impact on the polyurethane foaming reactions. Experiments were performed with 10 wt% of lignin with various pHs in polyols. Virgin lignin (pH 2.5, 35% moisture) has the most negative impact as it reduces the initial foam rising rate by 85% and the foam's final height by 35% as compared to the reference foam, lignin free. Drying of this lignin at 80 degrees C for 12 h can reduce this impact while alkaline treatment to bring the lignin's pH to 6.6 almost cancel it. As revealed by in situ dielectric constant measurements, both reactions, gelling via polymerization and blowing via CO2 degassing, are impacted. In situ Fourier transform infrared analysis of the foaming process demonstrated that blowing reaction is the most pH sensitive. Two methods to counter the pH influence by pH modification were tested and provide interesting results but also significant drawbacks limiting their applicability.
机译：商业木质素的低pH值对聚氨酯发泡反应有灾难性的影响。在多元醇中加入10 wt%的木质素和各种pHs进行试验。原始木质素（pH 2.5，35%水分）的负面影响最大，因为与无木质素的参考泡沫相比，原始木质素降低了85%的初始泡沫上升率和35%的泡沫最终高度。这种木质素在80摄氏度下干燥12小时可以减少这种影响，而碱处理使木质素的pH值达到6.6几乎可以消除这种影响。原位介电常数测量表明，通过聚合形成凝胶和通过CO2脱气吹气这两种反应都受到影响。对发泡过程的原位傅里叶变换红外分析表明，发泡反应对pH最敏感。对两种通过pH改性来对抗pH影响的方法进行了测试，提供了有趣的结果，但也存在限制其适用性的显著缺陷。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
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