Chemical Engineering and Materials Science, Michigan State University, East Lansing, MI 48824, USA.
Department of Forestry, Michigan State University, East Lansing, MI 48824, USA.
Molecules. 2021 Apr 15;26(8):2302. doi: 10.3390/molecules26082302.
This study was focused on evaluating the suitability of a wide range of lignins, a natural polymer isolated from different plant sources and chemical extractions, in replacing 20 wt.% of petroleum-based polyol in the formulation of PU flexible foams. The main goal was to investigate the effect of unmodified lignin incorporation on the foam's structural, mechanical, and thermal properties. The hydroxyl contents of the commercial lignins were measured using phosphorus nuclear magnetic resonance (P NMR) spectroscopy, molar mass distributions with gel permeation chromatography (GPC), and thermal properties with differential scanning calorimetry (DSC) techniques. The results showed that incorporating 20 wt.% lignin increased tensile, compression, tear propagation strengths, thermal stability, and the support factor of the developed PU flexible foams. Additionally, statistical analysis of the results showed that foam properties such as density and compression force deflection were positively correlated with lignin's total hydroxyl content. Studying correlations between lignin properties and the performance of the developed lignin-based PU foams showed that lignins with low hydroxyl content, high flexibility (low T), and high solubility in the co-polyol are better candidates for partially substituting petroleum-based polyols in the formulation of flexible PU foams intended for the automotive applications.
本研究专注于评估各种木质素的适用性，木质素是一种从不同植物来源和化学提取中分离出来的天然聚合物，可替代配方中 20wt%的石油基多元醇，用于制备 PU 软质泡沫塑料。主要目标是研究未改性木质素的加入对泡沫塑料的结构、机械和热性能的影响。使用磷核磁共振（P NMR）光谱法、凝胶渗透色谱法（GPC）测量商业木质素的羟基含量，并使用差示扫描量热法（DSC）技术测量其热性能。结果表明，加入 20wt%木质素可提高所开发的 PU 软质泡沫塑料的拉伸、压缩、撕裂扩展强度、热稳定性和支撑因子。此外，结果的统计分析表明，泡沫塑料的密度和压缩力挠度等性能与木质素的总羟基含量呈正相关。研究木质素特性与所开发的基于木质素的 PU 泡沫塑料性能之间的相关性表明，羟基含量低、柔韧性高（低 T）且在共聚多元醇中溶解度高的木质素是在用于汽车应用的柔性 PU 泡沫塑料配方中部分替代石油基多元醇的更佳候选材料。
