Zhu Shiyun, Chen Kefu, Xu Jun, Li Jun, Mo Lihuan
State Key Laboratory of Pulp and Paper Engineering, South China University of Technology Guangzhou Guangdong 510640 China
Plant Micro/Nano Fiber Research Center, South China University of Technology Guangzhou 510640 Guangdong China.
RSC Adv. 2018 Apr 26;8(28):15754-15761. doi: 10.1039/c8ra01089g. eCollection 2018 Apr 23.
Enzymatic hydrolysis residues (EHR) from corn stalk are industrial waste from the cellulosic ethanol industry. Lignin was separated as a bio-based polyol from EHR replacing partial petroleum-based polyether polyol to prepare bio-based polyurethane (BPU) foams without any other biomass pretreatment. Single factor experiment and response surface methodology (RSM) were employed to optimize separation conditions and reveal the significant influence of the interaction of conditions on the yield of separated lignin (SL). The effect of SL content (2.5, 5.0, 7.5, 10 and 15%) on the foams morphology and mechanical properties was assessed. Scanning electron microscopy (SEM) results implied that the cell shape was considerably affected by the large SL content, which contributed to an irregular, inhomogeneous, and thick cell wall. An astonishing 9.56 times increase in the compressive modulus and exponential 97.93 times boost in the compressive strength of BPU foams were attributed to the content of 15% SL without any further surface chemical modification. This present paper reports a green, potential and promising method for complete utilization of lignin from EHR in consideration of their abundant supply to greatly enhance the mechanical properties of BPU foams.
玉米秸秆酶解残渣（EHR）是纤维素乙醇工业产生的工业废料。从EHR中分离出木质素作为生物基多元醇，替代部分石油基聚醚多元醇，无需任何其他生物质预处理即可制备生物基聚氨酯（BPU）泡沫。采用单因素实验和响应面法（RSM）优化分离条件，并揭示条件间相互作用对分离木质素（SL）产率的显著影响。评估了SL含量（2.5%、5.0%、7.5%、10%和15%）对泡沫形态和力学性能的影响。扫描电子显微镜（SEM）结果表明，高含量的SL对泡孔形状有显著影响，导致泡孔壁不规则、不均匀且增厚。在未进行任何进一步表面化学改性的情况下，BPU泡沫的压缩模量提高了9.56倍，压缩强度呈指数增长，提高了97.93倍，这归因于15%的SL含量。考虑到EHR中木质素的丰富供应，本文报道了一种绿色、有潜力且前景广阔的方法，可实现对EHR中木质素的完全利用，从而大幅提高BPU泡沫的力学性能。
