A kraft lignin was liquefied in solution reagents such as polyethylene glycol (PEG) and glycerol under microwave heating. The effects of glycerol concentration, molecular weight of PEG and lignin mass were investigated on lignin liquefaction process through microwave irradiation. For this purpose, the prepared polyols were characterized by gel permeation chromatography, Fourier transform infrared spectroscopy, proton nuclear magnetic resonance and carbon-¹³ nuclear magnetic resonance techniques. Further, the hydroxyl value (OHV) of polyols was determined by titration method. The results indicated that addition of glycerol increased liquefaction yield and OHV of polyols due to its role as co-solvent in liquefaction process and as a microwave absorber. Glycerol could be used up to 30 wt%, though the beneficial amount of glycerol was obtained as 20 wt%. In another run, it was observed that PEG with a molecular weight of 400 g/mol was an efficient solvent in liquefaction process, which introduced the highest amount of OHV in lignin polyol. A study on the effect of lignin mass was carried out with sufficient amount of glycerol and PEG400 as liquefaction reagents. The results revealed that with further increase in lignin/solvent weight ratio, the molecular weight of polyol increased while its OHV was reduced. Therefore, there was a limiting range in addition of lignin due to insufficient liquefaction solvent in causing enhanced condensation reaction during the liquefaction process. Finally, the polyol with sufficient amounts of testing components was nominated as an optimal polyol with the highest OHV (630 mg KOH/g) and suitable liquefaction yield.

中文翻译：

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一些材料参数对微波加热木质素生物聚合物液化的影响

在微波加热下，将牛皮纸木质素在溶液试剂（例如聚乙二醇（PEG）和甘油）中液化。通过微波辐射研究了甘油浓度，PEG分子量和木质素质量对木质素液化过程的影响。为此，通过凝胶渗透色谱，傅里叶变换红外光谱，质子核磁共振和碳¹³表征制备的多元醇。核磁共振技术。此外，多元醇的羟值（OHV）通过滴定法测定。结果表明，甘油的添加由于其在液化过程中作为助溶剂和作为微波吸收剂的作用而增加了多元醇的液化产率和OHV。甘油的使用量最高为30重量％，尽管获得的甘油的有益量为20重量％。在另一轮中，观察到分子量为400 g / mol的PEG是液化过程中的有效溶剂，这在木质素多元醇中引入了最高量的OHV。用足够量的甘油和PEG400作为液化剂进行了木质素质量影响的研究。结果表明，随着木质素/溶剂重量比的进一步增加，多元醇的分子量增加，而OHV降低。因此，由于在液化过程中引起增强的缩合反应的液化溶剂不足，因此添加木质素的范围是有限的。最后，将具有足够量的测试组分的多元醇提名为具有最高OHV（630 mg KOH / g）和合适的液化收率的最佳多元醇。