The objective of this study was to produce a polyol from spent coffee grounds via acid liquification process that meets performance requirements for use in polyurethane applications. The spent coffee grounds based polyol was characterized and evaluated on a fully catalyzed model rigid polyurethane foam system. The pH of the polyol was 6.8, acid value 4.12 mg KOH/g, and hydroxyl value 302.6 mg KOH/g, which are in the range of polyols used in rigid polyurethane foams. The reactivity study confirmed enhanced reactivity of the spent coffee grounds polyol compared to standard sucrose-glycerol initiated polyether polyols, which can be attributed to higher content of primary reactive hydroxyls. Scanning electron microscopy microphotographs of the foams prepared with 10%, 20%, and 30% spent coffee grounds polyol based on total polyols in the formulation revealed a drained dodecahedron type cell structure with intact cell windows as a clear indication of the closed cell structure typical for the rigid polyurethane foams used in thermal insulation applications. Results of this study confirmed the feasibility to produce polyols from spent coffee grounds with performance characteristics suitable for polyurethane application. The fact that spent coffee grounds are readily available industrial waste generated in instant coffee manufacturing, makes this biomass residue a sustainable source of raw materials for scalable production of polyols for polyurethanes.

中文翻译：

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来自废咖啡渣的多元醇：模型现场浇注硬质聚氨酯泡沫系统的性能

本研究的目的是通过酸液化工艺从废咖啡渣中生产多元醇，以满足聚氨酯应用的性能要求。在完全催化的模型硬质聚氨酯泡沫系统上表征和评估基于废咖啡渣的多元醇。多元醇的pH值为6.8，酸值为4.12mg KOH/g，羟值为302.6mg KOH/g，属于硬质聚氨酯泡沫中使用的多元醇范围。反应性研究证实，与标准蔗糖-甘油引发的聚醚多元醇相比，废咖啡渣多元醇的反应性增强，这可归因于较高的反应性伯羟基含量。用 10%、20%、和基于配方中总多元醇的 30% 废咖啡渣多元醇显示出排水十二面体型泡孔结构，具有完整的泡孔窗，这清楚地表明了用于绝热应用的硬质聚氨酯泡沫的典型闭孔结构。该研究的结果证实了从废咖啡渣中生产具有适用于聚氨酯应用的性能特征的多元醇的可行性。废咖啡渣是速溶咖啡制造过程中产生的现成工业废物，这一事实使这种生物质残留物成为可扩展生产聚氨酯多元醇的可持续原材料来源。