Bio-based high-density polyethylene (BioHDPE)-loaded composites with different amounts of spent coffee powder (up to 30 wt.%) were successfully produced. The use of coffee residues coming from the alcoholic beverage industry in a BioHDPE matrix resulted in a remarkable improvement in the antioxidant properties of the composites. Waste spent coffee powder reduced the elastic modulus, hardness and storage modulus; the reduction was proportional to the amount of by-product considered. To improve the interaction between the highly hydrophobic BioHDPE matrix and the highly hydrophilic spent coffee powder, a copolymer – namely, poly(ethylene-graft-maleic anhydride) (PE-g-MA) – was used. PE-g-MA addition resulted in an improved interaction between the particles and poly(lactic acid), as confirmed by field emission scanning electron microscopy. On the other hand, the presence of the lignocellulosic filler resulted in a low load transfer between the two components, which led to a decrease in tensile strength. The introduction of coffee powder resulted in an improvement in thermal stability, as confirmed by thermogravimetry and differential scanning calorimetry. Finally, antioxidant activity was also observed in the composites, wherein a 27% reduction in 2,2-diphenyl-1-picrylhydrazyl was reported for the composite with the highest coffee content. The presence of antioxidant substances (coffee oil) was confirmed by Fourier transform infrared spectroscopy.

中文翻译：

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基于酒精工业咖啡副产品的绿色抗氧化复合材料

成功生产了载有不同量废咖啡粉（高达 30 wt.%）的生物基高密度聚乙烯 (BioHDPE) 复合材料。在 BioHDPE 基质中使用来自酒精饮料行业的咖啡残渣，显着改善了复合材料的抗氧化性能。废弃的废咖啡粉降低了弹性模量、硬度和储能模量；减少量与所考虑的副产品数量成正比。为了改善高度疏水性 BioHDPE 基质与高度亲水性废咖啡粉之间的相互作用，使用了一种共聚物，即聚（乙烯-接枝-马来酸酐）（PE- g -MA）。PE-克-MA 添加导致颗粒与聚（乳酸）之间的相互作用得到改善，如场发射扫描电子显微镜所证实的那样。另一方面，木质纤维素填料的存在导致两种组分之间的载荷传递较低，从而导致拉伸强度降低。热重分析法和差示扫描量热法证实，咖啡粉的引入提高了热稳定性。最后，还在复合材料中观察到抗氧化活性，据报道，咖啡含量最高的复合材料的 2,2-二苯基-1-苦基肼减少了 27%。抗氧化物质（咖啡油）的存在通过傅立叶变换红外光谱法确认。