Bartczak Przemysław, Stachowiak Julia, Szmitko Marta, Grząbka-Zasadzińska Aleksandra, Borysiak Sławomir
Faculty of Chemical Technology, Institute of Chemical Technology and Engineering, Poznan University of Technology, Berdychowo 4, PL-60965 Poznan, Poland.
Materials (Basel). 2022 Dec 28;16(1):278. doi: 10.3390/ma16010278.
Currently, the fundamental activity that will allow for the development of an economy with closed circulation is the management of food waste and production waste for the preparation of biocomposites. The use of waste materials of natural origin allows for the creation of innovative composites with improved physicochemical and functional properties. The present investigation concerns the use of coffee grounds (2.5-20 wt.%) and oak sawdust (2.5-20 wt.%) as effective fillers of rigid polyurethane foam. Innovative composite materials, previously indebted in the literature, were subjected to the necessary analyses to determine the application abilities: processing times, free density, water absorption, dimensional stability, mechanical properties (compressive strength), thermal conductivity, morphology, and flame resistance. The results with respect to the mechanical tests turned out to be the key. Increasing the number of coffee additives has a positive effect on the compressive strength. The addition of this filler in the range of 5-15 wt.% increased the compressive strength of the composites, 136-139 kPa, compared to the reference sample, 127 kPa. The key parameter analysed was thermal conductivity. The results obtained were in range of the requirements, that is, 0.022-0.024 W/m·K for all used amounts of fillers 2.5-20 wt.%. This is extremely important since these materials are used for insulation purposes. The results of the burning-behaviour test have confirmed that the addition of renewable materials does not negatively affect the fire resistance of the received foams; the results were obtained analogously to those obtained from the reference sample without the addition of fillers. The height of the flame did not exceed 17 cm, while the flame decay time was 17 s for the reference sample and the composite with coffee grounds and 18 s for the composite with oak sawdust. In this work, the practical application of bioorganic waste as an innovative filler for the insulation of flooded polyurethane foam is described for the first time. The introduction of fillers of natural origin into the polymer matrix is a promising method to improve the physicochemical and functional properties of rigid polyurethane foams. Composites modified with coffee grounds and sawdust are interesting from a technological, ecological, and economic point of view, significantly increasing the range of use of foam in various industries.
目前，实现经济内循环发展的一项基础性活动是对食物垃圾和生产垃圾进行管理，以制备生物复合材料。使用天然来源的废料能够制造出具有改善的物理化学和功能特性的创新型复合材料。本研究关注使用咖啡渣（2.5 - 20重量%）和橡木锯末（2.5 - 20重量%）作为硬质聚氨酯泡沫的有效填料。此前文献中提及的创新型复合材料经过了必要分析以确定其应用能力：加工时间、自由密度、吸水性、尺寸稳定性、机械性能（抗压强度）、热导率、形态以及阻燃性。机械测试结果是关键所在。增加咖啡添加剂的用量对抗压强度有积极影响。与参考样品（127 kPa）相比，在5 - 15重量%范围内添加这种填料使复合材料的抗压强度提高到了136 - 139 kPa。所分析的关键参数是热导率。对于所有2.5 - 20重量%用量的填料，所获得的结果都在要求范围内，即0.022 - 0.024 W/m·K。这极其重要，因为这些材料用于隔热目的。燃烧行为测试结果证实，添加可再生材料不会对所得到的泡沫的耐火性产生负面影响；所得到的结果与未添加填料的参考样品类似。火焰高度未超过17厘米，参考样品以及含咖啡渣的复合材料的火焰衰减时间为17秒，含橡木锯末的复合材料的火焰衰减时间为18秒。在这项工作中，首次描述了生物有机废料作为创新型填料用于填充聚氨酯泡沫隔热的实际应用。将天然来源的填料引入聚合物基体是改善硬质聚氨酯泡沫物理化学和功能特性的一种有前景的方法。从技术、生态和经济角度来看，用咖啡渣和锯末改性的复合材料很有吸引力，显著扩大了泡沫在各个行业的使用范围。
