Abstract:

With the continuous advancement of society, people pay more and more attention to the protection of the ecological environment. The green composite materials that can coexist harmoniously with the environment and benefit human health have received continuous attention from the scientific community. In this paper, the waste coffee husks powder was used as raw material. In order to avoid the decrease of the reinforcing effect caused by the agglomeration of the nanocellulose mixture, the urea ball milling system was innovatively used to prepare the submicron cellulose mixture (including hemicellulose and lignin) and compared with the preparation of nano-scale cellulose mixture (containing a small amount of hemicellulose and lignin). The effects of different scales of cellulose mixture on polyethylene reinforced wood powder wood-plastic composites were discussed. It showed that both the nano-scale cellulose mixture (CSNC) and the sub-micron cellulose mixture (CCMC) increased the viscosity of the wood-plastic composite at room temperature, improving the heat resistance and creep resistance of the composite. For the properties of the material, the flexural modulus of the composite increased by 35% after adding 4% PE quality CSNC, but the bending strength and impact strength decreased and the brittleness of the material increased. After adding 4% PE quality CCMC, the flexural modulus of the wood-plastic composite material was unchanged, the impact strength and bending strength were both increased by 7%, and the material strength was enhanced. In terms of water absorption, CSNC significantly increased the water absorption of the material, and the addition of CCMC had little effect on the water absorption of the material. Submicron cellulose blends were superior in improving the properties of wood-plastic composites, making preparation easier and more convenient.

Key words: wood plastic material, coffee husks, nanocellulose, polyethylene, ball milling

摘要：

随着社会的进步，人们对生态环境的重视程度在不断地提高，环境友好型的绿色复合材料受到了科学界的持续关注。本文利用废弃咖啡壳粉为原料，探讨不同尺度的纤维素混合物对聚乙烯增强木粉木塑复合材料的影响。为避免纳米纤维素混合物的团聚引起的增强效果下降，创新使用尿素球磨体系制备亚微米级纤维素混合物（含半纤维素与木质素），与制备工艺复杂的纳米级纤维素混合物（含少量半纤维素与木质素）进行对比。研究结果表明，在室温下纳米级纤维素混合物（CSNC）与亚微米级纤维素混合物（CCMC）都使木塑复合材料的黏度升高，提高了复合材料的耐热性和抗蠕变性。对于材料的性能，当加入添加量为4%PE的CSNC后，复合材料的弯曲模量提高了35%，但弯曲强度和冲击强度均有所下降，材料脆性增加。加入4%PE质量的CCMC后木塑复合材料弯曲模量不变，冲击强度与弯曲强度均升高7%，材料强度得到增加。在吸水率方面，CSNC使材料的吸水率显著提高，CCMC的加入对材料吸水率影响不大。亚微米级纤维素混合物在改善木塑复合材料的性能方面更为出色，制备更为简单方便。

关键词: 木塑材料, 咖啡壳, 纳米纤维素, 聚乙烯, 球磨