Maradini Grazielle da Silva, Oliveira Michel Picanço, Guanaes Gabriel Madeira da Silva, Passamani Gabriel Zuqui, Carreira Lilian Gasparelli, Boschetti Walter Torezani Neto, Monteiro Sergio Neves, Pereira Artur Camposo, de Oliveira Bárbara Ferreira
Forest and Wood Sciences Department, Federal University of Espírito Santo, Jeronimo Monteiro 29550-000, Brazil.
Forestry Engineering Department, Federal University of Viçosa, Viçosa 36570-900, Brazil.
Polymers (Basel). 2020 Nov 28;12(12):2838. doi: 10.3390/polym12122838.
The application of cellulose nanocrystal has lately been investigated as polymer composites reinforcement owing to favorable characteristics of biodegradability and cost effectiveness as well as superior mechanical properties. In the present work novel nanocomposites of unsaturated polyester matrix reinforced with low amount of 1, 2, and 3 wt% of cellulose nanocrystals obtained from conifer fiber (CNC) were characterized. The polyester matrix and nanocomposites were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), bending test, and thermogravimetric analysis (TGA). The result showed that the addition of only 2 wt% CNC increased the nanocomposite flexural strength by 159%, the ductility by 500% and the toughness by 1420%. Fracture analyses by SEM revealed a uniform participation of the CNC in the polyester microstructure. The resistance to thermal degradation of the CNC reinforced nanocomposites was improved in more than 20 °C as compared to neat polyester. No significant changes were detected in the water absorptions and XRD pattern of the neat polyester with incorporations up to 3 wt% CNC. These results reveal that the 2 wt% CNC nanocomposite might be a promising more ductile, lightweight and cost-effective substitute for conventional glass fiber composites in engineering applications.
由于具有生物可降解性、成本效益以及优异的机械性能等有利特性，纤维素纳米晶体作为聚合物复合材料增强剂的应用近来受到了研究。在本研究中，对由针叶树纤维（CNC）制得的、添加了低含量（1 wt%、2 wt%和3 wt%）纤维素纳米晶体增强的不饱和聚酯基新型纳米复合材料进行了表征。通过扫描电子显微镜（SEM）、X射线衍射（XRD）、弯曲试验和热重分析（TGA）对聚酯基体和纳米复合材料进行了研究。结果表明，仅添加2 wt%的CNC就能使纳米复合材料的弯曲强度提高159%、延展性提高500%、韧性提高1420%。SEM断口分析表明，CNC在聚酯微观结构中均匀分布。与纯聚酯相比，CNC增强纳米复合材料的热降解抗性提高了20多摄氏度。添加量高达3 wt%的CNC时，纯聚酯的吸水率和XRD图谱未检测到显著变化。这些结果表明，2 wt%的CNC纳米复合材料可能是工程应用中传统玻璃纤维复合材料一种更具延展性、重量轻且成本效益高的有前途的替代品。
