Use a polyurethane sizing agent to improve the interfacial properties of carbon fiber-reinforced polyurethane composites
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摘要: 经阳极氧化的炭纤维丝束用水性聚氨酯进行上浆,考察上浆剂对炭纤维增强聚氨酯复合材料界面性能的影响,并结合元素分析、官能团分析、热重分析和示差扫描热分析进行机理研究。结果显示,上浆剂可以显著提高复合材料界面性能。层剪强度从氧化后的39.5 MPa提升到上浆后的46.4 MPa,提升17.5%。上浆的炭纤维经170 °C 热处理后层剪强度进一步提高到50.8 MPa。这归因于上浆剂与炭纤维表面的含氧官能团进行反应形成化学键,而上浆剂与基体以氢键相互作用。经进一步热处理后,上浆剂的封端剂脱除,释放出异氰酸酯与基体中的氨基甲酸酯反应生成尿基甲酸盐。因此,此水性聚氨酯上浆剂提高了炭纤维增强聚氨酯复合材料的界面性能。Abstract: An anodized carbon fiber tow was continuously sized using aqueous polyurethane to improve the interfacial properties of carbon fiber-reinforced polyurethane composites. These were investigated by interlaminar shear strength (ILSS) tests, elemental and functional group analysis, thermal gravimetric analysis, and differential scanning calorimetry. Results show that the polyurethane sizing agent significantly improves the interfacial properties of the composites. The ILSS of the sized carbon fiber-reinforced composite is increased by 17.5% (from 39.5 to 46.4 MPa) compared to that of the oxidized carbon fiber-reinforced counterpart. Treating the sized carbon fiber-reinforced composite at 170 °C further increased the ILSS by 9.5% to 50.8 MPa. It is considered that the sizing agent interacts with oxygen-containing functional groups on the oxidized carbon fiber surface to form hydrogen bonds with the resin matrix. Upon heating at 170 °C, blocking groups in the sizing agent are unblocked to expose the isocyanate roots that react with the carbamate of the matrix to generate allophanate. It is concluded that a polyurethane sizing agent is suitable for improving the interfacial properties of carbon fiber-reinforced polyurethane resin composites, and that heating after curing further improves these properties.
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Key words:
- Carbon fiber /
- Polyurethane /
- Sizing agent /
- Heat treatment /
- Composites
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Table 1. The element content of carbon fiber surface
Carbon fiber Element content Element ratio C O N O/C N/C OCF 87.4% 10.3% 2.3% 11.8% 2.6% 0.58%PUS-CF 74.9% 15.5% 9.6% 20.7% 12.8% Table 2. The relative content of functional groups based on the splited peak areas of C1s
Carbon fiber C―C/H C―O―C/H O=C―O OCF 76.7% 19.8% 3.5% 0.58%PUS-CF 61.5% 27.8% 10.7% -
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