Fatigue life improvement of CFRP due to hybrid modification of polymer matrix with cellulose nano fibers and nano rubber particles

采用包括细菌纤维素在内的不同类型的纤维素纳米纤维(CNF)对碳纤维增强塑料(CFRP)的环氧树脂进行物理改性。与未改性的碳纤维相比，任何类型的碳纤维都能显著延长碳纤维的疲劳寿命。当CNF同时与纳米橡胶粒子混合时，改性CFRP的拉伸强度明显提高，而不会因混杂效应而影响其他性能。由于适当的混合改型，预计会有更多的疲劳寿命延长。还测试了直径为50 nm的PVA、500 nm的玻璃纤维和700 nm的PET纤维，而不是CNF。这些纤维虽然力学性能不同，但也延长了CFRP的疲劳寿命。细纤维(小于1μm)可用作碳纤维增强塑料的基质改性剂。在环氧树脂中加入适量的CNF，纤维脱粘现象较少。其他树脂基质，如乙烯基酯，可以用CNF进行改性，以延长疲劳寿命。

Epoxy matrix of CFRP was physically modified with different types of cellulose nano fibers (CNF) including bacterial cellulose, whose weight content was about 0.3-0.8wt%. Any types of CNF incredibly extend the fatigue life of CFRP in comparison with the unmodified one. An excessive amount of CNF decreases the life extension effect.When CNF were simultaneously mixed with nano rubber particles, the tensile strength of modified CFRP appreciably increased without scarifying other properties due to a hybrid effect. More fatigue life extension is expected due to an appropriate hybrid modification. 50nm (in diameter) PVA, 500nm glass and 700nm PET fibers were also tested instead of CNF. Those fibers extended the fatigue life of CFRP as well in spite of difference in their mechanical performance. Thin (smaller than 1 μm) fibers are useful as a matrix modifier of CFRP. When an appropriate content of CNF was mixed into epoxy matrix, less fiber debonding occurred. Other resin matrices such as vinylester can be modified with CNF for fatigue life extension.