碳纳米管增强聚合物纤维增强机理(英文).ppt

1、Adv. Funct. Mater. 2011, 21, 364371,Reading Report,Outline,Innovation and inspiration,Result and discussion,Experimental,Conclusion,Introduction,Introduction,Very few studies have reported measurements of the mechanical properties of polymer-nanotube composite bers as a function of nanotube content

2、Krenchel extended Coxs original model to show that the modulus and strength of composites lled with rodlike llers scales linearly with0 , However to our knowledge, it has never been demonstrated experimentally that this scaling holds for a range of orientations (i.e., a range of 0 values) for any na

3、nocomposite. it should be possible, not only to quantitatively examine the Cox-Krenchel equation, but to demonstrate the production of relatively stiff, strong bers.,Experimental,Materials,Methods,Puried SWNTs (HiPCO, Unidym), polyvinyalcohol (J. T. Baker, Mw= 77,00079,000 g mol 1, 9999.8% hydrolyse

4、d) and the surfactant sodium cholate (Aldrich),NT,sodium cholate,deionised water,sonic tip processor,centrifuged,Polyvinylalcohol solution,spinning,drawing,dried,test,For perfectly aligned bers (0=1) prepared with long nanotubes (lY=1), dY/dVf=YNT, which has a maximum value of 1000 GPa,the mechanica

5、l properties of composite bers are limited by the nanotube length, the strength of the polymer-nanotube interface and the degree of nanotube alignment.,Here the bers have dY/dVf600 GPa and dB/dVf7GPa for DR40%,S=0 for random orientation to S=1 for perfect axial alignment,In the ideal case,YEff shoul

6、d be identical to dY/dVf,For undrawn bers and for DR22%, dY/dVf =YEff. However, for higher draw ratios, dY/dVf YEff,XRD,YNT=48040 GPa or about half the expected value,The values of dB/dVf achieved, even for the drawn bers are relatively low;7GPa compared to a potential value of 50130 GPa,=404MPa. Th

7、is is very close to the known shear yield strength of PVA (41 MPa),&,Conclusion,developed a method to control and measure the nanotube volume fraction in polyvinylalcohol-nanotube bers. By drawing bers with VfYEff, suggesting that drawing induces additional forms of reinforcment the ber strength als

8、o scales linearly with 0. This allows us to calculate the effective interfacial shear strength and critical length to be 40 MPa and 1250 nm respectively,Innovation & Inspiration,the rst to comprehensively measure mechanical properties as a function of volume fraction allowing accurate measurement of dY/dVf in the linear region experimentally demonstrated and quantied both the volume fraction and orientation dependence contained in the Cox-Krenchel version of