Mechanical and Electrical Properties of Injection Molded Polymer Matrix Carbon Nanotube Composites

Carbon nanotubes (CNTs) are expected to be one of the most promising nano-materials for improvingpolymer matrix composites mechanical properties as electrical properties of polymer matrix composites. However，因为CNTs is on the nanometer order，there are little reports about the experimental evaluation of their properties by ctmanipulation, which is performed in a scanning electron microscope （SEM）原子力微生物（AFM）. In the material design for using nano-materials，it is essential to understand the characteristics of nano-materials experimentally. We attempted tomeasure Young's modulus of various types of CNTs. A cantileverwhich is sually used for an AFM and made of silicon，这是mounted on the piezo-driving stage. the apparent Young's modulus of the CNT is calculated fromconventional relationship between the load applied to the CNT and the displacement of the tip ofCNT.五个类型的CNTs are used in the series of experiments. They are ARC-CNTs，电- cnts……More, two types of Vapor-grown CNTs；named VG80 and VG50, which are 80nm and 50nm in average diametersrespectively. The relative intensities ratio of The D-band around 1350cm <-1> to The G-band around1580 cm <-1>(ID/IG) in Raman spectra was obtained using the Gaussian fitting. An rc - cnt was bentlike a bending beam by a lateral force applied by a提示of the cantilever. For calculating theapparent Young's modulus of CNTan equation for the conventional bending beam was applied.自年轻的模块actually calculatedincludes the influence of the section modulus and indicates the flexural rigidityapparent Young's modulus of The ARC-CNT used here was "apparent Young's modulus of The ARC-CNT used here was3.3 TPa. This value is slightly lower than the theoretical Young's modulus (5.5 TPa) ofthe single-walled CNT，这是典型的使用molecular dynamics. same measurements and calculation were performedon other CNTs，and the relationship between the apparent Young's modulus obtained from TEM measurements and theID/IG obtained from the Raman spectra is summarized. the result clearly shows that the result clearly shows that thehigh-crystallinity CNT has a high apparent Young's modulus.Next，we studied injection molding of MWCNT filled polystyrene (PS) and evaluation of the mechanical and电子properties comparing with the composites in which conventional carbon fillers werefilled. As a result，the resistivity of the composites filled with CNT drops significantly between 3 and 4 vol % andafter which it decreases linearly above 4 vol.%. The resistivity of The composites filled with CNTis1.2 x10 when the CNT concentration is 11.6 vol.%. the resistivity is significantly lowerthan of the composites which were filled with conventional carbon fillers. the elastic modulusslightly improves with increasing CNT concentration The tensile strength is almost constant in Thepristine CNT concentration range from 0 to 12 vol.%. Then we applied DLC coating andamino-functionalization of CNTs and found that the tensile strength increases up to 20% using the函数CNTs in PP matrix. Less

Carbon nanotubes (CNTs) are expected to be one of the most promising nano-materials for improving mechanical properties as well as electrical properties of polymer matrix composites. However, since the size of CNTs is on the nanometer order, there are little reports about the experimental evaluation of their properties by direct manipulation, which is performed in a scanning electron microscope (SEM), an atomic force microscope (AFM). In the material design for using nano-materials, it is essential to understand the characteristics of nano-materials experimentally. We attempted to measure Young's modulus of various types of CNTs. A cantilever, which is usually used for an AFM and made of silicon, was mounted on the piezo-driving stage. The apparent Young's modulus of the CNT is calculated from the conventional relationship between the load applied to the CNT and the displacement of the tip of the CNT. Five types of CNTs are used in the series of experiments. They are ARC-CNTs, CVD-CNTs … More , two types of Vapor-grown CNTs (VGCNTs); named VG80 and VG50, which are 80nm and 50nm in average diameters, respectively. The relative intensities ratio of the D-band around 1350 cm^<-1> to the G-band around 1580 cm^<-1>(ID/IG) in Raman spectra was obtained using the Gaussian fitting. An ARC-CNT was bent like a bending beam by a lateral force applied by a tip of the cantilever. For calculating the apparent Young's modulus of CNT, an equation for the conventional bending beam was applied. Since Young's modulus actually calculated includes the influence of the section modulus and indicates the flexural rigidity, it was termed "apparent Young's modulus". The apparent Young's modulus of the ARC-CNT used here was obtained as 3.3 TPa. This value is slightly lower than the theoretical Young's modulus (5.5 TPa) of the single-walled CNT, which was simulated using molecular dynamics. The same measurements and calculation were performed on other CNTs, and the relationship between the apparent Young's modulus obtained from TEM measurements and the ID/IG obtained from the Raman spectra is summarized. The result clearly shows that the high-crystallinity CNT has a high apparent Young's modulus.Next, we studied injection molding of MWCNT filled polystyrene (PS) and evaluation of the mechanical and electrical properties comparing with the composites in which conventional carbon fillers were filled. As a result, the resistivity of the composites filled with CNT drops significantly between 3 and 4 vol.% and after which it decreases linearly above 4 vol.%. The resistivity of the composites filled with CNT is 1.2x10^2 W・cm when the CNT concentration is 11.6 vol.%. The resistivity is significantly lower than that of the composites which were filled with conventional carbon fillers. The elastic modulus slightly improves with increasing CNT concentration The tensile strength is almost constant in the pristine CNT concentration range from 0 to 12 vol.%. Then we applied DLC coating and amino-functionalization of CNTs and found that the tensile strength increases up to 20% using the functionalized CNTs in PP matrix. Less