Study On The Preparation And Properties Of Polymer/Carbon Nanotubes Composites

With the appearance of the nanotechnology in the end of last century ,the particular properties of the nanomaterials have absorbed comprehensive attention. Through combination nanomaterials with polymers, preparing the composite materials which have good synthetic function or special function have become the hotspot in the field of polymer. As one of the nanomaterials, Carbon nanotubes(CNTs) is the most special which has the nano diameter, superior tenacity and conductivity. Trough different methods, we can prepare some composite which have the properties of good mechanical, conductivity and electromagnetic shielding and so on. So the usage of the CNTs has the profound foreground. In this thesis, we adopted the different methods to prepare the different carbon nanotube composites, and mainly studied their mechanical properties, electric properties and thermal properties. Moreover, we discussed how the addition of carbon nanotubes effected the structure and properties of the composite materials. Through the process of ultrasonic, the CNTs were dispersed in the monomer. Then via in-situ polymerization, the polyurethane /CNTs composite was prepared. The disperse configuration of CNTs was studied via SEM and TEM, then we studied the thermal properties, mechanical properties and electric properties. The result showed that the CNTs were dispersed well in the composite, the mechanical property of the composite was best when the content of CNTs was 2%, of which the Peak Stress, Strain At Break and Modulus were enhanced 11.6%, 11.3 %and 10.4% respectively. At the same time, 1% weight of CNTs can make the composite have the ability of antistatic. Then we carried out modified experiment scheme aimed at the high viscosity and binding force of CNTs and PU. The result showed that CNTs were dispersed better and the reaction went on more complete with the help of tween80. As the compatibility of the two phases was boosted ,the mechanical properties and conductivity were increased more. Polyethylene/carbon nanotubes composites were prepared with the method of cross blend in solution. The disperse configuration of CNTs was studied via SEM and the thermal properties was studied, at the same time the tensile and the conductivity were discussed. The result showed that CNTs dispersed in the matrix in nanometer scale and interface bonding was good. As CNTs exerted the function of heterogeneous nucleation, the degree of crystallinity was enhanced that result in the fracture behavior of the polymer altered from plastic to fragile and the melt temperature increased. The addition of carbon nanotubes was benefit to improving mechanical property, at the same time the composite has the ability of antistatic.