Research On Self-assemble Behavior Of Carbon Black And Its Application In Conductive Polymer Composites

Combined with the radical trapping nature of carbon black (CB), thermal degradation and ultrasonic degradation methods were used to prepare two different kinds of organic compound grafted CB. Two kinds of grafted CB have good dispersiblity and stability in organic solvent or water, respectively. Take advantage of the non-covalent bond between grafted CB and polymer microsphere, or the electrostatic heterocoagulation between grafted CB and inert clay nanorods to create different self-assembly composite particles. Controllable morphology of composite particles were acted as building blocks in order to create conductive networks with the polymer matrix, and fabricated through tailoring the process of self-assemble behavior of CB. According to the study for layer-by-layer (LBL) self-assemble behavior of CB, the CB/polymer thin film with controllable thickness and electrical property was prepared. The main conclusions are as follow:1. A simple in-situ solid grafting approach was used to prepare Irganox1330 grafted CB. Take advantage ofπ-πinteraction between Irganox1330 and polystyrene (PS) to prepare PS/CB self-assembly microspheres. The morphology of PS/CB microsphere was tailored through adjusting the polarity of heterocoagulation process, and investigated by SEM and AFM. The wetability of PS/CB microsphere was measured by water contact angle (WCA). The results indicated that the morphology and surface property was determined by the CB concentration of PS/CB self-assembly microsphere.2. PS/CB self-assembly microspheres were prepared by heterocoagulation process from grafted CB and PS microspheres through aπ-πinteraction. Their morphologies could be tailored as the coverage dgree of CB on PS microsphere and were investigated by SEM. The CB/PS composites and CB/PS/PC composites prepared by using PS/CB microspheres were investigated. The effects of concentration of PS, coverage degree of CB and concentration of CB on electrical properties were studied. The results showed that, compared with general composites, the percolation threshold of composites could be improved by utilizing the interaction between the morphology of self-assembly microsphere and resistivity. In addition, the zero birefringence of PS/PC blends improved the light transmittance of such composites.3. Polyelectrolyte poly (methyl vinyl ether-co-maleic acid) (PVM/MA) was grafted on the surface of CB by ultrasonically degraded method. FT-IR, TGA were used to analyze the surface properties and structure of PVM/MA grafted CB. The pH-responsive of PVM/MA grafted CB influence the particle size of grafted CB in water. A thin film was frabicated from LBL assembly of grafted CB and polyethyleneimine (PEI) due to different surface charge. AFM was used to investigate the surface morphology of this grafted CB/PEI film. pH value, immersion time and the number of deposition circles affected the film thickness. The light tansmittance and resistivity of film were improved as the increase of deposition circles. 4. PVM/MA grafted CB had better dispersibility and compatibility than that of pristine CB in water-bonre polyurethane (WPU) and corresponding solid composites. DLS and HRTEM results demonstrated that anionically charged grafted CB nanoparticles were heterocoagulated on the surface of cationically charged ATT nanorods and improved the stabilization of ATT in wate as dispersing aids. The microstructure development in matrix that depended on various weight ratios of the nanoparticles ultimately influenced the electrical conductivity and mechanical property of WPU composites. The results showed that both electrical conductivity and storage modulus of composite could be improved simultaneously when CB and ATT had a appropriate weight ratio.5. ATT/CB/Epoxy (EP) composites were prepared by liquid mixing method. The stability of CB and (or) ATT suspensions in acetone was analyzed by UV-Vis and Zeta potential. The microstructures and volume resistivity of the composites were examined by scanning electron microscope (SEM), resistance meter and DMA. The results indicated that ATT can effectively improve the dispersion of CB in solution, which resulted in conductive networks in the matrix and improved storage modulus.