Study On Preparationand Properties Of Polymer Composites Materials Based On Carbons

Fullerenes, carbon nanotubes, graphene and other carbon nanomaterialsdue to unique physical and chemical properties have been widely used inbiomedical, electronics, magnetic materials, optical materials, moleculardevices, automotive, stealth technology. Expanded graphite because of itslarge specific surface area and special shape, easy to form a conductivechannel in a polymer matrix, has widely application prospects in improvingelectrical properties, mechanical properties of the polymer. The use of nanointercalation technology to prepare low percolation threshold of carbon-basedconductive polymer composites is one of the hot attention.In this paper, polypropylene, polyethylene as the matrix, a carbonmaterial as filler, prepared expanded graphite/multi-walled carbon nanotube/polypropylene (EG/MWCNTs/PP), expanded graphite/carbon black/polyethylene (EG/CB/PE) conductive polymer composites, using differentialscanning calorimetry (DSC), thermal gravimetric analyzer (TGA), universaltesting machine, scanning electron microscopy (SEM) techniques to study theeffect of amount of carbon material on polymers. The results showed that:1. In the expanded graphite/multi-walled carbon nanotube/polypropylene(EG/MWCNTs/PP) system, layered expanded graphite and fibrousmulti-walled carbon nanotubes formed a complete and stable conductivity "Network ",in the polypropylene matrix, and with good dispersion effect, resulting polypropylene tensile strength and elongation at break of thecomposites significantly improved, especially when EG/MWCNTs=0.1/0.1pbw, the tensile strength and elongation at break of composites reachmaximum. The addiction of carbon-based materials, has impact of thecrystallization behavior of polypropylene and improves the heat resistance ofpolypropylene composite material, significantly improves the electricalproperties of polypropylene composites, its percolation threshold is EG/MWCNTs0.1/0.1to0.5/0.5pbw. Polypropylene non-isothermalcrystallization system in line with Mo equation. By Kissinger method tocalculate, when EG/MWCNTs=0.1/0.1pbw, reach the minimum activationenergy of crystallization of the composite system, with the increasing contentof filler added, the crystallization activation energy increases.2. In the expanded graphite/carbon black/polyethylene (EG/CB/PE) systems,layered expanded graphite and spherical carbon black in polyethylene matrixuniformly dispersed carbon black played a "bridge" in the system, and withexpanded graphite forming a stable conductive path. Since the tunneling gapbetween the two electrically conductive filler result in properties withexcellent electrical conductivity. When EG/CB=0.2/0.4pbw, the tensilestrength and elongation at break of the composites is Minimum. Polyethylenesystems in line with the non-isothermal crystallization process Morseequation. By Kissinger method to calculate, when packing EG/CB=0.2/0.4parts by crystallization activation energy of the composite system ofminimum, to222.4KJ/mol, indicating that the addition of carbon-basedmaterial in the system reduce the crystallization activation energy, helpcrystallization system.