Preparation And Performance Study Of Graphite Nickel PET-based Composite Smart Materials

Conductive composite is a kind of functional material, whose properties are often subjected to external field and have the characteristics of force-sensitive, temperature-sensitive, non-linear feature, and so on, which is the forefront and important subject in the field of current material science and engineering. The graphite nickel PET-based composite smart materials were prepared, composed of PET (Polyethylene Terephthalate), as matrix material, graphite and nickel, as conductive phase functional filler. The mechanical properties, conductivity and pressure sensitivity of the materials were systematically investigated by laboratory test and theoretical analysis, which would be further researched and provided basic theory and data support for its engineering application. The main contents and conclusions obtained were as follows:1. The effects of PET dosage, aggregate gradation, the dosages and types of conductive phase on the mechanical properties of PET-based composites were investigated. It was shown that:when the PET:aggregate=1:3, the mechanical properties of coarse continuous aggregate composites were more excellent; the graphite could decrease the mechanical properties of the composites, however, the nickel could effectively improve the mechanical properties.2. The improvement effects of graphite and nickel with different dosages on the conductivity of PET-based composites were investigated. The results showed that: compared to graphite, nickel could better improve the conductivity of the composites; when the graphite dosages increased from8%to12%, the resistivity of the composites decreased to46.45Ω·m from3.5×106Ω·m; when the nickel dosages increased from15%to40%, the resistivity of the composites decreased to0.09Ω·m from3.3×104Ω·m.3. Through the electromechanical response test of PET-based composites, the relationship between dosages of conductive phase and pressure sensitivity of the materials was analyzed. It was demonstrated that:the composites did not exhibit desirable pressure sensitivity when the dosages of conductive phase were too low or too high; when the dosages of conductive phase were close to the percolation threshold, the pressure sensitivity of the composites was excellent.4. The effects of compressive stress grades and loading rates on the pressure sensitivity of PET-based composite materials were analyzed. The results indicated that: graphite/PET-based composites were sensitive to low grades of compressive stress and nickel/PET-based composites to high grades; the pressure sensitivity of graphite/PET-based composite materials was significantly influenced by loading rates, while, to that of nickel/PET-based composites, the influence was small.5. The sensor performance of PET-based composite smart materials was investigated, and the results showed that, PET-based composites exhibit more ideal full-scale value, smaller non-linear errors and greater sensitivity.