Research On Preparation And Properties Of Polyaniline/Epoxy Shape Memory Composites

Shape memory polymers is a new kind of polymer intelligent material. It is the trend of the development of multiple functional research to meet the needs of different engineering applications. In the current field of electronic engineering, the intelligence, portability and low cost of the products is the development direction of electronic industry, which means the demand for such new type of smart materials as shape memory polymers is extremely urgent. However, the insulating property of shape memory polymer materials is a technical bottleneck in the field of electronic engineering. Therefore, it is of great significance to develop a new type of shape memory polymer material with electrical conductivity, which is very important for the application of shape memory polymer in the field of electronic engineering. In this paper, the functional properties of such two kinds of materials as epoxy shape memory polymer and conductive polyaniline are fully analyzed. And then, a series of Polyaniline / epoxy composites with remarkable shape memory effect are prepared by using the method of mechanical blending in this paper, and the doping process is also carried out to realize the conductive function. What's more, the thermodynamic properties, electrical conductivity and shape memory effect of such Polyaniline /epoxy composites are studied.(1)The prepared polyaniline / epoxy shape memory composites have good thermodynamic properties and excellent shape memory effect. With the increase of polyaniline content, the thermal decomposition temperature and the glass transition temperature of composites both increase first and then decrease, the maximum value of the thermal decomposition temperature is reached when the polyaniline content is4wt%, namely 244?; And the maximum value of the glass transition temperature is reached when the polyaniline content is 10wt%, namely 41?. Static tensile test results show that the tensile strength and elastic modulus of the composites increase first and then decrease with the increase of polyaniline content, while the elongation at break decreases gradually. When the polyaniline content is 8wt%, the tensile strength reaches the maximum value, which is 35 MPa. The test results of dynamicmechanical properties show that, with the increase of the content of polyaniline, the storage modulus of the material increases gradually, the peak value of tan ? decreases gradually, and the corresponding temperature of tan ? peak value increases at first and then decreases. A pre-deformation treatment above glass transition temperature to the prepared materials is also carried out, it is found that shape fixed rate is above 98.9%,and the shape recovery rate all can be close to 100%.(2)The polyaniline / epoxy composites are doped to realize their electrical conductivity, and the doping treatment parameters affecting the electrical conductivity of Polyaniline / epoxy composites are also studied and optimized. The conductive properties of pure polyaniline are investigated after compression molding, it is found that the electrical conductivity is 0.94S/cm. After the comparison of doping treatment effect of organic acids( camphorsulfonic acid) and inorganic acid(hydrochloric acid),the result shows that the doping effect of hydrochloric acid is better. Under the same doping time, with the increase of the concentration of HCl, the conductivity of the composites increases first and then decreases, when the concentration of HCl is 1mol/L, the conductivity of composites is highest; When carrying out doping treatment with the same concentration of hydrochloric acid, it is found that the conductivity of the material is the highest when the doping time is 2h. And under the condition of1mol/L HCl concentration and 2h doping time, we find that, with the increase of polyaniline content, the conductivity of the composite increases first and then decreases, when the polyaniline content is 12wt%, the conductivity of the composites is the highest. Therefore, the conductive performance optimization results of Polyaniline / epoxy shape memory composites are: When the polyaniline content is12wt%, the HCl concentration is 1.0mol/L and the doping time is 2h, the conductivity of the composite is the highest, which is 2×10-3 S/cm.(3)The paper also studies the influence of doping treatment on the shape memory effect of the material. It focuses on the comparison of thermal driven shape memory effect of composites with a polyaniline content of 12wt% after being doped with1mol/L HCl for 2 hours, then the paper studies the electrically driven shape memory effect. The results show: The thermal stability and Tg of the doped composites weredecreased; The tensile strength of the composite changed from 28.5MPa variable to12.5 MPa; The elastic modulus changed from 284.4MPa to 105.3MPa; The elongation at break increased from 11.6% to 12.7%. In addition, the hardness of the composite decreased from 100 HA to 93 HA. Dynamic mechanical performance test results show that doping treatment reduces the rigidity and damping capacity. Findings from electrically driven shape memory effect test show that the material shape recovery can be gained through applying 120 V or above to the two ends of the material after the pre-deformation treatment, materials can be fully shape recovered.The complete recovery time of the shape of the material decreases gradually with the increase of voltage. To sum up, the doped composite material has excellent thermal driven and electrically driven shape memory effect.