Fabrication Of High Dielectric Property Of Polyurethanes And Investigation Of Their Relationship Between Microstructure And Properties

Recently, the application prospect of dielectric elastomers in the fields of sensors, energy collection and drives has been well received by researchers. Polyurethane is an elastomer material with good performance good mechanical and physical properties. Polyurethanes contain polar groups such that their dielectric constants are higher than 7, and the different dielectric constants can be obtained by the choice of raw materials. This advantage makes it a wide range of interest for scientists,but its development is also confronted with many Challenges, how to get high dielectric constant polyurethane elastomer has been the key to the problem and the structure and performance of dielectric polyurethane materials is not clear. In this paper, a high dielectric constant polyurethane elastomer was synthesized by the selection of raw materials,and the structure and properties of the polyurethanes were characterized by FTIR, SAXS, XRD, DSC, TGA and DMA. The main contents are as follows: (1) Synthesize polyurethane with different soft segment structure,and to study its effect on the structure and properties of polyurethane dielectric elastomer. (2) Study the effect of hard structure on the structure and properties of polyurethane dielectric elastomer (3) The effects of different hard content on the structure and properties of polyurethane dielectric elastomers were investigated. (4) The polyurethane materials were prepared by using chain extenders of amines and alcohols, and study the effects of chain extender on the dielectric properties of polyurethane(5) The effect of heat treatment on the structure and properties of polyurethane dielectric elastomer was studied.The results show that: 1) The dielectric properties of the same hard segment structure and content of the hydroxyl group polybutadiene(HTBN) and the terminal hydroxyl butadiene-acrylonitrile copolymer(HTBN) -based polyurethane material show that the soft segment contains Polar groups of HTBN-based polyurethane materials show higher dielectric properties, and the dielectric constant of HTBN-based polyurethane material can reach 9.2 at 1000 Hz; 2) In the HTBN and HTPB-based polyurethane material, the dielectric constant of HDI-based polyurethane is higher than the dielectric constant of the polyurethane material with the corresponding MDI and TDI as hard segments. 3) In the HTBN and HTPB systems, the dielectric constant increases from 7.8 to 8.6 and increases from 5.1 to 5.8 as the hard content increases. 4) The results show that the chemical structure of chain extender also affects the dielectric constant of polyurethane materials, dielectric constant of polyurethane that was synthesized by amine chain extender is higher than alcohol chain extenders, and amine chain extenders synthetic polyurethane dielectric constant with the heat treatment temperature lower, alcohol chain extenders are the opposite. The results of the above studies show that the dielectric properties of the polyurethane material can be controlled by changing the chemical structure of the hard segment,the chain extender and the chemical structure of the soft segment. And the degree of phase separation and crystallinity, and the polarity of the soft segment which is beneficial to improve the dielectric constant of polyurethane materials, especially the dielectric constant of low frequency.