Abstract
Two series of fluorinated copolymerized polyimide films with different dianhydride ratios were prepared via the conventional two-step method by using 4,4-oxydianiline(ODA) as the diamine monomer, 4,4'-(hexafluoroisopropylidene) diphthalic anhydride(6FDA), 4,4'-oxydiphthalic anhydride(ODPA) and 3,3',4,4'- biphenyl tetracarboxylic dianhydride(BPDA) as the dianhydride monomer in N, N-dimethylacetamide. With the increase of 6FDA in the proportion of dianhydride, the tensile strength of the polyimide film showed a decreasing trend. This work provided a high performance film. The mass retention rate at 800°C was above 50%. The glass transition temperatures of the two films were 260 °C and 275 °C. The storage modulus of the two were 1500 MPa and 1250 MPa. The loss modulus were 218.70 MPa and 120.74 MPa. The transmittance of the film was 71.43%. The transmittance of fluorinated copolymerized polyimide films were significantly improved in the visible region of ultraviolet light, indicating that the polyimide film with high transmittance, high tensile strength, high heat resistance and high storage modulus was successfully prepared. It had an excellent application prospect in the field of flexible display.
Highlights
Polyimides were widely used in aerospace[1], fluorine-containing groups could weaken the intermolecular microelectronics[2], national defense technology[3] and other forces and increase the transparency.fields[4], due to its excellent thermal stability, mechanical properties, chemical stability and good dielectric properties[5,6,7]
We found that the carbonyl stretching vibrations on the fluorinated polyimide-imide rings moved toward higher wave numbers
Two series of polyimides were synthesized by the two-step method from ODA and several commercial dianhydrides
Summary
Polyimides were widely used in aerospace[1], fluorine-containing groups could weaken the intermolecular microelectronics[2], national defense technology[3] and other forces and increase the transparency.fields[4], due to its excellent thermal stability, mechanical properties, chemical stability and good dielectric properties[5,6,7]. The third monomer was introduced into the molecular chain by a method of copolymerization, which changes the symmetry and regularity of the molecular chain, at the same time, the thermal stability of the polyimide film has not changed. This regularity could lead to a reduction in intermolecular interactions, which in turn results in new transfer(CT) effect between molecules, the molecular chain features, such as modified thermomechanical and gas has strong absorption and low transparency in the UV visible permeation properties, and altered solubility. The band, which restricts its application in the field of optical properties of copolymer polyimides could be adjusted and photoelectron[11,12]
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