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Synthesis and properties of new double - o- phthalonitrile resin

Author: LiWenZuo
Tutor: LiuXiaoBo
School: University of Electronic Science and Technology
Course: Applied Chemistry
Keywords: Dual phthalonitrile Curing rate Processing temperature window Thermal stability Thermo-oxidative stability
CLC: TQ323.9
Type: Master's thesis
Year: 2009
Downloads: 73
Quote: 1
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Abstract

Phthalonitrile resins are a class of high-performance thermosetting resins, it is mainly at high temperatures by the phthalonitrile monomer polymerization by the addition of the nitrile group. Phthalonitrile resin due to its excellent thermal stability, and thermal-oxidative stability, chemical stability, flame retardancy, low water absorption and good workability, and has broad application prospects in the field of aerospace, and other high-tech. First, we studied the biphenyl double o-phthalonitrile resin curing reaction process (BPh). In the the BPh curing process is not only adding a cross-linking agent selected ammonium molybdate as catalyst. The study showed that: a better control of the curing reaction rate can be by controlling the amount of catalyst is added. Content within a certain range (0.5-1wt%) of the catalyst can improve the thermal stability of the cured product under this condition BPh residual carbon ratio is higher than 74% of the resin under a nitrogen atmosphere in 800oC in an air atmosphere with a high at the carbon residue rate of 60%, the material has good thermal stability and thermo-oxidative stability. However, the catalyst is added in excess, it will reduce the thermal stability of the cured samples. The study showed that the excellent resin properties can be obtained when the crosslinking agent content of 2-3wt%, and the catalyst content of 1wt%. Dynamic studies of the rheological properties of gelation time of the sample frequency parameters show some regularity. When the frequency is 1.2Hz, the gelation time min. In addition, the temperature scanning mode dynamic rheological properties of gelation time decreases with the increase of heating rate and its variation with a smooth curve coincide. In subsequent studies, the equations of this curve can be applied to predict the corresponding conditions, the gelation time. Secondly, we synthesized an ether nitrile-containing chain segment of a bisphenol A type bis o-phthalonitrile the resin (nPEN BAPh), and its structure has been supported by FTIR, 1H-NMR and 13C-NMR spectra. Through the test shows that the melting or softening point of the resin of this series is about 60oC, a curing temperature of about 220oC, so such material has a larger processing temperature window. Further, nPEN-BAPh the curing reaction more easily compared BPh occur, in the absence of a catalyst, can also be carried out in only through the change of the crosslinking agent content and a better control of the rate of the curing reaction. When n is greater than 6, the heat of the resin and the thermo-oxidative stability are greatly decreased, especially in the temperature is higher than 600oC cured mass loss larger. Finally, the characteristics of the above two types of resin, prepared BPh / nPEN-BAPh copolymer. Related parameters of the cured BPh/6PEN- BAPh the initial decomposition temperature in the atmosphere of nitrogen and air, 5% mass loss temperature of 800 oC residual carbon rate than a single 6PEN-BAPh resin has been greatly improved . At the same time, BPh/6PEN-BAPh processing temperature window compared BPh about 30oC. Such material has good thermal and thermo-oxidative stability, but also has a high processing temperature window, which proposed a new technology roadmap for the enrichment and development of double-phthalonitrile system.

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