CN1245434C - Poly-benzobisoxazole polymer containing hydroxyl group and process for preparing same - Google Patents

Abstract

The present invention discloses a poly-benzobisoxazole polymer containing the base group of a hydroxyl group and a preparation method thereof. A polymer solution obtained by the present invention can be used for preparing high-performance fibers by using dried spray and wet spinning through a screw extruder. The molecular structural fragment of the polybenzoxazole polymer of the present invention discloses in the specification.

Description

Polybenzobisoxazole polymer containing hydroxyl group and preparation method thereof

technical field

The invention relates to a polybenzobisoxazole polymer and a preparation method thereof.

Background technique

In the 1960s, the successful development of poly-p-phenylene terephthalate (PPTA) fibers set off a research boom in high-performance fibers. Through molecular design and liquid crystal spinning technology, various high-performance fibers with excellent properties have been continuously developed. High-performance fibers prepared from aromatic heterocyclic polymers represented by poly-p-phenylenebenzobisoxazole (PBO) It is the best among them. Based on the research of the U.S. Air Force Materials Laboratory and Dow Chemical Company, Japan Toyobo successfully realized the industrial production of PBO fiber in the 1990s, and its trade name was "Zylon". Zylon has a tensile strength of 5.8GPa and a tensile modulus of 300GPa, which are twice that of PPTA fibers, respectively. In addition, Zylon also has excellent thermal stability (thermal decomposition temperature up to 650°C) and flame retardancy (LOI=68). Therefore, Zylon has important application value in aerospace, military and national defense, transportation, sports equipment, construction, high temperature protection and other fields, and has an irreplaceable role for other materials. Especially since mankind entered the information age, the competition among countries in terms of comprehensive national strength has become increasingly fierce, and the development and exploration of future war weapons and equipment and space resources have continued to deepen, all of which need to be supported by advanced materials that are lighter, stronger, and more energy-efficient. The development and application of high-strength, high-modulus, high-temperature-resistant, flame-retardant high-performance fiber materials represented by Zylon and their advanced composite materials reflect the development level of a country's cutting-edge technology to a certain extent, and become a class of strategically significant Material resources.

However, Zylon is not perfect, and its compressive strength, torsional modulus, etc. are still insufficient. The axial compressive strength of Zylon is 200-400MPa, which is far lower than its tensile strength; when Zylon is used to prepare composite materials, there is also the problem of poor adhesion between the fiber and the matrix, which is caused by the macromolecule of PBO, the raw material for preparing Zylon. determined by the structural properties. PBO is obtained by polymerization of terephthalic acid (TA) and 4,6-diaminoresorcinol hydrochloride (DAR) in polyphosphoric acid (PPA) medium, and its synthesis route is as follows:

From the perspective of molecular structure, PBO is a rod-shaped rigid chain macromolecule, and there are only van der Waals interactions between molecules, lacking entanglement; and there is no polar group in the molecular structure.

Contents of the invention

The technical problem to be solved in the present invention is to disclose a polybenzoxazole polymer and a preparation method thereof, so as to obtain high-performance fibers with better comprehensive properties.

The chemical name of the polybenzoxazole polymer of the present invention is poly 2,5-dihydroxyphenylenebenzobisoxazole, referred to as DHPBO, which has the following molecular structure fragments:

Among them: n=89～100, the number average molecular weight is 23000～27000;

Above-mentioned poly 2, the preparation method of 5-dihydroxyphenylene benzobisoxazole comprises the steps:

4,6-diaminoresorcinol hydrochloride (DAR for short, the same below) and 2,5-dihydroxyterephthalic acid (DHTA for short, the same below) in polyphosphoric acid (PPA for short) in an inert atmosphere , the same below), carry out the polycondensation reaction, the reaction temperature is 50-100 ° C, the HCl in the DAR is completely removed after the reaction, and the gas released by the reaction can be detected by pH test paper to be neutral;

Then react at 130°C-150°C for 3-6 hours, then react at 170-175°C for 10-14 hours, and finally react at 185°C-200°C for 16-24 hours to complete the polymerization reaction, and then use conventional methods Collect said polymer from the reaction product, generally wash with a large amount of water to completely remove polyphosphoric acid in the system, and then vacuum dry.

In the polymerization reaction, the molar ratio of DAR to DHTA is 1:0.8-1.2.

The chemical structure of said 4,6-diaminoresorcinol hydrochloride is as follows:

The chemical structure of said 2,5-dihydroxyterephthalic acid is as follows:

4,6-diaminoresorcinol hydrochloride and 2,5-dihydroxyterephthalic acid can adopt literature Wolfe J.F., Arnorld F.E., Macromolecules 1981,14,909 and literature Klop E A, Lammers M.Polymer 1998 , 39,5981 disclosed method for preparation, or use commercially available finished products.

Said polyphosphoric acid is H ₆ P ₄ O ₁₃ .

The molar ratio of polyphosphoric acid to DAR is: 1:0.3～0.6

The polymer obtained by the present invention can form hydrogen bonds between macromolecules or in macromolecules (Klop E A, Lammers M. Polymer 1998, 39, 5987, Hageman J CL, van der Horst J W, de Groot R A. Polymer 1999, 40, 1313-1323), thereby improving the compressive properties of high-performance fibers prepared from it. The polymer solution obtained in the invention can be used to prepare high-performance fibers through a screw extruder by dry-jet wet spinning, and the compression modulus can be measured by a three-point bending test method.

Detailed ways

Example 1

In a 0.5L reactor equipped with a strong stirring device, _N2 inlet and outlet _, and a feeding port, first pass high-purity _N2 to replace the air, and then add 5.4455g of 4,6-diaminom-benzenediene under the protection of N2 Phenol hydrochloride (DAR), 5.0620 g 2,5-dihydroxyterephthalic acid (DHTA), 25.67 g H ₆ P ₄ O ₁₃ (P ₂ O ₅ concentration 80 wt%) and 10.3649 g P ₂ O ₅ , sealed Reactor.

Raise the temperature of the reaction materials in the reactor to 50°C and keep for 3 hours to make the materials mix initially, then slowly raise the temperature to 65°C and keep for 5 hours to further dissolve the materials. Raise the temperature of the reaction kettle to 100°C and react for 24 hours until the neutral color is detected at the gas escape port with pH test paper, which means that the system has completely removed HCl. Raise the temperature to 130°C for 3 hours, 150°C for 5 hours, then raise the temperature to 175°C for 14 hours, and finally react at 185°C for 24 hours to complete the polymerization reaction. [η] of the polymerization product = 20.7 dL/g. . Solid ¹³ C-NMR analysis results (ppm): δ=162.1, 149.3, 137.7, 113.4, 93.3. FTIR analysis results (KBr pellet method, cm ^-1 ): 3417, 1627, 1573, 1488, 1428, 1366, 1228, 1190, 1105, 1057, 937, 868, 803, 776. Elemental analysis results: The theoretical value of each element content is: C: 63.16%, H: 2.26%, N: 10.53%; the experimental value is C: 59.44%, H: 1.98%, N: 10.46%

The polymer solution is prepared into fibers with a fineness of 2dtex by a dry jet wet spinning process through a screw extruder. The compression modulus of the fibers is 512MPa; the thermal decomposition temperature in air is 504°C, and the thermal decomposition temperature in nitrogen is 522°C.

Example 2

In a 0.5L reactor equipped with a strong stirring device, _N2 inlet and outlet _, and a feeding port, first pass high-purity _N2 to replace the air, and then add 5.4455g of 4,6-diaminom-benzenediene under the protection of N2 Phenol hydrochloride (DAR), 5.0620 g 2,5-dihydroxyterephthalic acid (DHTA), 25.67 g H ₆ P ₄ O ₁₃ (P ₂ O ₅ concentration 80 wt%) and 10.3649 g P ₂ O ₅ , sealed Reactor.

Raise the temperature of the reaction materials in the reactor to 65°C and keep for 3 hours to make the materials mix initially, then slowly raise the temperature to 80°C and keep for 5 hours to further dissolve the materials. Raise the temperature of the reaction kettle to 150°C and react for 24 hours until the neutral color is detected at the gas escape port with pH test paper, which means that the system has completely removed HCl. Then the temperature was raised to 175° C. for 22 hours, and finally at 200° C. for 24 hours to complete the polymerization reaction. [η] of the polymerization product = 25.9 dL/g. Solid ¹³ C-NMR analysis results (ppm): δ=162.3, 149.3, 137.6, 113.2, 93.3. FTIR analysis results (KBr pellet method, cm ^-1 ): 3405, 1720, 1633, 1551, 1449, 1417, 1369, 1196, 1119, 1044, 993, 956, 881, 718, 677, 629. Elemental analysis results: the theoretical value of each element content C: 63.16%, H: 2.26%, N: 10.53%; the experimental value C: 62.32%, H: 2.07%, N: 10.48%.

The polymer solution is prepared into fibers with a fineness of 1.8dtex by a dry jet wet spinning process through a screw extruder, and the compression modulus of the fibers is 557MPa; the thermal decomposition temperature in air is 524°C, and the thermal decomposition temperature in nitrogen is 543°C .

Claims (3)

1. a polybenzobisoxazole polymer containing hydroxyl group, is characterized in that, has following molecular structure segment:

Among them: n=89～100. 2. the preparation method of polybenzobisoxazole polymer according to claim 1, is characterized in that comprising the steps: 4,6-diaminoresorcinol hydrochloride and 2,5-dihydroxyterephthalic acid are subjected to polycondensation reaction in polyphosphoric acid, the reaction temperature is 50-100°C, and 4,6-diamino The HCl of resorcinol hydrochloride is completely removed; Then react at 130°C-150°C for 3-6 hours, then react at 170-175°C for 10-14 hours, and finally react at 185°C-200°C for 16-24 hours to complete the polymerization reaction, wash with water after the reaction, Then vacuum dry. 3. method according to claim 2 is characterized in that, in polyreaction, 4, the ratio of the molar number of 6-diaminoresorcinol hydrochloride and 2,5-dihydroxyterephthalic acid is : 1:0.8～1.2.