Ternary light-resistant liquid crystal copolymer containing oxazole structure and preparation and application thereof
阅读说明：本技术 一类含咪噁唑结构的三元耐光液晶共聚物及其制备与应用 (Ternary light-resistant liquid crystal copolymer containing oxazole structure and preparation and application thereof ) 是由 金宁人 陈汉庚 高胜 张亚川 郑志国 于 2019-09-06 设计创作，主要内容包括：本发明公开了一类含咪噁唑结构的三元耐光液晶共聚物及其制备与应用。所述含咪噁唑结构的三元液晶共聚物的结构如式I所示,特性粘数为4-16dL/g；<Image he="164" wi="700" file="DDA0002194125360000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>式I中：n,m,k分别为三种分子链节数目,其中n、m、k均为自然数,k/(n+m+k)的范围为10-40％,n/(n+m+k)的范围为10-30％；X表示O原子或功能基NH；Y和Y<Sub>1</Sub>各自独立选自H或OH；Ar<Sub>0</Sub>表示下列4价有机骨架结构之一：<Image he="133" wi="700" file="DDA0002194125360000012.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>所述的含咪噁唑结构的三元液晶共聚物兼具高耐热、高耐光、良好的可纺性、低密度、低成本特点,本发明公开了其在制备纤维中的应用,所制备的复丝纤维耐热温度高、耐光性能优异、抗张强度高的特点。(The invention discloses a ternary light-resistant liquid crystal copolymer containing an imidazole structure, and a preparation method and application thereof. The structure of the ternary liquid crystal copolymer containing the oxazole structure is shown as a formula I, and the intrinsic viscosity is 4-16 dL/g; in formula I: n, m and k are respectively the number of three molecular chain links, wherein n, m and k are natural numbers, the range of k/(n + m + k) is 10-40%, and the range of n/(n + m + k) is 10-30%; x represents an O atom or a functional group NH; y and Y 1 Each independently selected from H or OH; ar (Ar) 0 Represents one of the following 4-valent organic framework structures: the ternary liquid crystal copolymer containing the imidazole structure has the characteristics of high heat resistance, high light resistance, good spinnability, low density and low cost, the invention discloses the application of the ternary liquid crystal copolymer in preparing fibers, and the prepared multifilament fibers have the characteristics of high heat resistance temperature, excellent light resistance and high tensile strength.)
1. The structure of the ternary liquid crystal copolymer containing the oxazole structure is shown as a formula I, and the intrinsic viscosity is 4-16 dL/g;
in formula I: n, m and k are respectively the number of three molecular chain links, wherein n, m and k are natural numbers, the range of k/(n + m + k) is 10-40%, and the range of n/(n + m + k) is 10-30%;
x represents an O atom or a functional group NH;
y and Y1Each independently selected from H or OH;
Ar0represents one of the following 4-valent organic framework structures:
the ternary liquid crystal copolymer containing the imidazole structure is prepared by mixing DABA and AHBA with at least one of AB type monomer shown in formula II and composite salt monomer shown in formula III, and contains P2O5The polyphosphoric acid polymerization medium is prepared through copolycondensation reaction;
and, when X ═ O,And Y ═ Y1When H, the structural formula of the mesogen-containing terpolymer is as follows:
the ternary liquid crystal copolymer O containing the oxazole structure4the-PBO-ABPBI is AB type monomer represented by formula II, DABA, AHBA, and P2O5The polyphosphoric acid polymerization medium is prepared by copolycondensation reaction.
2. The mesogen copolymer containing an imidazole structure of claim 1, wherein: the heatproof temperature of the ternary liquid crystal copolymer containing the imidazole structure is 510-580 ℃.
3. The mesogen copolymer containing an imidazole structure according to claim 1 or 2, wherein: the ternary liquid crystal copolymer containing the imidazole structure is selected from one of the following components:
wherein k/(n + m + k) ranges from 20% to 40%, and n/(n + m + k) ranges from 10% to 20%;
wherein k/(n + m + k) ranges from 20% to 40%, and n/(n + m + k) ranges from 10% to 20%;
4. The mesogen copolymer containing an imidazole structure according to claim 1 or 2, wherein: in the medium for polymerization of polyphosphoric acid, P2O5The mass concentration of (A) is 85-88.5%.
5. A method for preparing a terpolymer liquid crystal copolymer containing an imidazole structure according to claim 1, which comprises the steps of:
1) sequentially adding quantitative P into a glass polymerization reaction column2O5Into polyphosphoric acid, reacting P2O5Basically dissolving to prepare PPA polymerization medium; in the PPA polymerization medium, P2O5The mass concentration of the active carbon is 85-88.5%;
2) general formula (N)2Slowly adding the monomer under protection to form a polymerization reaction system containing 10-18% of the total mass concentration of the terpolymer, slowly heating to 125-170 ℃ for 0.5-2 h at a stirring speed of 350-400r/min after the addition is finished, generating whole body fluorescence, finally controlling the temperature to be between 150-185 ℃ and polymerizing for 10-80 min to form filaments until the rotation speed is obviously reduced, finishing the polymerization reaction, and stopping stirring to obtain the PPA liquid crystal stock solution of the terpolymer containing the oxazole structure.
6. The method of claim 5, wherein: the reaction formula of the preparation method is selected from one of the following:
7. the use of the ternary liquid crystal copolymer containing an imidazole structure according to claim 1 for the preparation of fibers, said use being in particular: directly drawing the polyphosphoric acid liquid crystal stock solution of the ternary liquid crystal copolymer containing the imidazole structure to prepare monofilament fibers, or preparing the multifilament fibers by using a liquid crystal spinning technology of a dry jet wet method.
8. The use of claim 7, wherein: the preparation method of the nascent-AS multifilament fiber containing the ternary liquid crystal copolymer with the imidazole structure specifically comprises the following steps:
1) pre-polymerization: sequentially adding polyphosphoric acid with certain concentration and quantitative P into a prepolymerization material pressing kettle2O5Prepared into a mixture containing 85 to 88 percent of P2O5The polyphosphoric acid is sealed in a polymerization kettle, after uniform stirring, three types of quantitative monomers are sequentially added within 2-5 minutes under the protection of nitrogen, the feeding temperature is controlled below 90 ℃, a polymerization reaction system with the total mass concentration of the monomers of 15-25% is formed, after air is repeatedly replaced by nitrogen, the temperature is slowly raised from 90 ℃ to 160 ℃ within 0.5-2 hours under the protection of nitrogen until prepolymerization is finished, stirring is stopped, a prepolymer liquid crystal material liquid is obtained, and a barrel body of the polymerization kettle is dismounted;
screw machine reaction extrusion polymerization: rapidly transferring the cylinder filled with the prepolymer liquid crystal material liquid to a pressing device, sequentially pressing the prepolymer liquid crystal material liquid into a twin-screw machine-1 and a twin-screw machine-2 which are connected in series by using a feeding device, wherein the temperature of a four-section temperature control area of the twin-screw machine-1 is controlled to be between 150 ℃ and 160 ℃, the temperature of a four-section temperature control area of the twin-screw machine-2 is controlled to be between 155 ℃ and 165 ℃, and the proper screw rotating speed is controlled, so that the total post-polymerization residence time of the materials in the two twin-screw machines which are connected in series is 30-60min, and then the materials are strictly degassed at 160 ℃ by a degasser and filtered by a high-viscosity filter to be used as a liquid crystal spinning stock solution of the terpolymer to enter a spinning section;
2) pressing a liquid crystal spinning stock solution into a spinning assembly preheated to 120 ℃ in a spinning machine, accurately controlling the feeding amount by a spinning metering pump, jetting dry tows at a high pressure by a spinneret plate at the temperature of 100-120 ℃ under the pressure of 5-20 MPa, rapidly stretching the dry tows in a hot air bath at the temperature of 50-60 ℃, then entering a coagulating bath with a coagulating liquid being a phosphoric acid water solution for coagulation and stretching to make the fibers compact, then entering an alkali washing tank after traction and primary water washing in a double-roller traction machine with tension isolation and water washing to remove the phosphoric acid in the wet fibers, finally carrying out water circulation washing by a double-roller water washing machine, drying at the temperature of 120-150 ℃ by a double-roller steam drying machine, and rolling at a certain linear speed by a winding machine to obtain the nascent-AS multifilament fibers of the terpolymer containing the imidazole structure.
9. The use of claim 8, wherein: in the step 2), the coagulation liquid adopts multi-stage gradient coagulation baths, and specifically adopts the operations of n-stage coagulation bath series connection and reverse operation of fiber and coagulation liquid:
the multistage gradient coagulation bath is formed by sequentially connecting n coagulation bath grooves in series, wherein the value of n is 3-5, the setting height from the coagulation bath groove 1 to the coagulation bath groove n is gradually raised, each coagulation bath groove is provided with an overflow port, so that the coagulation liquid in the coagulation bath groove n can overflow and be input into the adjacent coagulation bath groove n-1, the coagulation liquid in the coagulation bath groove n-1 can overflow and be input into the coagulation bath groove n-2, and the like; the coagulating liquids in the n coagulating baths are phosphoric acid aqueous solutions, the concentration of the phosphoric acid aqueous solution in the coagulating baths is expressed by C, and C is1To CnThe concentration is reduced in turn; the coagulation bath temperature of the coagulation bath is represented by T from which1To TnThe temperature of the solidified liquid is reduced in sequence; in the solidification process, the dry fiber bundles sprayed and stretched under high pressure sequentially and continuously pass through a solidification bath 1 and a solidification bath 2 until reaching a solidification bath n, and simultaneously, water is continuously supplemented into the solidification bath n, so that the solidification liquid in the solidification bath n overflows into a solidification bath n-1 to dilute the solidification liquid in the solidification bath n-1, the problem of solidification liquid concentration rise caused by solvent diffusion in fibers in the solidification bath n-1 is solved, and the constant concentration of phosphoric acid in the solidification bath n-1 in continuous operation is maintained; in the same way, other adjacent coagulating bath grooves are also subjected to the same process to maintain the concentration of the phosphoric acid in the coagulating bath grooves to be constant, and finally, the phosphoric acid is coagulated in the coagulating bath groovesThe overflow of the bath 1 discharges the phosphoric acid aqueous solution with higher concentration.
10. The use of claim 9, wherein: the coagulation liquid adopts 4-grade gradient coagulation bath, namely n is 4, wherein the concentrations of the coagulation liquid in the coagulation bath 1, the coagulation bath 2, the coagulation bath 3 and the coagulation bath 4 are respectively maintained at 22-28 wt%, 8-12 wt%, 3-5 wt% and 1-1.5 wt%; t is1＝48-56℃，T2＝38-46℃，T3＝28-36℃，T4＝18-26℃。
Technical Field
The invention relates to a ternary liquid crystal copolymer containing an imidazole structure, and a preparation method and application thereof.
Background
At present, the performance indexes of various high-performance fibers are listed in the following table
TABLE 1
Data of medium blue and morning light
The high performance fibers listed in table 1, the carbon fibers have the best compression resistance, less than M5; the fracture strength and Limiting Oxygen Index (LOI) of PBO are best, but the compressive strength is lowest; m5 has the highest tensile modulus, but also has a high density and a low decomposition temperature; the m-PBI has the lowest density, the highest elongation at break and moisture regain and low strength; since these advantages and disadvantages of high-performance fibers coexist, research and development on modification of high-performance fibers have been promoted.
Nowadays, the organic high performance fiber is known as poly-p-Phenylenebenzobisoxazole (PBO), and the excellent properties of the fiber, such as high strength, high modulus, heat resistance, flame retardance, softness and impact resistance, are the best of the organic fibers. The comprehensive properties (5.8GPa tensile strength, 270GPa modulus, 68 limiting oxygen index and 650 ℃ decomposition temperature) of the Zylon-HM fiber are greatly concerned by research departments and industrial industries when the Zylon-HM fiber is used as a novel material in the fields of aerospace, national defense military industry, special civil use and the like. The technology has been gradually expanded from original equipment for aerospace, national defense, military industry and impact resistance protection to more than twenty industrial fields such as special civil (radiation resistance, high-strength rope and sports), rail transit, industrial (high-temperature resistant industrial materials, building engineering material reinforcement and optical fiber communication cable reinforcement) and the like. But the problems of easy degradation by visible light, poor recombination and compression performance and the like exist.
Polybenzimidazole (m-PBI), although beginning in the sixties of the 20 th century, was successfully co-developed by the United states space agency (NAS A), Hoechst Celanese corporation and the American military materials research institute (AFML). The Celazone fiber company started to produce the fiber in 1983, and the name of the fiber is Celazole, and the fiber is prepared by mixing, condensing and polymerizing 3,3 ', 4, 4' -Tetraaminobenzidine (TABP) and diphenyl isophthalate (DPIP) into poly [2, 2-m-phenylene-5, 5-dibenzoimidazole ] resin and then processing the poly [2, 2-m-phenylene-5, 5-dibenzoimidazole ] resin into m-PBI fiber.
The current commercialized m-PBI fiber has the characteristics of non-combustibility in air, good mechanical property with Limit Oxygen Index (LOI) > 41%, large moisture absorption amount but no hydrolysis, high moisture regain, very good chemical stability, ultraviolet irradiation resistance, corrosion resistance, high temperature resistance and the like. However, the development is very slow due to the influence of the quality, especially the high price, of TABP, a key monomer, and the defects of 100 ℃ lower heat-resistant temperature and lower strength than PBO.
However, besides the commercial Celazole molecular structure m-PBI, the Polybenzimidazole (PBI) structure mainly comprises the following two aromatic PBI (the molecular main chain is composed of a benzene ring and an imidazole ring) of poly-p-phenylene-benzobisimidazole (PBI) and poly-2, 6-benzimidazole (ABPBI).
Aiming at the field of high-performance fibers at present, the invention comprehensively considers 1) the high-strength, high-heat-resistance and light-fastness properties of the PBO structure; 2) the low strength and the low modulus of the PBI structure and the high light resistance and the low density; 3) on the basis of three characteristics of improving the composite performance and forming hydrogen bonds with imidazole NH and the like, the hydroxyl group provides a ternary liquid crystal copolymer containing an imidazole structure, and provides a corresponding preparation method and application thereof in the field of comprehensive high-performance fibers.
Disclosure of Invention
The invention aims to provide a ternary liquid crystal copolymer containing an imidazole structure, which has the characteristics of high heat resistance, high light resistance, good spinnability, low density and low cost.
The second purpose of the invention is to provide the preparation method of the ternary liquid crystal copolymer containing the imidazole structure, which does not generate any corrosive gas and interference thereof in the preparation process, and has the advantages of high polymerization speed, high productivity and convenient implementation.
The third purpose of the invention is to provide the application of the ternary liquid crystal copolymer containing the imidazole structure in preparing the ternary copolymer fiber containing the imidazole.
The purpose of the invention is realized by the following technical scheme:
a ternary liquid crystal copolymer containing an imidazole structure shown as a formula I belongs to a copolymer which takes ABPBI as a base (m chain link) and is modified by PBI (n chain link) and ABPBO (k chain link), and the intrinsic viscosity number is 4-16 dL/g;
in formula I: n, m and k are respectively the number of three molecular chain links, wherein n, m and k are natural numbers, the range of k/(n + m + k) is 10-40%, and the range of n/(n + m + k) is 10-30%;
x represents an O atom or a functional group NH;
y and Y1Each independently selected from H or OH;
Ar0represents one of the following 4-valent organic framework structures:
the ternary liquid crystal copolymer containing the imidazole structure is prepared by mixing DABA and AHBA with at least one of AB type monomer shown in formula II and composite salt monomer shown in formula III, and contains P2O5Prepared by copolycondensation reaction in PPA (polyphosphoric acid) polymerization medium;
and, when X ═ O,
the ternary liquid crystal copolymer O containing the oxazole structure4the-PBO-ABPBI is AB type monomer represented by formula II, DABA, AHBA, and P2O5The PPA (polyphosphoric acid) polymerization medium is prepared by copolycondensation reaction.
The ternary liquid crystal copolymer containing the oxazole structure, PBO4The chain segment (namely k chain segment) aims at improving the heat-resistant temperature, increasing the spinnability and reducing the cost (compared with PBO), the PBZ chain segment (namely n chain segment) aims at improving the heat-resistant temperature, the strength and the modulus, the ABPBI chain segment (namely m chain segment) aims at improving the light-resistant performance, reducing the density and reducing the cost, and the three components cooperate to ensure that the ternary liquid crystal copolymer containing the imidazole structure has the characteristics of high heat resistance, high light resistance, good spinnability, low density and low cost.
Preferably, the heatproof temperature of the ternary liquid crystal copolymer containing the imidazole structure is 510-580 ℃.
Preferably, the ternary liquid crystal copolymer containing the imidazole structure is selected from one of the following:
More preferably, the ternary liquid crystal copolymer containing the imidazole structure is O4-PBO-ABPBI、O4-PBI-ABPBI、O4-HPBO-ABPBI or O4-PDBI-ABPBI, wherein O4-HPBO-ABPBI and O4PDBI-ABPBI, the composite and compression resistance performance is further improved due to the introduction of hydroxyl.
Preferably, in the PPA polymerization medium, P2O5The mass concentration of (A) is 85-88.5%.
In a second aspect, the present invention provides a method for preparing a terpolymer containing an imidazole structure, the method comprising the steps of:
1) sequentially adding quantitative P into a glass polymerization reaction column2O5To polyphosphoric acid (PPA), adding P2O5Basically dissolving (one skilled in the art can promote dissolution by stirring, heating and the like according to actual needs) to prepare a PPA polymerization medium; in the PPA polymerization medium, P2O5The mass concentration of (A) is 85-88.5% (the lower limit is used for AB type monomer, the upper limit is used for composite salt monomer);
2) general formula (N)2Under protection, slowly adding monomers (which can be respectively added in sequence or directly added after uniform mixing) to form a polymerization reaction system containing 10-18% (calculated value) of the total mass concentration of the terpolymer, slowly raising the temperature to 125-170 ℃ at a stirring speed of 350-400r/min for 0.5-2 h after the addition is finished, displaying liquid crystal state after 10-45 min, finally controlling the temperature to be 150-185 ℃, polymerizing for 10-80 min to form filaments until the rotation speed is obviously reduced, finishing the polymerization reaction, and stopping stirring to obtain the PPA liquid crystal stock solution of the terpolymer.
Preferably, the reaction formula of the preparation method is selected from one of the following:
in a third aspect, the invention provides an application of the ternary liquid crystal copolymer containing the imidazole structure in preparing fibers, and the application specifically comprises the following steps: the PPA liquid crystal stock solution of the ternary liquid crystal copolymer containing the imidazole structure is directly subjected to filament drawing to prepare monofilament fibers, or the PPA liquid crystal stock solution of the ternary liquid crystal copolymer containing the imidazole structure is subjected to liquid crystal spinning by a dry jet wet method to prepare multifilament fibers.
Further, the monofilament fiber of the ternary liquid crystal copolymer containing the imidazole structure is prepared by the following steps: the PPA liquid crystal stock solution of the terpolymer containing the imidazole structure is used as a raw material, the material temperature is controlled to be 80-130 ℃, monofilaments are continuously drawn (extracted) from the liquid crystal stock solution, the extracted dry monofilaments are put into water for solidification, and then are washed for a plurality of times by hot water and dried in vacuum to obtain the monofilament fiber of the terpolymer containing the imidazole structure. The monofilament fiber is used for measuring and researching the basic properties (molecular weight, heat-resisting temperature, strength and spinnability) of the fiber. The intrinsic viscosity of the prepared ternary light-resistant liquid crystal copolymer is 4-16dL/g, and the heat-resistant temperature is 510-580 ℃; the diameter of the monofilament fiber is 20-120um, the fineness is 1.1tex, and the monofilament tensile strength is 1.5-3.0 GPa.
Further, the multifilament fiber of the terpolymer liquid crystal copolymer containing the imidazole structure is prepared by firstly preparing a liquid crystal stock solution of the terpolymer liquid crystal copolymer containing the imidazole structure on a polymerization spinning scale test device (comprising a polymerization device), and then directly adopting a liquid crystal spinning technology of a dry jet wet method to prepare the multifilament fiber (see figure 6); the preparation method of the multifilament fiber comprises the following steps:
step 1): the method comprises the working procedures of prepolymerization and screw machine reaction extrusion polymerization to obtain a liquid crystal spinning solution of the terpolymer;
step 2): comprises the working procedures of high-pressure jet extrusion of dry filaments, stretching in an air bath, coagulation in a coagulation bath, alkali washing, water washing and drying to obtain the nascent-AS multifilament fiber of the terpolymer.
Further, the preparation method of the nascent-AS multifilament fiber of the terpolymer comprises the following steps:
1) pre-polymerization: sequentially adding PPA with certain concentration and quantitative P into a prepolymerization material pressing kettle2O5Prepared into a mixture containing 85 to 88 percent of P2O5The PPA is closed, after uniform stirring, three types of monomers are sequentially added in a quantitative manner within 2-5 minutes under the protection of nitrogen, the feeding temperature is controlled below 90 ℃, a polymerization reaction system with the total mass concentration of the monomers of 15-25% is formed, after air is repeatedly replaced by nitrogen, the temperature is slowly raised from 90 ℃ to 160 ℃ within 0.5-2 hours under the protection of nitrogen until prepolymerization is finished (the eta of the prepolymer is about 5-10dL/g), stirring is stopped, a prepolymer liquid crystal material liquid is obtained, and a polymerization kettle barrel is dismounted;
screw machine reaction extrusion polymerization: rapidly transferring the cylinder filled with the prepolymer liquid crystal material liquid to a pressing device, sequentially pressing the prepolymer liquid crystal material liquid into a double-screw machine-1 (a four-section temperature control area at 150-160 ℃, preferably a four-section temperature control area at 150 ℃, 152 ℃, 154 ℃ and 156 ℃) and a double-screw machine-2 (a four-section temperature control area at 155-165 ℃, preferably a four-section temperature control area at 158 ℃, 160 ℃, 162 ℃ and 164 ℃) which are connected in series by using a feeding device, controlling the proper screw rotating speed to ensure that the total residence time of post-polymerization extruded materials in the two double-screw machines connected in series is 30-60min, strictly degassing at 160 ℃ by using a degasser, filtering by using a high-viscosity filter, and then feeding the liquid crystal spinning solution serving as the terpolymer into a spinning section;
2) pressing the liquid crystal spinning stock solution into a spinning pack preheated to 120 ℃ in a spinning machine, accurately controlling the feeding amount by a spinning metering pump, jetting dry tows at high pressure by a spinneret plate at the temperature of 5-20 MPa and 100-120 ℃, rapidly stretching the dry tows in a hot air bath at the temperature of 50-60 ℃ (the stretching ratio is controlled by the rotating speed of a traction machine), then the fiber is solidified and stretched in a coagulating bath with phosphoric acid aqueous solution as coagulating liquid to make the fiber compact, then the fiber is drawn in a double-roller drawing machine with tension isolation and water washing and primarily washed, and then the fiber enters an alkali washing tank to remove the phosphoric acid in the wet fiber, finally the fiber is circularly washed by a double-roller washing machine, and after the fiber is dried by a double-roller steam dryer at the temperature of 150 ℃, and (3) winding by a winding machine at a certain linear speed (50-200m/min) to obtain the nascent (AS) multifilament composite fiber of the terpolymer liquid crystal copolymer containing the imidazole structure. Intrinsic viscosity (molecular weight), IR, tensile strength, modulus, moisture, heat resistance temperature (thermogravimetric analysis) of AS multifilament fibers were measured.
In the step 2), the coagulation liquid adopts multi-stage gradient coagulation baths, specifically adopts the operation of connecting n-stage coagulation baths in series and reversely running the fiber and the coagulation liquid (see the attached figure 7):
the multistage gradient coagulation bath is formed by sequentially connecting n coagulation bath grooves in series, wherein the value of n is 3-5, the setting height from the
As will be understood by those skilled in the art, the concentration C of the coagulation liquid and the temperature T of the coagulation liquid in each coagulation bath are difficult to maintain constantly during the coagulation operation, so that the term "constant concentration" as used herein does not necessarily mean that the concentration is maintained at a constant value, but is usually maintained within a certain range, and the temperature T is the same.
In the invention, the preferred coagulating liquid adopts 4-grade gradient coagulating bath, namely n is 4. Preferably, the concentrations of coagulation liquids in
The invention adopts the multi-stage double-gradient coagulating bath, and has multiple technical effects: the fiber can be further stretched while the compactness of the fiber is improved and the cavities on the cross section are reduced, the phosphoric acid in the wet fiber can be washed away to the maximum extent, and the higher concentration C can be conveniently carried out1And the phosphoric acid solidification liquid is recovered to prepare polyphosphoric acid and is recycled.
Compared with the molecular structure and the technology of the existing fiber, the invention has the beneficial effects that:
1) the ternary liquid crystal copolymer containing the imidazole structure has the advantages of excellent ultraviolet light resistance stability, low density which can achieve light weight, high heat resistance, low cost, good spinnability and the like. Especially O4-HPBO-ABPBI improves the recombination performance in hydroxylMeanwhile, O of hydroxyl in HPBO and H of secondary amino in ABPBI are utilized to form hydrogen bonds between molecular chains, so that the axial compression resistance of the polymer fiber is improved (see O shown in figure 8)4-HPBO-ABPBI (1:1:3) molecular chain building blocks with hydrogen bonds of the middle row H-O- - -H-N). The invention uses three AB type monomers (ABAA, AHBA, DABA) to prepare O by copolycondensation4The heat-resisting temperature of the-PBO-ABPBI monofilament fiber reaches 576 ℃, the intrinsic viscosity is 15.08dl/g, and O is prepared by copolycondensation of a composite salt and two AB type monomers (HD and AHBA, DABA)4The heat resistance temperature of the-HPBO-ABPBI monofilament fiber reaches 578 ℃, and the intrinsic viscosity is 12.62 dl/g.
2) The preparation method of the ternary liquid crystal copolymer containing the imidazole structure has the characteristics of no need of HCl removal in the polymerization process, short polymerization time, early appearance of fluorescence and liquid crystal, high yield, excellent rheological property of spinning stock solution, better spinnability than PBO (Poly-p-phenylene benzobisoxazole) and convenient industrialization implementation, and the monomer concentration can reach more than 20%.
3) The ternary liquid crystal copolymer containing the imidazole structure has good spinnability in PPA solvent, the concentration of the liquid crystal polymer can reach 15 percent on the premise of being processed into fibers, and the ternary liquid crystal copolymer can be directly used for preparing corresponding high-performance fibers by using a polymer liquid crystal stock solution at the end of polymerization without taking out. The prepared multifilament fiber has the characteristics of high heat resistance temperature, excellent light resistance and high tensile strength.
Drawings
FIGS. 1-a and 1-b are respectively O prepared from AB monomer ABAA in example 1 of the present invention4-infrared spectrum and thermogravimetric analysis (576 ℃) of PBO-ABPBI (1:1:3) monofilament fibers.
FIGS. 2-a and 2-b are respectively O prepared from a Complex salt monomer DTH according to comparative example 1 of the present invention4-infrared spectrum and thermogravimetric analysis (556 ℃) of PBO-ABPBI (1:1:3) monofilament fibers.
FIGS. 3-a and 3-b are each O prepared according to example 2-A of the present invention4-infrared spectrum and thermogravimetric analysis (578 ℃) of HPBO-ABPBI (0.5:1.25:3) monofilament fibers.
FIGS. 4-a and 4-b are respectively O prepared in example 3 of the present invention4-PBI-ABPBI (1:0.5:1) sheetInfrared spectroscopy and thermogravimetric analysis (513 ℃ C.) of silk fibers.
FIGS. 5-a and 5-b are respectively O prepared in example 4 of the present invention4-infrared spectrum and thermogravimetric analysis (532 ℃) of a PDBI-ABPBI (1:0.5:1) monofilament fiber.
FIG. 6 is a schematic process flow diagram of one embodiment of the present invention for preparing a light fast terpolymer multifilament fiber containing an imidazole structure.
FIG. 7 is a schematic representation of a four-stage dual gradient coagulation bath employed in the present invention.
FIG. 8 is O prepared according to the present invention4-HPBO-ABPBI structural schematic.
Detailed Description
The present invention will be described in further detail with reference to examples, but the embodiments of the present invention are not limited thereto.