KR100992557B1 - Preparation Method of Ion Selective Fibrous Nano-form using Hyperbranched Polystyrene with Reactive Acrylic Resin - Google Patents

Abstract

The present invention synthesizes hyperbranched polystyrene (hereinafter referred to as HPS), blends with polystyrene- co- Acylic acid (hereinafter referred to as PSAA), and then introduces sulfonic acid groups to introduce nanofiber structures by electrospinning. And by functionalizing it to prepare a highly selective ion exchange nanofiber structure, and more specifically, the high-branch reactive resin solution is presulfonated to prepare an ion exchange solution. The functional nano ion exchanger was prepared by ionizing nanoprecursor using electrospinning method and photocrosslinked by UV irradiation method. It is able to introduce a large amount of functional groups compared to conventional ion exchange fiber, and has excellent ion exchange ability and ion It is a method for producing nano ion exchange fibers having excellent selectivity.

More specifically, styrene monomer as a raw material of the ion exchange spinning solution and hyperbranched polystyrene using living radical polymerization were synthesized and branded in a solution state with a PSAA radical copolymer, followed by sulfonic acid group (-SO ₃ ^- ) Is introduced. These ion exchange solutions are electrospun to obtain nano-sized ultra-fine fibers, which are used to photocrosslink reactive resins through UV irradiation.

     Development of ion-exchange nanofibers with excellent efficiency and selectivity for their application to medical materials such as recovery of trace trace metals and high-sensitivity sensors, catalysts, and drug delivery using nano-ion-exchange fibers according to the present invention The purpose.

High branch polystyrene, reactive acrylic acid resin, ion selection, nanofiber structure

Description

Preparation Method of Ion Selective Fibrous Nano-form using Hyperbranched Polystyrene with Reactive Acrylic Resin

The present invention synthesizes hyperbranched polystyrene (hereinafter referred to as HPS), blends with polystyrene- co- Acylic acid (hereinafter referred to as PSAA), and then introduces sulfonic acid groups to introduce nanofiber structures by electrospinning. And by functionalizing it to prepare a highly selective ion exchange nanofiber structure, and more specifically, the high-branch reactive resin solution is presulfonated to prepare an ion exchange solution. The functional nano ion exchanger was prepared by ionizing nanoprecursor using electrospinning method and photocrosslinked by UV irradiation method. It is able to introduce a large amount of functional groups compared to conventional ion exchange fiber, and has excellent ion exchange ability and ion It is a method for producing nano ion exchange fibers having excellent selectivity.

Conventional ion exchange fiber is a functional ion exchange filter media manufactured by treating radiation or electron beam to polyolefin nonwoven fabric and grafting polymerization and functionalization, and harmful gases in air or water in semiconductor clean room, chemical industry and civil industry. Excellent removal performance. However, ion-exchange fibers have a large volume, low packing density, high cost, and high pressure differentials compared to resins in water treatment applications.

 In addition, the nanofibers manufactured so far are mainly used for various purposes such as filter materials, coated fabric materials, wiper materials, extreme environmental protection materials, carbon fiber materials, energy storage materials, and medical materials. Research on functionalized nanofibers through surface modification has been poorly performed using only large surface area and very small pores per unit volume.

  Therefore, new research is needed to improve the disadvantages of the existing ion exchange fibers. In particular, according to the field of application of ion exchange fibers, advanced fields such as medical and military industries, semiconductor display fields, etc., require much higher sensitivity and selectivity than sensors, catalysts and existing nanofibers. Therefore, there is an urgent need for the production of highly functional ion exchange fibers that have improved this.

 Therefore, in the present invention, to improve the disadvantages of the existing ion exchange fibers, the synthesis of a hyper-branched (high-branched) polymer polymer capable of introducing a large amount of functional groups, and to produce a composition by blending the acrylic acid resin copolymer to increase the mechanical properties In addition, the present invention provides a method for producing nano-ion exchange fibers by sulfonating the composition by electrospinning.

More specifically, it is characterized by increasing the free volume that can be functionalized in the polymer main chain by controlling the aromatic branch structure irregularly or regularly in the molecular structure of the highly branched polystyrene through the synthesis of high branched polystyrene (HPS). . In addition, the ion-exchange solution sulfonated is characterized in that the polyfunctional in which the sulfonic acid group is substituted in the highly branched aromatic ring. The molecular weight distribution of the hyperbranches shows a low distribution between 1.2 and 1.7 compared to the conventional radical polymerization, and the nano ion exchange fibers prepared as described above have high ion selectivity and ion exchange capacity.

  Functional nano-ion exchange fiber produced by the present invention to compensate for the disadvantages of the existing ion exchange resin has a high filling density, small filling volume for filling and introducing multi-functional group through the hyperbranched polymer ion ion and ion Can improve exchange ability. Ion-exchange nanofibers are obtained by electrospinning the pre-functionalized polymer solution, so that a separate sulfonation process can be omitted later.

More specifically, the present invention synthesizes hyperbranched polystyrene (hereinafter referred to as HPS), blends with polystyrene- co- Acylic acid (hereinafter referred to as PSAA), and introduces sulfonic acid groups to electrospinning. By preparing a nanofiber structure and functionalizing it to produce a highly selective ion exchange nanofiber structure, more specifically, a high-branch reactive resin solution is pre-sulfated to prepare an ion exchange solution. The functional nano ion exchanger was prepared by ionizing nanoprecursor using electrospinning method and photocrosslinked by UV irradiation method. It is able to introduce a large amount of functional groups compared to conventional ion exchange fiber, and has excellent ion exchange ability and ion It is a method for producing nano ion exchange fibers having excellent selectivity.

    The polyfunctional ion exchange solution prepared by substituting a sulfonic acid group on a branched branch has a photocrosslinking characteristic of the radical group of -COOH of the blended composition. Unreacted chlorosulfonic acid reacts with heat to improve ion exchange capacity and selectivity at the same time.

     In addition, the brittleness problem of PS-based nanofibers compensates for low molecular weight HPS generation after spinning and is a method of controlling the degree of crosslinking through optical crosslinking.

     Therefore, the present invention is to provide a method for producing a highly selective nano-ion exchange fiber using the sulfonic acid group introduced into the hyperbranched polymer and radical copolymer blending composition.

The present invention for achieving the object of the above invention,

Functional nano ion exchange fibers are prepared by synthesizing a high branched polymer using a styrene monomer and a small amount of divinylbenzene, and then blending an acrylic resin copolymer, such as styrene-acrylic acid copolymer, in a MIBK solvent. Prepare the composition. A method of preparing a multifunctional cation exchange solution is then provided by solvent addition of chlorosulfonic acid or sulfuric acid to the solution to introduce a sulfonic acid group, which is a cation exchanger.

The preparation of the ion exchange solution is preferably performed within 20 minutes of water at room temperature (25 ° C.) when chlorosulfonic acid is added, and 30 to 40 minutes at 60 ° C. when sulfuric acid is used to improve ion exchange performance. desirable. This ion exchange solution is made of ion exchange fibers having a diameter of about 1100 ~ 1600nm by electrospinning.

Crosslinking of the nanofibers is characterized by simultaneous crosslinking and functionalization of the unreacted chlorosulfonic acid due to heat generated at the same time as the photocrosslinked by the radical copolymer (-COOH) of the composition through UV irradiation.

Nano-ion exchange fiber multi-functionality using the highly divergent composition according to the present invention is suitable for the field requiring high functionality in the field of catalysts and drug delivery, advanced bio-application materials, military industry, extreme protection materials and semiconductors in the application range It is expected that various applications such as the display industry will be made, and new ion exchange resins having a large ion exchange amount were prepared.

Hereinafter, the present invention will be described in detail according to each process.

The present invention relates to a method for preparing ion-exchange nanofibers by blending hyperbranched polystyrene and acrylic acid resin copolymers. The production of ion-exchange nanofibers by electrospinning using hyperbranched polystyrene synthesis, sulfonation, and solutions thereof Process, UV light cross-linking process.

(1) Hyperbranched Polymer Resin Synthesis Process

 Synthesis of hyperbranched polymers was carried out using Atom transfer radical polymerization (hereinafter referred to as ATRP) method among living radical polymerization methods. A Lewis acid such as styrene monomer, divinylbenzene (hereinafter referred to as DVB), and a transition metal copper bromide (CuBr) is used as a catalyst component, and bipyridine is used as a reaction accelerator. Put the mixture into a three-necked flask reactor as possible and mix it uniformly, and then add 1-bromoethylbenzene (hereinafter referred to as BEB) as an initiator to the mixed solution, and react the reaction temperature under a nitrogen atmosphere of 60 to 100 ° C, preferably about 80 ° C. The reaction was carried out using the ATRP method while stirring at a constant temperature for 24 to 48 hours. The obtained mixture was removed with a basic alumina column and the catalyst was reprecipitated with methanol to obtain a white powder. 1 and 2 show the synthesis mechanism and structure of the hyperbranched polymer.

(2) sulfonation process

    The cation exchange solution is a solution of the above-described HPS and acrylic acid copolymer, for example, polystyrene acrylic acid copolymer, in a organic solvent such as methyl isobutyl ketone (MIBK) in a ratio of 1: 1 to 2: 1, preferably 1.5: 1 by weight. Blend and adjust the viscosity to 600-800 CP. Chlorosulfonic acid (Chlorosulfonic acid) is added to the solution in a solution of 5 to 20 vol%, preferably 10 vol%, and then stirred at a reaction temperature of 20 ° C to 40 ° C for 10 minutes to 30 minutes under a nitrogen atmosphere. Proceed with the sulfonation reaction. The sulfonated cation exchange solution was prepared by varying the concentration of sulfonating agent (FIG. 3).

(3) Ion exchange solution electrospinning process

   The hyperbranched ion exchange nanofibers were prepared using the functionalized polymer as described above using electrospinning. The pre-functionalized ion exchange solution was injected into a 30cc syringe to fix the distance between the syringe nozzle and the focusing roller at 15 cm, the polymer solution supply flow rate was 0.1 ml / h, and the voltage was 10-14 kV, preferably 12 KV. Hyper branch ion exchange nanofibers were prepared. The focusing roller used a stainless steel circular drum with a length of 20 cm and a circumference of 25 cm, and the rotational speed and the reciprocating speed were fixed at 30 cm / min and 2 m / min, respectively. The diameter of the ion exchange fiber prepared in this manner was prepared to about 1100 ~ 1600nm.

(4) UV light crosslinking process

The prepared nanofibers were exposed to UV radiation to form crosslinks. The radical copolymer PSAA was crosslinked by irradiating a wavelength between 270nm and 300nm which can be crosslinked, and the irradiation amount is preferably about 20 minutes at a UV intensity of 500W.

Figure 3 shows the overall schematic diagram of the production of high functional nano-ion exchange fiber.

Example

 The present invention relates to the preparation of ion-selective functional nanostructures prepared ion-exchange membranes using high-branch reactive resins.

Example 1

10.52 g (100 mmol) of styrene, 1.627 g (10 mmol) of divinylbenzene (hereinafter abbreviated as DVB) for the production of hyperbranched polymers, Cubr (I) 0.146 g (1 mmol), bipyridine 0.237 g (1.5 mmol) of the mixed solution was prepared and the ATRP method was initiated with BEB. The reaction temperature was maintained at 80 ° C. for 24 (Example 1-1), 32 (Example 1-2), 40 (Example 1-3), and 48 (Example 1-4) hours.

The reacted solution was dried and washed to obtain a polymer such that HPS: PSAA (styrene: 95 wt%, acrylic acid: 5 wt%) and 1.5: 1 wt% were mixed in a MIBK solvent at 1: 1 wt% (about 800 cps). After sulfonation with 10 vol% of chlorosulfonic acid (sulfonation conditions: temperature: 10-30 ° C, reaction time: 10-20 minutes) and UV photocrosslinking after electrospinning (12kv) according to the above conditions. : 15 to 30 minutes, UV intensity: 500 W, fiber average diameter: 1,100 to 1600 nm. Meanwhile, the nanofibers were prepared and immersed in a 40 vol% sulfuric acid solution, stabilized within 60 minutes, washed repeatedly with deionized water several times, and dried in a vacuum oven at 60 ° C. for 5-10 hours to prepare an ion exchange nanofiber structure.

Example 2 Synthesized Hyperbranched Polymer (Molecular Weight Distribution: 1.13, MW: 14,410), respectively, HPS: PSAA 1: 1 (Example 2-1), 1.5: 1 (Example 2-2_ 2: 1 (Example) Example 2-3) was blended and sulfonated under the same conditions as in Example 1 to be electrospun.

Example 3 5 (Example 3-1) and 10 (Example 3) of the prepared hyperbranches (PDI: 1.13, MW: 14,410) respectively by blending HPS: PSAA 1.5: 1 to prepare chlorosulfonic acid -2), 15 (Example 3-3) and 20 vol% (Example 3-4) were added and sulfonated under the same conditions as in Example 1 to be electrospun.

3. Characterization

(1) Ion exchange fiber structure and molecular weight analysis

The molecular weight of the hyperbranched polystyrene synthesized as described above was measured by gel chromatography, and ion exchange nanofibers obtained by electrospinning were analyzed using a Fourier transform infrared spectrometer.

(1) structure and molecular weight analysis

The conversion rate of the synthesized hyperbranched polymer was calculated using Equation (1).

(1)

(One)

(2) Measurement of ion exchange capacity

In order to measure the ion exchange capacity, the ion exchange capacity was determined by equation (2) by acid salt titration using 1N NaOH aqueous solution and 1N HCl aqueous solution.

(2)

(2)

(3) moisture content measurement

The ion exchange nanofibers were cut to a certain size (3 ㅧ 3 cm) and then immersed in a 0.1 M NaCl solution to swell sufficiently, then free water on the surface of the ion exchange membrane was removed and weighed, and dried in a vacuum oven at 60 ° C for 24 hours. After cooling, moisture content was determined by equation (3).

(3)

(3)

  Example
Response time (h) % Conversion Mw
(g / mol) Mw / Mn
(PDI) Water content
(%) Ion exchange capacity
(meq / g) 1-1 24 34.6 14,410 1.13 21.80 4.65 1-2 32 42.2 24,710 1.14 20.86 4.57 1-3 40 49.1 23,880 1.18 19.57 4.12 1-4 48 69.8 30,820 1.48 17.82 3.89

The nano ion exchange fibers synthesized under the conditions of Example 1 exhibited moisture content and ion exchange capacity from Examples 1-1 to 1-4 according to the molecular weight and molecular weight distribution (PDI) of the hyperbranched polymer. When the hyperbranched polymer was synthesized, the high molecular weight was formed according to the reaction time and the PDI increased.

The ion exchange capacity was the highest when the molecular weight distribution was low as 1.13. Also, the lower the molecular weight, the easier the control of the degree of crosslinking during UV irradiation, and the higher the branched polymer having the narrower molecular weight distribution, the more favorable the ion exchange capacity. 4 shows the SEM image of the morphology of the spun fiber of Example 1-1.

  Example
Mw (g / mol) Mw / Mn
(PDI) HPS / PSAA
(vol%)  Water content (%) Ion exchange capacity
(meq / g) 2-1 14,410 1.13 1: 1 19.77 4.35 2-2 1.5: 1 21.80 4.65 2-3 2: 1 22.50 4.72

Table 2 shows Examples 2-1 to 2-3 according to the blending ratio of HPS and PSAA during the blending of compounds synthesized according to the conditions of Example 2. Relative water content and ion exchange capacity increased with increasing HPS content. Ideally, the ratio of [HPS] / [PSAA] 1.5: 1 volume ratio, which is suitable for spinning with sulfonating agent and does not affect the degree of crosslinking during fiber crosslinking, is ideal for preparing an ion exchange solution.

  Example
Mw (g / mol) Mw / Mn
(PDI) Chlorosulfonic acid
(vol%)  Water content (%) Ion exchange capacity
(meq / g) 2-1 14,410 1.13 5 18.97 4.10 2-2 10 21.80 4.65 2-3 15 22.81 4.72 20 23.10 4.62

 2-1 to 2-3 different from Example 3 were sulfonated according to the concentration of chlorosulfonic acid, and the electrospun UV crosslinked under the same conditions as above. The concentration of chlorosulfonic acid affects the ion exchange capacity, but the concentration of chlorosulfonic acid is closely related to the viscosity of the spinning solution. As the acid crosslinking reaction (R-SO2-R) occurs simultaneously, it is not suitable for producing fibers by electrospinning.

1 is a hyperbranched polystyrene synthesis mechanism

Figure 2 shows the FT-IR spectrum of sulfonated hyperbranches

Figure 3 is a schematic diagram of the production of nano ion exchange fiber structure

Figure 4 is a SEM photograph of the nanoion exchange structure

Claims (5)

(a) preparing high beanched polystyrene (HPS); (b) blending the HPS with an acrylic acid copolymer; (c) sulfonating the blending resin; (d) spinning the sulfonated blending resin to prepare fibers; (e) photocrosslinking the spun fibers; Method for producing an ion exchange fiber comprising a. The method of claim 1, The sulfonation step is a method for producing an ion exchange fiber made of chlorosulfonic acid The method of claim 2, The sulfonated blending resin is a method of producing an ion exchange fiber prepared by electrospinning    The method of claim 3, wherein    The acrylic acid copolymer is a method of producing an ion exchange fiber, characterized in that the copolymer of styrene and acrylic acid.    The method according to any one of claims 1 to 4,    The high branched polystyrene has a molecular weight distribution of 1.2 to 1.7.

Images