REDUCING AGENT MONOMER FOR PREPARING STYRENE-ACRYLIC EMULSION BY OXIDATION-REDUCTION REACTION AT ROOM TEMPERATURE, AND SYNTHESIS METHOD THEREOF

Abstract

A reducing agent monomer for preparing a styrene-acrylic emulsion by an oxidation-reduction reaction at room temperature and a synthesis method thereof are disclosed. Maleic anhydride (MAH) and dimethylethanolamine (DMEA) are used as raw materials to synthesize the reducing agent monomer: 4-(2-(dimethylamino)ethoxy)-4-oxobut-2-enoic acid, and the synthesis method involves inexpensive easily-available raw materials, simple synthesis conditions, and easy purification. With the synthesized reducing agent monomer as a reducing agent, potassium persulfate (KPS) as an oxidizing agent, water as a dispersion medium, sodium dodecyl sulfate (SDS) as an emulsifier, and styrene, butyl acrylate (BA), and methylmethacrylate (MMA) as comonomers, free-radical microemulsion polymerization is conducted at room temperature to obtain a styrene-acrylic emulsion. In the synthesis of the styrene-acrylic emulsion, a monomer conversion rate is high, and a styrene-acrylic emulsion with a high molecular weight and a branched structure can be obtained at room temperature.

Claims

1. (canceled)

2. (canceled)

3. (canceled)

4. Use of a reducing agent monomer synthesized by a synthesis method of the reducing agent monomer for preparing a styrene-acrylic emulsion by an oxidation-reduction reaction at room temperature, wherein an oxidation-reduction initiation system is formed from the reducing agent monomer and a persulfate; the synthesis method comprises: using maleic anhydride (MAH) and dimethylethanolamine (DMEA) as raw materials to synthesize the reducing agent monomer: 4-(2-(dimethylamino)ethoxy)-4-oxobut-2-enoic acid; and a preparation method of the styrene-acrylic emulsion comprises: adding a pH regulator, an emulsifier, the reducing agent monomer, and a dispersion medium (H.sub.2O) into a reaction flask, and stirring a resulting mixture for 3 min to 4 min to allow thorough dissolution; adding comonomers having styrene, butyl acrylate (BA), and methylmethacrylate (MMA), and pre-emulsifying with stirring for 30 min; vacuum-pumping, and adding a persulfate at an argon atmosphere; and subjecting a resulting system to free-radical microemulsion polymerization in a thermostat water bath to obtain the styrene-acrylic emulsion.

5. The use of the reducing agent monomer according to claim 4, wherein a quantity ratio of the reducing agent monomer to the persulfate is 1:(1-2); and the persulfate is ammonium persulfate (APS) or potassium persulfate (KPS).

6. The use of the reducing agent monomer according to claim 4, wherein the water is added at a mass 1.5 times a total mass of the solids; and the styrene, BA, and MMA have a quantity ratio of 1:1:0.25.

7. The use of the reducing agent monomer according to claim 4, wherein the emulsifier is sodium dodecyl sulfate (SDS), which is added at a mass 0.5% to 1% of a total mass of the reducing agent monomer.

8. The use of the reducing agent monomer according to claim 4, wherein the free-radical microemulsion polymerization is conducted at 25° C. for 8 h to 12 h.

9. The use of the reducing agent monomer according to claim 4, wherein the pH regulator is NaHCO.sub.3, which is added at a mass 3% of the total mass of the reducing agent monomer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIG. 1 is a nuclear magnetic resonance (NMR) spectrum of the reducing agent monomer: 4-(2-(dimethylamino)ethoxy)-4-oxobut-2-enoic acid.

[0025] FIG. 2 shows a differential molecular weight distribution curve of the polymer obtained in Example 4.

[0026] FIG. 3 shows a differential molecular weight distribution curve of the polymer obtained in Example 5.

[0027] FIG. 4 shows a differential molecular weight distribution curve of the polymer obtained in Example 6.

[0028] FIG. 5 shows a Mark-Houwink curve of the polymer obtained in Example 4.

[0029] FIG. 6 shows a Mark-Houwink curve of the polymer obtained in Example 5.

[0030] FIG. 7 shows a Mark-Houwink curve of the polymer obtained in Example 6.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] The technical features of the present disclosure are further illustrated with the following examples, but a protection scope of the present disclosure is not limited to the following examples.

Example 1

[0032] Synthesis of a Reducing Agent Monomer

[0033] MAH (4.9 g, 0.05 mol) was added to a three-neck flask equipped with a thermometer, 30 mL of chloroform was added, and a resulting mixture was stirred at room temperature until the MAH was completely dissolved; DMEA (4.5 g, 0.05 mol) was dissolved in 10 mL of chloroform, and a resulting solution was added to the reaction flask all at once; a resulting system reacted at room temperature for 5 h to obtain a white suspension; 40 mL of diethyl ether was added, and a resulting mixture was thoroughly shaken and centrifuged to obtain a white solid; and the white solid was washed with 40 mL of diethyl ether, then suction filtration was conducted twice, and a resulting filter cake was vacuum-dried to a constant weight to obtain a white powder, with a total yield of 94.5%. An NMR spectrum of the product is shown in FIG. 1 of the specification.

Example 2

[0034] Synthesis of a Reducing Agent Monomer

[0035] MAH (4.9 g, 0.05 mol) was added to a three-neck flask equipped with a thermometer, 30 mL of chloroform was added, and a resulting mixture was stirred at room temperature until the MAH was completely dissolved; DMEA (2.3 g, 0.025 mol) was dissolved in 8 mL of chloroform, and a resulting solution was added to the reaction flask all at once; a resulting system reacted at room temperature for 4 h to obtain a white suspension; 40 mL of diethyl ether was added, and a resulting mixture was thoroughly shaken and centrifuged to obtain a white solid; and the white solid was washed with 40 mL of diethyl ether, then suction filtration was conducted twice, and a resulting filter cake was vacuum-dried to a constant weight to obtain a white powder, with a total yield of 65.7%.

Example 3

[0036] Synthesis of a Reducing Agent Monomer

[0037] MAH (4.9 g, 0.05 mol) was added to a three-neck flask equipped with a thermometer, 30 mL of chloroform was added, and a resulting mixture was stirred at room temperature until the MAH was completely dissolved; DMEA (9.0 g, 0.10 mol) was dissolved in 20 mL of chloroform, and a resulting solution was added to the reaction flask all at once; a resulting system reacted at room temperature for 8 h to obtain a white suspension; 40 mL of diethyl ether was added, and a resulting mixture was thoroughly shaken and centrifuged to obtain a white solid; and the white solid was washed with 40 mL of diethyl ether, then suction filtration was conducted twice, and a resulting filter cake was vacuum-dried to a constant weight to obtain a white powder, with a total yield of 57.7%.

Example 4

[0038] Emulsion Polymerization

[0039] NaHCO.sub.3 (0.0772 g, 3 wt % of total monomer), SDS (0.0117 g, 0.5 wt % of total monomer), the reducing agent monomer obtained in Example 1 (0.0187 g, 0.0001 mol), and H.sub.2O (4.2132 g, 60 wt % of emulsion) were weighed and added into a 50 mL reaction flask, and a resulting mixture was stirred for 3 min to 4 min to allow thorough dissolution; then styrene (1.0415 g, 0.01 mol), BA (1.2817 g, 0.01 mol), and MMA (0.2503 g, 0.0025 mol) were added, and pre-emulsification was conducted with stirring for about 30 min; vacuum-pumping was conducted, and APS (0.0228 g, 0.0001 mol) was added at an argon atmosphere; and a resulting system reacted for 8 h in a 25° C. thermostat water bath to obtain the styrene-acrylic emulsion. As determined, a styrene conversion rate was 94%, a BA conversion rate was 94%, an MMA conversion rate was 96%, and a solid content was 59%. Then the emulsion was dropped into absolute methanol for demulsification, a resulting mixture was subjected to suction filtration with a Buchner funnel, and a resulting filter cake was dissolved in THF; and the absolute methanol precipitation was repeated three times to obtain a polymer M1. The polymer was analyzed by three-detection gel permeation chromatography (TG-GPC), and results were as follows: M.sub.n.SEC=4,120,000 g/mol, M.sub.w.SEC=30,090,000 g/mol, PDI=7.3, Mark-Houwink index α=0.568, and average branching factor g′=0.91. A differential molecular weight distribution curve of the obtained polymer M1 is shown in FIG. 2 of the specification; and a Mark-Houwink curve of the polymer M1 is shown in FIG. 5 of the specification.

Example 5

[0040] Emulsion Polymerization

[0041] NaHCO.sub.3 (0.0772 g, 3 wt % of total monomer), SDS (0.0119 g, 0.5 wt % of total monomer), the reducing agent monomer obtained in Example 1 (0.0561 g, 0.0003 mol), and H.sub.2O (4.3377 g, 60 wt % of emulsion) were weighed and added into a 50 mL reaction flask, and a resulting mixture was stirred for 3 min to 4 min to allow thorough dissolution; then styrene (1.0415 g, 0.01 mol), BA (1.2817 g, 0.01 mol), and MMA (0.2503 g, 0.0025 mol) were added, and pre-emulsification was conducted with stirring for about 30 min; vacuum-pumping was conducted, and APS (0.0684 g, 0.0003 mol) was added at an argon atmosphere; and a resulting system reacted for 8 h in a 25° C. thermostat water bath to obtain the styrene-acrylic emulsion. As determined, a styrene conversion rate was 99%, a BA conversion rate was 99%, an MMA conversion rate was 92%, and a solid content was 59%. Then the emulsion was dropped into absolute methanol for demulsification, a resulting mixture was subjected to suction filtration with a Buchner funnel, and a resulting filter cake was dissolved in THF; and the absolute methanol precipitation was repeated three times to obtain a polymer M2. The polymer was analyzed by TG-GPC, and results were as follows: M.sub.n.SEC=2,310,000 g/mol, M.sub.w.SEC=17,800,000 g/mol, PDI=7.8, Mark-Houwink index α=0.521, and average branching factor g′=0.84. A differential molecular weight distribution curve of the obtained polymer M2 is shown in FIG. 3 of the specification; and a Mark-Houwink curve of the polymer M2 is shown in FIG. 6 of the specification.

Example 6

[0042] Emulsion Polymerization

[0043] NaHCO.sub.3 (0.0772 g, 3 wt % of total monomer), SDS (0.0121 g, 0.5 wt % of total monomer), the reducing agent monomer obtained in Example 1 (0.187 g, 0.001 mol), and H.sub.2O (4.7734 g, 60 wt % of emulsion) were weighed and added into a 50 mL reaction flask, and a resulting mixture was stirred for 3 min to 4 min to allow thorough dissolution; then styrene (1.0415 g, 0.01 mol), BA (1.2817 g, 0.01 mol), and MMA (0.2503 g, 0.0025 mol) were added, and pre-emulsification was conducted with stirring for about 30 min; vacuum-pumping was conducted, and APS (0.228 g, 0.001 mol) was added at an argon atmosphere; and a resulting system reacted for 8 h in a 25° C. thermostat water bath to obtain the styrene-acrylic emulsion. As determined, a styrene conversion rate was 100%, a BA conversion rate was 97%, an MMA conversion rate was 96%, and a solid content was 59%. Then the emulsion was dropped into absolute methanol for demulsification, a resulting mixture was subjected to suction filtration with a Buchner funnel, and a resulting filter cake was dissolved in THF; and the absolute methanol precipitation was repeated three times to obtain a polymer M3. The polymer was analyzed by TG-GPC, and results were as follows: M.sub.n.SEC=1,880,000 g/mol, M.sub.w.SEC=18,900,000 g/mol, PDI=10.0, Mark-Houwink index α=0.408, and average branching factor g′=0.65. A differential molecular weight distribution curve of the obtained polymer M3 is shown in FIG. 4 of the specification; and a Mark-Houwink curve of the polymer M3 is shown in FIG. 7 of the specification.

Example 7

[0044] Emulsion Polymerization

[0045] NaHCO.sub.3 (0.0768 g, 3 wt % of total monomer), SDS (0.0023 g, 0.1 wt % of total monomer), the reducing agent monomer obtained in Example 1 (0.187 g, 0.001 mol), and H.sub.2O (4.7734 g, 60 wt % of emulsion) were weighed and added into a 50 mL reaction flask, and a resulting mixture was stirred for 3 min to 4 min to allow thorough dissolution; then styrene (1.0415 g, 0.01 mol), BA (1.2817 g, 0.01 mol), and MMA (0.2503 g, 0.0025 mol) were added, and pre-emulsification was conducted with stirring for about 30 min; vacuum-pumping was conducted, and KPS (0.5411 g, 0.002 mol) was added at an argon atmosphere; and a resulting system reacted for 12 h in a 25° C. thermostat water bath to obtain the styrene-acrylic emulsion. As determined, a styrene conversion rate was 92%, a BA conversion rate was 86%, an MMA conversion rate was 90%, and a solid content was 57%. Then the emulsion was dropped into absolute methanol for demulsification, a resulting mixture was subjected to suction filtration with a Buchner funnel, and a resulting filter cake was dissolved in THF; and the absolute methanol precipitation was repeated three times to obtain a polymer. The polymer was analyzed by TG-GPC, and results were as follows: M.sub.n.SEC=2,070,000 g/mol, M.sub.w.SEC=22,200,000 g/mol, PDI=6.3, Mark-Houwink index α=0.608, and average branching factor g′=0.77.

Comparative Example 1

[0046] NaHCO.sub.3 (0.0770 g, 3 wt % of total monomer), SDS (0.0021 g, 0.1 wt % of total monomer), and H.sub.2O (7.3060 g, 60 wt % of emulsion) were weighed and added into a 50 mL reaction flask, and a resulting mixture was stirred for 3 min to 4 min to allow thorough dissolution; then styrene (1.0420 g, 0.01 mol), BA (1.2812 g, 0.01 mol), and MMA (0.2510 g, 0.0025 mol) were added, and pre-emulsification was conducted with stirring for about 30 min; vacuum-pumping was conducted, and an oxidizing agent of KPS (0.5413 g, 0.002 mol) and a reducing agent of dimethylaminoethyl methacrylate (DMAEMA) (0.3145 g, 0.002 mol) were added at an argon atmosphere; and a resulting system was placed in a 25° C. thermostat water bath, and no reaction occurred in the system.

Comparative Example 2

[0047] NaHCO.sub.3 (0.0770 g, 3 wt % of total monomer), SDS (0.1040 g, 5 wt % of total monomer), and H.sub.2O (7.3060 g, 60 wt % of emulsion) were weighed and added into a 50 mL reaction flask, and a resulting mixture was stirred for 3 min to 4 min to allow thorough dissolution; then styrene (1.0420 g, 0.01 mol), BA (1.2812 g, 0.01 mol), and MMA (0.2510 g, 0.0025 mol) were added, and pre-emulsification was conducted with stirring for about 30 min; vacuum-pumping was conducted, and an oxidizing agent of KPS (0.5413 g, 0.002 mol) and a reducing agent of DMAEMA (0.3145 g, 0.002 mol) were added at an argon atmosphere; a resulting system reacted for 12 h in a 25° C. thermostat water bath, and the system underwent agglomeration; and demulsification was conducted. As determined, a styrene conversion rate was 63%, a BA conversion rate was 55%, an MMA conversion rate was 60%, and a solid content was 30%. Then the emulsion was dropped into absolute methanol for demulsification, a resulting mixture was subjected to suction filtration with a Buchner funnel, and a resulting filter cake was dissolved in THF; and the absolute methanol precipitation was repeated three times to obtain a polymer. The polymer was analyzed by TG-GPC, and results were as follows: M.sub.n.SEC=207,800 g/mol, M.sub.w.SEC=898,000 g/mol, PDI=4.3, Mark-Houwink index α=0.7173, and average branching factor g′=0.98.

Comparative Example 3

[0048] NaHCO.sub.3 (0.0768 g, 3 wt % of total monomer), SDS (0.1032 g, 5 wt % of total monomer), and H.sub.2O (7.3066 g, 60 wt % of emulsion) were weighed and added into a 50 mL reaction flask, and a resulting mixture was stirred for 3 min to 4 min to allow thorough dissolution; then styrene (1.0415 g, 0.01 mol), BA (1.2817 g, 0.01 mol), and MMA (0.2503 g, 0.0025 mol) were added, and pre-emulsification was conducted with stirring for about 30 min; vacuum-pumping was conducted, and an oxidizing agent of KPS (0.5411 g, 0.002 mol) and a reducing agent of sodium bisulfite (0.2609 g, 0.0025 mol) were added at an argon atmosphere; and a resulting system reacted for 24 h in a 25° C. thermostat water bath to obtain a styrene-acrylic emulsion. As determined, a styrene conversion rate was 89%, a BA conversion rate was 85%, an MMA conversion rate was 86%, and a solid content was 38%. Then the emulsion was dropped into absolute methanol for demulsification, a resulting mixture was subjected to suction filtration with a Buchner funnel, and a resulting filter cake was dissolved in THF; and the absolute methanol precipitation was repeated three times to obtain a polymer. The polymer was analyzed by TG-GPC, and results were as follows: M.sub.n.SEC=306,000 g/mol, M.sub.w.SEC=2,110,000 g/mol, PDI=6.9, Mark-Houwink index α=0.7896, and average branching factor g′=1.