Dispersants

Chapter 12

Dispersants A.  NANOTUBE DISPERSANTS Pyridinium-based Ionic Compounds Title: US Patent: Author: Assignee:

Ionic organic compound 7,858,799 (December 28, 2010) Masaru Yoshida et al. National Institute of Advanced Industrial Science and Technology (Tokyo, JP)

Significance:

Single-walled nanotube dispersions that were stable in water for over 6 months were prepared by blending with 1 wt% of a selected polymeric pyridine-containing ionic liquid followed by ultrasounding the mixture for 1 h. The ionic solvents were prepared in quantitative yield and in a single step, which did not require purification before using.

Additive Names

Poly(4-(4-benzyl)amidopyridinium) hexafluorophosphate (I) Poly(4-(4-benzyl)amido-2,6-dichloropyridinium) ­hexafluorophosphate (II) Poly(4-pentylamidopyridinium) hexafluorophosphate (III) Poly(4-(N-benzyl)-N′-pyridinium urea) hexafluorophosphate (IV)

Safety Concerns

The toxicity of poly(4-(4-benzyl)amidopyridinium) hexafluorophosphate or polyvinylpyridinium hexafluorophosphates is known to cause moderate skin and eye irritation. Ingestion may cause nausea, cardiac disturbances, or central nervous system effects.

Next Generation of International Chemical Additives. DOI: http://dx.doi.org/10.1016/B978-0-444-53788-1.00012-7 Copyright © 2013 Elsevier B.V. All rights reserved.

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Additive Structures n

n

n

NH O

NH

O

PF6

N

NH

O

N

Cl

(I)

Cl

HN

NH

PF6

PF6

N

PF6

N

n (IV)

(III)

(II)

O

Additive Preparation n O

NH2

Cl

n CH2Cl2

+

O

23 C 12 Hours

N

H2O O

80 OC 5 Minutes

NH

Hydrogel

NH4PF6 Reflux 10 Minutes

O

NH

Cl N

Cl

Single Walled Nanotubes

PF6

N

Ultrasound 1 Hour

O

PF6

NH

N

n

n

n

O

NH

O

NH

N

N

PF6

PF6

Single Walled Nanotube Single Walled Nanotube Dispersion

Additive Synthesis 1.  Preparation of poly(4-(4-benzyl)amidopyridinium) chloride At ambient temperature, a round bottom flask was charged with 4.27 g of 4-aminopyridine and 8.34 g of 4-(chloromethyl)benzoic acid chloride dissolved in 100 ml of anhydrous methylene chloride and then treated with 6.95 ml of triethylamine and stirred overnight. The reaction mixture was then filtered, and the product was isolated as a white precipitate in an 85% yield after filtration.

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2.  Preparation of poly(4-(4-benzyl)amidopyridinium) chloride hydrogel A 1 wt% aqueous solution of the Step 1 product was mixed and heated to 80 °C to give a colorless solution. The solution was then slowly cooled to an ambient temperature for about 5 min whereupon a stable translucent hydrogel was formed. The critical gelation concentration was determined to be 7.5 g/l at an ambient temperature in neutral water. 3.  Preparation of poly(4-(4-benzyl)amidopyridinium) hexafluorophosphate A reaction kettle was charged with 860 mg of the Step 2 product and 200 ml of water and then heated until all the solids dissolved. The solution was then treated with 20 ml of an aqueous solution of 625 mg of ammonium hexafluorophosphate and then heated under reflux for 10 min. Thereafter, the solution was hot filtered, and the polymer was isolated in quantitative yield. 4.  Preparation of single-walled carbon nanotubes dispersed in liquid poly(4-(4-benzyl)amidopyridinium) hexafluorophosphate A 5-ml solution of the Step 3 product was treated with 0.5 mg of single-walled carbon nanotubes, and the mixture was ultrasonically irradiated for 1 h at 130 W and 35 kHz, and a black solution was formed without the appearance of precipitates. After 6 months, the single-walled carbon nanotube solution remained unchanged. Near infrared/UV spectra indicated the presence of sharp absorptions characteristic of individually dispersed single-walled carbon nanotubes in the wavelength range of 400–1600 nm when deuterated water was used.

Testing No additional testing information was provided by the author.

Advantages over Prior Art Although composites of single-walled nanotubes and polymeric solvents have been previously prepared, several distinct synthetic advantages are apparent in the current invention. First, the synthesis of the polymeric substrate is simple, requires inexpensive reagents and does not require purification before being used in subsequent blends. In addition, the synthesis quantitatively produces the target polymer. Finally, using small compact monomers to prepare the ionic substrate optimizes the ionic conductivity of the polymer.

Notes 1. In an earlier investigation by Zheng,1 aqueous dispersions of single-walled nanotubes were prepared using peptide nucleic acid molecules such as single-stranded DNA and RNA dissolved in solutions containing tris(2-aminoethyl)amine, N-(2-hydroxyethyl)piperazine-N′-(2-ethanesulfonic) acid or 2-(N-morpholino)ethanesulfonic acid. 2. Caroll2 prepared polymer nanotube composite dispersions by the emulsion copolymerization of vinylidene difluoride containing hexafluoropropylene nanotubes.

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3. A composite material was prepared by Asgari,3 which consisted of a solgel covalently bonded to the nanoparticle, and this was then blended with a low molecular polysiloxane (DYNASIL®-40) and then gelled using 2-aminoethyl-3-aminopropyltrimethoxysilane (Dynasylan®). 4. Ford4 solubilized carbon nanotubes in water by heating nanotubes containing 0.7–0.8 wt% of carboxylic acid groups with urea to 160 °C to form the ammonium salt.

REFERENCES 1. Ming Zheng et al, US Patent 7,588,941 (September 15, 2009)   E.I. du Pont de Nemours and Company (Wilmington, DE) 2. David Carroll et al, US Patent 7,834,077 (November 16, 2010)   Clemson University Research Foundation (Clemson, SC) 3. Soheil Asgari, US Patent 7,780,875 (August 24, 2010)   Cinvention AG (Wiesbaden, DE) 4. William E. Ford et al, US Patent 7,854,914 (December 21, 2010)   Sony Deutschland GmbH (Cologne, DE)

B.  CEMENT DISPERSANTS Methacrylic Acid Terpolymers Containing Polyethylene Glycol Title: US Patent: Author: Assignee:

Polymer and cement admixture using the same 7,851,576 (December 14, 2010) Tsutomu Yuasa et al. Nippon Shokubai Co., Ltd. (Osaka, JP)

Significance:

A reaction mixture of methoxypolyethylene glycol methacrylic acid ester and methacrylic acid initiated with the macroinitiator poly(oxyethylene-co-diazo) generated a terpolymer containing randomly incorporated polyethylene glycol. When this terpolymer was compounded with cement, sand, and water, the prehardened cement had an enhanced fluidity and dispersibility before setting.

Additive Name

Poly(ethylene glycol-ter-methacrylic acid-ter-methoxypolyethylene glycol methacrylic acid ester) (I)

Safety Concerns

While there are no toxicological data available for this additive, users are warned that polymethacrylic acid is an irritant and that gloves, chemical goggles, or a mask should be used.

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215

Additive Structure

O

n

O

50

O

HO

O

O 23

OCH3

(I) Additive Preparation Water O

N

O

+

O

N

50 90

O

OH

O

O

OCH3

23

O 50

n

O

O HO

95 C 5 Hours

O

O 23

OCH3

Additive Synthesis 1.  Preparation of poly(ethylene glycol-ter-methacrylic acid-ter-methoxypolyethylene glycol methacrylic acid ester) A glass reaction vessel equipped with a thermometer, stirrer, addition funnel, nitrogen inlet tube, and reflux condenser was charged with 100.0 g of water, then heated to 95 °C, and treated with 70.1 g of methoxypolyethylene glycol methacrylic acid ester having an ethylene oxide repeat unit of 23 and 9.9 g of methacrylic acid dissolved in 120.0 g of water. The polymerization was then initiated by the dropwise addition of the polyethylene glycol diazomacroinitiator having an Mn of approximately 4000 Da (VPE®-0401) dissolved in 80.0 g of water and added incrementally over a period of 3 h. The mixture was then heated for an additional 2 h at 95 °C, then concentrated, and the polymer was isolated. Physical properties of selected dispersants are provided in Table 1.

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TABLE 1  Physical properties for copolymers prepared by using various ratios of methoxypolyethylene glycol methacrylic acid ester and methacrylic acid using the macroinitiators VPE®-0401, VPE®-0201, or VPE®-0601

Example

Monomers

Macroinitiator

Chain Transfer Agent

1

1) Methoxypolyethylene glycol methacrylic acid ester

VPE-0401®*

None

52,300

VPE-0201®**

None

91,600

VPE-0601®***

None

85,600

V-50®****

None

24,200

Ammonium ­persulfate

3-Mercaptopropionone

24,000

Mw (Da)

2) Methacrylic acid 2

1) Methoxypolyethylene glycol methacrylic acid ester 2) Methacrylic acid

3

1) Methoxypolyethylene glycol methacrylic acid ester 2) Methacrylic acid

Control-1

1) Methoxypolyethylene glycol methacrylic acid ester 2) Methacrylic acid 3) 30% Sodium hydroxide

Control-2

1) Methoxypolyethylene glycol methacrylic acid ester 2) Methacrylic acid

*Poly(oxyethylene-co-diazo) having an Mn of approximately 23,500 Da with polyethylene oxide having an Mn of approximately 2000 Da (dp ~ 50) in the repeat unit and with a polymer repeat unit of 90.

N

O

N

~50 90

**Poly(oxyethylene-co-diazo) having an Mn of approximately 33,500 Da with polyethylene oxide having an Mn of approximately 2000 Da in the repeat unit and with a polymer repeat unit of 45. ***Poly(oxyethylene-co-diazo) having an Mn of approximately 31,000 Da with polyethylene oxide having an Mn of approximately 6000 Da in the repeat unit and with a polymer repeat unit of 90. ****2,2′-Azobis(2-methylpropioneamidine) dihydrochloric acid salt

NH2 HN

N NH2

N

NH

2HCl

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217

Testing 15. Hit Flow Rate An experimental sample consisting of 550 g of Taiheiyo Normal Portland Cement, a 220 g of solution containing a selected experimental additive at varying concentrations, and the antifoaming agent MA404® were mixed in a Hobert-type mortar mixer for 30 s. During the mixing procedure, 1350 g of standard sand was added, and the mixture was further blended for an additional 30 s. The mortar was then hit 15 times with a stick, and after 15 s, the diameter of the hole was measured to determine the effect of the additive on cement dispersibility. Test results are provided in Table 2.

Test Results TABLE 2  Effect on experimental additives on cement dispersibility using the 15 Hit Flow Rate Test. Higher values are indicative of enhanced cement dispersibility and stability Polymer Content in Cement Mixture (wt%)

15 Hit Flow Rate (mm)

1

0.09

229

2

0.10

239

3

0.09

240

Control-1

0.12

217

Control-2

0.18

223

Example

Advantages over Prior Art The novel method of randomly introducing polyethylene glycol into the terpolymer containing methoxypolyethylene glycol methacrylic acid ester and methacrylic acid using the macroinitiator poly(oxyethylene-co-diazo) has produced a cement dispersant able to form very fine small aggregates of prehardened cement compositions. Previously prepared cement dispersants containing block polyethylene glycol and derivatized with (meth)acrylate or styrene appear to lack the required structural segments or orientations needed to become better adsorbed onto cement particles.

Notes 1. Kraus1 prepared a block copolymer effective as a cement dispersant, (II), using the atom transfer radical of the macroinitiator bromoisobutyric ester of polyethylene glycol monomethyl ether having an Mn of approximately 500 Da with t-butylmethacrylate.

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a O

b O

O

O O

t-C4H9

OCH3

12

(II) 2. Bichler2 prepared a yellowish cement dispersant copolymer (III) consisting of polyethylene glycol monovinylether having an ethylene glycol component with an Mn of approximately 5800 Da and acrylic acid. a HO

b O

O

O

OH

115

(III)

3. Kraus3 prepared a cement dispersant copolymer (IV) containing poly(ethylene glycol) monomethyl ether methacrylate having a glycol component with an Mn of approximately 500 dalton functionalized with ethylene glycol methacrylate phosphate, which was also effective as an aqueous solid suspension stabilizer. a O H3CO

O

b O

O O

O 15

(IV)

P O

OH OH

4. A fluid loss control additive and cement dispersant consisting of humic acid salt containing grafted 2-acrylamido-2-methylpropanesulfonic acid salt, acrylamide, acrylic acid salt, and diallyldimethylammonium chloride was prepared by Lewis4 and used in cement compositions to improve flowability.

REFERENCES 1. Alexander Kraus et al, US Patent 7,425,596 (September 16, 2008)   Goldschmidt GmbH (DE)   Construction Research & Technology GmbH (DE) 2. Manfred Bichler et al, US Patent 7,855,260 (December 21, 2010)   BASF Construction Polymers GmbH (Trostberg, DE)

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219

3. Alexander Kraus et al, US Patent 7,842,766 (November 30, 2010)   Construction Research & Technology GmbH (DE) 4. Sam Lewis et al, US Patent 7,842,652 (November 30, 2010)   Halliburton Energy Services, Inc. (Duncan, OK)

C.  PIGMENT DISPERSANTS Poly(ethylene oxide)- or Poly(ethylene oxideb-propylene-b-polybutylene oxide) Title: US Patent: Author: Assignee:

Dispersions containing alkoxylates of alicyclic polycyclic compounds 7,868,074 (January 11, 2011) Lisa Marie Fine et al. Ethox Chemicals, LLC (Greenville, SC)

Significance:

Surface active dispersants containing poly(ethylene oxide)- or poly(ethylene oxide-b-propylene-b-polybutylene oxide) have been found to be effective in lowering the interfacial tension of coloration pigments in both aqueous and nonaqueous media. Optimum pigment dispersion was obtained using cyclodecyloxopolyethylene oxide containing 70 moles ethylene oxide at a treatment level of 2.0 wt%.

Additive Name

Cyclodecyloxy-poly(ethylene oxide) (I) Adamantanoxy(ethylene oxide) (II) Terpineoxypoly(ethylene oxide) (III) Cyclodecyloxy-poly(ethylene oxide-ter-propylene oxide-ter-butylene oxide) (IV)

Safety Concerns

While polyethylene oxide and poly(ethylene oxide-co-propylene oxide-co-butylenes-oxide are considered to be safe overall, the presence of residual initiator raises health concerns. When handling these materials, contact lenses must not be worn. In the case of contact with the eyes, immediately flush eyes with cool water. In the case of skin contact, gently wash the contaminated area with soap and water.

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Additive Structures

O

O

H

a

O

O

70 H

(II)

(I) a=50,70,100,120

O

O

O

H

70

O

O 25

25

O

25

n

(III) (IV)

Additive Preparation OH

+ 70

O

NaOH (aq) 0.1 wt% CH3COOH Parr Reactor 140 OC ~ 2 Hours

O

O

H

70

Additive Synthesis 1.  Preparation of cyclodecyloxy-poly(ethylene oxide) A Parr pressure reactor was charged with one equivalent of cyclodecyl alcohol and 0.1% potassium hydroxide and then purged with nitrogen and vacuum stripped for 30 min at 105 °C. The vessel pressure was then reduced, and ethylene oxide was slowly introduced to initiate the reaction. Thereafter, an additional 70 equivalents of ethylene oxide was introduced at 140 °C, and the reaction was continued until all ethylene oxide had been consumed. The reactor was then vacuum stripped, and the crude material was neutralized with acetic acid and the product isolated from the reactor.

Testing 1.  Viscosity In a typical process, pigments having an average particle diameter of 10–35 nm and a DBP of 60–150 ml/100 g were blended with a selected experimental dispersant containing 25–40 wt% solvent. The stability of the mixture was then ascertained by the shear rate in revolutions per minute needed to break the suspension. Test results for Phthalo Blue and Lithol Rubine dispersions are summarized in Tables 3 and 4, respectively.

Chapter | 12  Dispersants

221

Testing Results 1.  Viscosity Testing for Phthalo Blue Dispersions

TABLE 3  Solution viscosities of Phthalo Blue dispersions stabilized after 48 h with cyclodecyloxy-poly(ethylene oxide) having an ethylene oxide content of 70 moles Solution Viscosity Solution using Viscosity Cyclodecy(Conloxy-poly RPM trol) (EO)70 (0.5%)

Solution Viscosity using Cyclodecyloxypoly(EO)70 (1.0%)

Solution Viscosity Solution using Viscosity using CyclodecyloxyCyclodecyloxypoly poly(EO)70 (1.5%) (EO)70 (2.0%)

1.5

92160

2190

1210

2310

940

3

57410

1930

1030

2080

810

6

34940

1710

900

1840

720

12

22250

1440

800

1600

660

30

11990

1120

660

1320

580

60

7040

920

580

1120

520

2.  Viscosity Testing for Lithol Rubine Dispersions

TABLE 4  Solution viscosities for Lithol Rubine dispersions stabilized after 24 h with cyclodecyloxy-poly(ethylene oxide) having an ethylene oxide content of 70 moles

Solution Viscosity RPM (Control)

Solution Viscosity using Cyclodecyloxy-poly (EO)70 (0.5%)

Solution Viscosity using Cyclodecyloxy-poly (EO)70 (1.0%)

Solution Viscosity Solution using Viscosity using CyclodecyCyclodecyloxyloxy-poly poly(EO)70 (1.5%) (EO)70 (2.0%)

1.5

92460

7470

4370

11010

14070

3

56870

5770

3680

8370

10590

6

35410

4340

2920

6250

7820

12

22400

3200

2280

4600

5710

30

12180

2120

1630

4570

3720

60

7450

1520

1220

3060

–

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Next Generation of International Chemical Additives

Advantages over Prior Art Although colorant pigment dispersants are well reported, there are very few instances of organic and inorganic pigment dispersants that can be used in both aqueous and nonaqueous media as described in the current invention. In addition, these additives are easily blended with pigments without causing flocculation to provide dispersions having very high flowability.

Notes 1. Styrenic polyethers (V) prepared by Weipert1 were effective in dispersing insoluble fine powders in nonaqueous liquids and provided long-term stability without the formation of a hard cake or precipitates. O O

O

b H

a (V)

a ~ 100 b ~ 70

2. Waki2 prepared an aqueous pigment dispersion for Yellow 5G pigment using poly(styrene-b-methylstyrene-b-acrylic acid) having an Mn of approximately 8000 Da and with a Tg = 75 °C blended glycerin and isopropyl alcohol. Fastgen Blue pigment TGR was also dissolved in poly(styrene-b-acrylic acid) having an Mn of approximately 12,000 Da with a Tg = 70 °C also blended with glycerin and isopropyl alcohol. 3. Weber3 prepared diazo pigment dispersants that had a high affinity for those groups having diazo-containing dyes (IV) and (V). O N

N

Cl

O Cl

Diazo-containing Dye #1 (VI)

SO3

N(CH3)2(C18H35)2

H3CO2C

O

H N

O

N H

CO2CH3

H N O OCH3

CH3 O

Diazo-containing Dye #2 (VII)

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223

4. Hoogmartens4 formed stable nonaqueous inkjet inks for diketopyrrolo-pyrrole pigments using polyethylene glycol dimethyl ether having an Mn of approximately ≥250 Da as the dispersing solvent.

REFERENCES 1. Paul David Weipert et al, US Patent 7,271,211 (September 18, 2007)   Ethox Chemicals, LLC (Greenville, SC) 2. Minoru Waki et al, US Patent 7,858,676 (December 28, 2010)   Seiko Epson Corporation (Tokyo, JP) Mikuni Shikiso Kabushiki Kaisha (Himeji-shi, JP) 3. Joachim Weber et al, US Patent 7,855,041 (December 21, 2010)   Clariant Produkte (Deutschland) GmbH (Frankfurt, DE) 4. Ivan Hoogmartens, US Patent 7,854,799 (December 21, 2010)   Agfa Graphics NV (Mortsel, BE)