Shear Rate (s -1 ) - Quartz Presentations Online

SHEAR-THICKENING IN
AQUEOUS SURFACTANT-
ASSOCIATIVE THICKENER
MIXTURES
Raymond H Fernando, PhD
Polymers and Coatings Program
Department of Chemistry and Biochemistry
California Polytechnic State University
San Luis Obispo, CA 93407
www.polymerscoatings.calpoly.edu

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►Introduction
Outline
• Shear rate dependence of viscosity
• Associative thickener types
• HEAT associative thickeners
• Surfactant effects
►Results
• Shear thickening
• Cyclodextrin effects
►Discussion
►Summary

If viscosity of a fluid is
independent of shear rate, it is
Newtonian
Shear Stress, Pa
Viscosity, Pa s
Shear Rate, s -1 Shear Rate, s -1

Shear Thinning Behavior
Viscosity Measured with ARES
100000
Viscosity (cps)
10000
10 0 0
10 0
10
0.01 0.10 1.00 10.00 100.00 1000.00
Shear R ate (s-1)
Shear Stress, Pa
Shear Rate, s -1

Thixotropy – time
dependence of viscosity
Viscosity
Viscosity
Time
Shear Rate

Shear Rates for Various Sub-Processes
Sag & Leveling
Settling
log (Viscosity)
Wicking
Brush/Roll
Pick Up
Mixing
(Slurries)
Roll
Coating
Spray
Coating
10 -2 10 -1 10 0 10 +1 10 +2 10 +3 10 +4 10 +5 10 +6
log (Shear Rate (s -1 ))

Shear Rate Dependence of
Thickening Mechanisms
log (Viscosity)
10 -2 10 -1 10 0 10 +1 10 +2 10 +3 10 +4 10 +5 10 +6
log (Shear Rate (s -1 ))
10

Shear Rate Dependence of
Thickening Mechanisms
log (Viscosity)
Brownian Motion
Flocculation
Aggregation
Chain Entanglements
Intermolecular
Associations
Hydrodynamic Volume
Adsorption
Aggregation
Intermolecular
Associations
Hydrodynamic Volume
Adsorption
10 -2 10 -1 10 0 10 +1 10 +2 10 +3 10 +4 10 +5 10 +6
log (Shear Rate (s -1 ))
11

High shear can break up
entanglements
Viscosity
Shear Rate

Associative thickeners - HEUR
R-N-C-(O-CH
2 -CH
2 ) x -[O-C-N-R” R”-N-C-(O-CH
2 -CH
2 ) x ] n -O-C-N-R’
-
H
= O
R, R’ = C 12
12 -C 18
= O
-
H
H-
= O
18 ; R” = C 7 -C 36 ; x = 90 - 455; n = 1-4
= O
H-
(C 12 H 25 Terminal Hydrophobes; 40,000 Approx. M.W.)
• Polymeric surfactants
• Amphiphilic polymers
13

O(
Associative Thickeners -
HASE
CH 3
CH 3
(-CH 2 -C-) (-CH 2 -CH-) (-CH 2 -C-)
C=O C=O C=O
OH OC 2 H 5
O
CH 2
CH 2
(
20
C 18 H 37
14

Sensitivity of Associative Thickeners
Performance Sensitivity to Formulation Variables -
A Drawback of Associative Thickeners
► Latex Particle Surface
Characteristics
► Surfactants
► Dispersants
► Cosolvents
15

Assoc. Thickener Sensitivity
to Latex
Surface Stabilization
Latex
Polymer
Composition
Particle
Size(nm)
Protective
Colloid
Non-Ionic
Surfactants
Anionic
Surfactants
Acid
Monomer
VAE155 Vinyl Acetate (87)
Ethylene (13)
VAEVCl Vinyl Acetate (36)
Ethylene (24)
Vinyl Chloride (39)
VAE145 Vinyl Acetate (85)
Ethylene (15)
EVCl Ethylene (15)
Vinyl Chloride (85)
155 Yes Yes No No
154 No Yes Yes Yes
145 No Yes No Yes
131 No No Yes Yes
UrAcr Urethane-Acrylic 85 No No No Yes
Acr All-Acrylic 130 -- -- -- --
VAcr Vinyl-Acrylic 149 -- -- -- --
Fernando, Wickmann, Louie, and Chelius, ICE Proceedings, 2000

HEUR-2020
(1.0wt.%)/Latex (30
30wt.%)
Aqueous Blends
Viscosity (mPa s)
1.E+04
1.E+03
1.E+02
1.E+01
∗ - VAE155; • - VAEVCl
+ - VAE145; - EVCl
× -UrAcr; -Acr
• -VAcr
1.E+00
1.E- 02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04
Shear Rate (s -1 )
Fernando, Wickmann, Louie, and Chelius,ICE Proceedings, 2000

Thickener Sensitivity to Surfactant
[HEC]
Tergitol 15S7 Addition to 0.75% HEC Solution
Viscosity, centipoise
1000000
100000
10000
1000
100
10
1
1.0E-2 1.0E-1 1.0E+0 1.0E+1 1.0E+2 1.0E+3
Shear Rate, s-1
0.00%
0.10%
2.00%

Thickener Sensitivity to Surfactant
[HASE]
Tergitol 15S7 Addition to HASE 0.5% Solution
Viscosity, centipoise
1000000
100000
10000
1000
100
10
1
1.0E-2 1.0E-1 1.0E+0 1.0E+1 1.0E+2 1.0E+3
Shear Rate, s-1
0.00%
0.10%
2.00%

Thickener Sensitivity to Surfactant
[HASE]
Tergitol 15S7 Addition to 0.5% HASE 935 Solution
Viscosity, centipoise
200000
150000
100000
50000
0
0.0% 1.0% 2.0% 3.0% 4.0% 5.0%
Tergitol Concentration
Shear Rate,s -1
0.08
8.00
7000
6000
5000
4000
3000
2000
1000
0

Surfactant/Polymeric
Surfactant Interactions
Polymer / surfactant
complex formation
21

Associative Thickeners -
HASE Type
CH 3
CH 3
(-CH 2 -C-) (-CH 2 -CH-) (-CH 2 -C-)
C=O C=O C=O
OH OC 2 H 5
O
• Hulden, Colloids and Surfaces A (1994)
• Jenkins et al., Polymeric Dispersions: Principles and
Applications (1997)
• Oleson et al., Progress in Organic Coatings (1998)
• Enghlish et al., J. Rheology (1997); Ind. Eng. Chem Res.
(2002)
• Kulicke et al., Colloid Polymer Sci. (1998)
• Tam et al., J. P{olym. Sci.: Part B (2000)
• Talwar et al., J. Rheology (2006)
(
CH 2
CH 2
20
C 18 H 37
O(
22

Generic Structure of Hydrophobically-
Modified, Aminoplast Thickener (HEAT)
Optiflo L100
(20% in water)
Supplied by
Sud Chemie
Steinmetz, A.L., FSCT Mid-Year Symposium
Ft. Lauderdale, FL (2004)

HEAT Thickener
US 5,627,232 – Glancy & Steinmetz
US 5,629,373 – Glancy & Steinmetz
HEATs are Glycoluril based;
M.W. 30,000 – 80,000

Ethoxylated, Octylphenol Surfactants
Used in the Study
► Triton X-45
(n=4.5)
► Triton X-100
(n=9.5)
► Triton X-102
(n= 13)
► Triton X-405
(n= 40)
CH 3
CH 3
H 3
C C CH 2
C
O CH 2
CH 2
O H
n
CH 3
CH 3
Proceedings of ICE 2007

CMC and HLB Values of Surfactants
Surfactant
CMC (mM)
CMC
(wt.%)
HLB
Triton X-45
0.11 0.0045 9.8
Triton X-100
0.24 0.0150 13.4
Triton X-102
0.28 0.022 14.4
Triton X-405
0.81 0.16 17.6

Viscosity Dependence on Surfactant
Concentration for Aqueous L100 (0.5
wt.%) and Surfactant Blends
Viscosity (cP)
1000.00
100.00
10.00
1.00
Viscosity of Optiflo L100 blends at 9.283 1/s
0 1 2 3 4 5
Surfactant Concentration (wt%)
X-45
X-100
X-102
X-405

Shear-thickening of L100
solutions
Viscosity dependence on shear rate of Triton X-45 surfactant
(varying concentrations) and Optiflo L-100 (1.0 Wt.%) aqueous
blends. Data point equilibration time – 30 seconds

Shear-thickening of L100
solutions
Viscosity dependence on shear rate of Triton X-45 surfactant (1.5 Wt.%)
and Optiflo L-100 (1.0 Wt.%) aqueous blend. Data point equilibration
time – 30 & 90 seconds represented by circle and square symbols,
respectively.

Shear-thickening of L100 solutions
Viscosity dependence on shear rate of Triton X-45 surfactant (1.0
Wt.% - closed circles & 2.5 Wt.% - open circles) and Optiflo L-100
(1.0 Wt.%) aqueous blends.
1 – Shear rate ramp-up; 2 – Shear rate ramp-down.

Complex Viscosity of L100
Solutions
complex viscosity (h*) dependence on frequency of Triton X-45
surfactant (varying concentrations) and Optiflo L-100 (1.0 Wt.%)
aqueous blends.

Cyclodextrin Structure
Capable of removing hydrophobic
interactions by forming inclusion complexes

β-Cyclodextrin
Structure
Capable of breaking
up hydrophobic
interactions by
forming inclusion
complexes
Lau, W., “Frontiers in Emulsion Polymerization in Coatings”,
American Coatings Conference, 2010

Effect of m-βCD
on viscosity of
HEUR-C16-51K (2% in water)

Proposed viscosity reduction
mechanism

β-cyclodextrin
effect on L-100
1% L-100
2% L-100
Viscosity (Pa*s)
0.1
0.01
1% L-100
w ith 1% BCD
Viscosity (Pa*s)
0.1
0.01
2% L-100
w ith 1% BCD
0.001
1 10 100 1000
Shear Rate (1/s)
0.001
1 10 100 1000
Shear Rate (1/s)
0.1
3% L-100
0.1
4% L-100
3% L-100
w ith 1% BCD
Viscosity (Pa*s)
0.01
Viscosity
0.01
4% L-100
w ith 1% BCD
0.001
1 10 100 1000
Shear Rate (1/s)
0.001
1 10 100 1000
Shear rate (1/s)

β-cyclodextrin
effect on
L-100/X-45 blend
0.1
1% L-100
1% L-100
w ith 1% BCD
w ith 1% BCD and
1% X-45
w ith 1% X-45
Viscosity (Pa*s)
0.01
0.001
1 10 100 1000
Shear Rate (1/s)

Effect of order of order of addition
0.1
1% L-100
0.1
1.5% L-100
Viscosity (Pa*s)
0.01
X-45 equilibrated
first
BCD equilibrated
first
0.001
1 10 100 1000
Shear Rate (1/s)
Viscosity (Pa*s)
0.01
X-45 Equilibrated
First
BCD Equilibrated
First
0.001
1 10 100 1000
Shear Rate (1/s)
0.1
2% L-100
0.1
3% L-100
Viscosity (Pa*s)
0.01
0.001
X-45 Equilibrated
First
BCD Equilibrated
First
1 10 100 1000
Shear Rate (1/s)
Viscosity (Pa*s)
0.01
0.001
X-45 Equilibrated
First
BCD Equilibrated
First
1 10 100 1000
Shear Rate (1/s)

0.05
Time Dependence of Viscosity at Constant Shear Rate
2% L-100 with 10/s Shear
0.04
Viscosity ( Pa*s)
0.03
0.02
2% L-100
with 1% BCD
with 1 % X-45
with 1% BCD and 1% X-45
0.01
0
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
Time (Minutes)

Summary
►HEAT L100
thickener exhibits shear-
thickening in the presence of the highly
hydrophobic X-45
surfactant
►Shear-thickening is observed within a
narrow range of shear rates
►Effect of β-cyclodextrin indicate shear-
thickening is caused by specific
hydrophobes that are not disrupted by
cyclodextrin

Acknowledgement
►Dr. Alan Steinmetz (Southern Clay)
►Dow Chemical
►Cal Poly Bill Moore Fellowship Fund
►Cal Poly Students
• Laura Johnson
• Sean Manion
• Gary Deng
• Adam Paiz