Polyacrylamide and its derivatives for oil recovery

Table 1 
List of surfactants and their performance used in the water-free S/O suspension 
polymerization system. 
Surfactant 
Comments 
Result 
Stable/Unstable 
Oleic Acid 
HLB = 1 
S 
SorbitanTrioleate
(Span 85) 
HLB = 1.8 
S 
SorbitanTristearate 
 (Span 65) 
HLB = 2.1 
S 
SorbitanMonostearate 
(Span 80) 
HLB = 4.7 
S 
Tergitol 15-S-3 
C12-C14 Secondary 
alcholethoxylate with 3 moles of 
ethylene oxide (EO); 
HLB = 8.3 
U 
Igepal CO-520 
HLB = 10 
U 
Igepal CO-530 
HLB = 10.8 
U 
Neodol 1-3 
HLB = 8.7 
U 
Neodol 1-5 
HLB = 11.2 
U 
Neodol 1-7 
HLB = 12.7 
U 
Polysorbate 60
(Tween 60) 
HLB = 14.9 
U 
Polysorbate 80
(Tween 80)
HLB = 15 
U 
Ethomeen C/15 
HLB = 15 
U 
Ethomeen C/25 
Bis(2-hydroxyethyl) 
cocaalkylamides 
U 
Butoxyethanol 
- 
U 
Surfynol CT-141 
- 
U 
Calamide CW-100 
Modified with coconut 
diethanolamide 
U 
Calamide CWT 
Modified with coconut 
amidesoapsueramide 
U 
Calamide F 
Vegetable oil, diethanolamide 
U 
Ethomeen S/12 
Bis(2-hydroyethyl) 
soyaalkylamines 
U 
Calimulse PR 
Isopropylamine branched 
akylBenazene 
U 
S:stable; U: unstable 

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Fig. 2. 
Phase diagram: stable suspension of surfactant and monomer.
 
Surfactant Span-85 was selected to study the effect of the surfactant’s amount on 
stabilizing the S/O suspension system to minimize the consumption of the surfactant and 
maximize the addition of monomer. The relationship between the feed of acrylamide and 
the amount of surfactant was displayed in Figure 2. In a low monomer feed, only a little 
bit surfactant is required to stabilize the suspension. The minimum required amount of 
surfactant is in a direct proportion to the feed of monomer. When the feed of monomer is 
more than 12 wt. -%, it is hard to stabilize the S/O suspension even consuming over 5 
wt.-% surfactant. A heavy heat release had been observed during the polymerization, 
especially with high monomer feeding. In normal W/O system, monomer was dissolved 
in water to form aqueous phase generally with ratio less than 60 wt.-%.[35-37] In our S/O 
system, polar in non-polar suspension system, pure liquid monomer formed the polar 

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phase dispersed in non-polar phase. The monomer ratio reached to 100 wt.-%, without 
water content. 
3.1.3.
 
 Copolymerization of AM and octadecylacrylamide 
Different from the normal suspension/micellar polymerization, in which the 
surfactant only helps to emulsify the system and will be discarded after polymerization, 
the sufmer can work not only as emulsifier but also can be polymerized into polymer 
chain. N-alkylacrylamides are common vinyl hydrophobic monomers to be introduced 
into polyacrylamide to make HMPAM by micellar polymerization. Generally, extra 
surfactants are required to solubilize n-alkylacrylamides.[3, 29, 38, 39] In our system, n-
alkylacrylamide per se worked as surfactant to form stable the system, see Figure 3.