Detailed explanation
- Sulfonate groups resist cationic shielding effectHighly anionic sulfonate side chains on SMAS hardly get screened by massive Ca²⁺、Mg²⁺、Na⁺ in high-salinity water. Polymer molecular chains stay fully stretched to maintain complete crosslinking network, while conventional HPAM shrinks severely under high ion concentration to destroy gel skeleton.
- Stable coordination crosslinking with Cr³⁺Sulfonate and carboxyl groups jointly coordinate with trivalent chromium to form multi-site crosslink bonds. The composite crosslink structure is insensitive to ambient inorganic salt intrusion and avoids bond dissociation caused by salt ion competition.
- Hydration protection from sulfonic acid groupsStrong hydrophilic sulfonate groups form dense hydration shell around the three-dimensional gel network, blocking inorganic ions from permeating into gel interior and preventing dehydration shrinkage or syneresis under high mineralization.
- Steric hindrance improves network toughnessMethyl branched structure of SMAS introduces steric hindrance into crosslinked network, enhancing the whole gel’s structural rigidity and anti-compression capacity against osmotic pressure from high-concentration brine.
- Good compatibility with organic crosslinkersSMAS’s multifunctional groups evenly react with organic crosslinking agents to build uniform crosslinking nodes, avoiding local loose network induced by high salinity, so gel strength stays steady for long-term reservoir environment.
Concise academic version
Thanks to sulfonate’s anti-ion-shielding, multi-site crosslinking with Cr³⁺ and hydration protection, Sodium Methallyl Sulfonate (SMAS) crosslinked gels maintain intact network and stable mechanical strength in high-salinity oilfield water.
