To sum up, there are several methods to improve the tackifying effect, temperature resistance and salt resistance of water-soluble polymers:

1. The monomer containing ionic groups is introduced to charge the polymer chain, so as to expand the molecular chain, increase the hydrodynamic volume and increase the viscosity.

2. Introduce huge side groups to increase the molecular weight of the polymer or enhance the rigidity of its molecular chain to increase its bulk viscosity.

3. Introduce hydrophobic groups to make them associate to change their aggregation structure and fluid rheological behavior.

The principle of molecular recombination between polymers is used to improve viscosity, temperature resistance and salt resistance. Specific measures include:

A improve the thermal stability of polymer molecular main chain. Improving the thermal stability of polymer molecular main chain is an effective way to improve the temperature resistance of polymer. As a polymer for water loss reduction, the smaller the decrease of the apparent viscosity of its aqueous solution with the extension of aging time, the better the thermal stability. The higher the molecular weight of the polymer, the more obvious the viscosity reduction. Oxygen is the main factor causing the decrease of polymer molecular weight, so deoxidation can reduce the decrease of polymer aqueous solution viscosity. From the perspective of molecular design, the selection of carbon chain polymer and the introduction of ring structure that can increase the rigidity of molecular chain can significantly improve the thermal stability of polymer. Such polymer aqueous solution can maintain high viscosity at high temperature, even if the aging process is accompanied by molecular chain fracture. Due to the steric effect of rigid side groups, the molecular motion resistance is large, and the apparent viscosity of polymer solution decreases slightly. Monomers that can provide large side groups or rigid side groups include styrene sulfonic acid, n-alkyl maleimide, acrylamide long-chain alkyl sulfonic acid, etc.

b. Introduction of salt tolerant groups

The salt tolerance of polymers can be significantly improved by introducing salt insensitive sulfonic groups into the molecules. Because of the special structure of 2-acrylamide-2-methylpropanesulfonic acid (AMPS) and its molecule contains - s which is insensitive to salt; Therefore, the copolymerization of amps and acrylamide (AMPS / AM) has good temperature resistance and salt resistance. The acrylic acid synthesized by Liang Bing et al

The results of amine (AM) / NN dimethylacrylamide (DMAM) / 2-acrylamide-2-methylpropanesulfonic acid (AMPS) copolymer show that the metal cations have a great influence on the viscosity of the copolymer aqueous solution, and the anion introduced by the comonomer amps is the reason for the salt sensitivity of the copolymer. Under the combined influence of AMPS and DMAM, the copolymer obtained good temperature and anti-aging properties.