The effect of plasma cleaning machine plasma treatment on the salt resistance of super absorbent resin:
Super absorbent resin is a new type of functional polymer material developed in the past ten years. It has the characteristics of absorbing and storing water. When it comes into contact with water, it can absorb and retain water that is hundreds to thousands of times its own mass. At present, super absorbent resins are mostly focused on the polymerization process of different monomers and the performance of absorbing deionized water. Under normal circumstances, the amount of salt absorbing solution of water absorbing resin is only 10% of deionized water or even lower, and its resistance to high-priced electrolytes is even worse. .

Plasma cleaning machine Plasma is a gas with basically the same amount and density of partially ionized positive and negative charges, including electrons, positive ions, negative ions, ground state atoms or molecules, excited atoms or molecules, free radicals, etc. 6 types Active particles.
These ions may introduce specific functional groups on the surface through surface reactions, causing surface erosion, forming a cross-linked structure layer or generating surface free radicals. At present, low-temperature plasma cleaners have been widely used in surface modification of polymer materials.
Plasma cleaning machine treatment improves the resin surface performance. With the prolongation of the ion treatment time, the generated free radicals increase, so that the active points generated on the resin surface increase, and a cross-linked layer is obtained on the resin surface, and the surface modification effect is gradually obvious. When the discharge time is longer, the salt water absorption rate will continue to decrease as the treatment time continues to extend.
When a certain period of time is reached, the generation and loss of free radicals on the resin surface reach a relative balance. At this time, the resin modification effect reaches a very good state. With the further extension of time, too many free radicals are generated on the surface of the polymer, and the interaction between the free radicals may cause the polymer chain to break. At the same time, the plasma generates a lot of heat in the glow discharge process in an air atmosphere, and the generated heat will destroy the three-dimensional network structure of the resin, causing its salt water absorption rate to drop rapidly.
It is generally believed that the modification reaction involving high-energy particles such as free radicals, ions, and electrons generated by the plasma of the plasma cleaner may introduce specific hydrophilic functional groups on the surface through surface reactions, and at the same time produce surface erosion, forming a cross-linked structure layer Or generate surface free radicals.
It can also generate reactive groups such as free radicals on the polymer chain. These reactive free radicals can initiate the grafting of unsaturated bond-containing monomers to the surface of the material, especially when there is oxygen in the plasma generating space, the oxygen directly or indirectly It generates peroxides with free radicals, and the peroxides are easily decomposed by heating to generate free radicals, thereby initiating polymerization, surface modification, and generating partial polar hydrophilic groups on the surface.
In a certain period of time, when the treatment intensity is too low, the concentration of active particles produced is low, and the number of free radicals generated on the polymer surface is small, so that the modification effect of plasma on the resin is not obvious; when the treatment intensity is too high, the plasma etching The role becomes dominant. Too many active particles can not only break the polymer chain, but also damage the cross-linked structure of the material by etching, which makes the salt water absorption rate of the resin drop sharply. Therefore, when the treatment strength is too low or too high, the salt water absorption rate of the resin is not ideal.
Plasma cleaning machine plasma treatment can significantly improve the salt resistance of water-absorbing resin. After plasma treatment, the functional group and structure of AMPS/AA/AM/PVA resin can be changed. At the same time, the heat of the resin after treatment can be seen through differential thermogravimetric analysis. The stability has been improved to a certain extent.