The effect of calcium chloride and sodium alginate, sodium alginate plus calcium chloride.

　　In the production of sodium alginate, the tensile strength and water absorption of sodium alginate first increase and then decrease with the increase of calcium chloride concentration. The following sodium alginate manufacturers will introduce the three major effects of calcium chloride concentration on the production of sodium alginate, the role of calcium chloride and sodium alginate, and the specific reactions of sodium alginate plus calcium chloride.

　　Sodium alginate condenses when it meets calcium chloride, and calcium chloride is added dropwise to form sodium alginate colloidal particles, and then calcium chloride slowly infiltrates to form solid sodium alginate particles, which in turn form hollow sodium alginate particles.

　　1. When the concentration of calcium chloride is lower than 2.0%, the cross-linking degree between calcium ion and sodium alginate is low due to the slow exchange speed between calcium ion and Ca2+, the coagulation ability is too weak and the skin layer is very thin, so the cross-linking degree of the gel gradually increases with the increase of calcium chloride concentration, so the stretching degree of the gel gradually increases. At the same time, the increase of crosslinking degree leads to the compactness of the gel structure and its water absorption increases gradually.

　　2. When calcium chloride reaches 2.0%, the tensile strength and water absorption of calcium alginate gel are the largest.

　　3. When the concentration of calcium chloride is higher than 2.0%, because the concentration of calcium chloride is too high, a dense cross-linked structure is quickly formed on the surface of the gel, which hinders the diffusion of Ca2+ into the gel, so that the gel cannot form a complete gel structure inside, which directly affects the tensile strength of the gel. For the same water absorption rate, because the network structure on the surface of the gel is too dense, the water holding capacity of the incomplete calcium alginate inside the gel is low, so the water absorption rate of the gel decreases.

　　How much can sodium alginate and calcium chloride be mixed into a harder gel?

　　50g of sodium alginate was dissolved in 850mL of water to prepare a viscous liquid. The viscous liquid was spread on a plastic film with a thickness of 2mm and soaked in 500mL of 10% calcium chloride solution for 10min to obtain an alginate gel.

　　The gel was cut into 2mm wide strips, soaked in 100g/L calcium chloride aqueous solution for 5min, then washed with running water for 10min, and the remaining calcium chloride was washed away to obtain 900g noodle-like alginic acid gel.