| Name | Polyurethane prepolymer |
| Synonyms | Polyurethane prepolymer |
| CAS | 103837-45-2 |
| EINECS | 692-816-4 |
| Molecular Formula | (C15H10N2O2.C3H8O2.C3H6O.C2H4O)x |
| Physical and Chemical Properties | EPA Chemical Information 1,2-Propanediol, polymer with 1,1 '-methylenebis[isocyanatobenzene], methyloxirane and oxirane (103837-45-2) |
| Use | Applications intermediates for the production of various types of polyurethane elastomer products |
overview
Polyurethane (PU) is a kind of multi-block copolymer with alternating soft and hard segments with repeated urethane structure on the molecular chain. The strong polarity of urethane groups and the hydrogen bonding between polyurethane molecules give polyurethane materials good toughness, excellent elasticity, wear resistance, solvent resistance, corrosion resistance and many other advantages. Polyurethane prepolymer (PPU) refers to a reactive intermediate containing urethane groups in the skeleton obtained by the reaction of polyisocyanate and polyol. The chain growth reaction of the prepolymer and the low molecular weight compound containing active hydrogen can produce linear or cross-linked polyurethane. The polyol and isocyanate provide the soft and hard segments of the prepolymer, respectively.
application
Polyurethane hydrogel is widely used in biomedical and industrial fields due to its advantages of both hydrogel and polyurethane, high mechanical strength and wide range of performance control. Among them, one-component polyurethane hydrogel with high water volume can be used as an excellent polymer sand fixation material due to its advantages of low cost, convenient construction, and ecological environmental protection. It is suitable for desertification control, slope ecological protection, and prevention. Soil erosion and other fields. The key to the preparation of polyurethane hydrogel lies in the synthesis of polyurethane prepolymer. The structure and characteristics of polyurethane prepolymer determine the performance of the formed polyurethane hydrogel.
classification
polyurethane prepolymer can be divided into: isocyanate-terminated prepolymer, hydroxyl-terminated prepolymer, and closed prepolymer. The end-isocyanate prepolymer is a prepolymer with isocyanate groups at both ends. During the preparation process, the isocyanate is excessive. Because the prepolymer is isocyanate groups at both ends, the reaction activity is high and it is not easy to store. The two ends of the end-hydroxyl prepolymer are hydroxyl groups. In the preparation process, the general polyol is excessive. Because the hydroxyl activity is significantly lower than the isocyanate group, the storage stability is better, and the storage time is longer than the end-isocyanate prepolymer. The closed prepolymer is to block the isocyanate group exposed at both ends of the end isocyanate group with an active hydride-containing blocking agent to reduce its reactivity, thereby improving the storage stability of the prepolymer, prolonging the storage time, and unblocking when it is used. Expose the isocyanate group.