The difference and characteristics of polyether polyols and polyester polyols.
Difference
1.Raw materials and synthesis technology
Polyether polyols: Usually low molecular compounds containing active hydrogen (such as ethylene glycol, propylene glycol, etc.) are used as starting agents. Under the action of chemical agents, they are formed by ring-opening polymerization of epoxy compounds such as ethylene oxide (EO), propylene oxide (PO), tetrahydrofuran (THF), etc.For example, with glycerol as the initiator, polyether triols can be obtained by ring-opening polymerization of propylene oxide.
Polyester polyols: Generally prepared by polycondensation reaction of dicarboxylic acids (such as adipic acid, phthalic anhydride, etc.) and diols (such as ethylene glycol, 1,4-butanediol, etc.).For example, adipic acid and ethylene glycol undergo a polycondensation reaction under certain conditions to produce polyethylene adipate polyols.
2.Molecular structure
Polyether polyols: The molecular backbone is connected by an ether bond (-0-) and has more ether bond structures.Its molecular chain is relatively supple and its steric resistance is small.
Polyester polyols: The molecular backbone contains an ester group (-COO-), and the presence of an ester group makes the molecular chain have a certain polarity and rigidity.
3.Appearance and status
Polyether polyols: generally colorless or light yellow transparent viscous liquid, with relatively low viscosity and good fluidity.
Polyester polyols: Usually colorless to light yellow viscous liquid or waxy solid, their viscosity is generally higher than that of polyether polyols, especially polyester polyols with larger molecular weights may be in a solid state at room temperature.