polykarbonatpolyolit

Polycarbonate polyol, also known as polycarbonate diol, is a type of polyol used in polyurethane formulations. It consists of carbonate linkages in the polymer backbone and terminates with hydroxyl groups that react with isocyanates to form polyurethanes. The carbonate segments impart certain stability and performance characteristics, including resistance to hydrolysis and weathering.

Synthesis of polycarbonate polyols is typically achieved through transesterification or polycondensation routes. Common methods include transesterification of dimethyl carbonate with diols, often catalyzed by metal catalysts, and polycondensation of dihydroxy compounds with carbonate reagents such as diphenyl carbonate. These processes yield polycarbonate polymers with terminal hydroxyl groups suitable as reactive chain extenders in polyurethane systems. The choice of diol monomer, chain length, and processing conditions influence the final molecular weight and the properties of the resulting polyol.

Properties of polycarbonate polyols include good thermal and chemical stability, improved hydrolytic resistance, and favorable aging and weathering characteristics compared with many ester-based polyols. They can offer transparent or color-stable soft segments in polyurethanes and typically contribute to higher heat resistance, dimensional stability, and UV durability in end products. The exact properties depend on the carbonate content, molecular weight, and the diol components used.

Applications of polycarbonate polyols are mainly in polyurethane systems where enhanced hydrolytic stability and weather resistance are desired. They are used as soft segments in coatings, elastomeric materials, adhesives, and sealants, where durability and long-term performance under humid or outdoor conditions are sought.

Advantages and considerations include improved hydrolytic and UV stability and higher-temperature performance, balanced against higher material costs and formulation considerations compared with conventional polyols.