Abstract: A method of preparing a multiarm polymer includes reacting a branched polyol with one or more functionalizing reagents to effect substitution of an ionizable functional group or a protected ionizable functional group, Y, to form a mixture comprising (i) unsubstituted branched polyol containing no Y groups; (ii) a monosubstituted polyol comprising one Y group, and (iii) a multisubstituted polyol (e.g., a disubstituted polyol comprising two Y groups); followed by purifying the mixture to separate the monosubstituted polyol from other species Thereafter, a water-soluble and non-peptidic polymer segment is attached to the monosubstituted branched polyol at the site of at least one of the hydroxyl groups. The invention also provides purified monosubstituted branched polyols and multiarm polymers prepared by the method and polyol precursors for use in the method.

Abstract: The present invention provides a low-modulus low-stress resin which has such heat resistance that cohesive force and reliability can be retained even at high temperatures and which is applicable as various functional materials. The resin is a thermoplastic resin having a modulus of elasticity at room temperature, 25° C., of 1 GPa or lower and a modulus of elasticity at 250° C. of 1 MPa or higher, or a precursor resin thereof.