Processes of making thermoplastic compositions comprising melt-mixing one or more thermoplastic polymers with a hyperbranched polymer made by heating in the presence of a mild basic/nucleophilic esterification catalyst a monomer mixture comprising a hyperbranching monomer consisting of compounds having two COOH groups and one OH group, compounds having one COOH group and two OH groups, compounds having one COOH group and three OH groups, or compounds having three COOH groups and one OH group, wherein the mild basic/nucleophilic esterification catalyst is selected from tin, titanium, aluminum, antimony, manganese, zinc, and calcium derivatives. Upon molding the thermoplastic composition into a test specimen having a thickness of 2 millimeters and after aging the test specimen at 121° C., 2 atm and 100 percent relative humidity for 50 hours, the test specimen retains at least 50 percent of its initial tensile strength as measured according to ISO 527-2/5A.