prepolymer

https://doi.org/10.1351/goldbook.PT07163
Polymer or @O04283@ the molecules of which are capable of entering, through reactive groups, into further @P04740@ and thereby contributing more than one structural unit to at least one type of chain of the final polymer.
Source:
PAC, 2004, 76, 889. (Definitions of terms relating to reactions of polymers and to functional polymeric materials (IUPAC Recommendations 2003)) on page 897 [Terms] [Paper]