Homo- or copolyoxymethylenes are described and contain the repeat structural unit of formula I -A-O—R1—O—CO—(R2—CO—)m—O—  (I), where A is a radical derived from a homo- or copolyoxymethylene, R1 is an alkylene radical having at least two carbon atoms, or a cycloalkylene radical, R2 is a direct carbon-carbon bond, or an alkylene, cycloalkylene, arylene, or aralkylene radical, and m is 0 or 1. These polymers may be prepared by reacting end-group-functionalized homo- or copolyoxymethylenes with selected chain-linking agents.The reaction products can be used to produce moldings.