The present invention is a rheology-modifiable polymeric composition or a free-radical crosslinkable polymeric composition, wherein the resulting rheologymodifying bond or crosslinking bond is a thermally-reversible bond. The resulting polymer is prepared from at least one polymer which upon forming free radicals preferentially degrades or carbon-carbon crosslinks. The present invention permits suppression of the preferential reaction while permitting the polymer to be coupled or crosslinked through a thermally-reversible bond. Suppressing the undesirable degradation or carbon-carbon crosslinking reaction and permitting the desirable reaction yield a rheology-modified polymer or a free-radical thermally-reversibly crosslinked polymer.