Phthalate plasticizers covalently linked to PVC via copper-free or copper catalyzed azide-alkyne cycloadditions

- (2-Ethylhexyl) phthalate esters are synthesized with ester or ether alkyne linkages.
- These derivatized alkyne phthalates react with a simple secondary azide model.
- Phthalates are attached to azidized PVC by thermal or Cu catalyzed cycloaddition.
- The rotationally free ether is a better internal plasticizer by Tg than the ester.

Plasticization of PVC was carried out by covalently linking phthalate derivatives via copper-free (thermal) or copper catalyzed azide-alkyne cycloadditions. Di(2-ethylhexyl) phthalate derivatives (DEHP-ether and DEHP-ester) were synthesized and appended to PVC at two different densities. The glass transition temperatures of the modified PVC decreased with increasing content of plasticizer. PVC-DEHP-ether gave lower glass transition temperatures than PVC-DEHP-ester, reflecting the enhanced flexibility of the ether versus ester linker.

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