Unentangled Star-Shape Poly(ε-caprolactone)s as Phthalate-Free PVC Plasticizers Designed for Non-Toxicity and Improved Migration Resistance

We develop a nontoxic unentangled star-shape poly(e-caprolactone) (UESPCL) plasticizer with excellent migration resistance for the production of phthalate-free flexible poly(vinyl chloride) (PVC) by means of the ring-opening polymerization of e-caprolactone, initiated from the multifunctional core, combined with end-capping, and vacuum purification processes. UESPCL is a transparent liquid at room temperature and exhibits unentangled Newtonian behavior because of its extremely short branched segments. UESPCL is biologically safe without producing an acute toxicity response. Torque analysis measurements reveals that UESPCL offers a faster fusion rate and a higher miscibility with PVC compared to a typical plasticizer, di(2-ethylhexyl) phthalate (DEHP). The solid-state 1H nuclear magnetic resonance (NMR) spectrum reveals that PVC and UESPCL are miscible with an average domain size of less than 8 nm. The flexibility and transparency of the PVC/UESPCL mixture, that is, phthalate-free flexible PVC, are compara...