All-PVC Flexible Poly(vinyl Chloride): Nonmigratory Star-Poly(vinyl Chloride) as Plasticizers for PVC by RAFT Polymerization

Xanthate-mediated RAFT polymerization has been used to prepare 3-star and 4-star-poly(vinyl chloride) (star-PVC) with a number average molar mass (M-n) in the range of 1 to 7 kg mol(-1). The T-g of star-PVC reduces with molar mass and with the number of arms. The star-PVC have substantially lower glass-transition temperatures (T-g) than that of linear PVC of similar M-n, with the T-g of low-molar mass 4-star-PVC being -7.4 degrees C. The star-PVC are effective in lowering the T-g of blends with commercial PVC when added at 10-30 wt % PVC. When added even at 10 wt %, they are effective in improving the ductility of PVC with an elongation at break (EB) of similar to 350% (4-star-PVC) and similar to 300% (3-star-PVC) relative to commercial PVC, which is substantially higher than that for PVC conventionally plasticized with 30 wt % dioctyl phthalate under similar conditions (EB similar to 160%). Importantly, the star-PVC, despite their low molar mass, do not migrate from the PVC blends when tested under standard conditions. The performance of the star-PVC as non-migratory plasticizers for PVC demonstrates the potential for an all-PVC flexible PVC.

Automated summary

Xanthate-mediated RAFT polymerization has been used to prepare star-PVC with different molar masses, which can effectively reduce the glass-transition temperature of PVC and improve its ductility, showing the potential to be non-migratory plasticizers for PVC.