Enhancing flexibility and durability of PVC with liquid epoxidized natural rubber: Innovative UV treatment to mitigate plasticizer migration

Abstract

This manuscript elucidates the preparation and utilization of liquid epoxidized natural rubber (LENR) with 50 mol% epoxidation level (LENR50) as a polymeric plasticizer for poly(vinyl chloride) (PVC), and further immobilization of the plasticizer in the plastic matrix through subsequent ultraviolet (UV)‐curing treatment. The plasticizing effect induced by LENR50 at 50 wt% loading was evident with a reduction of Tg from a high of 72.0 to 11.4°C. Positive enhancements were also documented in the mechanical properties of the LENR50‐plasticized PVC, specifically the big improvement in elongation at break and elastic modulus, from 106% to 430%, and from 646 to 7 MPa, respectively. The UV‐treated PVC/LENR film also exhibited superior resistance to migration compared with formulations with conventional plasticizers such as di‐2‐ethylhexyl phthalate (DEHP) and triethyl‐2‐acetyl citrate (ATEC). A similar outcome was recorded in the leaching resistance test, where LENR50 had the best resistance to leaching in four different solvents (water, soap solution, ethanol, and toluene). The LENR50‐plasticized PVC film recorded the lowest weight loss following 24 h immersion in both hydrophilic and lipophilic solvents. The findings from this study suggest that LENR50 could serve as an efficient bio‐based polymeric plasticizer for PVC.Highlights LENR as bio‐based polymeric plasticizer for PVC. Significant reduction in Tg and elastic modulus of PVC plasticized with LENR. UV treatment improved tensile strength and elongation at break of LENR/PVC film. UV‐treated PVC/LENR has superior plasticizer migration and leaching resistance.