An oligomer of the bis-uracil derivative as an organic thermal stabilizer with a super low migration ratio for PVC

An excellent migration resistant thermal stabilizer, an oligomer of bis-uracil derivative (P-UESU), was synthesized by the polymerization of UESU. The UESU was obtained by the reaction of 10-undecenyl aldehyde and 6-amino-1,3-dimethyluracil (DAU). The results of FTIR, DSC, and MS indicated that UESU and P-UESU were synthesized successfully, and P-UESU was an oligomer with more than four polymerization degrees. P-UESU could be used as the thermal stabilizer for PVC due to its high thermal stability. The super low migration ratio of P-UESU in PVC was proved by the migration resistant test, which is lower than 0.2%, better than OSU, USU, and commercial Ca/Zn thermal stabilizers. The reasons were ascribed to its big molecular volume and the physical entanglement with PVC molecular chains, which was confirmed by Flory–Huggins theory. Moreover, the static and dynamic thermal stability time of PVC with P-UESU/ESBO/TPP reached more than 160 min and 41 min, respectively. It was interesting that the excellent migration resistance of P-UESU was not affected by the addition of the auxiliary thermal stabilizers. The tensile strength and elastic modulus of PVC were also high, which were 26.93 MPa and 28.85 MPa. In conclusion, P-UESU had a good application prospect in practical application due to its excellent migration resistance and good thermal stability effect on PVC.