A facile strategy to simultaneously enhance the flame retardancy, toughness and ultraviolet shielding performance of unsaturated polyester resin: Adjusting the unsaturated degree of flame retardant.

The impact of three phosphonate oligomers with different unsaturation degrees on the flame retardancy, mechanical properties and optical performance of unsaturated polyester resins (UPRs) were investigated. The three phosphonate oligomers were poly(2-butyne-1,4-diol phenylphosphonate) (PY) containing C C, poly(cis -2-butene-1,4-diol phenylphosphonate) (PE) containing C C and poly(1,4-butanediol phenylphosphonate) (PO) without unsaturated bonds. The flame retardancy and UV-shielding effect of UPRs were positively correlated with the unsaturation degree of oligomers. Specifically, only adding 20 wt% PY made UPR pass UL-94 V-0 rating and 22 wt% PE was needed, while 22%PO/UPR was still in UL-94 NR rating. Further, PE containing C C exhibited the highest efficiency in improving the toughness of UPR. The impact strength and elongation at break of 22%PE/UPR were significantly improved by 460 % and 200 % respectively, compared with pure UPR. Meanwhile, the high transparency of UPRs benefits from the good compatibility between oligomers and matrix. This work provides the basis for development and utilization of novel high-performance and multifunctional UPRs with potential versatile applications. [Display omitted] • Three multifunctional flame retardant/toughening oligomers were prepared. • The flame retardancy, toughness and UV-shielding effect of UPRs were greatly strengthened. • The unsaturated degree of oligomers exerted significant influence on all the properties of UPRs. [ABSTRACT FROM AUTHOR]