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(-2-butene-1,4-diol phenylphosphonate) (PE) containing CC 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 CC 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.

中文翻译：

---

同时增强不饱和聚酯树脂阻燃性、韧性和紫外线屏蔽性能的简便策略：调整阻燃剂的不饱和度

研究了三种不同不饱和度的膦酸酯低聚物对不饱和聚酯树脂（UPR）阻燃性、力学性能和光学性能的影响。三种膦酸酯低聚物是含有CC的聚(2-丁烯-1,4-二醇苯基膦酸酯)(PY)、含有CC的聚(-2-丁烯-1,4-二醇苯基膦酸酯)(PE)和聚(1,4-丁二醇苯基膦酸酯）（PO），不含不饱和键。 UPRs的阻燃性和紫外线屏蔽效果与低聚物的不饱和度呈正相关。具体来说，仅添加20 wt% PY即可使UPR通过UL-94 V-0等级，并且需要22 wt% PE，而22% PO/UPR仍处于UL-94 NR等级。此外，含有CC的PE在提高UPR韧性方面表现出最高的效率。与纯UPR相比，22%PE/UPR的冲击强度和断裂伸长率分别显着提高460%和200%。同时，UPR的高透明度得益于低聚物与基体之间良好的相容性。这项工作为开发和利用具有潜在多功能应用的新型高性能和多功能UPR提供了基础。