Novel phosphinate‐containing zinc polyacrylate and its utilization as flame retardant for polyamides.

A new organophosphorus, zinc‐containing polyacrylate is synthesized that has potential use as flame retardant for polyamides. To achieve this goal, the Phospha‐Michael addition is utilized to selectively add 9,10‐dihydro‐9‐oxa‐10‐phospha‐phenanthrene‐10‐oxide (DOPO) to one acrylate group of zinc acrylate followed up by radical polymerization of the remaining acrylate group in a one‐pot approach. To verify the effectiveness of the synthesis method, it is compared to a second two‐step approach via diethyl zinc. In order to investigate the influence of molecular weight as well as phosphorus content on the flame retardant properties, the small‐molecule complex zinc bis(3‐(6‐oxidodibenzo[c,e][1,2]oxaphosphinin‐6‐yl)propionate) and the nonphosphorus thermoset poly(zinc diacrylate) are synthesized as well. All three substances are investigated as flame retardants for pure and glass‐fiber (GF) reinforced polyamide 6 (PA 6) and 66 (PA 66) in different compounds with and without melamine polyphosphate (MPP). Most of the samples show excessive dripping in the vertical burning test UL‐94 V. However, V‐1 classification is achieved in GF‐reinforced PA 66 with the DOPO‐ and zinc‐containing polyacrylate in combination with MPP. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47586. [ABSTRACT FROM AUTHOR]