Performance Characterization of a Novel Flame Retardant Material Poly(lactic acid-<i>co</i>-melamine)

Abstract

Directly starting from D,L-lactic acid (LA) and melamine (MA), poly (lactic acid-co- melamine) [P(LA-co-MA)] as a kind of potential polymeric flame retardant is synthesized via melt polycondensation. The properties of P(LA-co-MA) s at different molar feed ratios are characterized by XRD, DSC and TGA. Most decomposition temperatures of P(LA-co-MA) s are higher than these of homopolymer poly (D,L-lactic acid) (PDLLA). For the char yield, all copolymers have higher char yield than PDLLA. Furthermore, the more MA in the feed content, the higher char yield.

Design, synthesis, and characterization of a potential flame retardant poly(lactic acid‐co‐pyrimidine‐2,4,5,6‐tetramine) via direct melt polycondensation

“…At the same time, compared with P(LA‐ co ‐MA) synthesized from the cyclic monomer with the same nitrogen atom number and the similar structure, the thermal stability of P(LA‐ co ‐PTA)s is basically higher, and the charring ability is obviously improved. Even at the same thermal decomposition temperatures, the char yield of P(LA‐ co ‐PTA)s is several times bigger than that of P(LA‐ co ‐MA) . However, compared with P(LA‐ co ‐DAB) containing the similar fused heterocycle, the thermal stability of P(LA‐ co ‐PTA) is slightly lower, but P(LA‐ co ‐PTA) has the higher charring ability, even its char yield at 800°C is three times of the P(LA‐ co ‐DAB)'s char yield at the 600°C .…”

“…Comparing MA with DAB, MA obviously has higher nitrogen content than DAB, but for the resulted copolymer, P(LA‐ co ‐DAB) has better charring ability and thermal stability than P(LA‐ co ‐MA), which indicates that the benzimidazole unit should be important for the compatible polymeric flame retardant. If so, can the combination of this special structure with higher nitrogen content achieve a synergistic effect?…”

“…Due to the relatively short synthetic process without reaction solvent, the simple and efficient direct melt polycondensation of lactic acid (LA) is being received increasing attention in the synthesis of PLA materials . In our previous work, respectively using 3,3′‐diaminobenzidine (DAB) and melamine (MA) as monomer for the direct melt copolycondensation with LA, we have synthesized P(LA‐ co ‐DAB) and P(LA‐ co ‐MA) . Due to the introduction of nitrogen series flame retardants, such as MA and benzimidazole which is formed in situ by the reaction of LA with DAB during the direct melt polymerization, both P(LA‐ co ‐DAB) and P(LA‐ co ‐MA) significantly have better charring ability and thermal stability than the homopolymer poly( d , l ‐lactic acid) (PDLLA) …”