An Efficient Composite Modifier Prepared for Enhancing the Crystallization and Flame-Retardancy of Poly(m-xylylene adipamide)

Abstract

Poly(m-xylylene adipamide) (MXD6) has good gas barrier properties and high mechanical strength. However, in nature, this resin has a low rate of crystallization. In order to overcome this obstacle in its applications, this study prepares a new, efficient modifier for MXD6 by combining the synthesized DOPO derivative (DT) and P22. It is found that the use of the binary modifier exhibits obvious effects on the crystallization of MXD6. When 11.0 wt.% DT is added together with 0.1 wt.% P22 (DT/P22), the crystallization temperature of MXD6 shifts to a higher temperature of 19.7 °C, and the crystallinity degree of MXD6 is significantly increased by 60%. Meanwhile, this modifier exhibits obviously intumescent flame-retardancy on MXD6 by increasing the limited oxygen index (LOI) from 26.4% to 33.4%. The results of the cone calorimeter test (CCT) reveal that the peak heat release rate (PHRR), total heat release (THR) and average effective heat release (av-EHC) are obviously suppressed due to the use of this modifier. Moreover, the influences of this modifier on the crystal structures, mechanical and rheological properties of MXD6 are analyzed in detail. This study can provide an efficient modifier for MXD6.

Synthesis of High-Molecular-Weight Bifunctional Additives with both Flame Retardant Properties and Antistatic Properties via ATRP

“…Vahabi proposed a dimensionless measure to quantify the flame retardancy of thermoplastic polymer matrix composites by measuring the peak of the heat release rate (pHRR), total heat release (THR), and time to ignition (TTI) based on cone calorimetry, and defined it as the flame retardant index (FRI). The FRI was defined as the ratio T H R × true( pHRR TTI true) between the neat polymer and the corresponding thermoplastic composite containing only one flame retardant additive, and the FRI can be categorized into FRI < 1, 1 < FRI < 10, and 10 < FRI < 100, corresponding to the flame retardancy performance symbolized as “poor”, “good” and “excellent”, respectively. ,,− flame retardancy index false( FRI false) = [ T H R × true( pHRR TTI true) ] neat polymer [ T H R × true( pHRR TTI true) ] composite …”

“…The FRI was defined as the ratio between the neat polymer and the corresponding thermoplastic composite containing only one flame retardant additive, and the FRI can be categorized into FRI < 1, 1 < FRI < 10, and 10 < FRI < 100, corresponding to the flame retardancy performance symbolized as “poor”, “good” and “excellent”, respectively. 1 , 24 , 64 − 66 …”

“…When 11.0 wt % DT and 0.1 wt % P22 were added, the crystallinity of MXD6 increased by 60%, LOI increased by 26.52%, and the FRI was 1.65. 24 and increases the char yield at 750 °C. With the addition of 6 wt % DTP (P content: 0.5 wt %), the LOI value of the epoxy resin composite was 31.42% and obtained a V-0 rating in a UL-94 test.…”

“…Zhao et al synthesized an efficient modifier for MXD6 by combining a DOPO derivative (DT) and the nucleating agent Bruggolen P22. When 11.0 wt % DT and 0.1 wt % P22 were added, the crystallinity of MXD6 increased by 60%, LOI increased by 26.52%, and the FRI was 1.65 . Zhao et al synthesized a reactive flame retardant (DTP) containing triazole, phosphaphenanthrene, and hydroxy groups; although the addition of DTP weakens the stability of epoxy thermosets, it decreases the degradation rate and increases the char yield at 750 °C.…”

“…When 11.0 wt % DT and 0.1 wt % P22 were added, the crystallinity of MXD6 increased by 60%, LOI increased by 26.52%, and the FRI was 1.65. 24 Zhao et al synthesized a reactive flame retardant (DTP) containing triazole, phosphaphenanthrene, and hydroxy groups; although the addition of DTP weakens the stability of epoxy thermosets, it decreases the degradation rate and increases the char yield at 750 °C. With the addition of 6 wt % DTP (P content: 0.5 wt %), the LOI value of the epoxy resin composite was 31.42% and obtained a V-0 rating in a UL-94 test.…”