Xu Bo, Zhu Shouao, Zhao Siheng, Wang Xiangdong
School of Chemistry and Materials Engineering, Beijing Technology and Business University, Beijing 100048, China.
Beijing Key Laboratory of Quality Evaluation Technology for Hygiene and Safety of Plastics, Beijing 100048, China.
Polymers (Basel). 2023 Mar 30;15(7):1713. doi: 10.3390/polym15071713.
A high-phosphorus-content polyphosphonate (PBDA), containing two phosphorus-based structures: phosphaphenanthrene (DOPO) and phenyl phosphonate groups, was synthesized and used in flame retardant polyethylene terephthalate (PET). Good self-extinguishing property (high UL 94 grade and LOI value), superior flame retardancy (lower heat/smoke release), and high quality retention (high carbon residue) were endowed to PET by PBDA. When 10 wt% PDBA was added, the peak heat release rate (pHRR), total heat release (THR), and total smoke rate (TSR) of PDBA/PET were found to be significantly reduced by 80%, 60.5%, and 21%, respectively, compared to the pure PET, and the LOI value jumped from 20.5% for pure PET to 28.7% with a UL-94 V-0 rating. The flame-retardant mode of action in PET was verified by thermogravimetric analysis-Fourier transform infrared (TGA-FTIR), pyrolysis gas chromatography/mass spectrometry (Py-GC/MS), real-time FTIR, and scanning electron microscopy (SEM). Phosphaphenanthrene and phosphonate moieties in PDBA decomposed in sequence during heating, continuously releasing and keeping high-content PO· and PO· radicals with a quenching effect and simultaneously promoting the formation of viscous crosslinked char layers causing a high barrier effect. PDBA mainly acted in the gas phase but the condensed-phase flame retardant function was also considerable.
合成了一种高磷含量的聚膦酸酯（PBDA），其含有两种磷基结构：磷菲（DOPO）和苯基膦酸酯基团，并将其用于阻燃聚对苯二甲酸乙二酯（PET）。PBDA赋予了PET良好的自熄性能（高UL 94等级和极限氧指数值）、优异的阻燃性（较低的热释放/烟雾释放）以及高残碳率（高质量保留）。当添加10 wt%的PDBA时，发现与纯PET相比，PDBA/PET的热释放速率峰值（pHRR）、总热释放量（THR）和总烟释放速率（TSR）分别显著降低了80%、60.5%和21%，并且极限氧指数值从纯PET的20.5%跃升至28.7%，具有UL-94 V-0等级。通过热重分析-傅里叶变换红外光谱（TGA-FTIR）、热解气相色谱/质谱联用仪（Py-GC/MS）、实时傅里叶变换红外光谱和扫描电子显微镜（SEM）验证了PET中的阻燃作用模式。加热过程中，PDBA中的磷菲和膦酸酯部分依次分解，持续释放并保持高含量具有猝灭作用的PO·和PO·自由基，同时促进形成具有高阻隔效应的粘性交联炭层。PDBA主要在气相中起作用，但凝聚相阻燃功能也相当可观。
