在过去的六十年中,由于其成本效益和适应性特征,塑料生产经历了显着增长,导致广泛使用添加剂来提高其性能和寿命。由于对塑料的高需求,塑料废物产量增加,通过浸出添加剂污染环境和生物,在其他物质中。热解在回收技术中脱颖而出,因为它可以处理混合的聚合物废物原料。然而,了解添加剂的热解分布是评估塑料废物热解过程的基础。这项研究调查了两种常用抗氧化剂的热解产物分布,即,Irgafos168和硬脂酸锌(ZnSt),使用配备有四重质谱仪(GC-MS)的一维气相色谱和耦合到火焰离子化检测器和飞行时间质谱仪(GC×GC-FID/TOF-MS)的二维气相色谱。虽然GC分离技术提供的产品分布信息有限,GC×GC提供了增强的分辨率和分解产物的识别。在550°C的Irgafos168热解中,GC鉴定出18种产品,GC×GC鉴定了198种产品,代表增加了大约11倍。同样,对于ZnSt,GC鉴定出67种产品,GC×GC鉴定出434种产品,代表增加了6倍。GC×GC确定了Irgafos168的15种不同化学类别和ZnSt的16种化学类别的分解产物,与GC鉴定的4种和11种化学类别相比,分别。苯酚及其衍生物是Irgafos168分解产物中的主要化学类别,产率为9.51wt。%.相比之下,烯烃产品是ZnSt的主要产品,产率为9.73wt。%.Irgafos168和ZnSt的主要分解产物是2-叔丁基甲基苯酚(C11H16O)和C6烯烃(C6H12),产率为3.88wt。%,和1.13wt。%,分别。利用GC×GC分离法提高了分解产物的识别能力,这最终可以导致更好地了解在热解过程中发生的抗氧化剂降解。GC×GC还提供了次要和共洗脱产物以及主要抗氧化剂降解产物的彻底表征。此外,还将Irgafos168和ZnSt的分解产物分布与主要抗氧化剂进行了比较,Irganox1010,Irganox1076和BHT,在第一部分研究。分析表明,在Irganox1010,Irganox1076和ZnSt中,烯属化学类别是主要的一类。而酮类是BHT分解的主要化学类别,酚类在Irgafos168中的产率最高。
Plastic production has experienced a significant increase in the last sixty years due to its cost-efficiency and adaptable characteristics, leading to the extensive use of additives to improve its performance and longevity. Due to the high demand for plastic, plastic waste production has increased, contaminating the environment and living beings by leaching additives, among other substances. Pyrolysis stands out among recycling techniques because it can handle mixed polymer waste feedstock. However, understanding the pyrolyzates distribution of additives is fundamental to assessing pyrolysis process of plastic waste. This study investigated the pyrolysis product distributions of two commonly used antioxidants, namely, Irgafos 168 and zinc stearate (ZnSt), using one-dimensional gas chromatography equipped with a quadruple mass spectrometer (GC-MS) and two-dimensional gas chromatography coupled to flame ionization detector and time-of-flight mass spectrometer (GC×
GC-FID/TOF-MS). While
GC separation technique provided limited information on product distribution,
GC×
GC offered enhanced resolution and identification of the decomposition products. In the pyrolysis of Irgafos 168 at 550 °C,
GC identified 18 products, while
GC×
GC identified 198 products, representing an increase of approximately 11-fold. Similarly, for ZnSt,
GC identified 67 products, while
GC×
GC identified 434 products, representing a 6-fold increase. GC×GC identified decomposition products from 15 different chemical classes for Irgafos 168 and 16 chemical classes for ZnSt, compared to 4 and 11 chemical classes identified by GC, respectively. Phenols and their derivatives were the major chemical class in the decomposition products of Irgafos 168 with a yield of 9.51 wt.%. In contrast, olefinic products were the dominant ones for ZnSt, with a yield of 9.73 wt.%. The major decomposition product of Irgafos 168 and ZnSt was 2‑tert‑butyl‑methylphenol (C11H16O) and C6 olefin (C6H12) with yields of 3.88 wt.%, and 1.13 wt.%, respectively. Utilizing the
GC×
GC separation method improved the ability to identify decomposition products, which can ultimately lead to a better understanding of antioxidant degradation that occurs during the pyrolysis process. GC×GC also provided thorough characterization of minor and co-eluted products along with major antioxidant degradation products. Additionally, the decomposition product distribution of Irgafos 168 and ZnSt was also compared with the primary antioxidants, Irganox 1010, Irganox 1076, and BHT, studied in part 1. The analysis indicated that the olefinic chemical class was the predominant one in Irganox 1010, Irganox 1076, and ZnSt, while ketones were the major chemical class in the decomposition of BHT and phenolics had the highest yield in Irgafos 168.