Vilaplana Francisco, Ribes-Greus Amparo, Karlsson Sigbritt
Department of Fibre and Polymer Technology, School of Chemical Science and Engineering, KTH, Royal Institute of Technology, Teknikringen 56-58, SE-10044 Stockholm, Sweden.
Anal Chim Acta. 2007 Nov 26;604(1):18-28. doi: 10.1016/j.aca.2007.04.046. Epub 2007 Apr 27.
Various analytical techniques (thermal analysis, vibrational spectroscopy, and chromatographic analysis) were used in order to monitor the changes in polymeric properties of recycled high-impact polystyrene (HIPS) throughout mechanical recycling processes. Three key quality properties were defined and analysed; these were the degree of mixing (composition), the degree of degradation, and the presence of low molecular weight compounds. Polymeric contaminations of polyethylene (PE) and polypropylene (PP) were detected in some samples using differential scanning calorimetry (DSC). Vibrational spectroscopy showed the presence of oxidised parts of the polymeric chain and gave also an assessment of the microstructure of the polybutadiene phase in HIPS. The presence of low molecular weight compounds in the HIPS samples was demonstrated using microwave-assisted extraction followed by gas chromatography-mass spectrometry (GC-MS). Several volatile organic compounds (VOCs), residues from the polymerisation, additives, and contaminations were detected in the polymeric materials. Styrene was identified already in virgin HIPS; in addition, benzaldehyde, alpha-methylbenzenaldehyde, and acetophenone were detected in recycled HIPS. The presence of oxygenated derivates of styrene may be attributed to the oxidation of polystyrene (PS). Several styrene dimers were found in virgin and recycled HIPS; these are produced during polymerisation of styrene and retained in the polymeric matrix as polymerisation residues. The amount of these dimers was highest in virgin HIPS, which indicated that emission of these compounds may have occurred during the first life-time of the products. This paper demonstrates that a combination of different analytical strategies is necessary to obtain a detailed understanding of the quality of recycled HIPS.
为了监测再生高抗冲聚苯乙烯（HIPS）在整个机械回收过程中聚合物性能的变化，采用了各种分析技术（热分析、振动光谱和色谱分析）。定义并分析了三个关键质量特性；它们是混合程度（组成）、降解程度和低分子量化合物的存在情况。使用差示扫描量热法（DSC）在一些样品中检测到了聚乙烯（PE）和聚丙烯（PP）的聚合物污染。振动光谱显示了聚合物链氧化部分的存在，还对HIPS中聚丁二烯相的微观结构进行了评估。通过微波辅助萃取结合气相色谱-质谱联用（GC-MS）证明了HIPS样品中存在低分子量化合物。在聚合物材料中检测到了几种挥发性有机化合物（VOCs）、聚合反应的残留物、添加剂和污染物。在原始HIPS中已鉴定出苯乙烯；此外，在再生HIPS中检测到了苯甲醛、α-甲基苯甲醛和苯乙酮。苯乙烯的氧化衍生物的存在可能归因于聚苯乙烯（PS）的氧化。在原始和再生HIPS中发现了几种苯乙烯二聚体；这些是在苯乙烯聚合过程中产生的，并作为聚合残留物保留在聚合物基体中。这些二聚体的含量在原始HIPS中最高，这表明这些化合物可能在产品的首次使用期间就已释放。本文表明，需要结合不同的分析策略才能详细了解再生HIPS的质量。
