裂解气相色谱-质谱法研究聚氯乙烯树脂的热降解

采用裂解气相色谱-质谱联用技术对聚氯乙烯(PVC)的裂解行为进行了研究.在氦气氛围中,分别在300、400、500、600、700、800和900 ℃下对PVC进行热裂解,并通过毛细管气相色谱-质谱对裂解产物进行了定性和半定量分析,共鉴定出氯化氢、萘、联苯、菲、蒽等40种裂解产物.结果发现,PVC在600 ℃以下裂解产物主要以氯化氢和苯等易挥发的物质为主,而在600 ℃以上时多环芳烃开始大量产生,并且随着裂解温度的升高,裂解产物越来越复杂,有害物质如萘、联苯、菲等的含量也逐渐增加.根据裂解产物的种类及相对含量变化规律,表明对废PVC塑料的裂解回收过程适合采用分段裂解工艺,从而降低热裂解温度和提高热裂解效率.

Study on thermal decomposition of PVC by pyrolysis GC/MS

The pyrolysis behavior of PVC was investigated by py-rolysis-gas chromatography-mass spectrometiy (GC-MS) in the presence of helium. GC-MS was used for the qualitative and semi-quantitative analysis of the pyrolysis products of PVC at 300, 400,500,600,700,800 and 900 ℃ , respectively. Altogether 40 pyrolysis products were detected, including hydrogen chloride, benzene, naphthalene, biphenyl, and phenanthrene. The results indicated that volatile substances, such as hydrogen chloride and benzene, were released from parent compound under 600 ℃. Moreover, with an increasing pyrolysis temperature, complicated pyrolysis products appeared, and the content of harmful sub-stances, such as naphthalene, biphenyl and phenanthrene, were also increased. According to the relative content and category of the pyrolysis products, the technology for pyrolysis of PVC in dif-ferent temperature ranges should be applied to lower the pyrolysis temperature and increase the pyrolysis efficiency.