含增塑剂DBP的聚氯乙烯树脂热裂解行为研究

Investigation of the Pyrolysis Behavior of PVC Mixed with DBP by Pyrolysis-Gas Chromatography-Mass Spectrometry

采用裂解气相色谱-质谱联用技术对含有邻苯二甲酸二丁酯(DBP)的聚氯乙烯(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和800℃下对含有DBP的PVC进行热裂解,并通过毛细管气相色谱-质谱法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、菲等37种裂解产物.通过与单一组分PVC树脂裂解产物比对,在300℃时含DBP的PVC以释放DBP为主而不发生分解反应,这与单一组分PVC树脂裂解行为有明显不同.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600℃以上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、芴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,表明对含增塑剂的废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.

The pyrolysis behavior of PVC mixed with Dibutyl Phthalate （DBP） was investigated by pyrolysis-gas chromatography-mass spectrometry （Py-GC/MS） in the presence of helium. GC/MS was used for the qualitative and semi-quantitative analysis of the pyrolysis products of the compound at 300, 400, 500, 600, 700 and 800℃respectively. There are altogether 37 pyrolysis products were detected, including Hydrogen chloride, Benzene, Naphthalene, Biphenyl and Phenanthrene. There are wide differences between the behavior of PVC mixed with DBP and that of the pure PVC at 300℃. In comparation with thermal decomposition of pure PVC, the PVC mixed with DBP is not pyrolysised but released DBP. The results indicated that flavorous and refreshing substances, such as Hydrogen chloride, Benzene, were released from parent compound under 600℃. Moreover, with the raise of pyrolysis temperature, complicated pyrolysis products appeared, and the content of harmful substances, such as Naphthalene, Biphenyl and Phenanthrene, were also increased. According to the relative content and category of the pyrolysis products, Pyrolysis technology of PVC in different temperature ranges should be applied to lowering pyrolysis temperature and increasing pyrolysis efficiency.