聚对苯二甲酸丁二酯纤维热裂解分析

采用裂解气相色谱-质谱法研究了400～700℃聚对苯二甲酸丁二酯(PBT)纤维热裂解作用,并对其裂解机理进行了分析。结果表明:400℃时PBT裂解,仅检测到9种主要裂解产物。随裂解温度上升,裂解产物增加。在600℃时,检测到28种裂解产物,较高相对含量的主要裂解产物为苯甲酸、1,4-苯二甲酸-3-丁烯酯、1,4-苯二甲酸-二-3-丁烯酯、苯甲酸丁烯酯、苯、四氢呋喃等6种裂解碎片。1,4-苯二甲酸-3-丁烯酯、1,4-苯二甲酸-二-3-丁烯酯、苯甲酸丁烯酯、二苯甲酸-1,4-丁酯、对甲基苯甲酸丁烯酯、3-丁烯基苯等裂解产物是PBT特征性产物。1,4-苯二甲酸-3-丁烯酯、1,4-苯二甲酸-二-3-丁烯酯、苯甲酸丁烯酯是鉴别PBT纤维的主要碎片峰。PBT裂解过程中,发生链剪切作用,由聚合物链断裂成二聚体。

Analysis of pyrolysis of poly (butylene terephthalate) fiber

The pyrolysis of poly(butylene terephthalate)(PBT)fiber was studied at 400-700℃by pyrolysis gas chromatogra- phy-mass spectroscopy.The pyrolysis mechanism was also analyzed.The results showed that only nine dominating kinds of pyro- lysates were detected when PBT was pyrolyzed at 400℃.The pyrolysates were increased with the pyrolysis time.Among 28 kinds of pyrnlysates detected at 600℃,those with relatively high contents included benzoic acid,3-butenyl-1,4-terphthalate,bis-3- butenyl-1,4-terephthalate,butenyl benzoate,benzene and tetrahydrofuran fragments.The characteristic pyrolysates of PBT in- cluded 3-butenyl-1,4-terphthalate,bis-3-butenyl-1,4-terephthalate,butenyl benzoate,1,4-butanediol dibenzoate,p-methyl butenyl benzoate and 3-butenyl-benzene.The major fragment peaks for discriminating PBT fiber from other fibers covered 3-bute- nyi-1,4-terphthalate,bis-3-butenyl-1,4-terephthalate and butenyl benzoate.The polymer chain was broken and formed into dim- mer units when the chain scission occurred during the pyrolysis of PBT.