聚酯宏观形态对其醇解反应的影响

Effect of PET macroscopic morphology on its glycolysis

以纯涤纶军装(1#)、涤棉军装(2#)、废瓶片(3#)、熔融挤出料(4#)、有光切片(5#)5种不同宏观形态聚酯(PET)产品为原料,乙二醇(EG)为醇解剂,碳酸钠为(Na2CO3)为催化剂,进行PET的醇解反应;研究了醇解时间、醇解温度及PET/EG质量比(mPET/mEG)等对PET醇解的影响,并对醇解产物进行表征。结果表明:5种不同宏观形态PET醇解后的主要产物均为对苯二甲酸双羟乙酯(BHET);催化剂Na2CO3能明显提高醇解速度,BHET产率随醇解时间、醇解温度、EG用量的增加而增加;最佳醇解条件是醇解时间60 min,醇解温度190℃,Na2CO3∶PET质量比为0.003∶1,mPET∶mEG为1∶4,5种不同宏观形态PET的醇解速度从大至小依次为2#,3#,1#,4#,5#,醇解后的BHET产率从大到小依次为5#,4#,3#,1#,2#,其BHET的色度L值大小依次为5#,3#,2#,4#,1#。

The glyeolysis process of polyesters （PETs） with different macroscopic morphology, i.e. pure polyester military fabric （1^#）, polyester cotton military fabric （2^#）, bottle flake （3^#）, melt extrusion material （4^#）, bright chips （5^#）, was conducted using ethylene glycol （EG） as a degradation agent and sodium carbonate （Na2CO3 ） as a catalyst. The effects of glycolysis time and temperature and PET/EG mass ratio （ mpET/mEG ） on the glycolysis of PET were studied. The glycolysis products were characterized. The results showed that bishydroxyethyl terephthalate （BHET） was the principal glycolysis product of these five kinds of PETs with different macroscopic morphology; Na2 CO3 catalyst profoundly increased the glycolysis speed, and the BHET yield was increased with the increase of glycolysis time and temperature and EG amount; and for these five kinds of PETs with different macroscopic morphology, the glycolysis speed followed the order from high to low of 2^#, 3^#, 1^#, 4^#, 5^#, the BHET yield 5^#, 4^#, 3^#, 1 ^#, 2^#, and the L color value of BHET 5^#, 3^#, 2^#, 4^#, 1 ^# under the conditions optimized as followed glycolysis time 60 min and temperature 190 ℃ , Na2CO3/PET mass ratio of 0.003 ： 1 and ropET ：mEG of 1 ： 4.