The Effect Of Additives Of The Thermal Stability Of Biodegradable Polyglycolide

This paper studies the effect of heating processing on the thermal stability of polyglycolic acid(PGA).By using TG thermal analysis technology analysis of PGA thermal decomposition process,the thermal degradation of PGA in 220,225,230 and 235℃ molten state according to the actual processing situation,analysis of the thermal degradation of PGA residue components to verify its thermal degradation mechanism by infrared spectroscopy,thermal decomposition kinetics of PGA,a effective evaluation of the thermal stability of PGA is established.Inorder to improve the thermal stability of modling processing of PGA,anti hydrolytic stabilizer,chain extender,antioxidant were added to modify PGA through the melt blending method,to study the 6 kinds of stabilizing additives on the thermal stability of PGA.The main contents are as follows:1.The thermal decomposition process of PGA was analyzed by TG-DTG thermogravimetric analysis.The results show that the thermal decomposition of PGA includes only one stage of thermal weightlessness.Whether nitrogen atmosphere or air atmosphere,when the heating rate is 20K/min,the initial thermal decomposition temperature of PGA is about 200℃,and the fastest thermal decomposition temperature is 371-381℃,the complete thermal decomposition temperature is about 400℃.The initial thermal decomposition temperature of PGA is about 200℃,and the fastest thermal decomposition temperature is 381℃,the complete thermal decomposition temperature is about 400℃,there is only one weightlessness process,and the thermal decomposition process is almost the same as that of 100%PGA,after 1%antihydrolysis stabilizer 1,2 and chain extenderl,2 and antioxidantl were added respectively.The initial thermal decomposition temperature of PGA is about 230℃,and the fastest thermal decomposition temperature is 410℃,the complete thermal decomposition temperature is about 440℃,after antioxidant2 were added respectively.The addition of antioxidant 2 can effectively improve the thermal stability of PGA,and the amount of 1%and 0.5%of the same effect.2.According to the actual production conditions of PGA,the thermal degradation of PGA at the melting state of 220,225,230 and 235℃,20min was studied.The results showed that after thermal degradation in nitrogen atmosphere,the PGA remaining 94.5%,95.8%,93.1%,respectively,after the thermal degradation in the air atmosphere r,the PGA remaining 95.7%,94.0%,92.4%respectively.After 1%anti hydrolysis stabilizer 1,2,chain extender 1,2 and antioxidantl were added into PGA respectively,thermal degradation of PGA is basically the same in 220,225,230 and 235℃ at molten state.After antioxidant 2 were added into PGA,thermal degradation of PGA effectively slowed down,and 0.5%of the amount of antioxidant 2 can reach the same effect as 1%.3.The thermal decomposition residue of PGA in molten state was studied by infrared spectroscopy,and its thermal degradation mechanism was analyzed.The results showed that the residues of PGA at 220,225,230,and 235℃ after 20min decomposition were mainly PGA.The residue of PGA with different kinds of additives at 220,225,230,and 235℃ after 20min decomposition was still dominated by PGA.4.According to the FWO method,Coats-Redfern method and Kissinger method,the thermal decomposition activation energy values of PGA were 130.7,123.1 and 131.7KJ/mol under the nitrogen atmosphere,the thermal decomposition activation energy values of PGA were 118.8,108.8,117.3KJ/mol under the air atmosphere thermal decomposition.After 1%anti hydrolysis stabilizer 1,2,chain extender 1,2 and antioxidant1 were added into PGA respectively,the thermal decompositionactivation energy values of PGA is basically the same with 100%PGA.After the addition of antioxidant 2,the thermal decompositionactivation energy values of PGA increased significantly,whether in nitrogen and air atmosphere.And the amount of 1%and 0.5%is basically the same.Thus,antioxidant 2 can effectively improve the thermal stability of PGA.Research shows the impact that the melt blending method of adding anti hydrolysis stabilizer 1,2,and chain extenderl,2,and antioxidant 1 into PGA respectively on the thermal stability of PGA is limited,and the addition of antioxidant 2 can effectively improve the thermal stability of PGA when processing,and the amount of 0.5%of the effect and the effect of 1%is basically the same.