Study On Toughening And Properties Of Polyglycolic Acid

Polyglycolic acid(PGA)is the simplest linear aliphatic polyester with excellent biodegradability and biocompatibility.At the same time,it has excellent gas barrier performance.It has become a medical degradable material and packaging material with great market prospect at present.However,due to the inherent brittleness and high crystallinity of PGA,its application in many other fields is limited.At present,the research on toughening of PGA has not been reported,and there is a lot of basic research work needing to be explored.In this paper,PGA provided by Jinzhu Alloy Company will be used as raw material.It is toughened by adding three different toughening materials: polyoxyethylene(PEO),ethylene butyl acrylate glycidyl methacrylate(PTW)and polycaprolactone(PCL).The thermodynamic properties,mechanical properties and microstructure of the blends were studied.Firstly,we select a common additive PEO to toughen PGA.The relationship between time and torque of the blend material shows that PEO has a good lubrication effect on PGA.Differential scanning calorimeter(DSC)was used to analyze the change of thermodynamic parameters of PGA/PEO blends with different contents.It was found that the addition of PEO effectively reduced the crystallinity of the blend materials.Tensile and impact tests show that the PGA/PEO blend with 15wt% PEO has the best toughening effect.The elongation at break is 54.14% and the elongation at break is 1375.2% higher than that of pure PGA.Field emission scanning electron microscope(SEM)found that when the content of PEO reached 20 wt%,the phase separation appeared.Secondly,a kind of elastomer PTW was selected to toughen PGA.Through the analysis of infrared spectra,it was verified that the interfacial chemical reaction did take place in the process of PTW toughening PGA,and the epoxy group in PTW reacted with hydroxyl-terminated and carboxyl-terminated groups in PGA.Through DSC,it can be found that the interfacial chemical reaction between PGA and PTW can reduce the crystallinity of PGA and make PGA crystallize more easily.The tensile and impact tests showed that the PGA/PTW blends with 20wt% PTW had the best toughening effect,the elongation at break was 37.34%,and the elongation at break was 903.8% higher than that of pure PGA.The whole process of PGA toughening can be analyzed from the microscopic point of view by SEM,and it is found that there are two toughening mechanisms in the process of PTW toughening PGA.Finally,taking into account the preservation of the biodegradability of PGA as much as possible,we selected a biodegradable polymer material PCL to toughen PGA.The tensile and impact tests showed that the PGA/PCL blends with 5wt% PCL had the best toughening effect,the elongation at break was 11.5%,and the elongation at break was 11.3% higher than that of pure PGA.The analysis of SEM showed that there were great problems in the compatibility of PGA and PCL,which was the main reason for the poor toughening effect of PGA.