Abstract: Polyglycolic acid （PGA） usually has a high degradation rate， which leads to poor storage stability and short shelf life. In this study， the effects of different packaging materials， atmospheres inside the packages， and storage temperatures on the properties of PGA pellets were systematically investigated. The packaging materials evaluated in this work included low density polyethylene （PE-LD） and PE-LD/polyamide internal packaging materials and aluminum/plastic composite external packaging material. Air， nitrogen， and vacuum were used as packaging atmospheres. The storage temperatures were set to be ?16， 5， and 25 ℃. The melt flow rates， molecular weights and molecular weight distributions， and thermal properties of PGA were assessed after different storage times， and the effect of packaging conditions on the degradation of PGA were analyzed. The results indicated that there was an increase in the melt flow rates of PGA with a variation of storage temperature along with a correspondingly decrease in its molecular weight. Both the moistures of the packaging atmospheres and the moisture barrier properties of the packaging materials influenced the degradation and properties of PGA.

Key words: biodegradable polymer, polyglycolic acid, degradation, packaging material, packaging condition