In order to analyze the influence of density on photo-oxidation degradation properties of polyethylene (PE)

the materials parameters (mechanical properties

thermal stability

melting characteristic

chemical structure and surface morphology) of different density polyethylene including high

low

linear low and medium density polyethylene (HDPE

LDPE

LLDPE and MDPE) were studied by mechanical experiments

gel permeation chromatography (GPC)

thermogravimetry analysis (TGA)

differential scanning calorimetry (DSC)

attenuated total reflection infrared spectroscopy (ATR-FTIR) and scanning electron microscope (SEM). The results show that LDPE resulted in the decreased faster in the bending property

thermogravimetry analysis characteristic temperature and oxidation induction temperature mainly concentrated in the early part of aging. After 24 days of aging

the impact strength of HDPE and LDPE decreased. After 64 days of aging

the molecular weight of different density polyethylene decreased and the variations of weight average molecular weight of LDPE decreased more intensely. The degree of unsaturation of LDPE and LLDPE increased significantly and there were no obvious differences in the variations of chain branching of the different density polyethylene. The variations of chain breaking

oxidation

carbonyl index

hydroxyl index and surface morphology of LDPE were more significantly and severe. The branch breaking the regularity leaded that LDPE was prone to aging.