The thermal-oxidative degrading regulation of blends containing starch

polyethylene and additives which is made up of combination of Fe3+ -oleic acid at simulating composting emperature(70℃) was stdied．Sample films were made by conventional extrusion blowing．The additives and starch were introduced into the LDPE matrix in the form of masterbatchs in the amount of 10％(W／W) and 60％(W／W)

respectively．Samples were put into two different degrading environments

a certain number of filmswere taken out after an interval of ten days for testing．The mechanical properties

viscosity-average molecular weight and hydroperoxide concentration of the samples in the matrix were measured Moreover

the superficial conformation and crystal capability of the aged samples were also characterized by SEM and XRD．It was showed that the adopted additives could catalyze the degradation of PE efficiently．Besides

it was found that though the concentration of O2 affected very much the degrading behavior of PE

the catalyzing efficiency of some additives

such as F5

with high content of Fe3+ was almost unaffected under low O2 concentrations So it was more suitable for initiating degradation of PE at real composting environment The degrading mechanism of PE matrix was deduced according to the experimental results The kinetics of hydroperoxide formation corresponded to an exponential law as claimed in the 1iterature．The Curve of hydroperoxide accumulation well conformed to a quadratic law in the early stage

when the progress deviated from the induction period

passed the maximum rate

and reached the limit concentration [POOH]∞ at deceleration