mi is the initial dry mass of the test material; mr is the dry mass of
the residual test material recovered by sieving. Sample of PLA based
film and PLA/Whey film were tested by Thermal Gravimetric
Analysis as raw materials and as fragments recovered after the
disintegration tests by a TA Instrument Q500 (TA Instruments, New
Castle, DE, USA), in nitrogen flow at 10 C/min rate, from 25 C to
600 C. The compost was monitored during the test and analysed at
the end of the test, the extract of the compost at 60 %RHwas diluted
at 30% by weight with water and used for germination test on 10
seeds of cress seed (lepidum sativum), in 10 cm diameter petri
dishes, stored in the dark for 48 h at 28 C, each sample was tested
in three replicates, the germination percentage was calculated
versus the 100% of control (distilled water).