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Effect of photo‐initiators on melt degradation of polypropylene and starch‐filled polymer
Author(s) -
Bagheri Rouhallah,
Naimian Faranak
Publication year - 2002
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/pi.892
Subject(s) - melt flow index , polypropylene , starch , viscosity , ferric , polymer , intrinsic viscosity , polymer chemistry , degradation (telecommunications) , materials science , rheology , stearate , polymer degradation , chemistry , nuclear chemistry , chemical engineering , copolymer , composite material , organic chemistry , telecommunications , computer science , engineering
Six series of the processed polypropylene (pp) samples containing 0.25–1 wt% photo‐initiators (PIs, four aromatic carbonyl, two ferric compounds) and also a series of 6 wt% corn‐starch‐filled pp containing 0.5 wt% of each PI, were prepared using a mixer in a closed system at 180 °C for 5 min. The melt flow index (MFI) and apparent viscosity measurments of the processed pp–PI samples showed a large increase in MFI/or decrease in apparent viscosity at 0.25 wt% of the PIs. Further increase in the amounts of PIs led these properties to reach a constant value at 0.5 wt% of the PIs. The presence of corn starch in the samples corresponded to a much lower increase in the MFI or decrease in the apparent viscosity. Ferric stearate and Irgacure 184 amoung the PIs showed the highest and lowest melt degradation effects, respectively. Carbonyl measurments of all the film samples showed good correlations between chemical changes in the pp structure and variations in the flow properties during processing. UV absorption of the films also evidenced the presence of the aromatic carbonyl PIs in the pp matrix after melt processing. © 2002 Society of Chemical Industry