Premium
Effect of hydroperoxide decomposer and slipping agent on recycling of polypropylene
Author(s) -
Agrawal Ashwini K.,
Singh Sanjeev K.,
Utreja Amit
Publication year - 2004
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.20357
Subject(s) - zinc stearate , polypropylene , materials science , stabilizer (aeronautics) , ultimate tensile strength , slipping , zinc , chemical engineering , extrusion , polymer , degradation (telecommunications) , bottle , composite material , polymer chemistry , chemistry , organic chemistry , metallurgy , raw material , mechanical engineering , telecommunications , computer science , engineering
Abstract Polypropylene (PP) recycling has always been challenging because the polymer is highly susceptible to thermooxidative degradation during extrusion. Recycled (degraded) PP is normally blended with virgin PP to achieve reasonable mechanical properties after reprocessing operations. However, impurities present in recycled PP tend to degrade even the virgin PP in this process. In this study, standard recycled PP was produced in a laboratory by repeated extrusion and pelletization operations of virgin PP. This material was blended with virgin PP in a ratio from 3 : 7 to 7 : 3. An attempt was made to stabilize the recycled blend by adding a peroxide decomposer (triphenylphosphite, TPP) and a slipping agent (zinc stearate) in contrast to radical scavengers normally used in reprocessing. It was found that by using 0.3–0.5 wt % of TPP and 2 wt % of zinc stearate, this degradation could be effectively attested. Compared to the tensile strength retention of 68% (based on strength of pure virgin PP) of a 60 : 40 (recycled : virgin) PP blend without any stabilizer, a value of 77% was obtained for the same blend with the above‐mentioned stabilizers. This stabilization effect was attributed to decomposition of unstable hydroperoxides to stable compounds in the recycled materials by TPP, and lower generation of new radicals in the presence of zinc stearate. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3247–3251, 2004