Premium
Radiation Induced Long Chain Branching in High‐Density Polyethylene through a Reactive Extrusion Process
Author(s) -
Sardashti Pouyan,
Tzoganakis Costas,
Polak Maria A.,
Penlidis Alexander
Publication year - 2014
Publication title -
macromolecular reaction engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.37
H-Index - 32
eISSN - 1862-8338
pISSN - 1862-832X
DOI - 10.1002/mren.201300134
Subject(s) - branching (polymer chemistry) , reactive extrusion , high density polyethylene , dispersity , photoinitiator , materials science , extrusion , rheology , polyethylene , viscoelasticity , polymer , plastics extrusion , composite material , polymer chemistry , shear thinning , viscosity , chemical engineering , monomer , engineering
A reactive extrusion process is developed for the modification of the rheological properties of a high density polyethylene (HDPE) by inducing long chain branching (LCB) using a photoinitiator and ultraviolet (UV) light. A central composite response surface design is selected to design the experimental runs at different photoinitiator concentrations, polymer flow rates, and extruder screw speeds. The selected processing factors at the specified levels produce negligible amounts of gel as indicated by extraction experiments. Linear viscoelastic properties at low frequencies indicate the presence of long chain branches. Both zero shear viscosity and relaxation time of the modified samples are enhanced with the branching. According to further molecular characterization, the molecular weight averages are slightly increased, however, the polydispersity index (PDI) of the modified samples remains the same.