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Investigating Effects of Using Mixtures of Two External Electron Donors on Microstructure and Properties of Polypropylene/Poly(ethylene‐ co ‐propylene) in‐Reactor Blends Based on Ziegler–Natta Catalyst
Author(s) -
Moballegh Leila,
Hakim Shokoufeh,
Morshedian Jalil,
Nekoomanesh Mehdi
Publication year - 2015
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.201500002
Subject(s) - polypropylene , polyethylene , materials science , copolymer , polymer chemistry , polymer blend , ethylene , microstructure , ziegler–natta catalyst , glass transition , chemical engineering , catalysis , fourier transform infrared spectroscopy , dynamic mechanical analysis , ethylene propylene rubber , chemistry , polymer , composite material , organic chemistry , engineering
Novel results on using mixtures of two external electron donors “phenyltriethoxysilane (donor A)” and “cyclohexylmethyldimethoxysilane (donor C)” in the synthesis of polypropylene/poly (ethylene‐ co ‐propylene) in‐reactor blends were presented. Thermal gradient elution fractionation (TGEF) was carried out to separate crystallizable copolymer fractions from the blends. FTIR, DSC, DMTA, and SEM were used to analyze the microstructure of the blends and separated fractions. Although using donor A as pure decreased the catalyst activity and molecular weight, using “donor A” in combination with donor C had a synergistic effect on the molecular weight of polypropylene homopolymers and the blends. The glass transition temperature ( T g) of the blend rubbery phase was the lowest in the case of the blend based on pure donor A because of formation of higher sequences of polyethylene and the T g increased with increasing donor C concentration. PP–PE copolymer concentration and impact strength were found to be higher in the case of the blend based on donor ratio of A/C: 75/25 than other blends.