Nashrieh Shimi va Mohandesi Shimi Iran

Nashrieh Shimi va Mohandesi Shimi Iran

Investigation of Electron Beam Irradiation’s Effect on Physical and Rheological Properties of LLDPE/Poly(1-Hexene) Blends

Document Type : Research Article

Authors
Shima Shafiei 1
Gholamreza Nejabat 1, 2
Mostafa Ahmadi 3
Mohammadd Mahdi Mortazavi 4
Saeid Ahmadjo 4
1 Department of Polymer Engineering, Shiraz Branch, Islamic Azad University, Shiraz, I.R. IRAN
2 Department of Applied Researches, Chemical, Petroleum & Polymer Engineering Research Center, Shiraz Branch, Islamic Azad University, Shiraz, I.R. IRAN
3 Department of Polymer Engineering and Color Technology, Amirkabir University of Technology, Tehran, I.R. IRAN
4 Department of Polymer Engineering, Iran Polymer and Petrochemical Institute, Tehran, I.R. IRAN
Abstract
Upon electron irradiation of polyolefins, various types of branches are produced on the chains which can change various properties of them along with their phase morphology in blends. In the present article morphological and rheological behaviors of LLDPE/Poly(1-Hexene) (PH) blends before and after electron beam irradiation are studied. Varying amounts of PH (Mv=1.7×106 Da) were added to LLDPE and melt blended in an internal mixer and the blends were collected. The blends were exposed to electron beams (12 KGy, 10 Mev) under ambient pressure and temperature. Finally, various properties of them were studied. MFR studies of the samples before irradiation showed that as the PH percentage increases from 1.5 to 4.5, MFR increases from 0.59 to 0.82 g/10min while after irradiation it decreases so that no stave is seen which can be indicative of long chain branching (LCB) on LLDPE. DSC results showed that addition of PH to LLDPE does not have a considerable effect on thermal behavior of the samples while after irradiation the crystallinities of the samples decreased which can be due to the LCBs attached to LLDPE. The density of LLDPE/PH blends decreased upon irradiation which is in agreement with DSC crystallinity results. SEM micrographs of the samples after etching in boiling heptane showed semi-spherical holes dispersed in the matrix indicating droplet-matrix morphology; however the irradiated samples showed lower amount of holes, indicative of presence of chemical bonding between the phases. FTIR results showed that upon increasing the amount of PH the number of CH3 per 1000 carbon of the backbone increases, also the presence of vinyl groups was confirmed.  The amounts of gelation of the samples were zero indicating the absence of crosslinking during irradiation. Rheological studies on the samples confirmed the presence of LCBs in them.
Keywords
Poly(1-Hexene)
LLDPE
Rheology
Irradiation
LCB

Subjects

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