Characterization
Marzieh Alidadi-Shamsabadi; Ahmad Arefazar; Shirin Shokoohi; Mahnaz Shahzamani
Abstract
In this work, the influence of compatibilizing method on the phase morphology, mechanical properties and rheological behavior of ternary blends based on polystyrene(PS) /ethylene-propylene-diene terpolymer(EPDM)/ polyamide6 (PA6) was investigated. Two different methods (including in-situ grafted and ...
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In this work, the influence of compatibilizing method on the phase morphology, mechanical properties and rheological behavior of ternary blends based on polystyrene(PS) /ethylene-propylene-diene terpolymer(EPDM)/ polyamide6 (PA6) was investigated. Two different methods (including in-situ grafted and pre-grafted) were used to compatibilize PS/EPDM/PA6 ternary blends. In the first method, all reactive materials were mixed during mixing, but in the latter, modified EPDM was prepared first and then blended with other components. The chemical reactions occurred during blending followed by Attenuated Fourier Transform Spectroscopy (ATR-FTIR). Mechanical properties investigated by impact and tensile strength measurements. The phase microstructure was observed by Scanning electron spectroscopy (SEM) and the rheological behavior was carried out using a parallel plate rheometer in oscillatory mode. ATR-FTIR results confirmed the grafting and compatibilizing reactions. The morphology size of dispersed phase particles have dramatically changed by increasing EPDM-g-GMA content. The pre-grafted compatibilizing method has revealed finer microstructure than the other method. The modulus of all the ternary compatibilized blends has increased compared to PS/EPDM. In fact, the presence of PA6 introduces a new, more rigid phase in the blend. The pre-grafted compatibilizing method, which uses a compatibilizer content of less than 10 wt.%, is more effective than the in-situ grafted compatibilizing method. This approach results in a finer microstructure and enhanced impact strength. Additionally, it creates a more rigid interface, leading to greater elasticity, which manifests as a semi-plateau in the rheological behavior. In contrast, the in-situ grafted method produces more balanced mechanical properties overall.
Polyolefin degradation
Marzieh Alidadi-Shamsabadi; Shirin Shokoohi; Mahnaz Shahzamani; Homa Abbasian-Peykani
Abstract
In this work, the photo-aging behavior of high impact polystyrene (HIPS), polystyrene/ethylene propylene diene monomer (PS/EPDM) binary blends, and compatibilized polystyrene/ethylene propylene diene monomer/ polyamide 6 (PS/EPDM/PA6) ternary blends was studied and compared together. Photo-degradation ...
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In this work, the photo-aging behavior of high impact polystyrene (HIPS), polystyrene/ethylene propylene diene monomer (PS/EPDM) binary blends, and compatibilized polystyrene/ethylene propylene diene monomer/ polyamide 6 (PS/EPDM/PA6) ternary blends was studied and compared together. Photo-degradation of polymer blends faces considerable challenges, because a polymer blend is a compound of multiple components with particular interactions and its components may function as degrading or stabilizing agents. Photo-aging generally can cause changes in the color and mechanical properties of polymer compounds. Attenuated total reflection Fourier transform spectroscopy (ATR-FTIR) was conducted to study the chemical interactions between components in the prepared samples. The morphological structure of blends was studied by using scanning electron microscopy (SEM). The impact and tensile strength of the samples were measured and compared after exposure to UV radiation. To study the changes in the appearance, the yellowness index values of the samples were followed at different periods of exposure to UV irradiation. The post-radiation results showed similar mechanical performance of ternary and binary blends with the retention of mechanical properties close to each other. The impact strength and elongation-at-break for the HIPS sample were greatly reduced compared to the blends, showing their retention by 8.46 and 7.86%, respectively. The ultimate tensile strength retention in each sample is between 70 and 82% and there is no significant difference between them. The final yellowness index of HIPS was measured to be 1.6 and 1.2 times higher than that of the binary and ternary blends, respectively.
Characterization
Marzie Alidadi-Shamsabadi; Shirin Shokoohi
Abstract
Melt free-radical grafting reactions between ethylene-propylene-dieneterpolymer (EPDM) and glycidyl methacrylate (GMA) were investigated in a batch mixer (170°C, 60rpm). Effect of dicumylperoxide (DCP) initiator and GMA functionalizing monomer concentrations was studied on the grafted EPDM characteristics. ...
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Melt free-radical grafting reactions between ethylene-propylene-dieneterpolymer (EPDM) and glycidyl methacrylate (GMA) were investigated in a batch mixer (170°C, 60rpm). Effect of dicumylperoxide (DCP) initiator and GMA functionalizing monomer concentrations was studied on the grafted EPDM characteristics. Titration results indicated an increase in the graft degree (GD) and gel content (GC) values with increasing DCP concentration as a result of increasing primary free radical concentration and strengthening cross-linking side reaction. FTIR spectrums confirmed that GMA functionalities have been grafted onto EPDM with appearing carbonyl (C=O) peak. After that, the resultant EPDM-g-GMA was used as compatibilizer in PS(polystyrene)/EPDM/PA6 (polyamide6) ternary blends. The effect of rubbery compatibilizer on the blend morphology and mechanical properties was studied. The ATR-FTIR spectra of ternary blends, etched to remove unreacted PA6, demonstrated that the compatibilizing reactions occurred during melt blending. By investigating the SEM micrographs it was revealed that the EPDM-g-GMA compatibilizer at the concentration range of 5 wt.% to 15 wt.% changed the size and type of the blend morphology from separated dispersed to multicore-shell morphology. The finest morphology was achieved by using 7.5 wt.% EPDM-g-GMA. Also, the presence of compatibilizer up to 7.5 wt.% could improve the tensile modulus, yield stress and impact strength, but a decreasing trend was observed at higher concentration of the compatibilizer.
