Polymer processing
Luisiana Morales-Zamudio; Francisco Rodriguez-Gonzalez; Minerva A.M Zamudio; Tomas Lozano; Juan Guillermo Martinez-Colunga; Saul Sanchez-Valdes; Luciano Da Silva; Erika Lopez-Martinez; Sergio Flores-Gallardo
Abstract
In this research we provide a practical guide to achieve the successful extrusion of LDPE tapes commercially used in mesh fences, with controlled dimensions, good mechanical properties and weather resistance. Here we share: 1) The die design dimensions and its specialized slotted manufacture to get the ...
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In this research we provide a practical guide to achieve the successful extrusion of LDPE tapes commercially used in mesh fences, with controlled dimensions, good mechanical properties and weather resistance. Here we share: 1) The die design dimensions and its specialized slotted manufacture to get the veins of tape, 2) Processing temperatures profile, 3) Cooling method, 4) Hot stretch ratio (HSR), and 5) The effect of colorant and ultraviolet rays’ protector, due to the outdoor use of polymer privacy tape. The formulated tape (0.8 wt. % UV protector and 5 wt. % colorant) showed the best performance under accelerated aging and reached good mechanical properties up to a time of 2000 hours compared to its initial values. The dye and the UV additive improved the mechanical properties. All these, led to obtain a LDPE tape to fulfill the expectative and characteristic of a commercial tape used for mesh fences.
Characterization
Ivan Kuryndin; Sergei Kostromin; Rustam Mamalimov; Anton Chervov; Andrei Grebennikov; Sergei Bronnikov
Abstract
Swelling of high-density polyethylene (PE) in organic solvents, orthodichlorobenzene and orthoxylene, was investigated. The swelling kinetics of the PE specimen was described by the first-order equation. For the first time, the PE specimen swelling rate constant was shown to decrease with increasing ...
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Swelling of high-density polyethylene (PE) in organic solvents, orthodichlorobenzene and orthoxylene, was investigated. The swelling kinetics of the PE specimen was described by the first-order equation. For the first time, the PE specimen swelling rate constant was shown to decrease with increasing thickness of the specimens. The equilibrium swelling of the PE specimen was evaluated. It was found that equilibrium swelling is independent of the thickness of specimens. It was shown that storage of polyethylene specimens in organic solvents changes its mechanical properties (tensile strength, Young’s modulus, and elongation-at-break) due to polymer plasticization. We have shown that the increase in flexibility and elongation-at-break after relatively short-term immersion of PE samples in these organic solvents is significant. However, the tensile strength of swollen specimens remains high enough. The interaction between polymer chains and solvent molecules was not detected. The results obtained are important for the design and operation of PE coatings and PE products, such as pipes, tanks, and other accessories exposed to oil products.
Polymer processing
Fatemeh Hassan; Mehdi Entezam
Abstract
Irradiation of polymers is one of the most effective and economical methods for modifying their properties and for changing their applications. In this study, an extrusion grade polypropylene (PP) was treated by electron beam irradiation to produce a PP suitable for injection molding. Irradiation was ...
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Irradiation of polymers is one of the most effective and economical methods for modifying their properties and for changing their applications. In this study, an extrusion grade polypropylene (PP) was treated by electron beam irradiation to produce a PP suitable for injection molding. Irradiation was carried out at different doses (0-80 kGy) under atmosphere air and at ambient temperature. Melt flow index (MFI) measurements showed PP samples irradiated in the range of 10 to 40 kGy are suitable to use in injection molding. Electron beam irradiation decreased the viscosity and the shear thinning rheological behavior of PP. The differential scanning calorimetry (DSC) analysis revealed that electron beam irradiation increased the crystallinity percentage and temperature of PP, but decreased the melting temperature. Among all treated samples, the PP20, irradiated at the dose of 20 kGy, showed the highest impact resistance. It had higher Young’s modulus and tensile strength, but lower elongation-at-break in comparison with untreated PP.
Structure and property relationship
Fateme Khademeh Molavi; Sedigheh Soltani; Ghasem Naderi; Rohollah Bagheri
Abstract
A novel mixing approach for achieving a good dispersion of multi-walled carbon nanotubes (MWCNTs) in ethylene- propylene diene monomer (EPDM) matrix has been investigated. In this approach EPDM was modified with vinyltrimethoxysilane (VTMS) during melt mixing. In addition the effect of MWCNT concentration ...
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A novel mixing approach for achieving a good dispersion of multi-walled carbon nanotubes (MWCNTs) in ethylene- propylene diene monomer (EPDM) matrix has been investigated. In this approach EPDM was modified with vinyltrimethoxysilane (VTMS) during melt mixing. In addition the effect of MWCNT concentration on mechanical and rheological properties of modified EPDM has been studied. The formulated composites by this method exhibited significantly enhanced physical properties even at very low nanotube concentration. The grafting reaction was confirmed by Fourier transform infrared spectroscopy (FT-IR) peak at 1070 and 1250 cm-1according to Si-O and Si-C vibration. The state of dispersion of the fillers in the polymer matrix was evaluated through transmission electron microscopy (TEM) and scanning electron microscopy (SEM), In addition surface topology was studied with atomic force microscopy (AFM). The results showed that VTMS-grafted on the EPDM surface improved the dispersion of MWCNTs in the matrix. The rheological characteristics have been studied by rubber process analyzer (RPA). Some properties such as storage modulus (Ǵ) and complex viscosity (η^*) increased with increasing MWCNT content. It was found that at concentration of 2 wt.% MWCNT, the nanocomposites exhibited notably enhanced mechanical properties such as modulus and tensile strength.
