Simulation & Modeling
Parisa Mohammadzadeh Pakdel; Reza Yegani; Mahdi Salami Hosseini; Elham Shokri
Abstract
In the current study, the flow field and morphology development of a polyethylene (PE) and ethylene vinyl acetate (EVA) blend were investigated numerically during extrusion through a spinneret using Fluent 6.3.26 software. The interface of the two phases was tracked using the volume of fluid (VOF) method. ...
Read More
In the current study, the flow field and morphology development of a polyethylene (PE) and ethylene vinyl acetate (EVA) blend were investigated numerically during extrusion through a spinneret using Fluent 6.3.26 software. The interface of the two phases was tracked using the volume of fluid (VOF) method. In a conventional spinneret, EVA droplets near the walls break up due to the high shear rate, while the central droplet deforms without breaking up. To enhance the breakup of EVA droplets, the effects of device geometry, including the spinneret angle and the presence of one or two lamps, were investigated in detail. The numerical results indicated that a decrease in the spinneret angle from 60° to 45° causes the central droplet to become more elongated in the flow direction. Additionally, the results showed that the presence of one or two lamps in the conical zone of the spinneret causes a portion of the central droplet to break up.
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 ...
Read More
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.
Composites and nanocomposites
Linda Gouissem
Abstract
This study explores the development of high-density polyethylene (HDPE) composites reinforced with stearic acid-treated expanded perlite (TEP) to examine their thermal, mechanical, and processing properties. The composites were fabricated using a plastograph at 200°C, incorporating perlite concentrations ...
Read More
This study explores the development of high-density polyethylene (HDPE) composites reinforced with stearic acid-treated expanded perlite (TEP) to examine their thermal, mechanical, and processing properties. The composites were fabricated using a plastograph at 200°C, incorporating perlite concentrations from 5% to 20% by volume. The effects of stearic acid (SA) treatment and perlite content were analyzed through SEM, melt flow index (MFI), tensile and impact testing, and thermal analysis (DSC, TGA, and Vicat softening temperature). SEM analysis revealed that untreated perlite exhibited a highly porous structure, while HCl treatment induced fragmentation. At 5% SA, perlite particles were well dispersed with a thin coating, whereas at 10% SA, the coating was more pronounced, leading to agglomeration. The MFI increased with perlite loading, reaching 12.3 g/10 min at 20% perlite, compared to 8.88 g/10 min for neat HDPE. Mechanical testing showed that the elastic modulus increased by 36% (786 MPa) at 5% perlite, dropped to 460.8 MPa at 15%, and rose again to 707.7 MPa at 20%, suggesting structural reinforcement. Moderate perlite content (5-10%) preserved ductility, while higher concentrations (15-20%), especially with 10% SA, increased brittleness due to reduced interfacial adhesion. Thermal analysis showed a slight decrease in melting temperature and a slight increase in crystallization temperature with the addition of treated perlite, while thermal stability improved and the Vicat softening temperature remained unchanged. These results highlight the potential of SA-treated expanded perlite as a viable alternative to conventional fillers, offering a balance between stiffness, ductility, and thermal resistance. The developed composites are promising for light weight and cost-effective applications in energy management and construction.
Simulation & Modeling
Utkarsh A. Patil; Pravin Ramchandra Kubade
Abstract
The growing need for enhanced materials has led to the development of nanocomposites, which have shown great potential in various industries. However, optimizing the composition of these materials to achieve the best mechanical performance and cos t-effectiveness remains a challenge. This research addresses ...
Read More
The growing need for enhanced materials has led to the development of nanocomposites, which have shown great potential in various industries. However, optimizing the composition of these materials to achieve the best mechanical performance and cos t-effectiveness remains a challenge. This research addresses this challenge by employing a virtual experimental approach, utilizing Digimat for material modeling and CATIA for design and finite element analysis (FEA). This approach allows for the simulation and analysis of different nanocomposite compositions without the need for costly and time-consuming physical experiments. The study focuses on Polypropylene (PP) and polyvinyl chloride (PVC) based nanocomposites with graphene and carbon black reinforcements. The research investigates the impact of varying the weight percentages of these nanofillers on the mechanical properties of the composites. The PP/PVC blends are created in different weight ratios to provide further compositional control. The material preparation is carried out in Digimat, where the properties of the composites are defined using a micromechanical model. The FEA is then conducted in CATIA, where a standard AS TM D638 tensile specimen is simulated under controlled conditions. The results are validated by varying mesh sizes to optimize deflection and Von Mises s tress predictions. Furthermore, an economic analysis is conducted to evaluate the cos t-effectiveness of the different nanocomposite compositions. The study highlights the importance of virtual experimentation in materials science, as it allows for efficient exploration of various material compositions and reduces the need for physical prototyping. This approach accelerates the material development process and enables the optimization of material design for specific applications. The virtual trials explored alternatives to PVC using PP-based composites reinforced with graphene/carbon black. PP/PVC 40/60 reinforced with 1.5% wt. graphene (P4V6G15) and reinforced with 7.5% wt. carbon black (P4V6C75) showed 31.6% and 31.2% deflection reductions compared to pure PP, respectively. These results show that P4V6 blends, especially those with graphene or high carbon black concentrations, serve as promising alternatives to conventional PVC. Among them, P4V6C75 stands out by offering the best overall mechanical performance. It also provides the lowest production cos t. In terms of economic favorability, P4V6C75 is approximately 2.55 times more cos t-effective than the graphene-based blend P4V6G15. This combination of high performance and low cos t makes P4V6C75 the most suitable candidate for PVC replacement.
Polyolefins Functionalization
Valentin Olegovich Kudyshkin; Nurad Ismatovich Bozorov; Ruslan Khaitkulovich Madiev; Bektemir Khamidovich Ruziev; Nurbek Shodievich Ashurov; Sayera Sharafovna Rashidova
Abstract
Copolymers of methyl acrylate were grafted onto low-molecular-weight polyethylene in the presence of benzoyl peroxide in o-xylene. The formation of these copolymers was confirmed by functional analysis of the ether groups and Fourier-transform infrared spectroscopy. Various synthesis patterns were demonstrated, ...
Read More
Copolymers of methyl acrylate were grafted onto low-molecular-weight polyethylene in the presence of benzoyl peroxide in o-xylene. The formation of these copolymers was confirmed by functional analysis of the ether groups and Fourier-transform infrared spectroscopy. Various synthesis patterns were demonstrated, which furnished grafted copolymers with a wide range of compositions. X-ray diffraction analysis showed that grafting led to changes in the crystalline structure of low-molecular-weight polyethylene. The grafting sequences of the methyl acrylate units may disrupt the order of the crystalline planes in polyethylene, and with an increase in their content, the crystalline phase in polyethylene becomes less prominent. These copolymers can be used as compatibilizers for CB-filled polyethylene (CB: carbon black). The effect of the grafted copolymers on the properties of high-density polyethylene composites containing CB was evaluated. The composites of polyethylene and the grafted copolymers exhibited enhanced thermal stability, plausibly associated with a decrease in the average size of the CB particles.
Olefin polymerization and copolymerization
Fengtao Li; Jing Wang; Xuelian He
Abstract
In this study, a titanium-based constrained geometry catalyst, [t-BuNSiMe2(Me4Cp)]TiMe2, was synthesized and activated with methylaluminoxane for ethylene-propylene random and block copolymerization. The catalyst exhibited optimal activity at 70°C, yielding random copolymer chains with trace amounts ...
Read More
In this study, a titanium-based constrained geometry catalyst, [t-BuNSiMe2(Me4Cp)]TiMe2, was synthesized and activated with methylaluminoxane for ethylene-propylene random and block copolymerization. The catalyst exhibited optimal activity at 70°C, yielding random copolymer chains with trace amounts of long polyethylene crystalline segments. When the ethylene content fell below 35%, random copolymers failed to crystallize. The block copolymerization system achieved maximum catalytic activity at a reaction temperature of 50°C and an ethylene block duration of 10 minutes. Shorter ethylene block durations correlated inversely with enhanced catalytic activity, increased molecular weight (peaking at 2.88 × 105 g/mol), and a narrower molecular weight distribution. The predominant component comprised extended PPP segments, constituting over 50% of the total copolymer composition. Within the polymer chains, propylene monomers were primarily incorporated as PPP and PPE structural motifs. Moreover, a progressive decrease in [PPP] content was observed with increasing ethylene block duration, whereas [PPE] content exhibited the opposite trend. This inverse relationship suggested that PPP segments gradually transform into PPE configurations via ethylene monomer insertion. These findings demonstrated that product structure and properties can be effectively tuned by adjusting initial monomer feed ratios or the timing of monomer block introduction.
)
