Papers by Keyword: Polymer

Abstract: Some parts made of polymeric materials are used in abrasive environments. Any damage to their integrity by abrasive environments could have a negative effect on the operation of those parts. In the paper, it is proposed to use a process and equipment for evaluating the resistance to abrasive erosion based on the application of a process of enlarging a previously made hole in the polymer material specimen using a conical abrasive tool. The feed movement of the conical abrasive tool takes place under the action of a counterweight of known size. The duration of the process of enlarging by abrasion provides information on the resistance to abrasive erosion of the specimen material. An experimental study of the resistance to abrasive erosion of a polymeric material using the enlarging process with a conical abrasive tool was designed and implemented. The experimental results were processed mathematically, and an empirical mathematical model was obtained that highlights the influence of some input factors in the abrasive process on the resistance to abrasive erosion evaluated through the duration of the enlarging process with a conical abrasive tool. The possibility of using enlarging by abrasion as a procedure for evaluating the resistance to abrasive erosion was confirmed.

Abstract: Interpenetrating Phase Composites (IPCs) with biomimetic properties are promising materials for strengthening orthopaedic implants while also increasing their biocompatibility. Thanks to additive manufacturing techniques, lattice structures can be employed to develop biomaterials with controlled architectures, enabling the replication of human bone structures and offering advantages in terms of strength-to-weight ratio. This study investigates the behaviour of a bi-material steel-polymer lattice structure, observing that the epoxy resin increases the mechanical strength of gyroid, leaving the lightweight properties unchanged. Moreover, an equivalent constitutive model was calibrated, and a homogenization procedure based on the Representative Volume Element theory was applied. The effect on mechanical strength due to the 316L powder dispersed within the epoxy resin was investigated as well.

Abstract: Incremental Sheet Forming (ISF) has been widely studied for metallic materials, demonstrating significant potential in flexible and low-cost sheet metal forming (aluminum, magnesium or titanium). Recently, attention has shifted toward polymeric materials due to their growing relevance in medical and customized applications (PCL, UHMWPE, PEEK). However, the availability of commercial sheets is limited to thicknesses, geometries, and material options. In this context, Fused Deposition Modeling (FDM) has emerged as a complementary technique to produce tailored polymeric sheets, enabling the integration of additive manufacturing with ISF processes to overcome limitations in available commercial sheets and expand design flexibility. Considering the success of this hybridization for forming PCL, this work investigates the feasibility of applying Single Point Incremental Forming (SPIF) to PEEK sheets produced via Fused Deposition Modeling (FDM). The study analyzes the influence of printing parameters, forming conditions, and thermal treatment on part quality, porosity, forces, temperature, defects, and fracture behaviour.

Abstract: Sawdust and used plastic materials are generally considered as waste and due to the inability of the later to degrade, it constitutes a lot of hazard to the environment and ecosystem. This research aimed at evaluating the performance and quality of the extrudates produced from a single screw wood-plastic composite extruder. The machine performance was evaluated using shredded Poly ethylene, terephthalate (PET) and high-density polyethylene (HDPE) to produce wood-plastic composites. The composite comprising of six samples of different mix ratios (plastic to stone dust mix ratio of 60:40, 70:30 and 80:20 and plastic to sawdust mix ratio of 60:40, 70:30 and 80:20) of the materials. Temperature range of 200°C to 300°C was adopted throughout the evaluation. The plastic composite was shredded into smaller bits and then inserted into the plastic chamber for melting at a determined temperature. The functional efficiency, throughput capacity, specific energy consumption, and selected physical properties were evaluated. Data collected were analyzed using Microsoft Excel package. It was discovered that the extruder work optimally when the mixing ratio of plastic to sawdust and plastic to stone dust content were in the ratio 80% and 20% which gave the functional efficiency of 73% and 84% respectively. However, it was observed that the throughput capacity of the machine has the highest at the 70% and 30% mixing ratio of plastic to stone dust of 7.2 kg/hr and plastic to sawdust of 9.38 kg/hr respectively. Also, the specific energy consumption has its highest value at 60% and 40% mixing ratio of the plastic to stone dust and saw dust of 5.67 KWh/Kg and 1.7 KWh/Kg respectively. A linear trend on the effect of the percentage of wood and stone content on the unit density of the products was also observed. It was observed that the higher the wood or stone dust content in the composite the denser the products. There are no changes in the physical composition in terms of size (length and thickness ) and mass such as water absorption, thickness swelling and linear expansion. It was observed that the extruder performed optimally when the percentage of plastic & wood and plastic & stone dust were in the mix ratio of 80 and 20 respectively. These products can be use for internal and external applications in buildings and other structures.

Abstract: This research focuses on bibliometric analysis using R Studio and Bibliometrics as tools for data collection and evaluation related to advances and trends in developing organic-based composite materials with polymeric matrices. The importance of this analysis lies in understanding how these materials require a well-defined matrix that acts as a continuous phase, providing resistance to compressive stress while facilitating interaction with the discontinuous phase to withstand tensile forces. Additionally, it is essential to objectively establish the reinforcing fibers that make up the dispersed phase, as they protect the material against environmental factors and mechanical agents, preventing negative effects such as wear, buckling, and compressive stress. Proper selecting phases is crucial when evaluating the results obtained about the estimated values. Thus, one of the main challenges in formulating polymeric compositions for composite material development is the accurate identification of matrices along with the supporting material. As a result of the challenges associated with the production of these materials, this research confirms, through bibliographic analysis, the increasing exploration of such composites, their impact on various fields throughout history, the technical difficulties inherent in their fabrication in many proposed cases, and the costs involved in their manufacturing.

Abstract: The changes in the mechanical and physical properties of concrete prepared by incorporating various metal oxide nanoparticles into cement products used in both the oil/gas industry and construction have been analyzed in this review. The study compares the properties exhibited by transition metal oxide and some metal nanoparticles in both isolated and complex forms with polymers in concrete. Analyses were conducted primarily in the direction of changes occurring in properties due to the addition of metal oxide nanoparticles such as magnetite Fe₃O₄, TiO₂, ZnO, Fe₂O₃, Ag, CuO, TiO₂/SiO₂, Al₂O₃, ZrO₂, core/shell Fe₃O₄/SiO₂, in dispersed form as cement powder or in water. It has been showed that appropriate changes occur in properties such as compressive and flexural strength, adhesion, initial and final setting, water absorption, porosity, electrical conductivity, degradation when metal oxide nanoparticles are added to cement. The density and size of nanoparticles affect their response to various influences, alongside the fundamental properties of the material.

Abstract: The global growth of discarded end-of-life tires (ELT) is leading to a significant challenge of waste management. Many of these tires are incinerated or exported to countries with less stringent environmental regulations, exacerbating pollution and wasting resources. Until now, the main destinations for recycled rubber have been flooring, rubberized pavements, infill for synthetic turfs and moulded goods. The increasing necessity for the industry to adopt more sustainable products and processes by incorporating recycled materials, needs to be supported by innovative solutions. The present paper introduces a recycled rubber material, characterized by different certified laboratory tests performed to evaluate the mechanical and physical performance of a virgin rubber compound combined with different content levels of rubber powders derived from ELT, and with different particle sizes and production methods. There is extensive research on the ELT management systems and the various methods for recycling rubber from end-of-life tires, but limited studies on the impact of particle size and the influence of content of recycled rubber powders, added in new rubber compounds suited for performance-demanding applications. Based on the laboratory test results and the case study presented in this paper, it was possible to conclude that this recycled material can be incorporated into new rubber compounds, without compromising the performance. Numerous studies examine methods for recycling rubber from end-of-life tires, assessing their progress and limitations. Some focus on well-documented processes such as reclaiming, devulcanization, and surface modification, while others explore long-studied applications like rubberized concrete and rubber-modified asphalt. There is limited available information and published studies on the influence of particle size and content levels of recycled rubber powders that can be incorporated into new rubber compounds, for various applications such as new tires, conveyor belts, gaskets and profiles.

Abstract: Currently, great attention is paid to the creation of polymer composites using functional fillers and polymer matrices of various types, including thermoplastic and thermosetting types. These fillers also make it possible to increase the protective properties of the polymer against electromagnetic radiation by several orders of magnitude. The aim of the study is to study of the process of synthesis of functional fillers for polymer composites for protection against electromagnetic radiation. As a result of the studies conducted, the process of synthesizing functional fillers for polymer composites for electromagnetic radiation protection has been comprehensively examined. It has been shown that the recrystallization of titanium oxide from solution-melts of KCl-NaCl and KCl-NaCl-∑TiClₙ is possible under a flow of inert gas in the presence of a reducing agent, resulting in thread-like crystals of fibrous form. In the process, thread-like rutile crystals with cross-sectional dimensions of 3–30 μm and lengths of 10³–10⁴ microm were obtained. It has also been established that blowing KCl-NaCl-TiCl₄ without TiO₂ with inert gas in the absence of a reducing agent results in the crystallization of metallic titanium in the form of hollow microspheres. The obtained functional fillers have great potential in the development of polymer composite materials for electromagnetic radiation protection, providing a high combination of strength and spectral characteristics.

Abstract: The research focused on investigating the physical and mechanical properties of stretch films containing recycled materials. The objective of the study was to examine how the use of recycled materials affects the structure and physical and mechanical properties of 5-layer stretch films. The results showed that incorporating up to 50% recycled materials in the stretch films can be a viable option for securing containers on pallets, provided that the film's composition is appropriately modelled using specific primary polymers in the film layers. The study employed extrusion methods to create the stretch films.

Abstract: Composite fibers are a significant aspect in changing the mechanical properties through the direction of the fiber. The proposed composite fiber organized by the direction of 90º-45º-90º, 45º-90º-45º, and 90º-90º-90º can add to the substitution of composite fiber that enhances stiffness and impact strength. Thus, the Acrylonitrile-butadiene-styrene ABS arrangement has a place with amorphous polymers that can expand the effect and increase the impact and the mechanical properties, for example, woven ramie utilizing different direction orientations. The outcomes show that the elasticity direction of 45º-90º-45º is 56wt%, 90º-45º-90º is 83wt%, and further increments while utilizing 90º-90º-90º is 94%. The analyses incorporate tensile tests to obtain tensile stress, tensile strain, and elastic modulus, which are performed on the ASTM D3039 utilizing the General Testing Machine Zwick Roell Z020. Findings demonstrated that specimens with various directions demonstrated mechanical characteristics that produce different mechanical properties through stress-strain analysis. The toughness of various directions can endure influence stacking without a fracture with 90º-45º-90º, and toughness for 45º-90º-45º and 90º-90º-90º show the stored energy without having permanent deformation ASTM D256 utilizing Zwick Roell Effect Analyzer HIT 2P. Furthermore, SEM images were also obtained to see the morphological changes on the composite polymer surface due to the tensile test. Overall, the utilization of the tensile test shows the maximum stress that the structure can maintain. Assuming fibers are oriented parallel to the main loading direction 0° and 90° will provide greater strength in that direction, while fibres diagonal 45º more absorb energy. By observing the SEM results, there is no reduction in strength and toughness through the 90º-45º-90º orientation of the layers using the hand laid-up technique.