Researchers at the Institute for Plastics Processing (IKV) developed an automated cell for systematic characterization of polyurethane demoulding of permanent plasma polymer release coatings under production-like conditions. The modular mould integrates force, pressure, temperature, and dielectric sensors to monitor curing and quantify adhesive and shear forces. A hinged opening enables controlled peeling, while automated dosing and robotic removal ensure highly repeatable results for evaluating permanent release coatings.
The current investigation employs the Taguchi method to optimize the coefficient of friction (CoF) in rubber-based objects under dry sliding settings. Applying an L16 orthogonal array constructed with Minitab software, four input variables, rubber material type, grooves, normal load, and sliding velocity, were analyzed across four different Levels. The CoF reaction was explored using the signal-to-noise (S/N) ratio, resulting in the formulation of a mathematical model. The outcomes were confirmed using experimental and anticipated CoF comparisons, exhibiting good agreement. Predicted three-dimensional surface plots emphasize the interconnections between components and their impact on CoF. The presented approach exhibits the utility of the Taguchi method.
Traditional high pressure capillary rheometer (HPCR) measurements can only capture the pressure in front of the capillary. Consequently, the transition between wall adhesion and wall slip, which should display as a pressure drop, cannot be determined. The newly developed rotational slit rheometer (RSR) effectively captures pressures along the entire capillary. For the trials in this article, the device shows constant pressure gradients across various throughputs, no transition between wall adhesion and wall slip can be detected. Comparisons between RSF and HPCR measurements reveal similar viscosities. RPA-measurements with "Steady shear" conditions, also produce comparable viscosity data, indicating all measurements occurred under wall adhesion conditions.
This research focuses on the mechanical and tribological parameters of the bio-epoxy composite materials. The composites consist of varying weight percentages of the bio-epoxy resin, sisal fibers, and nHA nanoparticles. The optimal formulation, with a ratio of 60/20/20 (bioepoxy/sisalfiber/nHA), gives the highest mechanical properties, and a very low values of both wear rate coefficient of friction. The data provides details about the functions of the bioepoxy resin, sisal fibers, and nHANP in the consolidation of the toughening properties and low-friction performance of the nanocomposites. The findings illustrate nanocomposites as a new biomedical tool because of their enhanced mechanical properties and the biocompatible character they possess.
Due to their energy-intensive manufacturing process rubber parts offer great potential for reducing energy consumption and production cost as well as increasing productivity. By optimising the heating time for each cycle, significant amounts of energy can be saved. Furthermore, the parts can be produced with lower deviations in the elastic properties if the cycle is ended at a defined curing degree rather than a fixed heating time. Dielectric Analysis (DEA) was investigated towards its ability to detect changes in the degree of cure inside the mould during heating time. Differences caused by a varied accelerator content can be made visible by DEA.
The rapid growth of the automotive industry and the resulting accumulation of waste tyres pose significant environmental and public health concerns worldwide. This study explores innovative and sustainable waste tyre management strategies, reviewing conventional methods like landfilling, retreading, and energy recovery, as well as advanced thermo-chemical techniques such as pyrolysis, gasification, and liquefaction. Special emphasis is placed on material recycling pathways, particularly the emerging method of devulcanization, which selectively breaks sulphur bonds in vulcanizec rubber to allow high-quality reuse. The review further evaluates the integration of reclaimed rubber into civil engineering applications and polymer composites, along with recent developments in mechano-chemical, ultrasonic, microwave, and biological devulcanization.
Thermogravimetric analysis of various analytical methods was applied to obtain the activation energy of LLDPE containing various different concentration of the antioxidant reagent. ISO 11358-3 was difficult to apply to obtain the activation energy when the sample contained more than 0.125% of the reagent. Unlike tetrafluoroethylene propylene copolymer, the Kissinger plot could not be applicable to all. LLDPE used in this experiment. Activation energy obtained using the oxidation induction temperature was from 140 kJ/mol to 163 kJ/mol, which depended on the concentration of the antioxidant reagent.
The precise determination of the entropy reduction achieved by deformation in a chemically cross-linked elastomer material requires a comprehensive understanding of all influencing factors that affect the material-specific course of non-isothermal stress increase. The correct implementation of material behavior for simulations also depends on this. A model is presented specifically for static strain deformations that allows the specific heat capacity and thermal expansion coefficient to be derived from the storage component of the complex dynamic modulus of elasticity as a function of the degree of deformation. Further examples show how the magnitude of non-isothermal stress increase can be increased through targeted compound development.
The aim of this paper was to evaluate how heat-treating parameters influences on Shore hardness number of the polymethlmethacrylate (PMMA) and unsaturated polyester. Heat-treating parameters included the heating temperature, holding time, and cooling mode. Shore hardness test was carried out for the PMMA and unsaturated polyester. The results showed that Shore hardness number was significantly affected by heat-treating parameters. The highest values of Shore hardness number for the PM MA were occurred at the following heat-treating parameters: heat-treating temperature at 200 degrees C, heat-treating time for 135 minutes, slow cooling in a furnace. For unsaturated polyester, the holding time for 135 minutes showed the highest Shore hardness number.
Modern catalyst systems enable us to synthesize ethylene-propylene-diene polymers with well-defined properties. For example, the degree of polymer branching can be precisely adjusted to enhance the processability of rubber compounds. In this work, we compare four commonly used parameters obtained from Mooney stress relaxation, and frequency sweep, and amplitude sweep measurements. The corresponding test methods and parameters are discussed, and the advantages of the Delta delta-parameter obtained from frequency sweep measurements are elaborated. A series of model polymers with different degrees of branching was analyzed and good correlations are found between the Mooney stress relaxation rate, the Mooney relaxation area, the Delta delta-parameter, and the long-chain branching index.
The global economy is evolving toward a circularity, which targets on minimising waste and extending the useful life of resources. Every year the tyre produced is around 1.5 billion, and all the tyres will ultimately end up in the trash stream. The huge amount of scrap tyres that ends up in landfills causes environmental issues. Waste management techniques such as retreading, reclaiming, gasification, pyrolysis and other methods are addressed with new sustainability perspectives. New possibilities for recycling waste tyres in civil engineering applications are also reviewed, with the goal of providing practical and cost-effective methods and ensuring their continuing usage in a regenerative system. The main aim of this article focuses to investigate various scrap tyre management methods, their pros, and cons and to determine the best pathway.
Due to their energy-intensive manufacturing process and low recyclability rubber parts offer great potential for reducing material use and carbon footprint. Therefore, different approaches were investigated with the aim to reduce the resource use of a rubber sealing ring while maintaining specifications. The combination of bio-based and high-performance polymers and fillers, the foaming of rubbers using microspheres and a load-specific design enabled savings in weight of up to 26%. The material and process investigations were accompanied by a Carbon Footprint Analysis to evaluate the climate impact benefits of these strategies.
This study examines natural fillers in epoxy composites for improving slip resistance of industrial flooring. Ceramic tiles, plain epoxy, and epoxy with date seed powder were tested against three safety shoe types under dry, wet, oily, and oil/water conditions. A custom tribometer measured static and dynamic friction. Results show that date seed powder significantly improves slip resistance, especially on contaminated surfaces, making it suitable as an eco-friendly anti-slip coating in varied working environments.
Extrusion is widely used to precisely manufacture various rubber products, where the dimensional accuracy largely depends upon the die swell phenomena. The die swell is influenced by the rheology of the material involved. In this work, viscosity measurements of a rubber compound at varied shear rate were carried out using a Rubber Process Analyser (RPA). Material properties were calibrated, and multiple rheological models were used for the prediction of Garvey die extrusion profile using numerical simulation. Predicted dimensions were verified with the experimental profile.
The wall slip of various rubber compounds has far-reaching effects on the design of extrusion dies and extruder screws as well as on viscosity measurements. However, in most cases it is not possible to determine under which circumstances a compound adheres to the wall or slides. A new approach to measure the wall shear stress via the elongation of a steel strip inserted in the flow channel makes it possible to detect changes in the wall shear stress. This is a promising approach to directly record the transition from wall adhesion to wall slip.
The present work examines the dynamic behavior of three rubber materials with varying hardness levels under sinusoidal loading conditions, focusing on their stiffness, damping factor, and sound level. A Kelvin-Voigt viscoelastic model was constructed in MATLAB to evaluate the system's displacement and acceleration responses, dynamically including stiffness and damping parameters depending on material qualities and applied loads. The results show that softer rubber (Shore A 50) exhibits a high damping factor and lowest stiffness, making it ideal for vibration isolation and noise reduction, whereas harder rubber (Shore A 70) demonstrates greater stiffness, reduced damping, and higher sound levels, favoring applications requiring structural stability. Shore A 60 delivers a balanced performance.
Rubber compounds consisting of various components such as rubber, fillers, plasticisers and other additives are produced in a discontinuously working internal mixer. To ensure a high quality of the product, mixing instructions are developed for each recipe. Based on existing mathematical models, describing the ram position and torque curve of the internal mixer during filler incorporation, physically inspired correlations will be integrated. For this purpose, the effects of the drag volume flow, polymer type and carbon black content on the ram position and filler incorporation are analysed. In addition, a dependency between the polymer rheological properties on the power input or torque is identified.
Potassium alum applications as an antibacterial agent in safety rubber goods are examined in this study. The goal is to improve rubber products' hygienic qualities and longevity, especially in areas where microbiological contamination is an issue. The tests were conducted on the final rubber vulcanizates to assess its mechanical qualities (modulus, elongation at break, and tensile strength), rheological characteristics, and antibacterial effectiveness against common bacteria and fungi. The human normal fibroblast cell line (BJ1) cytotoxicity assay was also investigated. The findings showed that incorporation of potassium alum in rubber vulcanizates greatly increases their antibacterial activity by successfully preventing the growth of bacteria and fungi.
Lignin holds a promise to act as a sustainable reinforcing filler in rubber industry, replacing carbon black and silica. However, poor dispersion and weak rubber-filler interaction have hindered the use of lignin. The results of this study show, that with TESPD (bis (triethoxysilylpropyl) disulfide) and MPTES ((3-mercaptopropyl)triethoxysilane) rubber-filler interaction can be improved in normal mixing temperatures, whereas with APTES ((3-aminopropyl) triethoxysilane) high mixing temperature is needed to improve the micro dispersion significantly. As a result, better mechanical properties were achieved which increases the attractiveness of lignin as a sustainable filler for rubber industry.
