The development of thermally conductive rubber nanocomposites for heat management poses a formidable challenge in numerous applications, notably within the realm of tire technology. Notably, rubber materials are characterized by their inherently low thermal conductivity. Consequently, it becomes imperative to incorporate diverse conductive fillers to mitigate the propensity for heat build-up. Multi-walled carbon nanotubes (MWCNTs), as reinforcement agents within the tire tread compounds, have gained considerable attention owing to their extraordinary attributes. The attainment of high-performance rubber nanocomposites hinges significantly on the uniform distribution of MWCNT. This study presents the influence of MWCNTs on the performance of carbon black (CB)-reinforced natural rubber (NR)/styrene butadiene rubber (SBR) tire compounds prepared via high shear melt mixing. Morphological analysis showed a good distribution of MWCNTs in the NR/SBR/CB compound. The vulcanization parameters, such as the maximum and minimum torque, cross-linking density, hardness, abrasion resistance, tensile strength, and Young modulus, exhibited a progressive improvement with the addition of MWCNT. Remarkably, adding MWCNT into CB improved the heat conductivity of the NR/SBR/CB compounds, hence decreasing the heat build-up. A percolation mode was also proposed for the hybrid carbon fillers based on the data obtained.

Thermoplastic vulcanizates (TPVs) are multifunctional materials consisting of two or more phases with solid elastomeric properties at room temperatures and fluid-like properties above their melting point. They are produced through a reactive blending process known as dynamic vulcanization. The most widely produced TPV type is ethylene propylene diene monomer/polypropylene (EPDM/PP), which is the focus of this study. The peroxides are mainly selected to be used in crosslinking of EPDM/PP-based TPV. However, they still have some disadvantages, such as the side reactions resulting in the beta chain scission of the PP phase and undesired disproportionation reactions. To eliminate these disadvantages, coagents are used. In this study, for the first time, the use of vinyl functionalized polyhedral oligomeric silsesquioxane (OV-POSS) nanoparticles was investigated as a potential coagent in EPDM/PP-based TPV production via peroxide-initiated dynamic vulcanization. The properties of the TPVs having POSS were compared with the conventional TPVs containing conventional coagents, such as triallyl cyanurate (TAC). POSS content and EPDM/PP ratio were investigated as the material parameters. Mechanical properties of EPDM/PP TPVs exhibited higher values in the presence of OV-POSS, which resulted from the active participation of OV-POSS into the three-dimensional network structure of EPDM/PP during dynamic vulcanization.

The research and development (R&D) in rubber formulation development require reproducible, repeatable, fast, accurate, and efficient sample preparation. The lab-scale formulation development is conventionally carried out using small-scale internal mixers and two-roll mills. However, high torque laboratory twin-screw micro-compounder, which have been serving the plastic industry for more than 30 years, can be used to formulate new rubber compounds for fast and accurate sample preparation that on top can contribute to the economics of R&D. In this study, we investigated the possibility of using lab-scale 15 mL high torque twin-screw micro-compounder as a tool for new rubber compound development. For this purpose, we formulated EPDM/carbon black and EPDM/silica recipes through conventional way using a Banbury mixer followed by a two-roll mill, and through the possible way using a lab-scale 15 mL twin-screw micro-compounder. We crosslinked both systems via hot press at a predefined temperature and time. The rheological and mechanical properties of the compounds were investigated. Moreover, the dispersion of carbon black and silica in the EPDM matrix was judged by DisperGrader and scanning electron microscope (SEM). The conventional way of sample preparation was compared with a possible sample preparation method based on materials’ parameters and ease of operation.

This study explores the development of long fiber-reinforced thermoplastic (LFT) composites based on blends of poly(lactic acid) (PLA) and polyhydroxyalkanoate (PHA), reinforced with sisal fibers. A novel lab-scale LFT line was employed to fabricate the long fiber composites, effectively addressing the challenges associated with dispersing and processing high-aspect-ratio natural fibers. The rheological, mechanical, thermal, and morphological properties of the resulting bio-LFT composites were systematically characterized using FTIR, SEM, rotational rheology, mechanical testing, DSC, and TGA. The results demonstrated generally homogeneous fiber dispersion, although limited interfacial adhesion between the fibers and polymer matrix was observed. Mechanical tests revealed that sisal fiber incorporation significantly enhanced tensile strength and stiffness, while impact toughness decreased. Thermal analyses showed improved crystallinity and thermal stability with increasing PHA content and fiber reinforcement. Overall, this work highlights the potential of natural fibers to create high-performance, sustainable biocomposites and lays a solid foundation for future advancements in developing eco-friendly structural materials.

High-performance polyethylene fibers, renowned for their superior attributes encompassing a high strength, modulus, and lightness, are conventionally manufactured through the gel spinning method. However, this method is encumbered by several drawbacks, including the requisite application of a separate process to eliminate solvents from the fibers and the utilization of chemicals deleterious to both the environment and human health. Alternatively, the adoption of the melt spinning method presents a cleaner and environmentally friendly approach to attain high-performance fibers. In the present investigation, high-density polyethylene (HDPE) fibers were produced employing the melt spinning method. After the spinning process, strategic orientation procedures were implemented to enhance the crystallinity of the spun fibers. As a concluding step, seeking to elevate the overall performance of the oriented spun HDPE fibers, a cross-linking treatment was applied via UV irradiation. Notably, this study pioneers the incorporation of polyhedral oligomeric silsesquioxane (POSS) hybrid nanoparticles into HDPE during melt spinning, presenting a novel advancement aimed at further enhancing the mechanical properties of oriented HDPE fibers during UV irradiation. For this purpose, two distinct types of POSS, namely octavinyl POSS (OVPOSS) and methacryl POSS (MACPOSS), both having unsaturated double bonds capable of participating in the network structure of oriented HDPE spun during UV cross-linking, were used. The thermal, morphological, and mechanical properties, as well as the crystal structure of samples with and without POSS molecules, were investigated. The mechanical properties of the fibers exhibited higher values in the presence of OVPOSS. The incorporation of OVPOSS and MACPOSS resulted in a noteworthy improvement in the material’s tensile strength, exhibiting a marked increase of 12.5 and 70.8%, respectively. This improvement can be attributed to the more homogeneous dispersion of OVPOSS in HDPE, actively participating in the three-dimensional network structure. After orientation and UV irradiation, the tensile strength of HDPE fibers incorporating OVPOSS increased to 293 MPa, accompanied by a concurrent increase in the modulus to 2.8 GPa. The addition of POSS nanoparticles thus yielded a substantial improvement in the overall performance of HDPE fibers.

This study investigates the development of electrically conductive panels for application as emergency detection sensors in smart house systems. These panels, composed of wood chips coated with polymeric methylene diphenyl isocyanate, were modified with carbon black and carbon fibers to enable detection of moisture, temperature, and pressure variations. Manufactured via hot pressing, the panels retained standard mechanical properties and exhibited stable performance under diverse environmental conditions. Carbon black-filled panels achieved electrical percolation at a lower filler concentration (5%) compared to carbon fiber-filled panels. The incorporation of carbon black reduced the electrical resistivity to 8.6 ohm·cm, while the addition of carbon fibers further decreased it to 7.7 ohm·cm. In terms of sensor capabilities, panels containing carbon fibers demonstrated superior sensitivity to moisture and pressure changes. However, carbon black was ineffective for temperature sensing. Among the carbon fiber-filled panels, those with 20 wt.% concentration exhibited the best performance for moisture and pressure detection, whereas panels with 40 wt.% carbon fiber content displayed the most reliable and consistent temperature-sensing properties.