Macromolecular Symposia最新文献

The EU Regulation on Deforestation-Free Products (EUDR), effective from June 29, 2023, aims to ensure that imported goods into the European Union (EU) are not linked to deforestation or forest degradation. The regulation, which replaces the EU Timber Regulation (EUTR), sets a cut-off date of December 31, 2020, and emphasizes due diligence, including tracking the geographical coordinates of production sites. In response, the Malaysian Rubber Board (MRB) developed the Malaysian Sustainable Natural Rubber (MSNR) framework, aligned with the EUDR. Governed under the MRB Act 1996 (Act 551), MSNR focuses on five principles: no deforestation for new rubber cultivation, compliance with national land code, environmental sustainability, social compliance, and supply chain traceability. MSNR incorporates the same deforestation cut-off date as EUDR and requires recording the geographic coordinates of all rubber plantations in Malaysia, regardless of size, ensuring broader traceability. The EUDR's country benchmarking system will assess Malaysia's deforestation risk based on environmental and economic sustainability. As Malaysia's primary rubber export to the EU is natural rubber gloves, which are largely made from raw materials sourced from Thailand, the country's risk status will be influenced by Thailand's deforestation benchmarks. This highlights the complexity of Malaysia's rubber industry and its commitment to sustainable practices.

This study aims to investigate the effects of different peroxides and the triallyl isocyanurate (TAIC) as coagent on the curing, mechanical, and damping properties of fluoro vinyl methyl silicon rubber (FVMQ) elastomers. Rheological analysis reveals that dicumyl peroxide (DCP) provides faster curing rates, with a 50% higher Curing Rate Index (CRI) and 36% greater delta torque than 2,5-dimethyl-2,5-di(tertiary-butyl peroxy) hexane (DBPH), indicating improved crosslink density. Mechanical testing confirms superior tensile strength and stiffness in DCP-cured elastomers but at the expense of reduced elongation at break. TAIC further enhances crosslink density, increasing the elastic modulus by 50% and improving shock absorption properties. However, DBPH-cured systems exhibit superior damping behavior, characterized by higher relative hysteresis loss (tan δ), making them suitable for vibration-absorption applications. Di(2,4-dichlorobenzoyl)peroxide (DCLBP) systems failed to cure adequately, likely due to catalyst poisoning. These findings highlight the critical role of peroxide type and coagent in determining the properties of FVMQ elastomers for specific industrial applications, balancing stiffness, flexibility, and damping performance.

Couplings are machine elements used in power transmission. With changing needs, the performance requirements of couplings have also increased. Additional performance requirements such as the ability to transfer the transmitted power without backlash, to tolerate misalignment to a certain extent and to dampen the vibration caused by the power generator have emerged. In order to meet these requirements, elastomer-based materials and metal materials are used together to meet these requirements. Within the scope of the study, the behavior of different couplings that can provide these properties against the torsional force generated during power transmission is investigated. Within the scope of the study, the mechanical behaviors of the couplings were examined by applying torsional loads corresponding to the requirements of the end-user in a simulated analysis environment. Under these conditions, their compliance with the specified backlash-free performance criteria was evaluated. The stress points on the coupling in response to the torsion and the effect of the geometries of the couplings with different geometric structures on the stresses were analyzed. A model was developed to analyze ideal coupling formation based on geometries. This study identified optimal coupling components that ensure flexibility and backlash-free transmission. Within the scope of this study, three different geometries of flexible couplings were analysed by FEA analysis method under defined conditions and it was seen that the 4-tooth model as backlash-free and flexible provided the desired conditions better than the other two models.

This paper discusses the study of supercapacitors (SCs) with various smart sensors such as wireless biosensors and wearable sensors. To bridge conventional batteries and traditional capacitors, recent research into SCs has focused on improving their performance based on energy and power density. Numerous advances in materials, device architectures, and manufacturing processes for supercapacitor devices have been studied. Therefore, the recent progress on carbon material (as electrodes) and different electrolytes have also been discussed in the paper. The main focus is to elucidate the various materials based on carbon allotrope that enhance the specific capacitance and lead to improved energy density of SCs, which will mainly support the wireless sensors. Different characterization techniques for the SCs have been explored, such as galvanostatic charge–discharge and cyclic voltammetry, along with its self-discharge and charge-redistribution process. This paper also explains the recent progress of SC-operated smart sensors and the advantages and disadvantages of supercapacitor-based sensors. In the last section, challenges faced by supercapacitor-based wireless sensors have also been discussed.

Bi₄Ti₃O₁₂ (BTO) ceramic nanoparticle was synthesized by utilizing a cost-effective wet route. XRD analysis confirms the formation of a single-phase formation of BTO ceramic. The average crystallite size was calculated using Debye–Scherer equation and found to be 28.68 nm. The x-ray photoelectron spectroscopy (XPS) analysis verified that the Bi, Ti, and O were present in +3, +4, and −2 oxidation states. The presence of each element in BTO was confirmed by EDS. The highest dielectric constant for BTO ceramic was found 602 at 564 K and 100 Hz. Also, the lowest value for dielectric constant was found 99 at 564 K and 1 MHz. The tangent loss (tan δ) value of the BTO ceramic was found 0.42 at 563 K and 1 kHz. During photocatalytic studies, it was found that BTO degraded 63% Congo Red dye in 2.5 h, which is indicating about its potential for application in the field of wastewater treatment.

1,2-Epoxidized polybutadiene (1,2-epoxidized PB) has been used as an additive in poly(vinylidene fluoride-co-hexafluoropropylene) (fluoroelastomer [FKM]) formulations. As global awareness surrounding Sustainable Development Goals (SDGs) continues to rise, the demand for safer, eco-friendly materials is increasing, our rubber material aligns with the SDGs, specifically Goal 3 (Department of Economic and Social Affairs) and Goal 12 (Responsible Consumption and Production). Lead monoxide (PbO) has traditionally been used as an acid acceptor in halogenated rubbers. However, PbO is prohibited by various regulations due to its toxicity, and currently no candidate offering a good balance between acid acceptance and rubber properties. We have researched liquid 1,2-epoxidized PB, and our study shows it acts as a sustainable alternative as an acid acceptor in halogenated rubber formulations, replacing PbO. This innovative solution is a nonhazardous material formulation that complies with regulations set by REACH and RoHS.

Specialty engineering rubber has been put forward with more stringent requirements. In this paper, the material properties and reinforcing effects of several fillers were investigated, and polyamide was selected as the target reinforcing material to modify hydrogenated nitrile butadiene rubber (HNBR) in order to improve the temperature resistance of the system. It was concluded that the mechanical properties of PA1212/HNBR system were better than those of PC/HNBR system at 120°C. The optimum PA1212 additive amount was determined through the mechanical property test and dispersion state observation of the blended system, which proved that the PA1212 reinforcing system significantly improved the heat resistance and mechanical properties of HNBR. The modified HNBR has excellent tensile strength and elasticity, which effectively improves the reliability and service life of the sealing equipment under high temperature conditions, and provides experimental references and theoretical basis for the research and development of high-temperature resistant rubber.