SIAM: Science and Innovation of Advanced Materials

Statistical Analysis for Quality Control of Monodispersed Polystyrene Particles Certified Reference Materials

2024-09-12T13:45:40+07:00

Monodispersed polystyrene latex (PSL) particles serve as certified reference materials (CRMs) for ensuring quality, method validation, and calibration of particle size measuring instruments. They were produced in compliance with ISO 17034:2016 standards. However, limitations arise in the quality control of CRM characteristics due to challenges in synthesizing particles of consistent size across multiple batches. It is widely recognized that variations in particle size homogeneity between batches can occur in the particle manufacturing process even when conducted under identical conditions and ingredients. This paper aims to explain and demonstrate statistical analyses conforming to ISO Guide 35:2017 used for quality control and certifying reference values for monodispersed polystyrene particles. The procedure can be divided into three steps: 1) preliminary check by using dynamic light scattering (DLS), 2) preliminary check by using transmission electron microscopy (TEM), and 3) final homogeneity testing, along with short-term and long-term stability assessment and characterization. The described protocol can control the quality of particles from multiple batch productions by establishing criteria at each step to ensure particle size consistency. The certified value of a 100 nm diameter monodispersed polystyrene particle produced by the National Institute of Metrology, Thailand (NIMT) is 105.5 ± 4.6 nm, acceptable for measurement traceability for testing and calibration services.

Keywords: Quality control, polystyrene particles, certified reference materials

Influence of Different Grafted Natural Rubbers on Electrical and Mechanical Properties of Natural Rubber/Carbon Nanotubes Composites

2024-09-12T13:48:24+07:00

This study investigates the augmentation of electrical and mechanical characteristics of natural rubber (NR) film with different forms by integrating carbon nanotubes (CNTs). NR with different forms (i.e., natural rubber grafted with polystyrene (NR–g–PS) and polybutyl methacrylate (NR–g–PBMA)) were successfully synthesized. The success of these grafting was confirmed through Proton Nuclear Magnetic Resonance (¹H–NMR) and Attenuated Total Reflectance–Fourier Transform Infrared (ATR–FTIR) analyses, which showed that the grafting efficiency exceeded 90%. The properties of ungrafted NR and grafted NRs with CNTs were compared and analyzed. It was found that the NR/CNTs composites with grafting displayed significantly improved electrical properties and mechanical strength when compared to the NR/CNTs composites without grafting. It was found that the NR–g–PBMA exhibited an 860% increase in electrical conductivity at 100 kHz compared to ungrafted NR. This might be attributed to the synergistic of the high specific surface of CNTs and the high polarization of functional groups, which gave a higher value for the CNTs filled grafted NR than the ungrafted NR. Moreover, the mechanical properties of NR–g–PS composites showed a 114% increase in 100% modulus, 127% in tensile strength, and 37% in hardness, while the NR–g–PBMA composites exhibited a 159% increase in 100% modulus, 95% in tensile strength, and 34% in hardness compared to ungrafted NR. This enhancement can be attributed to the formation of chemical linkages between the grafted NR matrix and CNTs through functional groups from both. Consequently, it can be concluded that introducing functional groups on grafted NR assists in establishing a crosslinking network, enhancing both the mechanical and electrical properties. Additionally, this research emphasizes the benefits of producing flexible conductive materials with high modulus and enhanced electrical properties.

Keywords: Natural rubber latex, Graft copolymerization, Glutaraldehyde, Natural rubber composites, Electrical properties

Effect of Nanoclay Modification on Properties of Natural Rubber Nanocomposites Using Zinc Compound

2024-08-19T08:56:39+07:00

This study investigates the effect of nanoclay modification on the properties of natural rubber (NR) nanocomposites using zinc stearate (ZS) and di(hydrogenated tallow) dimethylammonium chloride (DHDT). The aim is to enhance the compatibility of modified nanoclay (NC) and NR molecules for determining cure characteristics, mechanical properties, and morphologies. The effect of unmodified and modified NC as the secondary filler was studied using the 10 phr NC regarding the received properties of the silica-based composites. Results indicated that the NR composites with modified NC exhibited a significant improvement of 32.06% estimated crosslink density, 16.6% tensile strength, 30.1% Payne effect together with the production time of 3.9 min relative to the composites with unmodified NC. This related to the dispersion and distribution degree of the NC and it suggests that the modification of nanoclay with ZS and DHDT can positively impact to the NR nanocomposites, enhancing their mechanical performance and processing characteristics.

Keywords: Modified nanoclay, Natural rubber, Nanocomposites

Co-precipitation Synthesis and Characterization Studies of Manganese Oxide Doped with Nickel for High-Performance Energy Storage Supercapacitor Application

2024-06-28T19:15:27+07:00

The advancement in nanotechnology research has facilitated the development of eco-friendly methods for the synthesis of nanoparticles. In this work, nickel (Ni)-doped manganese oxide was synthesized using the co-precipitation method. The prepared Ni-doped manganese oxide products have been characterized by X-ray powder diffraction, scanning electron microscopy (SEM), transmission electron microscope (TEM), and energy dispersive X-ray spectroscopy (EDS). The preliminary electrochemical characteristics include charge-discharge cycling, which improves the conductivity and capacitance of the high-performance aqueous asymmetrical supercapacitor. The CV analysis of the Ni-doped manganese oxide electrode demonstrated a distinctive pseudocapacitive behavior in 1 M KOH solution. The nickel (Ni) doped electrode has a higher specific capacitance value than the pure manganese oxide electrode, with a value of 2225.07 F×g^-1at a scan rate of 5 mV×s^-1.

Keywords: Supercapacitor, Co-precipitation method, Nanotechnology, Synthesized, Electrochemical

Devolopment of Co-doped Fe2O3 Nanoparticles for Electrochemical Supercapacitor

2024-06-28T18:34:20+07:00

Co-doped Fe₂O₃ nanoparticles were synthesized by the co-precipitation method. These crystalline nanostructures were characterized using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscope (TEM). The electrochemical characteristics include charge–discharge cycling, which improves the conductivity and capacitance for the high-performance supercapacitor. The CV analysis of the pure Fe₂O₃ and Co-doped Fe₂O₃ electrode was distinctive in the 1 M KOH solution case. The nanoparticle size electrode reveals enhanced specific capacitance compared to Co-doped Fe₂O₃ and Fe₂O₃ to the electrode has a specific capacitance of about 33.50 F×g^-1 and 13.74 F×g^-1 with a scan rate 5 mV×s^-1.

Keywords: Supercapacitor, Co-precipitation method, Electrochemical, Energy storage