SCG Chemicals (Thailand)

A multiscale steady state model of a multizone circulating reactor (MZCR) is developed for propylene homo- and copolymerization on supported pseudo-single-site catalyst. The model includes nonideal thermodynamics to describe monomer sorption effects, a population balance to predict the particle size distribution (PSD), momentum balances to describe the residence time distribution (RTD) of the particles, and a full kinetic model to calculate the polymerization rate, cumulative molecular weight (MWD), and chemical composition (CCD) distributions of a pseudo-single-site ZN catalyst. The model was first compared with the available literature data that was based on simplified kinetics and Henry’s law for monomer sorption. The full kinetic and thermodynamic models were then included to demonstrate that they are quite important to consider. The full model was then used to understand the relationship among the reactor operating conditions, reactor performance, and product characteristics in a commercial-scale MZCR reactor. When model predictions are compared to available patent data, the proposed model is shown to be capable of describing the MZCR performance in a large-scale operation as well as predicting the monomodal and bimodal shapes of the MWDs.

This study investigates the synergistic effects of incorporating modified zinc oxide–silica (ZnO-SiO2) into tire waste (TW) and epoxidized natural rubber (ENR) blends, with a focus on crosslinking dynamics, mechanical reinforcement, and antibacterial activity. The addition of ZnO-SiO2 significantly enhanced crosslink density, as evidenced by increased torque and accelerated cure rates. An optimal concentration of 10 phr was found to yield the highest performance. This optimal balance between chemical activation and mechanical reinforcement resulted in exceptional tensile properties, including notable improvements in Young’s modulus, tensile strength, and strain-induced crystallization (SIC). These enhancements were attributed to the strong interactions between ENR molecular chains and SiO2 surfaces. However, excessive ZnO-SiO2 concentrations caused filler agglomeration, which reduced both mechanical and antibacterial performances. An antibacterial analysis revealed a remarkable 99.9% bacterial reduction at 10 phr ZnO-SiO2, attributed to the Zn2+ ion release and reactive oxygen species (ROS) generation, with sustained activity even after thermal aging. This durability underscores the composites’ potential for long-term applications. The findings establish ZnO-SiO2 as a dual-functional filler that optimizes crosslinking, enhances mechanical properties, and provides durable antibacterial efficiency. These results highlight the potential of TW/ENR blends while offering critical insights into mitigating filler agglomeration to improve overall material performance.

Plastic waste was transformed into high-performance quantum dots (QDs), combining technological innovation with a focus on environmental sustainability. The excellent fluorescence properties of the synthesized quantum dots were utilized to detect Fe3+ and F- ions with high sensitivity and selectivity in an "on-off-on" dual-mode fashion. Additionally, the synthesized quantum dots exhibited stable solid-state fluorescence, enabling their use in solid-phase applications without the typical fluorescence loss observed in other materials. The versatility and tunability of the synthesized materials were demonstrated by producing three different emission colors, achieved through the incorporation of various heteroatoms during the synthesis process. This solid-state fluorescent material provides a pathway for sensing and optoelectronic applications, as well as advanced optical devices with customizable designs in the future.

Intrinsic reaction kinetics is an essential information in catalytic reaction engineering. This paper reviews the two laboratory reactors, i.e., the packed-bed reactor and gradient-less recycle reactor commonly employed for determining the intrinsic reaction kinetics of heterogeneous catalysts. Although both reactors have been well-known for kinetic studies for a long time, there are still efforts to address some essential issues and to further develop the reactors. For example, a new design of the gradient-less recycle reactor was developed to broaden the operating window for intrinsic kinetic studies at low pressure. Furthermore, the intrinsic kinetic modeling in the gradient-less recycle reactor and packedbed reactor, including the effects of mass transfer and axial dispersion, was also investigated. This review article provides in detail the types of both reactors, the development of both packed-bed reactor and gradient-less recycle reactor, intrinsic kinetic modeling, and the methods for determining heat-and mass-transfer limitations. All of these point out the suitable methods for determining intrinsic kinetics and perspectives for future works.