Synthesis and characterization of lanthanum supported halloysite nanotubes catalyst in obtaining low molecular weight of liquid epoxidized natural rubber

Abstract BACKGROUND Lanthanum catalyst supported on halloysite nanotubes (La/HNTs) was explored for the degradation of liquid epoxidized natural rubber (LENR) into low molecular weight LENR (lmw‐LENR). The La/HNT catalyst was synthesized using a simple impregnation method and characterized by X‐ray photoelectron spectroscopy (XPS), scanning electron microscopy with energy dispersive X‐ray (SEM–EDX), X‐ray fluorescence (XRF), Fourier‐transform infrared spectroscopy (FTIR), and nuclear magnetic resonance (NMR). These techniques were employed to examine the physicochemical properties of the catalyst and to evaluate its performance in LENR degradation. RESULT The characterization revealed the presence of lanthanum hydroxide (La(OH)₃‐n) species on the HNT surface. The La/HNTs effectively reduced the average molecular weight of LENR from 26 360 to 6961, corresponding to a 73.6% reduction under optimum conditions of 0.5 g catalyst loading at 150 °C for 4 h in a batch reactor. The degradation mechanism was attributed to hydroxide ions attacking the oxirane ring, leading to chain scission and the formation of shorter LENR chains. NMR and FTIR analyses confirmed the successful ring opening and cleavage of CC bonds, while the catalyst retained its structural integrity. Catalyst performance was strongly influenced by particle size, hydroxyl availability, and metal–support interactions. CONCLUSION This study demonstrates the efficiency of La/HNT catalysts in promoting LENR degradation via hydroxide‐driven chain scission. The significant reduction in molecular weight highlights their potential application in rubber processing and recycling, offering a sustainable approach to valorizing epoxidized rubber materials. © 2025 Society of Chemical Industry (SCI).