Reduction of Volatile Organic Compounds With Hydrazine-, Carboxybetaine- and Aminosilane-Functionalized Halloysite Nanotube in Recycled Polyolefin Blends

Recycled polyolefin (rPO) is a promising material for sustainable applications, but its use is limited by the release of volatile organic compounds (VOCs), which cause odor and reduce indoor air quality. This study introduces a strategy to address this issue by chemically modifying halloysite nanotubes (HNTs) to improve their VOC adsorption efficiency and multifunctional performance in rPO. HNTs were functionalized through a three-step process involving N-[3-(trimethoxysilyl)propyl]ethylenediamine (TMPED), monochloroacetic acid (MCA), and hydrazine hydrate (HH), producing amine-rich surfaces. Modified HNTs were incorporated into rPO at 2 and 5 wt% and compared with unmodified HNTs. VOC reduction was assessed using headspace gas chromatography–mass spectrometry (HS GC–MS) and jar testing, while structure and properties were analyzed by FTIR, NMR, TGA, DSC, SEM, BET, and tensile tests. The 5 wt% TMPED-MCA-HH-HNT composite reduced total VOC intensity by 91%, particularly, key odorants such as acetaldehyde and cyclotrisiloxane. This effect is attributed to dual action: physical adsorption in the HNT lumen/mesopores and selective chemisorption via hydrogen bonding and Schiff base formation between amine/hydrazide groups and polar VOCs. Thermal stability, tensile modulus (+25.3%), and crystallinity (73.4%) were also improved. These findings highlight functionalized HNTs as efficient additives for enhancing both the mechanical and odor performance of rPO.