Fuente: Journal of applied polymer Lugar: RESEARCH ARTICLE This study offers a multistep surface functionalization process for halloysite nanotubes (HNTs) involving TMPED, MCA, and hydrazine hydrate to effectively capture odor-active volatile organic compounds (VOCs) in recycled polyolefin blends which consist of polypropylene (PP) and polyethylene (PE). The modified HNTs provide dual functions of odor reducers and mechanical enhancers, enabling the development of cleaner, higher-performance recycled plastics.


ABSTRACT
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.