Enhancing odor reduction and properties in polypropylene-based wood plastic composites with halloysite nanotubes and beta-cyclodextrin

Official URL: https://dx.doi.org/10.1002/app.57661

Undesirable odor emissions that originate from polypropylene (PP)-based wood plastic composites (WPCs) caused by volatile organic compounds (VOCs) restrict their indoor applications. This research investigates the effectiveness of halloysite nanotubes (HNT) and beta-cyclodextrin (β-CD) in reducing VOC emissions while simultaneously improving the mechanical and thermal properties of WPCs. Composites are produced by incorporating 2 wt.% and 5 wt.% of HNT, β-CD and are compared to commercial odor-control additives. Odor intensity is tested using sensory (jar) odor and headspace gas chromatography–mass spectrometry (HS GC–MS) methods. Mechanical, thermal, morphological, and structural properties are characterized through tensile testing, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and Brunauer–Emmett–Teller (BET) analysis. The odor results show the addition of 5 wt.% HNT and 2 wt.% β-CD causes a reduction of VOC peaks by 14% and 35%, respectively. HNT results in a 36.6% reduction of 4-methyl-octane and improves tensile strength and modulus by 6.3 (±0.3) % and 12 (±0.8) %, whereas β-CD advances in toughness. The BET and FTIR analyses confirm distinct adsorption behaviors and interactions within the polypropylene matrix. These results suggest the potential of HNT and β-CD as sustainable additives to improve the indoor applicability of PP-based WPCs.