Reduction Of Volatile Organic Compounds In Wood Plastic Composites Using Functıonalized Halloysite Nanotubes

This thesis investigates the formulation of next-generation wood–plastic composites (WPCs) that meet the dual criteria of environmental responsibility and advanced material performance. The starting point of this study is to respond to increasing regulatory demands for eco-conscious material solutions, particularly in indoor environments where volatile organic compound (VOC) emissions generate unpleasant odors that hinder their use in applications such as automotive interiors. This thesis focusses on halloysite nanotubes (HNTs), their functionalized derivatives (Mod-HNTs), and β-cyclodextrin (β-CD) with regard to the capture of VOCs in WPCs, as well as their capabilities in odor reduction and structural changes. HNTs are naturally obtaining aluminosilicate nanotubes which have a high aspect ratio and being able to modify their internal and external surfaces. To improve their interaction with non-polar polymer matrices and polar VOCs, HNTs were surface-functionalized through aminosilane grafting and termed as Mod-HNT. In parallel, β-CD which has a cyclic oligosaccharide with a toroidal molecular architecture enables the selective inclusion of odor-causing VOCs, particularly aldehydes and aromatic compounds, within its hydrophobic cavity through host–guest complexation. WPCs are produced with high-shear thermo-kinetic mixing, also followed by injection moulding in order to simulate scalable manufacturing processes. The formulations consisted of PP, rPO, PA11 polymers, 30 wt.% wood fiber (WF) and additive concentrations of 2 wt.% and 5 wt.%. A multitude of analytical methods were used to measure the performance of the materials. VOC emissions were quantified via headspace gas chromatography–mass spectrometry (HS-GC-MS), and odor levels were evaluated through sensory Jar testing. Thermal behavior was analyzed through thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), while interfacial chemistry was investigated by Fourier-transform infrared spectroscopy (FTIR).The morphological properties were analysed by using scanning electron microscopy (SEM), meanwhile mechanical properties were measured with tensile testing. The experimental results revealed that unmodified HNTs increased stiffness and slightly decreased VOC levels. Mod-HNTs have shown a reduction of up to 96% in VOC emissions in PP-based WPCs and considerably improving fiber–matrix interaction. β-CD revealed selective binding attraction for aromatic and aldehydic compounds, which causes increased ductility, as illustrated by an increase in strain-at-break. The 5 wt.% Mod-HNT and 2 wt.% β-CD generated synergistic effects, improving both environmental and structural results Mechanical analysis suggested increases of up to 12% in tensile strength confirm by SEM imaging that revealed a decrease in interfacial voids and increased nucleation that yields crystallinity. FTIR analysis proved the presence of chemical interactions between the functional additives and the polymer matrices. The effect of matrix polarity on filler dispersion and performance has been discovered in different WPCs formulations. PA11- and rPO-based WPCs displayed distinct fibrillation and dispersion morphologies, which contributed to their unique mechanical profiles. This thesis presents a framework to produce high-performance, low-emission composite materials that comply with the principles of circular economy plans. This study uses functionalized nanofillers with petroleum-based, renewable, and bio-based polymer matrices, providing new insights into the interactions between fillers and matrices. It proposes an efficient strategy for the production of WPCs that suitable for high-performance applications, such as automotive interior, electronic, and building materials.