Thermal and viscoelastic behaviors of recycled polyvinyl chloride/styrene-acrylonitrile blend composites incorporating treated date palm fibers

Composites of a recycled polyvinyl chloride-styrene-co-acrylonitrile copolymer (rPVC-SAN) blended with a date palm fiber ratio of 30% by weight were produced. The composites were analyzed using combined thermogravimetric analysis (TGA)/differential thermal calorimetry (DSC) and dynamic mechanical analysis (DMA) to investigate their thermal and viscoelastic characteristics. Alkaline, silane, and combination alkaline-silane (ASiDF) treatments were assessed for fiber-matrix adhesion. A combination of melt-compounding techniques and hot-pressing molding was employed to create both untreated and treated composites. A thermal analyzer and a dynamic mechanical analyzer were used to test the thermal and DMA parameters of the composites, including glass transition temperature, storage modulus, loss modulus, initial thermal degradation temperature (Tonset), and maximum temperatures (Tmax1 and Tmax2). Compared to other treated composites, rPVC-SAN-ASiDF exhibited the greatest storage and loss moduli but the lowest peak damping factor. Cole-Cole analysis indicated a homogeneous distribution of fibers due to miscibility. This study demonstrated that rPVC-SAN composites reinforced with date palm fiber exhibited significant improvements in thermal and dynamic mechanical characteristics when enhanced by a combined ASiDF fiber treatment. The SAN concentration at the fiber-matrix interface increased during the extrusion process due to chemical interactions between the alkoxyl groups on 3-aminopropyltriethoxysilane and the nitrile groups on SAN, in addition to cross-linking between rPVC and SAN. The modified fibers positively influenced the DMA and thermal properties of the thermoplastic blend composites. Overall, the results indicated that composites suitable for automotive components exhibited enhanced thermal and dynamic performance when reinforced with a thermoplastic blend that included treated date palm fibers.