Environmentally Sustainable rPVC / SAN Composites Reinforced With Cellulose‐Rich Date Palm Fibers for Construction Materials

ABSTRACT

This study presents the development of environmentally sustainable construction composites using recycled poly(vinyl chloride)/styrene–acrylonitrile (rPVC/SAN) blends reinforced with untreated (BCU), bleached (BC‐Ble), and microcrystalline cellulose (BC‐MC) derived from date palm fibers (DFs). Fiber bleaching and acid hydrolysis were employed to remove lignin and hemicellulose, improve cellulose crystallinity, and enhance fiber‐matrix compatibility. Composites containing 30 wt.% reinforcement were produced using melt compounding followed by hot pressing and were evaluated for thermomechanical, rheological, and water resistance properties relevant to construction applications. BC‐U demonstrated reduced tensile strength (28.4 MPa) compared to the neat rPVC/SAN blend (BC‐U0) (32.1 MPa) due to insufficient interfacial adhesion. In contrast, bleached fibers enhanced tensile strength to 36.7 MPa, while BC‐MC achieved better performance, attaining 41.2 MPa and a modulus of 3980 MPa. Similar trends were observed in flexural behavior, with BC‐MC reaching a strength of 70.5 MPa and a modulus of 3850 MPa. Thermal investigations indicated enhanced high‐temperature resistance, with T _max increasing to approximately 423°C for BC‐MC. Dynamic mechanical (DMA) investigations confirmed improved stiffness and an increase in glass transition temperature ( T _g ) from approximately 62°C–80°C. Rheological evaluations revealed increased complex viscosity and storage modulus following fiber treatment, especially in BC‐MC, signifying limited chain mobility and the formation of a percolated cellulose network that improves melt strength and processing stability. Furthermore, water absorption decreased significantly from 6.6% in BC‐U to 3.6% in BC‐MC. The combination of mechanical, thermal, rheological robustness and low moisture absorption indicates that MCC‐reinforced rPVC/SAN composites are promising candidates for durable and sustainable construction materials. This method facilitates circular economy initiatives by integrating recycled polymers with reinforcements obtained from agricultural waste while satisfying essential performance criteria for building and construction applications.