Accelerated weathering and hydrothermal aging of poly(butylene succinate) composites reinforced with wood waste fillers torrefied at different temperatures

Growing demand for sustainable materials is accelerating research on lignocellulosic composite materials. A persistent bottleneck is the moisture sensitivity of lignocellulosic fillers, which compromises interfacial stability and long‑term properties under service exposure. Torrefaction offers a solvent- and chemical-free route to reduce hygroscopicity and tailor surface chemistry, yet its processing temperature-dependent effects on the compatibility with polymer matrices remain lightly studied. This study presents a systematic comparison of raw and torrefied wood waste fillers produced at 225, 275, and 300 °C, compounded into poly(butylene succinate) (PBS) at 30 and 50 wt%. Compatibility was assessed via tensile tests, SEM, surface wetting, and water uptake, which was fitted using Fickian diffusion. Composite durability was assessed via hydrothermal aging (20/50/70 °C) and accelerated UV weathering (504 h). Torrefaction, particularly at 275 and 300 °C, consistently reduced equilibrium water uptake by up to 2-fold and diffusion coefficients by up to 4.7-fold relative to raw filler, while mitigating tensile strength loss typically associated with lignocellulosic reinforcement. Composites with 50 wt% wood filler achieved an elastic modulus of up to 1.8 GPa, and those containing torrefied wood retained about 1.2 GPa after hydrothermal aging. Under UV weathering, color change ( ∆ E ab * > 5) occurred within 24–48 h for untreated wood composites but was delayed to 96–360 h with torrefied fillers. Collectively, the results establish a torrefaction temperature–structure–property framework that translates to long‑term durability. The findings highlight torrefied wood as an effective reinforcement for developing durable, UV- and moisture-resistant PBS-based alternatives to traditional wood-plastic composites. • Torrefaction of wood waste filler at 225, 275, 300 °C compared in PBS composites. • Torrefied fillers improved composite durability under hydrothermal and UV aging. • Water uptake lowered 2 × and diffusion 4.7 × with torrefied wood fillers. • Torrefaction at 275 and 300 °C enhanced adhesion and tensile strength retention. • Delayed discoloration in UV weathering achieved with torrefied fillers.