Long Jute Fiber‐Reinforced Polypropylene Composites for Lightweight Automotive Structures

ABSTRACT This study investigates the effects of long jute (LJ) fiber reinforcement on the mechanical, thermal and sound transmission loss (STL) properties of polypropylene (PP)‐based biocomposites. Long fiber thermoplastics (LFT) are increasingly used in various industries, including automotive applications, due to their superior mechanical performance and lightweight characteristics. The biocomposites were fabricated using an LFT‐G production line, incorporating different weight fractions of LJ fibers (20, 30, and 40 wt.%) into PP. The sound insulation properties of the composites were analyzed through STL measurements. Compared to neat PP, PP‐40LJ exhibited an STL increase of approximately 45% at 100 Hz and 55% at 1000 Hz, indicating improved frequency‐dependent sound attenuation with increasing jute fiber content. Mechanical characterization was performed through tensile, flexural, and impact tests, while morphological analysis was conducted via scanning electron microscopy (SEM). Thermomechanical performance was significantly enhanced, as evidenced by an increase in heat distortion temperature (HDT) from 57.9°C to 126.6°C and Vicat softening temperature (VST) up to 104.4°C, indicating a higher service temperature for the composites. These findings highlight the potential of LJ fiber‐reinforced PP composites for lightweight applications requiring enhanced sound insulation and thermal properties.