Temperature effect on the single and repeated impact responses of intraply flax/basalt hybrid polypropylene composites

Abstract Low‐velocity impacts can severely jeopardize the structural reliability of polymer composites. In view of this, the present work provides a thorough overview of the impact response of polypropylene (PP) composites reinforced with an ecofriendly intraply flax/basalt hybrid fabric, assessing the effect of different parameters: energy level, temperature, and number of impacts. Indeed, high‐energy single impacts are as dangerous as low‐energy repeated impacts for the structural integrity of laminates. Moreover, considering the poor interfacial adhesion between hydrophobic polyolefin matrices and hydrophilic vegetable fibers, the effect of a maleic anhydride coupling agent was evaluated. A detrimental effect of coupling agent on composites impact response was observed, determining a reduction of the impact life (impacts to failure from 83 to 63 at 10 J and from 30 to 9 at 15 J) because several energy dissipation mechanisms were prevented. Decreasing temperatures (−40°C) caused an embrittlement effect on neat PP composites with an increase between 7.3% and 20.3% of maximum force and a decrease between 7.5% and 10.9% of maximum displacement, whereas increasing temperatures (80°C) led to a softening of compatibilized composites with a decrease between 13.8% and 27.5% of maximum force and an increase between 28.1% and 34.4% of maximum displacement.