Under glass weathering of hemp fibers reinforced polypropylene biocomposites: Impact of Volatile Organic Compounds emissions on indoor air quality

Nowadays, natural fibers reinforced composite materials can be used in closed environments such as car cabins. It has hence become a necessity to study their emissions of Volatile Organic Compounds (VOCs) to check their impact on indoor air quality. The purpose of this work was first to study the emissions of VOCs from hemp fibers reinforced polypropylene (PP) biocomposites in comparison with neat PP. The influence of under windshield glass weathering on VOCs release was then investigated. The exposition lasted one year and the fiber loading influence on emissions was studied all along the weathering. The VOCs concentration at the material/air interface was determined using a passive sampling method involving an emission cell coupled with Solid Phase MicroExtraction (SPME). VOCs analysis was then carried out by gas chromatography coupled to mass spectrometry and flame ionization detections. One of the most significant results is the drastic increase of oxygenated compounds concentration during the exposition, especially for biocomposites. Among these oxidation by-products, formaldehyde, acetaldehyde, furfural and 2-furanmethanol, recognized as Cancerogen, Mutagen and toxic for Reproduction (CMR), were detected. A broad range of alkanes, specific of PP matrix degradation was also identified. Finally, measured concentrations of substances found in this work and listed in Vehicle Indoor Air Quality (VIAQ) standards were gathered in order to discuss the biocomposites emissions impact on indoor air quality.