Advanced VOC Emission Analysis for next generation Wood Plastic Composites for car interior trims in the SSbD4CheM project: Insights from Wood K plus

To meet the automotive sustainability targets of zero net carbon by 2050, there is an urgent need for the development and introduction of new materials like renewable composites with >80% renewable feedstock content addressing in parallel lower environmental impact and reduced material weight, thereby reducing fuel consumption of the used car. SSbD4CheM project funded under Horizon Europe CL4 Resilience 01-21 call covers the development of the next generation of Wood Plastic Composites (WPCs) with optimized emissions using sustainable natural fillers addressing the Key Performance Indicators (KPIs) for car interior trims. Wood K plus Bio-Based Composites and Processes Team covers WPC material development for injection molding applications in close collaboration with CRF Italy.  Wood K plus Indoor Quality and Emission Control (IQEC) Team takes care of detailed analysis of VOC (volatile organic compounds) emission testing of prepared materials. In this article we report more details on the ongoing work from Wood K plus Indoor Quality and Emission Control Team.

Indoor Quality and Emission Control (IQEC) Team

Cornelia has a background in microbiology and technical chemistry with a special focus on mycological wood modification and fungal biocontrol. As leader of the Indoor Quality and Emission Control (IQEC) team she possesses long-term experience in the field of microbial and biotechnological emission control as well as extractives analytics.

Martin is an experienced analytical chemist with focus on biomass extractives and VOC (volatile organic compounds). As senior researcher at Wood K plus, he has gained extensive knowledge in separating and analyzing organic substances using a wide range of chromatographic techniques, from small molecules to large polymers. His passion is to understand, analyze and optimize sustainable processes to minimize their impact on our environment.

Traditional VOC (volatile organic compounds) emission testing in the automotive sector, such as the VDA 278 method, primarily assesses materials based on a single sum value, specifically the total volatile organic compounds (TVOC). However, a more comprehensive approach focuses on the detailed monitoring of individual VOC emissions and their respective emission rates within a realistic exposure scenario. To achieve this goal, we coupled micro emission test chambers (Markes µ-CTE™ 250) with a PTR/TOF (Proton Transfer Reaction/Time of Flight, Vocus CI-TOF, Tofwerk, Switzerland) mass spectrometer from Tofwerk and monitored heating cycles of WPCs (Wood Polymer Composites) simulating a realistic exposure scenario (like a hot car in summer, 65°C for 4 hours; ISO 12219-3). PTR/TOF can be easily implemented to measure selected VOC emissions in the ppb range in a targeted analysis if calibration gas standards are available.¹ It can also be used for untargeted analysis to screen materials for unknown VOC emissions.

 

Discussion

The main VOC emissions detected from 2 WPC and a PP-(polypropylene) Matrix sample in both targeted and untargeted mode are shown in Figure 2. While these samples showed similar TVOC values (data now shown), the individual emissions detected by PTR/TOF showed some differences. In the PP-Matrix sample, mainly typical solvents like acetonitrile, acetone, toluene, phenol, ethyl acetate were detected, whereas in the WPC samples 30% Tencel and 30% Arbocel, VOC emissions from biogenic sources like acetic acid, propanoic acid, 2-propenal, furfural and -2-heptenal were found.

 

Outlook

Coupling of micro emission chambers with PTR/TOF-MS was successful and showed promising results for the individual monitoring of VOC emissions in a realistic exposure scenario. Individual VOC emissions detected in these WPCs in the untargeted analysis (screening) will be included in the targeted analysis in further studies to improve quantitative monitoring at the ppb level. In addition, the PTR/TOF will be coupled with emission test chambers [225L] for normative testing to find correlations with standard testing (VDA 278, ISO 12219-3), especially with quantitative TVOC determinations, to facilitate future TVOC analysis and individual VOC emission monitoring of materials for the automotive industry.

¹ Graus, M., Müller, M., & Hansel, A. (2011). High resolution PTR-TOF: quantification and formula confirmation of VOC in real time. Journal of the American Society for Mass Spectrometry, 21(6), 1037-1044

 

This project has received funding from the European Union’s Horizon Europe research and innovation programme under grant agreement n° 101138475. UK participants in SSbD4CheM project are supported by UKRI. CH participants in SSbD4CheM project receive funding from the Swiss State Secretariat for Education, Research and Innovation (SERI).