Building & Construction
Building & Construction Wheat gluten based bioplastic The energy released by the construction industries increases year after year, raising concerns about growing CO 2 emissions. It is worth noting that the construction industry is responsible for 23 % of world plastic waste production and ca. 37 % of global energy-related greenhouse gas (GHG) emissions are attributed to the construction sector [1]. Plastics-based products are used in the construction industries during packaging as well as in window panels, interior decor, and in electrical and electronic products. After the end-life of such products, a significant portion is recycled, while the remainder is either released into the environment or ends up in landfills, leading to serious environmental issues. This growing global environmental impact has steered construction science and engineering toward biobased plastics such as wheat gluten (WG), which could contribute to a low-carbon future. Bioplastics have evolved over time as a result of both scientific advances and market demand. For instance, DUS Architecture (Amsterdam, the Netherlands) has built a 700 m 2 canal house out of bioplastic using 3D printing technology [2 ]. Bioplastic has also been used in concretes as aggregates [3]. Elsewhere, Aectual, a Dutch company based in Amsterdam, has demonstrated the use of bioplastics to create sustainable, customizable flooring solutions [4]. These applications highlight the role of bioplastics in creating a more sustainable future. improve mechanical properties, it cannot improve flame resistance. On the other hand, the addition of a flame retardant imparts fire safety but reduces mechanical strength. Hence, gluten with balanced mechanical strength and flame resistance along with reduced water/moisture sensitivity could be a viable option for construction application. This issue was addressed by the research group at the Structural and Fire Engineering Division at Luleå University of Technology, Sweden. As part of their research, they treated gluten bioplastic with pyrolysis biochar and sustainable fireretardants using a novel technique. According to Oisik Das, a senior lecturer leading the study, this gluten with biochar and fire-retardant is more sustainable, eco-friendly, and efficient for creating potential structural components in construction engineering. His recently completed research project, funded by Brandforsk in Sweden (grant number 321- 002), sought to investigate the possibility of balancing the fire and mechanical properties in bioplastics by incorporating biochar doped with sustainable fire retardants. Sustainable fire-retardants were doped inside the numerous pores of biochar (Figure 1), and this functionalised biochar was then integrated within gluten bioplastic. The project discovered that using a thermal method, fire retardants can be effectively doped inside the pores of biochar and can then be used to create gluten bioplastic having good fire-safety properties without compromising on mechanical strength. Bioplastics, like gluten, are innocuous to the environment and their degradation does not lead to detrimental microplastic production. Gluten has acceptable mechanical and cohesive properties and can be formed into desired shapes. The use of WG-based bioplastics has the potential to replace traditional plastics in construction applications. Despite the fact that gluten is environmentally friendly and has mechanical properties comparable to conventional plastics, the question of “How effective is gluten bioplastic for construction applications?” remains somewhat unanswered. Aside from strength, gluten should also possess fire and water resistance properties to meet the requirements of construction applications. Unfortunately, gluten is sensitive to water and prone to degradation during a fire. However, reinforcements and flame retardants can help in resolving these issues, albeit separately. While reinforcement can Figure 1: Thermally doped fire retardants (here naturally-occurring lanosol) in biochar pores [5]. References: 1. Hamilton, I., Rapf, O., Kockat, D.J., Zuhaib, D.S., Abergel, T., Oppermann, M., Otto, M., Loran, S., Fagotto, I., Steurer, N. and Nass, N., 2020. 2020 global status report for buildings and construction. United Nations Environmental Programme. 2. https://www.bioplasticsmagazine.com/en/news/meldungen/2016-01-11-Bioplastic-elements-facade-Europe-Building.php (assessed on 19-09-2022). 3. Oberti, I. and Paciello, A., 2022. Bioplastic as a Substitute for Plastic in Construction Industry. Encyclopedia, 2(3), pp.1408-1420. 4. https://www.engineering.com/story/aectual-3d-prints-everything-from-floors-to-walls (assessed on 19-09-2022). 5. Perroud, T., Shanmugam, V., Mensah, R.A., Jiang, L., Xu, Q., Neisiany, R.E., Sas, G., Försth, M., Kim, N.K., Hedenqvist, M.S. and Das, O., 2022. Testing bioplastics containing functionalised biochar. Polymer Testing, p.107657. 6. Das, O., Loho, T.A., Capezza, A.J., Lemrhari, I. and Hedenqvist, M.S., 2018. A novel way of adhering PET onto protein (wheat gluten) plastics to impart water resistance. Coatings, 8(11), p.388. 24 bioplastics MAGAZINE [05/22] Vol. 17
Remaining water (%) Another major issue with gluten is its dimensional instability under high moisture conditions. Oisik Das and his co-workers came up with the novel idea of laminating gluten with polyethylene terephthalate (PET) film using cross-linkers, which resulted in significantly improved water barrier properties (Figure 2.a) while keeping the dimension 100 95 90 85 80 75 in construction Neat WG PET Ground Brushed (a) 70 0 1 2 3 4 By: Oisik Das, Senior Lecturer & International Coordinator Vigneshwaran Shanmugam Department of Civil, Environmental and Natural Resources Engineering Luleå University of Technology, Luleå, Sweden intact (Figure 2.b) under high moisture conditions. Based on the aforementioned, it is possible to alleviate some of the performance properties of gluten bioplastic taking it one step closer to being used in the construction industry, but further research is needed to determine its load-bearing capacity as well as creep resistance and fatigue-related properties. Figure 2: State of the neat and PET-layered gluten films (samples named Ground and Brushed) when exposed to saturated water vapor (100 % relative humidity) on the inside of a cup and 50 % relative humidity on the outside [6]. From Science & Research Days Leading Event on Carbon Capture & Utilisation Learn about the entire CCU value chain: • Carbon Capture Technologies and Direct Air Capture • CO2 for Chemicals, Proteins and Gases • Advanced CCU Technologies, Artificial Photosynthesis • Fuels for Transport and Aviation • Green Hydrogen Production • Mineralisation • Power-to-X 1 Best CO2 Utilisation 2023 O R G A N I S E R N OVA -I N S TIT U T E I N N OVAT I O N AWA R D Call for Innovation Apply for the Innovation Award “Best CO2 Utilisation 2023” Organiser Contact Dominik Vogt Conference Manager dominik.vogt@nova-institut.de co2-chemistry.eu bioplastics MAGAZINE [05/22] Vol. 17 25
