Mensah Rhoda Afriyie, Shanmugam Vigneshwaran, Kaynak Elif, Sokol Denis, Wahl Joel, Le Kim Cuong, Zhang Yang, Jiang Lin, Neisiany Rasoul Esmaeely, Turhan Emine Ayşe, Das Oisik
Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå, 97187, Sweden.
Institute of Chemistry, Faculty of Chemistry and Geosciences, Vilnius University, Naugarduko 24, Vilnius, LT-03225, Lithuania.
Sci Rep. 2025 Mar 17;15(1):9166. doi: 10.1038/s41598-025-93037-x.
Carbon-based materials are highly sought after due to their superior properties, making them valuable for high-performance applications. However, most carbon-based materials are derived from fossil sources, and their synthesis often involves hazardous chemicals. Therefore, it is essential to develop sustainable methods for synthesising these materials from renewable resources, using fewer solvents, catalytic reagents, and generating minimal waste. In this study, few-layer graphene oxide (GO) was directly synthesised from waste biomass, without the formation of an amorphous intermediate, and its use as a fire retardant in two bioplastics was evaluated. Waste birch wood biomass was converted directly into graphitic carbon using manganese nitrate as a catalyst, with varying concentrations (0.003 to 0.1 mol-metal/g-wood) and treatment durations (1 and 2 h). The catalyst was doped through vacuum soaking and mild heating (90 °C), which facilitated the formation of graphitic carbon at relatively lower temperatures (< 1000 °C), eliminating the need for producing amorphous biochar prior to graphitisation. After pyrolysis at 900 °C and 950 °C for 2 h, the sample containing 0.005 mol-metal/g-wood, treated at 950 °C, exhibited the highest degree of graphitisation. This sample was further processed in a planetary ball mill with melamine as a dispersant for 30 min. Characterisation showed a broad absorption peak at 230 nm and the presence of semi-transparent sheets (3-8 layers), indicating the presence of GO. To evaluate its performance as a fire retardant, 2 wt% of the synthesised GO was added to polyamide 11 and wheat gluten bioplastics, which were then subjected to cone calorimeter tests. The results showed a 42% and 33% reduction in the peak heat release rate for polyamide 11 and wheat gluten, respectively, compared to their neat counterparts. The flame retardancy index further indicated that GO had a more significant impact on improving the fire safety of wheat gluten compared to polyamide 11. This study highlights a sustainable method for the preparation of few-layer GO at lower temperatures than contemporary methods, making the process more energy-efficient, environmentally friendly, and cost-effective. Additionally, the effectiveness of few-layer GO as a fire-retardant additive for enhancing the fire safety of bioplastics has been demonstrated.
碳基材料因其卓越的性能而备受青睐，使其在高性能应用中具有很高的价值。然而，大多数碳基材料都来源于化石资源，其合成过程通常涉及危险化学品。因此，开发可持续的方法，以可再生资源为原料，使用更少的溶剂、催化试剂，并产生最少的废物来合成这些材料至关重要。在本研究中，从废弃生物质中直接合成了少层氧化石墨烯（GO），且未形成无定形中间体，并评估了其在两种生物塑料中作为阻燃剂的用途。使用硝酸锰作为催化剂，将废弃桦木生物质直接转化为石墨碳，硝酸锰的浓度不同（0.003至0.1摩尔金属/克木材），处理时间也不同（1小时和2小时）。通过真空浸泡和温和加热（90°C）对催化剂进行掺杂，这有助于在相对较低的温度（<1000°C）下形成石墨碳，从而无需在石墨化之前生产无定形生物炭。在900°C和950°C下热解2小时后，在950°C下处理的含有0.005摩尔金属/克木材的样品表现出最高程度的石墨化。该样品在行星式球磨机中以三聚氰胺作为分散剂进一步处理30分钟。表征显示在230nm处有一个宽吸收峰，并且存在半透明薄片（3 - 8层），表明存在GO。为了评估其作为阻燃剂的性能，将2wt%合成的GO添加到聚酰胺11和小麦面筋生物塑料中，然后对其进行锥形量热仪测试。结果表明，与纯聚酰胺11和小麦面筋相比，聚酰胺11和小麦面筋的峰值热释放速率分别降低了42%和33%。阻燃指数进一步表明，与聚酰胺11相比，GO对提高小麦面筋的火灾安全性有更显著的影响。本研究突出了一种在比当代方法更低的温度下制备少层GO的可持续方法，使该过程更节能、环保且具有成本效益。此外，还证明了少层GO作为阻燃添加剂对提高生物塑料火灾安全性的有效性。
