Upcycling of agricultural residues for additive manufacturing: corn straw waste as reinforcing agent in acrylonitrile-butadiene-styrene composite matrix

Abstract More than 1.2 billion tonnes of corn straw wastes (CSW) are generated worldwide each year. CSW is a fibrous, inexpensive, light material which is highly available. Currently, there are no pathways to manage such amount of CSW, being mainly burned in open field, with the environmental impact that this entails. In this work, the upcycling of CSW as a reinforcement material to be integrated in acrylonitrile-butadiene-styrene (ABS) composite matrix for additive manufacturing applications is proposed. ABS+CSW composite material has been used to manufacture 3D printing filaments, aiming to fabricate products via fused filament fabrication techniques. Standardized tensile and flexural test specimens were manufactured incorporating different contents of CSW (ranging from 1 to 5%, w/w) and glycerol (1%, w/w) to ABS: B1-1% (sample with 1% (w/w) of CSW), B2-3% (sample with 3% (w/w) of CSW), and B3-5% (sample with 5% (w/w) of CSW). The maximum tensile stress of the composites slightly increased by 1.3% (for B1-1%), exceeding 10% when B1-3% was used, compared to ABS. Moreover, it decreased to −3% for the specimen made with B3-5. In general terms, the higher the biomass content, the higher the flexural stress. However, the exception was provided by B1-1%, as the flexural stress decreased by 5% compared to ABS. The maximum flexural stress value was reached at 3% SCW, providing a value above 17%, compared to ABS and above 24%, compared to B1-1%. Furthermore, the incorporation of CSW into the ABS matrix resulted in lighter 3D printing filament materials and products compared to the use of ABS.