Nature provides a rich panoply of structural motifs comprised of composites whose mechanical properties exceed those of their individual components. The human endeavor to likewise craft value‐added structural materials from underappreciated, sustainably sourced feedstocks remains a formidable challenge. Herein, efforts are made to achieve durable composites by synergistic combination of sulfur and cellulose. Composites are achieved in which bulk sulfur is reinforced by a network of 1–20% by mass cellulose cross‐linked with polysulfide chains. Composites described herein are remeltable and have flexural strength exceeding that of Portland cement. A thorough analysis of these materials has been undertaken through nuclear magnetic resonance, infrared spectroscopy, Raman spectroscopy, elemental analysis, thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis. These analyses of both as‐prepared composites and fractionated materials unequivocally validate the formulation of these composites and the separability of the bulk sulfur from the reinforcing polysulfide‐cross‐linked cellulose network. The thermomechanical properties of these recyclable composites portend their tantalizing potential to supplant inherently unsustainable structural elements in numerous commercial applications. Further applications to improve the environmental resistance and flexural strength of Portland cement by treatment with the sulfur–cellulose composites are also discussed.
Interest in starch-based films has increased precipitously in response to a growing demand for more sustainable and environmentally sourced food packaging materials. Starch is an optimal candidate for these applications given its ability to form thermoplastic materials and films with affordable and often sustainably sourced plasticizers like those produced as waste byproducts by biodiesel and agricultural industries. Starch is also globally ubiquitous, affordable, and environmentally benign. Although the process of producing starch films is relatively straightforward, numerous factors, including starch source, extraction method, film formulation, processing methods, and curing procedures, drastically impact the ultimate material properties. The significant strides made from 2015 to early 2020 toward elucidating how these variables can be leveraged to improve mechanical and barrier properties as well as the implementation of various additives or procedural modifications are cataloged in this review. Advances toward the development of functional films containing antioxidant, antibacterial, or spoilage indicating components to prevent or signal the degradation of food products are also discussed.
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