Performance comes in all shapes and sizes but we hope to get “high” performance in materials science. The question is, what is “high” performance? The traditional view in materials science is that of something with high stiffness, strength, or toughness, especially if it is relative to a low density. This is because many applications in materials science simply require load-bearing capability and scientists and engineers look to push the boundaries of these properties. Volume 13, Issue 3 of Green Materials highlights several studies describing improved performance of engineered materials. Liu et al.1 melt compound wood flour (WF)-recycled polypropylene (rePP) thermoplastic composites. The studies show that maleic anhydride-grafted-polypropylene (MAH-g-PP) compatibilizer greatly improves the load-bearing capability of the composites as WF content increases. Fourier transform infrared (FTIR) spectroscopy shows the formation of chemical bonds between the WF and rePP when the compatibilizer is used and offers not only a high-performance material but one that utilizes economical biobased content and recycled thermoplastic for a more environmentally friendly material. Wang et al.2 also form new composite materials from natural sand filler and epoxy. Traditional properties like storage modulus and glass transition temperature show increases with various changes in viscoelastic damping below, near, and above the glass transition.
But materials performance does not necessarily have to be via. traditional means of, for instance, stiffness and strength. Li et al.3 formulate walnut shell/phenolic resin composites that are then carbonized to porous carbon electrodes for use in electrical applications. Electrodes with higher conductivity and lower resistivity are formed with lower walnut shell content and higher carbonization temperature. Suchat et al.4 make natural rubber latex-cellulose nanocrystal (NRL-CNC) composite films for mulching applications. Traditional mulching films are made from polyethylene (PE) and pose serious environmental problems for the specialty crop and horticulture industries because a lot of film is used each season and then discarded. The NRL-CNC films had good physical properties but interestingly, a study is conducted to show how the films affect cucumber growth. The NRL-CNC films outperformed traditional mulching materials resulting in enhanced plant growth.
Performance can be other things well beyond mechanical properties. Yuwvaranni et al.5 use plant extracts during the synthesis of iron oxide nanoparticles (FeNPs). The application for the FeNPs is for magnetic resonance imaging (MRI) contrast agents in medicine. The plant extracts contain a variety of phytochemicals that impart biocompatibility and anti-microbial and anti-inflammatory properties to the FeNPs, which enhance medical treatment. While environmental friendliness may not necessarily be a primary design criterion, in applications where there are stringent environmental conditions, having a “greener” material is very advantageous. One important property of drilling fluids is to inhibit clay swelling. Chang et al.6 use pomegranate peel extract as an additive in drilling fluids, which often contain potassium chloride as the swelling inhibitor along with other synthetic polymer additives. The pomegranate peel extract is capable of inhibiting clay swelling while offering a more environmentally friendly option.
Volume 13, Issue 3 of Green Materials continues to show the variety of research happening in the field. Interestingly, Chang et al.6 offer a brief techno-economic analysis of their pomegranate material and Wang et al. offer time-temperature superposition data. Both studies do so with the intent of fostering engineering design and commercial adoption, highlighting the importance of thinking down the line when researching new materials.
