Abstract
The present work describes new gels derived from cheap, abundant and non-toxic wood bark extracts of phenolic nature, behaving like elastomers. Especially, we show that these materials might be used as rubber springs. Such amazing properties were obtained by a quite simple synthesis based on the autocondensation of flavonoid tannins in water at low pH in the presence of a plasticizer. After gelation and drying, the materials presented elastic properties that could be tuned from hard and brittle to quite soft and deformable, depending on the amount of plasticizer in the starting formulation. Not only the materials containing the relevant amount of plasticizer had stress-strain characteristics in quasi-static and cyclic compression similar to most commercial rubber springs, but they presented outstanding fire retardance, surviving 5 min in a flame at 1000°C in air. Neither flame propagation nor drips were noticed during the fire test, and the materials were auto-extinguishable. These excellent features make these materials potential substitutes to usual organic elastomers.
Highlights
Natural rubber is a well-known material produced at the level of several million tons every year and used for many centuries, as the first uses were reported in the ancient Aztecs’ and Mayans’ culture [1]
The present work describes new gels derived from cheap, abundant and non-toxic wood bark extracts of phenolic nature, behaving like elastomers. We show that these materials might be used as rubber springs
The general shape of the curves presented by TEG(20) to TEG(47) are typical of what is known for commercial rubber springs, and with similar values of both stress and strain [8]
Summary
Natural rubber is a well-known material produced at the level of several million tons every year and used for many centuries, as the first uses were reported in the ancient Aztecs’ and Mayans’ culture [1]. Rubbers are elastomers obtained after a crosslinking step, called vulcanization in this context, and after which the polymer chains have enough mobility to reorganize for redistributing an applied stress. Rubber-like materials were prepared and characterized from plant-derived polyphenols. Whereas such raw materials are famous for giving hard resins from which adhesives can be obtained mainly for wood products [4], getting soft and elastic solids was unexpected. This could be achieved, by using the relevant plasticizer in relevant amounts so that neither the material remained brittle nor the crosslinking was prevented. The main steps describing the synthesis of these new rubber-like materials are presented, as well as a selection of physical and chemical properties
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
