SusChEM: Design and Evaluation of Soybean Oil Based Adhesives for Aqueous Environments

University Of Akron, Akron OH

Investigators

Abstract

Non-technical: Adhesives are extensively used in several applications and are almost always made from petroleum based starting materials, which is a depleting resource. Therefore replacing these resources with widely available and sustainable materials such as soybean oil for the synthesis of adhesives is a national need. In medicine, adhesives are a critical component, and in several instances such as in a cardiac surgery, medical adhesives are a necessity. However, the performance of human-made adhesives is often less than optimal when it is applied in surgical or wet environments. Nature provides spectacular examples of adhesives that work extraordinarily in wet and harsh conditions. Mussels are able to secrete protein based adhesives that enable them to stick to boats and docks underwater. The PIs have developed an adhesive that is made from readily available and sustainable soybean oil which demonstrates superior adhesion to surfaces in wet conditions. This award is aimed at providing a better understanding of the chemical processes that are responsible for strong adhesion of this soybean oil based adhesive in wet conditions. The PIs will systematically modify the chemical composition of these adhesives and examine the nature of the adhesion. Such studies will enable design of adhesives that perform in challenging environments and which are translationally viable. The award enables graduate students to gain expertise in techniques and methodologies that are at the cutting edge of their field. In addition, the award will provide research opportunities for undergraduate and high school students. Technical: Adhesives such as those secreted by mussels and sandcastle worms are impressive for their ability to function in harsh conditions such as sea water and high winds. Synthetic polymers fall far short in their ability to mimic this ability to perform in wet environments. This award is aimed at gaining a better understanding of the interactions at the interface that enable adhesion under wet environments. The PIs have designed a modular polyester platform that enables the incorporation of various functional groups into the designed polyester. The major monomer for the synthesis of the adhesive polyester is derived from soybean oil - a widely available and sustainable resource. The designed polyester will contain long-chain pendant groups derived from soybean oil, which will provide the hydrophobic character to enable exclusion of water. In addition, the adhesion to a substrate will be provided by catechol units. Cohesive strength will be provided by coumarin units that crosslink upon photoirradiation. It will also contain various functional groups such as hydroxyl and amine groups that will affect the adhesion. The contribution of these functional groups will be examined by techniques that probe the substrate interface. Sum-frequency spectroscopy, soft contact mechanics (JKR) and solid state NMR will provide insight into the processes that account for the improved adhesion of these polyesters in wet environments. Students trained through this award will gain expertise in polymer synthesis, polymer characterization using cutting edge surface characterization techniques, and the opportunity to work collaboratively on teams that bring complementary skills.