Study of interactions and stability of pyrethroids and cellulose allomorphs for controlled release applications
Type of DegreeMaster's Thesis
Forestry and Wildlife Science
Restriction TypeAuburn University Users
MetadataShow full item record
The study of controlled release materials is a growing field for applications like agricultural, biomedical, and insecticidal fibers. Cellulose, because of its abundance and ability to be modified and regenerated into many forms, is a sustainable and practical choice of controlled release substrate. In the search of active bio-based materials, the use of cellulose as a sustainable and renewable carrier for active ingredients as an alternative to synthetic polymeric systems such as polyesters; however, the understanding of the underlying interactions between relevant compounds such as insecticides and cellulose still need to be studied. Belonging to a class of insecticides called pyrethroids, deltamethrin and permethrin commonly used for killing disease carrying arthropods such as mosquitoes, therefore, it is important to investigate its interactions with various surfaces. Due to resistance being built up against these insecticides, synergists like piperonyl butoxide (PBO) are being added to products to inhibit the resistance of the mosquito against the pyrethroids for a short time. For this reason, these components were studied in this work to evaluate the behavior and interactions with different cellulose allomorphs using a model film approach through surface sensitive techniques such as Atomic Force Microscopy (AFM), Quartz Crystal Microbalance with dissipation monitoring (QCM-D), and Surface Plasmon Resonance (SPR). AFM was used to generate images of these films and confirm full coverage of the sensor by the sample. QCM-D and SPR were used in combination to quantify surface interactions with hydrophobic model films surfaces such as polystyrene and silica. Thus, the adsorption onto these model films would resemble the expected charges found in cellulose due to its hydrophilic nature, or other common polysaccharides such as chitosan with a positive charge, and lignin’s hydrophobic nature. Cellulose and other sustainable and renewable biobased materials have drawn interest as possible replacement of harmful synthetic polymeric 3 systems for the purpose of carrying an active ingredient. This as various industries like agriculture and textiles aim to substitute fossil-based materials in controlled -release of fertilizers or pesticides, for example. However, it is important to first understand the basic interactions between the carrier materials and the active ingredients. In addition, Nuclear Magnetic Resonance (NMR) was used to determine the stability of these chemicals in common cellulose solvent. In this study, in order to resemble the fiber- making process, ionic liquid was used to regenerate the native cellulose I to cellulose II for the interactions study with pyrethroids. Over time, at a controlled temperature, these insecticides were tested, and their degradation compounds were monitored to model their behavior in dry jet wet spinning. This work will be used in the future to determine the possibility of these being applicable to regenerated cellulose products (i.e. fibers, foams) for controlled release of insecticides.