3D-printing of the polymer/insect-repellent system poly(l-lactic acid)/ethyl butylacetylaminopropionate (PLLA/IR3535)

Sustainable Electrospun Poly(l-lactic acid) Fibers for Controlled Release of the Mosquito-Repellent Ethyl Butylacetylaminopropionate (IR3535)

“…By systematic variation of the electrospinning parameters, including voltage, nozzle-to-collector distance, flow rate, and solution composition, uniform fibers with a diameter close to 1 μm and containing a large amount of the repellent, exceeding 40 m%, were obtained. Such a high amount of repellent was impossible to incorporate into the polymeric carrier by melt extrusion and 3D printing, ,, where only up to about 25 m% IR3535 was added. Thermal and structural analyses revealed that IR3535 results in a decrease in the glass transition temperature of the polymer component, confirming thermodynamic solubility, as suggested in earlier works, , and causing plasticization of the amorphous PLLA phase.…”

“…Incorporating the repellent IR3535 into bio-sourced and biodegradable PLLA opens the way to the realization of an environment-friendly repellent-delivery device. After successful testing of melt extrusion , and 3D printing of semi-finished and final products of the PLLA/IR3535 system, in this work, electrospinning of fiber mats as an alternative technology for obtaining such an environment-friendly repellent-delivery system is investigated. By systematic variation of the electrospinning parameters, including voltage, nozzle-to-collector distance, flow rate, and solution composition, uniform fibers with a diameter close to 1 μm and containing a large amount of the repellent, exceeding 40 m%, were obtained.…”

“…The left plot of Figure 4 shows the TGA curves (Figure 4a), while in the right plot, their first derivatives are shown (Figure 4b). The degradation of neat IR3535, measured at identical conditions in an independent study, 25 commences at around 100 °C and is completed at about 200 °C, with the highest evaporation rate occurring at 185 °C. For PLLA fibers containing IR3535, two mass loss events are observed.…”

“…As such, in-depth analysis of the glass transition temperature by employing fast scanning chip calorimetry combined with in situ evaporation of the liquid to achieve controlled change of the system composition has revealed that PDLLA and IR3535 are thermodynamically miscible in the entire composition range . Regarding the polymer-rich part of the PLLA/IR3535 system, IR3535 acts as a functional plasticizer of PLLA, , offering additional advantages from the point of view of reducing the inherent brittleness of PLLA. , Recently, PLLA-parts/products accommodating up to 25 m% of IR3535 were manufactured by classical melt extrusion , and 3D printing, emphasizing their potential for controlled long-term release of IR3535. Since in the case of electrospun fibers, the carrier geometry/shape is qualitatively different compared to scaffold-like bulk structures and products with a rather low surface-to-volume ratio, it is expected that the IR3535-release characteristics are different, and that personal-protection devices based on fibers can be generated.…”

Structure, Properties, and Release Kinetics of the Polymer/Insect Repellent System Poly (l-Lactic Acid)/Ethyl Butylacetylaminopropionate (PLLA/IR3535)

“…Important from the point of view of obtaining end user products, PLLA parts, such as finger rings accommodating up to 25 m% liquid mosquito repellent IR3535, were successfully fabricated by 3D printing, suggesting novel materials/processing routes to obtain PLLA-based controlled repellent release devices [44]. Furthermore, melt extrusion of PLLA/IR3535 strands as an efficient processing route for obtaining semi-finished products has been investigated, focusing on thermal, rheological, and release properties of the samples containing up to 25 m% IR3535 [41].…”