Preparation of terpen-based microspheres via photo-initiated suspension polymerization

The recent depletion of resources from fossil fuels is a major concern today. Therefore, there is an obligation to find new materials based on renewable resources. The use of terpene for the production of renewable plastics has been a common research topic in recent years. The design and preparation of terpene-based polymers involves the application of different chemical strategies and a wide variety of polymerization techniques, taking advantage of the chemical functionality (eg, conjugated double bonds, hydroxyl and carboxyl groups) in terpene molecules. Microspheres are small spherical particles between 1 and 1000 𝜇𝑚 in diameter. Suspension polymerization processes are particularly suitable for the production of microspheres. In this technique, both the initiator and the monomer are insoluble in the polymerization medium, while the initiator dissolves in the monomer and polymerization occurs in monomer droplets. The monomer phase is suspended as small droplets in the medium by means of a stirrer and a suitable suspending agent. In this thesis, polymeric microspheres were synthesized using the suspension polymerization method of terpene-based β Mirsen (My) and 1,4-butanediol dimethacrylate (BDDMA) in different proportions. In order to obtain polymeric microspheres efficiently and quickly, polymerization was carried out by UV-irradiation in the presence of photoinitiator. The effect of the monomer composition was investigated by varying the My ratio in the oil phase composition from 10% to 90% by volume. The thesis study was carried out in two stages as the synthesis of polymeric microspheres and the characterization of the synthesized microspheres using the suspension polymerization method. The chemical structure of the prepared microspheres was examined by Fourier Transform Infrared (FT-IR) Spectroscopy and Nuclear Magnetic Resonance (NMR) spectroscopy, and the surface morphology and size were examined by Scanning Electron Microscopy (SEM). The specific surface areas were determined by applying the Brunauer-Emmett-Teller (BET) isotherm to the N2 adsorption/desorption isotherm. Particle sizes were determined by optical microscope and particle size distribution analysis was performed with Zetasizer. In addition, the swelling behavior of the microspheres was investigated and the crosslink density (q) and the average molecular weight (Mc) between the crosslinks were calculated using the Flory-Rehner Theory. As a result, it can be concluded that changing the monomer feed composition by changing the My ratio changes the particle morphology, size and distribution.