Department of Synthesis and Characterization of Polymers

The aim of the department is to cover completely the expertise in synthesis of polymers using various polymerization techniques including free radical, reversible-deactivation radical and anionic polymerizations. The second object of synthesis represents preparation, spectral characterization and mainly utilization of different fluorescence probes for characterization of polymer microstructure and for polymerization study mechanism. Modification of polymers by grafting, crosslinking and functionalizations and preparation of polymeric and inorganic nanoparticles and hybrids represents another part of synthetic direction. Prepared as well as comercial polymers are characterised by spectral methods (UV-VIS, FTIR, Fluorescence and Raman spectroscopy), thermal analysis (DSC, TGA, chemiluminescence, thermal and photo stability, flammability) and their molar characteristics by advanced HPLC techniques. Electron spin resonance (ESR) and positron annihilation lifetime spectroscopy (PALS) techniques are used for the microscopic structural-dynamic characterization of various pure and composed organic materials.

Research Topics:

1. Study and development of reversible-deactivation radical polymerizations and synthesis of functional polymers
2. Inorganic and carbon (nano)particles and hybrids
3. Polymeric (nano)particles, (hydro)gels and (nano)fibres
4. Synthesis and properties of photoactive compounds
5. Synthesis of polymers and polymeric materials from renewable monomers
6. Degradation, stabilization and flammability of polymers
7. Liquid chromatography research for effective separation of macromolecules
8. Structure and physico - chemical properties of polymers

3. Polymeric (nano)particles, (hydro)gels and (nano)fibres

Polymer and composite nanoparticles prepared using heterogeneous polymerizations

The synthesis of nanocomposite polymer and copolymer particles in miniemulsions is studied. Research efforts are focused on the factors affecting kinetics and mechanism of radical polymerization of convenctional and nonconvenctional monomers in both the direct and inverse miniemulsion. We investigate the locus of initiation, the mechanism of particle nucleation, deactivation of growing radicals within the polymer particles and the transport of monomer within the multiphase reaction system. Emphasis is given to understanding the principles of regulation of the reactivity of radicals and monomers and a phenomenological study of the processes responsible for the formation and changes in pure polymer and composite nanoparticles and disperse systems. The objective is to discover ways to prepare conventional and nonconventional polymer latexes and composite nanomaterials with predetermined chemical and physical properties for conventional and special applications. picture
Scheme of synthesis of Au and/or Ag nanoparticles using inverse microemulsion
In addition, 0D and 1D water- and oil-soluble metal nanoparticles are prepared by classical microemulsion approach and by high-temperature approach.

SEM analysis of PMBL nanoparticles prepared via batch heterogeneous polymerization
From tulips to polymeric nanoparticles. MBL was used as a monomer for the preparation of nanoparticles via heterogeneous polymerization process. The results are presented for the surfactant as well as surfactant-free polymerization of MBL with ionic, water soluble initiator potassium persulfate. The influence of polymerization technique (batch or semibatch), type of surfactant, surfactant concentration and ionic strength of the aqueous phase on molar mass and size of nanoparticles was studied. As a surfactant, sodium dodecyl sulphate, Tween 80 and monomer SHMB prepared by saponification of MBL were examined. The ionic strength was generated by addition of NaCl electrolyte. The size of the particles increases gradually with increasing ionic strength of the aqueous phase. The weight average molecular weights and molecular weight distributions were determined by size exclusion chromatography (SEC). Dynamic light scattering (DLS) was used to evaluate the size distribution profile and size of PMBL particles. According to experimental conditions nearly monodisperse polymer particles of 0.15 to 0.60 µm were produced.

Related recent publications:

  • I. Capek, „On photoinduced polymerization of acrylamide“, Design. Monom. Polym., Vol. 17 (4), p. 356-363 (2014).
  • M. C. Corobea, I. Capek, R. Ianchis, D. Donescu, R. Somoghi, M. Ghiurea, C. L. Nistor, V. Purcar, L. O. Cinteza, C. Radovici, G. Prodan, „Silica nanowires obtained on clay mineral layers and their influence on mini-emulsion polymerisation“, Appl. Clay Sci., Vol. 95, p. 232-242 (2014).
  • I. Capek, „On photoinduced miniemulsion polymerization of butyl acrylate with clay“, Design. Monom. Polym., Vol. 15 (4), p. 345-355 (2012).

Polymeric superabsorbent hydrogels

Polymers derived from nature were synthesized as a promising material with superabsorbent properties. α-Methylene-γ-butyrolactone (MBL), also known as Tulipalin A, is fungitoxic substance isolated mainly from tulips. In our research we focused on synthesis and properties of new superabsorbent polymers derived from hydrolyzed MBL - 4-hydroxy-2-methylenebutanoate (SHMB). Copolymerization of SHMB with acrylamide (AM) at various ratios in the presence of crosslinker yielded hydrogels with superior degree of swelling and comfortable handling. The effect of chemical composition (AM : SHMB ratio), the concentration of monomers in water and amounts of crosslinker were investigated. Hydrogels showed equilibrium degree of swelling in the range of 13,000 – 82,000%. Swelling capacity significantly increased with increased amount of SHMB. The viscoelastic characteristics of the hydrogels were significantly influenced by both the monomers ratio and crosslinker content.

Related recent publications:

Polymeric (nano)fibres and fiber composites prepared by electrospinning

Electrospinning is often used method, due to its versatility and cost-effectiveness that allows the production of functional nano-fibers from various materials including polymers, polymer blends, biopolymers, sol-gels and composite materials. Prepared fibers have several remarkable characteristics such as large specific surface area, pore size in nano-range, unique physical properties and flexible design, which allows chemical and physical binding of specific additives to the nano-fibers. In our experiments we studied the preparation and modification of electrospun fiber by specific “click” reaction to obtain particular materials for medicine and agrochemistry dependent on the active component. The main goal of this research is to prepare the functional electrospun fibers and immobilize the active molecules in the structure of fibers or on their surface for using in special applications. Fibrous mats are prepared from biodegradable polymers such as PVA, PLA, PCL, PHB, copolymers and natural polymers such as cellulose or silk.