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Original title in Czech: Chemie makromolekulárních materiálůFCHAbbreviation: DPCO_MCHAcad. year: 2011/2012
Programme: Macromolecular Chemistry
Length of Study: 4 years
Accredited from: 13.10.2010Accredited until: 1.11.2018
Guarantor
prof. RNDr. Josef Jančář, CSc.
Issued topics of Doctoral Study Program
Tutor: Jančář Josef, prof. RNDr., CSc.
It is proposed to investigate effects of adding SiO2 nanoparticles on the morphogenesis of spherulitic structure of industrially important plastics. Effects of silica surface treatment, molecular structure of the PP and PE homo- and copolymers, crystallization temperature and the way of nanocomposite preparation on the sherulite growth rate, crystalline structure of the lamellae, degree of crystallinity, density of tie molecules and deformation response of the nanocomposites will be investigated. The main aim of the proposed project is to obtain quantitative relationship between structural variables in PP/SiO2 and PE/SiO2 nanocomposites, their preparation conditions, crystalline structure and mechanical properties employing range of experimental techniques and multiscale modeling based on combining reptation dynamics and higher order micromechanics proposed previously. Another goal is to find structural and processing variables capable of controlling mechanical and processing properties of the resulting nanocomposites applicable in manufacturing of enhanced polymer fibers and films.
The idea to synthetize new multilevel, multiperformance heterogeneous materials mimicking to some extent natural materials such as wood, bone or tendon becomes the driving force in the current state-of-the-art in the science and engineering of new advanced materials. It has been realized that in order to prepare such materials, components of these compounds have to engineered on a nano-scale rather than on the micro- or makro-scale as the current state-of-the-art advanced materials. The scalling down to nano-scale brings about an urgent need to understand the nature of physico-chemical processes occuring at this scale, since the experimental data existing in the current literature cannot be interpreted using existing models derived for micro- or macro-scale. At the same time, nano-scale materials cannot be, in most cases, prepared by simple physical mixing of existing compounds ground down to this scale. These have to be synthetized with the specific performace of the ultimate application in mind. Needless to say, that some success has already been achieved in this area with intended applications in microelectronics or medicine. At the same time, there is a growing concern about the environmental friendliness of these synthetic nano-materials. It is also our goal to investigate the nature of interactions occuring at the inorganic-organic interface at the nano-scale, where many current models fail to explain experimentally observed phenomena. Still another goal is to combine the organic and anorganic compounds at nano-scale into multilevel and multiperfomance materials used as controlled lifetime coatings, adhesives and films in the industry, agriculture and medicine. Envisioned applications include breathable protective cloth fabric, controlled fertilizer and seed release films.
The main goal of the research will be to create heterogeneous injectable adhesives for repair of damaged bone tissue in the human body. The adhesive matrix material will consist of a hydrogel of a biocompatible, biodegradable tri-block copolymer of PLA-PGA-PEG. The matrix will be reinforced with a high concentration of bimodal or trimodal mixtures of core/shell particles consisting of a core of b-tricalcium phosphate and a shell of copolymer similar in organic composition to that of the matrix. The composite adhesive structure will be designed to provide desired balance of strength and porosity required for the support of the damaged bone and the regeneration of new bone tissue. The temporal strength and porosity of the heterogeneous adhesive will be controlled by appropriate choice of copolymer compositions of the matrix and particle shells. The primary scientific objectives of the research will be to characterize the effects of the molecular composition and composite structure on the in-vivo effectiveness of the heterogeneous adhesive with respect to its ability to bond to a damaged bone, to support a load in the absence of internal pins or other supports and to stimulate the regeneration of new bone tissue. If desirable, the tri-block copolymer could also contain reactive peptide end groups for stimulation of bioactivity during tissue regeneration.
Crosslinking mechanism and kinetics study of different PE grades by the aid of peroxide radical initiation in heterogeneous medium (solid states polymer particles). It includes literature survey, choice of polymers, initiators and other additives, providing planned experiments and evaluation of results attained. Evaluation is to be oriented mainly towards influencing structure, molecular weights distribution and rheological properties
Tutor: Petrůj Jaroslav, doc. RNDr., CSc.
Crosslinking mechanism and kinetics study of different PE grades by the aid of peroxide radical initiation in homogeneous medium (in the melt). It includes literature survey, choice of polymers, initiators and other additives, providing planned experiments and evaluation of results attained. Evaluation is to be oriented mainly towards influencing structure, molecular weights distribution and rheological properties.
The study will be focused on the investigation of the influence of ethene, propene and their mixtures on the catalyst performance and polymer structure during the 1-alkene coordination polymerization. The main interest will be focused on the investigation of the catalyst performance during the early and very early (<1 s) stages of polymerization. A new experimental facility suitable for performing and monitoring very short polymerization experiments will be constructed. Successful solving the problem provides a new insight on the nature of active sites present in the heterogeneous Ziegler-Natta catalyst, what facilitates the development of new polymer materials (random and block copolymers).
Tutor: Kratochvíla Jan, Ing., CSc.
The work is focused to observe kinetic behaviour of radical styrene polymerization in bulk. Modern biradical initiators will be used for influence initiator concentration to course of polymerization together with temperature profile of polymerization. Inflence of transfer agent and bifunctional comonomer will be also observed. The aim of work is to describe kinetics of bulk polymerization and prepare method for industrial production of polystyrene for optical applications.
The aim of the study is modeling structure and behavior if macromoleculer networks by means of moleculer models. The work is based on existing supermoleculer network model and molecular model of statistical random chain. The new hybrid model should give in correlation molecular paramteres of materals (bond lengths and angles), network parameters (such as crosslink density), and macroscopic parameters (density, deformation and swelling behavior). By the correct application can be discovered some cross-property bounds for example between stoichiometry, deformation and swelling. Such bounds can lead to decrease of number of experiment because when one property is known the other can be calulated. The examples of application are 1) Structural-mechanical influence of tropocollagen molecule in nanocomposites; 2) Interface between response of network models and finite element methods or 3) Relation between gel point and molecular weight.
The project is aimed at the preparation of new magnetic carriers with the surface coated by low- or high-molecular-weight compounds containing suitable chelating groups for the immobilization of transition metals. Coating suppresses non-specific interaction of proteins with the magnetic core of the particles, typically magnetite, maghemite, or ferrites. Magnetic core has the size in nano- (< 50 nm), or micrometer (500 nm - 1 µm) range. Compounds selected for coating of magnetic cores will contain both groups facilitating their firm anchoring by chelation binding to the surface of the magnetic oxides and also groups suitable for the immobilization of transition metals (Fe, Ga) necessary for functional interaction with a protein or peptide phosphate (immobilized metal affinity chromatography; IMAC). Manipulation of the carrier by means of a magnet is a qualitative improvement compared with conventional column or batch systems. The new magnetic carriers will make purification of the bacterial proteins possible, which are related to the bacterial virulence and pathogenesis.
Tutor: Horák Daniel, Ing., CSc.
Thermooxidation mechanism and kinetics study of different PE grades. It includes literature survey, choice of polymers, initiators and other additives, providing planned experiments and evaluation of results attained. Oxidation is to be carry out in oven on polymer films to a low conversion only. Evaluation is to be oriented mainly towards determination of primary oxidation products (hydroperoxides, peracids, ketones etc.). Evaluate results kinetically and compare thermooxidation course in dependence of polymer structure.
Preparation of bio-PU scaffolds and/or films modified by either natural polymers (collagen, chitosan, hyaluronic acid) or synthetic ones (PLGA/PEG, PCL) and hydroxyapatite with a view to evaluate the porosity, pore size of scaffolds, degradation, swelling, viscoelasticity etc.
Polymeranalogous Reactions of Polylactic Acid
Biodegradable aliphatic polyesters based on polylactones, and polylactides have been attracting considerable attention due to their many potential biomedical, pharmaceutical, agricultural and packaging applications. The aim of the thesis is to study the kinetics and mechanisms of ring-opening polymerization of cyclic monomers (lactones, lactides), catalyzed (initiated) by N-heterocyclic carbenes and triazole-based complexes of aluminium.The results obtained will be used to elucidate the function of polymerization catalysts and mechanism, and to control the reactivity and selectivity of active species in relation to the structure of the polymer being formed. Another aim consists in studying the biological properties of polymers, in particular from the viewpoint of their degradability and biocompatibility with regard to the presence of the residual monomers, oligomers, low molecular products and, especially, the catalytic systems under examination. Last but not least, the effect of molecular weight of polyesters on the rate of degradation will be investigated. An important aim will also be the study of the purification of the polymers prepared and of the methods for controlling residual monomers and catalytic systems.
The aim of the work is to analyze, what shape and size of particle agglomerates can be expected by different composites. Input of the model will be interparticle interaction. The result will be space distribution of particles and specifically the information whether the particles are present in form of globules or linear aggregates. Next factor influencing agglomerate shape can be direction-specific motion of small agglomeartes. In case of agglomeration of two particles, such small agglomerate will move quicker in direction of common axis of two particles. Then they will tend to create linear aggregates rather than the golbular ones. The integration of such factor of to the AGLOMER software can be useful in analysis and prediction of formation of agglomerates of different shapes and consequently properties of micro and nanocomposites.