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The Institute of Resource Ecology (IRE) is one of the eight institutes of the Helmholtz-Zentrum Dresden – Rossendorf (HZDR). The research activities are mainly integrated into the program “Nuclear Waste Management, Safety and Radiation Research (NUSAFE)” of the Helmholtz Association (HGF) and focused on the topics “Safety of Nuclear Waste Disposal” and “Safety Research for Nuclear Reactors”. Additionally, various activities have been started investigating chemical and environmental aspects of processing and recycling of strategic metals, namely rare earth elements. These activities are located in the HGF program “Energy Efficiency, Materials and Resources (EMR)”. Both programs, and therefore all work which is done at IRE, belong to the research sector “Energy” of the HGF. The research objectives are the protection of humans and the environment from hazards caused by pollutants resulting from technical processes that produce energy and raw materials. Treating technology and ecology as a unity is the major scientific challenge in assuring the safety of technical processes and gaining their public acceptance. We investigate the ecological risks exerted by radioactive and nonradioactive metals in the context of nuclear waste disposal, the production of energy in nuclear power plants, and in processes along the value chain of metalliferous raw materials. A common goal is to generate better understanding about the dominating processes essential for metal mobilization and immobilization on the molecular level by using advanced spectroscopic methods. This in turn enables us to assess the macroscopic phenomena, including models, codes, and data for predictive calculations, which determine the transport and distribution of contaminants in the environment.

<p>U ovom radu vr&scaron;ena su istraživanja u cilju razvoja novih postupaka sinteze za nekoliko vrsta polimernih mreža i hibridnih biopolimernih materijala za specijalne primene. Cilj je bio da se razvije novi postupak sinteze rotaksana na bazi poli(etilen glikola) i &beta;-ciklodekstrina kaoprekursora mreža. Dobijeni prekursori mreža iskori&scaron;ćeni su za sintezu topolo&scaron;kih gelova koji su umreženi preko hidroksilnih grupa ciklodekstrinskih prstena. Analiziran je i uticaj količine umreživača, odnosno gustine umreženja, na svojstva bubrenja. Proučavan je i uticaj nanopunila na svojstva modelnih epoksi mreža na bazi bisfenola A i poli(oksi propilen) diamina. Kao punila kori&scaron;ćene su nanočestice nemodifikovanog i povr&scaron;inski modifikovanog titanijum(IV)oksida (TiO₂). Dinamičko-mehaničkom analizom potvrđen je ojačavajući efekat punila. Razvijen je postupak sinteze poli(D,L-laktida) u mikrotalasnom polju, čime je drastično smanjeno vreme polimerizacije (sa 150 sati na 15 minuta) u odnosu na klasičnu termosintezu. Sintezom poli(laktida) kao i kopolimera poli(laktida) sa biorazgradivim monomerima (na osnovu obnovljivih sirovina) dobijeni su materijali izuzetnih ekolo&scaron;kih svojstava. Poli(laktid) se odlikuje veoma dobrim mehaničkim svojstvima i biorazgradivo&scaron;ću, dok je blok-kopolimerizacijom sa drugim biorazgradivim monomerima vr&scaron;ena sinteza termoplastičnih poliestara. Variranje dužine segmenata je ostvareno sintezom adekvatnih oligomera kao prekursora za kopolimerizaciju. Vr&scaron;eno je projektovanje sirovinskog sastava segmentiranih elastomera kod kojih postojanje mekih i tvrdih segmenata ima za posledicu mikrofaznu separaciju faza &scaron;to u toku eksploatacije utiče na mehanička svojstva i mogućnost III razgradnje. Na taj način dobijeni su elastomerni materijali željenih svojstava. Metodama FTIC i 1H NMR spektroskopijom potvrđena je pretpostavljena struktura segmenata i finalnih termoplastičnih poliestara. Analizom molskih masa poliestara metodama gel propusne hromatografije, viskozimetrije i osmometrije napona pare, potvrđena je izuzetna kontrola reakcija polimerizacije i uspe&scaron;nost primenjenih metoda sinteze. Analiza toplotnih svojstava blok poliestara diferencijalno skenirajućom kalorimetrijom je pokazala da zbog neme&scaron;ljivosti faza, tvrdih i mekih segmenata, finalni blok poliestri mogu da pokažu razlike u temperaturama faznih transformacija u zavisnosti od dužine i udela segmenata. Termogravimetrijskom analizom je potvrđen uticaj dužine segmenata i faznog razdvajanja na toplotna svojstva termoplastičnih poliestara. Očekuje se da će sintetisani materijali biti podesni za primene u inženjerstvu tkiva, a posebno kao materijali za kontrolisano otpu&scaron;tanje lekova.</p> / <p>The primary goal of the work described in this thesis was to develop new methods for the<br />synthesis of polymer networks and hybrid biopolymers for special applications. The purpose was a development of synthesis procedure for the preparation of rotaxane based on poly(ethylene glycol) and &beta;-cyclodextrin, as network precursors. These network precursors were then cross-linked through hydroxy groups on cyclodextrine rings. Polyrotaxanes are intermediary products in the synthesis of topological gels and they are formed by the insertion of the linear polymer chains of poly(ethylene oxide) into the &beta;-CD cavities. In this work polyrotaxanes from acetylated-&beta;-CD and poly(ethylene oxide) were synthesized. The influence of crosslinker contents, and crosslink density on swelling properties was investigated. The influence of synthesis parameters and filler modification on reactions and final properties of organic-inorganic hybrid materials based on epoxy resin and an organically modified titanium(IV)oxide (TiO2) was investigated. Dynamic-mechanical analysis was used to determine reinforcement effect of nanofiller on the epoxy resin properties. The aim of this work was the investigation of microwave irradiation on the polymerization of D,L-lactide. It was found that if heating is carried out in the microwave field polymerization time of D,Llactide rapidly decreases from 150 hours to 15 minutes. Environmentally friendly materials were obtained from poly(lactide) and copolymers of poly(lactide) and monomers based on renewable resources. Poly(lactide) is biocompatible and biodegradable polymer with high stretching and low extension capacities. It has been used for the production of orthopedic fraction fixators and sutures surgery. Poly(lactide) was used for thermoplastic polyester (TPE) synthesis. Most thermoplastic polyesters derive their properties from segmented or block structures which are achieved by alternating hard and soft segments. FT-IR and 1H NMR spectroscopy were confirmed the assumed structure of segments and final thermoplastic polyesters. Since the properties of these materials strongly depend on the degree of phase separation, the influence of the lenghts of soft and hard segment on final properties of obtained TPEs was studied. Analysis of molecular mass of these polyesters by gel permeation chromatography, vapor pressure osmometry and viscozimetric analysis confirmed that good control of polymerization was achieved and that synthesis methods were successful. Thermal properties were characterized by means of differential scanning calorimetry (DSC) and thermo-gravimetric analysis (TGA). Phase separation had strong influences on thermal properties of obtained TPEs. DCS measurements showed that due to poor mixability of hard and soft segments, final block polyesters could have different temperatures of phase transitions depending on the length of the segments. Thermal degradation and the influence of phase separation on thermal stability of segmented thermoplastic polyesters were confirmed by nonisothermal analysis, using thermogravimetric analysis. It is expected that synthesized materials will be suitable for tissue engineering and as drug carriers.</p>

The Institute of Resource Ecology (IRE) is one of the eight institutes of the Helmholtz-Zentrum Dresden – Rossendorf (HZDR). The research activities are mainly integrated into the program “Nuclear Waste Management, Safety and Radiation Research (NUSAFE)” of the Helmholtz Association (HGF) and focused on the topics “Safety of Nuclear Waste Disposal” and “Safety Research for Nuclear Reactors”. Additionally, various activities have been started investigating chemical and environmental aspects of processing and recycling of strategic metals, namely rare earth elements. These activities are located in the HGF program “Energy Efficiency, Materials and Resources (EMR)”. Both programs, and therefore all work which is done at IRE, belong to the research sector “Energy” of the HGF. The research objectives are the protection of humans and the environment from hazards caused by pollutants resulting from technical processes that produce energy and raw materials. Treating technology and ecology as a unity is the major scientific challenge in assuring the safety of technical processes and gaining their public acceptance. We investigate the ecological risks exerted by radioactive and nonradioactive metals in the context of nuclear waste disposal, the production of energy in nuclear power plants, and in processes along the value chain of metalliferous raw materials. A common goal is to generate better understanding about the dominating processes essential for metal mobilization and immobilization on the molecular level by using advanced spectroscopic methods. This in turn enables us to assess the macroscopic phenomena, including models, codes, and data for predictive calculations, which determine the transport and distribution of contaminants in the environment.