A5010090430- Polymer crystallization and properties
- biodegradable polymer synthesis and properties
- Polymer Nanocomposites and Properties
- Additive Manufacturing and 3D Printing Technologies
- Microplastics and Plastic Pollution
- Carbon dioxide utilization in catalysis
- Polymer Foaming and Composites
- Natural Fiber Reinforced Composites
- Rheology and Fluid Dynamics Studies
- Mycorrhizal Fungi and Plant Interactions
- Nanocomposite Films for Food Packaging
- Lichen and fungal ecology
- Forest Ecology and Biodiversity Studies
- Fiber-reinforced polymer composites
- Bone Tissue Engineering Materials
- thermodynamics and calorimetric analyses
- Injection Molding Process and Properties
- Fire dynamics and safety research
- Material Dynamics and Properties
- 3D Printing in Biomedical Research
- Flame retardant materials and properties
- Recycling and Waste Management Techniques
- Material Properties and Applications
- Advanced Chemical Sensor Technologies
Martin Luther University Halle-Wittenberg
2016-2025
Helmholtz Centre for Environmental Research
2015-2018
Decomposition by microorganisms of plastics in soils is almost unexplored despite the fact that majority released into environment end up soils. Here, we investigate decomposition process and microbiome one most promising biobased biodegradable plastics, poly(butylene succinate-co-adipate) (PBSA), under field soil conditions both ambient future predicted climates (for time between 2070 2100). We show gravimetric molar mass PBSA already largely reduced (28-33%) after 328 days climates....
Despite the important role of wood-inhabiting fungi (WIF) in deadwood decomposition, our knowledge factors shaping dynamics their species richness and community composition is scarce. This due to limitations regarding resolution classical methods used for characterizing WIF communities a lack well-replicated long-term experiments with sufficient numbers tree species. Here, we large scale experiment logs 11 at an early stage distributed across three regions Germany, identify Operational...
Abstract Prior work revealed distinct differences in the X‐ray diffraction patterns of poly(butylene succinate) (PBS) melt‐crystallized at different temperatures, regarding number, width, and position peaks, detected isotropic samples. To further evaluate whether observed are caused by a change unit cell, or solely due to crystal sizes perfection, fiber solid‐state oriented PBS acquired analyzed. The data reveal that crystallized high supercooling melt 20 °C contains crystals with enlarged...
Abstract The bulk enthalpy of melting α ‐crystals poly (L‐lactic acid) (PLLA) is evaluated by fast scanning calorimetry (FSC), correlating the samples different crystallinity with corresponding heat capacity at 90 °C, that a temperature higher than glass transition amorphous phase and lower temperature. Extrapolation this relationship for crystals formed 140 °C towards fully solid PLLA yields value 104.5±6 J g −1 when occurs 180–200 °C. analysis relies on two‐phase structure, is, absence...
Crystallization of poly(l-lactic acid) (PLLA) at temperatures lower and higher than about 100–120 °C leads to the formation α′- α-crystals, respectively. Related different crystal polymorphs after crystallization temperatures, small-angle X-ray scattering (SAXS) patterns only show a long-period maximum high when α-crystals are present. Reason for absence peak low-temperature is insufficient density contrast between formed α′-crystals amorphous phase but not lamellar stacks long-range...
The semicrystalline morphology of injection moldings polyamide 11 (PA 11) prepared using mold temperatures 25, 50, and 80°C was investigated. Regardless the temperature, position‐resolved X‐ray diffraction (XRD) polarized‐light optical microscopy (POM) revealed presence poor/imperfect α‐crystals with an almost hexagonal arrangement molecular stems in a nonspherulitic superstructure skin, formation spherulites core. With increasing thickness skin layer decreased, perfection spherulite size...
Polyamide 11 (PA 11) samples of different supermolecular structure, including the crystal-free glass and semi-crystalline PA largely morphology, were prepared by fast scanning chip calorimetry (FSC). These then annealed at temperatures well below transition temperature Tg. The main purpose low-temperature annealing experiments was calorimetric detection mobility chain segments as low −40 °C (≈Tg − 80 K) where still excellent impact resistance is predicted. It found that such temperature,...
Melt-crystallization of poly (butylene succinate) (PBS) at largely different melt-supercooling was analyzed by X-ray scattering techniques, direct imaging using microscopy, and fast scanning chip calorimetry, with the latter employed to achieve high melt-supercooling. Crystallization 100 20 °C, representing structure formation low melt-supercooling, respectively, yields lamellae thicknesses around 8 4 nm. In both cases, lamellar thickening is excluded as main mechanism isothermal secondary...
Microinjection-molding subjects the polymer melt to high cooling and shear rates, which significantly affects crystallization behavior during solidification. In this work, fast scanning chip calorimetry, conventional differential rheology experiments, polarized light optical microscopy permitted drawing conclusions about of polyoxymethylene under such processing conditions. Computer simulations Cox–Merz experiments predict orientation molecular segments shear-induced formation crystal nuclei...
Poly(butylene succinate) (PBS) forms small and imperfect crystals of low melting temperature at high supercooling the melt. Slow heating allows reorganization obtained semicrystalline structure with changes crystallinity size perfection analyzed by differential scanning calorimetry (DSC) temperature-resolved X-ray scattering techniques. Crystals generated 20 °C begin to melt reorganize a few K higher their initial imperfection thickness unchanged upon 70-80 °C. temperatures than yields...
Fast scanning chip calorimetry (FSC) allows subjecting polymer melts to well-defined vitrification, crystal nucleation, and growth pathways and, therefore, precise control of morphologies, from fully amorphous glassy states semicrystalline structures containing perfect crystals. Due the required use nanogram-sized samples, needed achieve high cooling rates, their mechanical properties, in order establish structure-property relations, are difficult assess. In this work, indentation modulus...
Abstract Nucleation and crystallization of polyamide 12 (PA 12) have been systematically investigated by fast scanning calorimetry at non‐isothermal isothermal conditions. The critical cooling rates crystal nucleation were determined as 300 10,000 K/s, respectively. Moreover, the half‐times ( t 1/2,nucl ) overall 1/2,cry show monomodal bimodal dependencies on temperature. has an approximate minimum value about 0.0005 s 333 K, which is 10–20 K above glass transition temperature, two minima...
Bio-sourced and biodegradable poly(butylene succinate) (PBS) strands containing up to 40 m% mosquito-repellent N,N-diethyl-3-methylbenzamide (DEET) were obtained by extrusion, for an initial evaluation of the DEET evaporation characteristics possible application such as slow-release repellent-delivery devices. For concentrations 20 m%, is entrapped in semicrystalline spherulitic superstructure PBS. In contrast, at higher concentrations, liquid repellent, least partially, not fully...
Physical aging and the glass transition dynamics of semicrystalline poly(lactic acid) (PLA), designed for three-dimensional (3D)-printing applications, are investigated by fast scanning calorimetry identifying effect crystallinity on relaxation behavior amorphous phase. PLA was crystallized annealing isotropic melt at 363 K different times between 100 1000 s, yielding a two-phase structure composed single phase up to 40% crystals. Then, these samples were physically aged temperatures 270 310...
The crystallization kinetics of metallocene-catalyzed heterophasic isotactic polypropylene composed a matrix (iPP) and rubbery particles made random ethylene–propylene copolymers (EPC), often denoted as iPP copolymers, was analyzed function the cooling rate supercooling in nonisothermal isothermal experiments, respectively. Fast scanning chip calorimetry (FSC) allowed assessing at processing-relevant conditions, variation content (0–39 wt %) composition (0–35 % propylene counits) EPC...