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Merseburg, Germany

Kroll M.,BASF | Langer B.,Polymer Service GmbH Merseburg | Grellmann W.,Polymer Service GmbH Merseburg | Grellmann W.,Martin Luther University of Halle Wittenberg
Journal of Applied Polymer Science | Year: 2013

To investigate the influence of moisture and EPR-g-MA content on the fracture behavior of glass-fiber reinforced PA6 materials, brittle-to-tough transition temperatures (T btt) were determined. Water absorption was taken into account by conditioning the analyzed materials. Tensile tests could reveal the temperature range of the largest moisture dependence of mechanical properties between 10 and 50°C. J-integral values were used to describe the fracture behavior under conditions of impact load as a function of temperature. The brittle-to-tough transition of reinforced polyamides was found to be less approximate than in unreinforced materials. Two different characteristic temperature points T s and T e were identified, which were the intercept between elastic and elastic-plastic deformation on the one hand and the starting point of dominating stable crack propagation with strong plastic deformation on the other hand. Characteristic brittle-to-tough transition temperatures T btt could be calculated as the arithmetic average of these two points. Copyright © 2012 Wiley Periodicals, Inc. Source

Kroll M.,BASF | Langer B.,Polymer Service GmbH Merseburg | Schumacher S.,BASF | Grellmann W.,Polymer Service GmbH Merseburg | Grellmann W.,Martin Luther University of Halle Wittenberg
Journal of Applied Polymer Science | Year: 2010

The toughness behavior of 30 wt % glass fiber reinforced PA6/PA66 blends colored with different masterbatches containing carbon black (CB) was characterized by the instrumented Charpy impact test. Two different CB types with different particle diameters as well as two different polymers, PE and PA6, were used to prepare the masterbatches. The CB concentration was varied from 0 to 1.2 wt % in the compounds and all materials were examined dry and after water absorption. The toughness of the compounds significantly decreased when CB was incorporated. Moisture conditioning of the materials led to increased toughness and ductility but did not compensate for the negative influence of CB. Using PE as a masterbatch polymer succeeded in limiting the influence of CB on toughness whereas the largest particle diameter led to the highest reduction in toughness. By taking into account crack resistance curves, it could be shown that there is a significant change in crack propagation behaviorwhen the concentration of the larger particle CB exceeds a certain level; this was ascribed to the existence of complex CB structures at this concentration. © 2009 Wiley Periodicals, Inc. Source

Nase M.,Hof University of Applied Sciences | Androsch R.,Martin Luther University of Halle Wittenberg | Henning S.,Fraunhofer Institute for Mechanics of Materials | Grellmann W.,Martin Luther University of Halle Wittenberg | Grellmann W.,Polymer Service GmbH Merseburg
Polymer Engineering and Science | Year: 2015

Peel films of blends of low density polyethylene (LDPE) and random isotactic copolymers of butene-1 with either ethylene (iPB-Eth) or propylene (iPB-Prop) were investigated regarding the effect of the copolymer composition on both the Form II mesophase to Form I crystal transformation of the copolymers, and the time-dependent peel behavior of their blends with LDPE in peel films. In general, there is observed a decrease of the peel force with increasing concentration of both ethylene and propylene co-units in random iPB-1 based copolymers and their blends with LDPE, after completion of the Form II to Form I transformation. Thus, to tailor the peel force, either the content of the peel component in the blends, or the concentration of ethylene or propylene co-units in the peel component may be varied. The effect of ethylene co-units in the random copolymers on the peel force is distinctly larger than that of propylene co-units. Parallel to the Form II to Form I transition of butene-1 based copolymers, the peel force decreases with a rate which depends on the copolymer composition. The Form II to Form I transition in iPB-Prop copolymers proceeds distinctly faster than in iPB-Eth copolymers of identical concentration of co-units. © 2014 Society of Plastics Engineers. Source

Kolesov I.,Martin Luther University of Halle Wittenberg | Dolynchuk O.,Martin Luther University of Halle Wittenberg | Borreck S.,Polymer Service GmbH Merseburg | Radusch H.-J.,Martin Luther University of Halle Wittenberg
Polymers for Advanced Technologies | Year: 2014

The capability of phase morphology of covalent networks on the basis of crystallizable polymer blends to control their multiple shape-memory (SM) behavior was proven, especially for invertible two-way SM effect, which is observed as an anomalous elongation of a sample under constant load during the non-isothermal crystallization. In order to achieve a triple-shape one- and two-way behavior, a set of binary blends with different contents of high-density polyethylene and poly(ε-caprolactone) and one 50/50 blend of ethylene-octene copolymer and trans-polyoctenamer cross-linked by peroxide were prepared. The considerable enthalpic effects in temperature ranges of crystallization and melting of both blend components point to possible softening/hardening of discussed blends caused by non-isothermal melting/crystallization at heating/cooling, respectively. The two-way SM behavior was investigated in tensile mode under constant load during cooling and heating sequentially. It is quite obvious that the distinct manifestation of triple-SM behavior is possible only when a continuous phase of blend has lower crystallization/melting temperatures in comparison with dispersed phase. By contrast, if crystallization/melting temperatures of dispersed phase are lower, then its ability to change a shape is suppressed by already solidified continuous phase. Obtained results allow conclude the following: first, the performances of both one- and two-way SME are enhanced with increasing cross-link density and crystallinity of polymer network as well as due to selection of optimal load; second, the key to improve the multiple SM behavior of polymer blends is further optimization of their phase morphology, especially better separation/decoupling of blend phases. © 2014 John Wiley & Sons, Ltd. Source

Le H.H.,Martin Luther University of Halle Wittenberg | Ilisch S.,Martin Luther University of Halle Wittenberg | Heidenreich D.,Martin Luther University of Halle Wittenberg | Wutzler A.,Polymer Service GmbH Merseburg | Radusch H.-J.,Martin Luther University of Halle Wittenberg
Polymer Composites | Year: 2010

The Fourier transformed infrared (FTIR) spectroscopy on the rubber-filler gel has been used as a tool for the quantitative characterization of the phase selective silica localization in styrene butadiene rubber (SBR)/natural rubber (NR) blends. The so-called rubber-layer L was introduced to describe the selective wetting behavior of the rubber phases to the filler. SBR/NR blends filled with silica were the focus of the experimental investigation. NR shows a higher wetting rate than SBR. Silane addition does not affect the wetting of NR but slowdowns the wetting of SBR. With increasing chamber temperature the value of the rubber-layer L of all mixtures increases owing to the different thermal activated rubber-filler bonding processes. Using the wetting concept the kinetics of silica localization in the phases of heterogeneous rubber blends was characterized. Because of the higher wetting rate of the NR component, in the first stage of mixing of NR/SBR blends more silica is found in the NR phase than in the SBR phase. In the next stage, silica is transferred from the NR phase to the SBR phase until the loosely bonded components of NR rubber-layer are fully replaced by SBR molecules. © 2010 Society of Plastics Engineers. Source

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