katja hase - Academia.edu (original) (raw)
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Wissenschaftszentrum Berlin für Sozialforschung - WZB
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Papers by katja hase
The present invention relates to a novel acrylates polymerization of (meth) at which the polymeri... more The present invention relates to a novel acrylates polymerization of (meth) at which the polymerization is initiated by isocyanates and special bases with the imine structure. With this new and targetable method and high molecular weight poly (meth) acrylates are made with partly narrow molecular weight distribution. In addition, using this new polymerization diverse polymer architectures, such as block, star or comb polymers available.
The International Journal of Advanced Manufacturing Technology, 2021
The paper describes a novel technological approach to influencing the rheological properties of t... more The paper describes a novel technological approach to influencing the rheological properties of thermoplastic materials exposed to acoustic energy. The flow behavior of polypropylene with different mass percentages of glass fibers is investigated in a parallel plate rheometer under high-frequency longitudinal excitation. The influence of oscillation frequency on the melt viscosity is explained by means of shear thinning criteria. The dependence of the oscillation shape using sinusoidal excitation on shear thinning as a function of different fiber reinforcement percentages is also investigated. A phenomenological view describes the mutually influencing parameters with regard to different material compositions and different excitation frequencies over the time course of the rheometric measurement. Interacting relationships are analyzed and discussed and the potential of the actuator system to influence the plastic melt is worked out. Based on this, a technological approach follows whi...
Journal of Materials Science Research, 2016
<p class="1Body&a... more <p class="1Body">Short glass fibre reinforcement is one of the most important measures to improve the mechanical properties of injection moulded parts. The need for increasing performance leads to high fibre contents which is a critical fact due to the contrasting behaviour of strength, stiffness and impact properties. In this study a high-fluidity polypropylene (PP) is compounded with short glass fibres up to 70 weight percent and comparatively investigated with the adding of maleic anhydride (MAH) as compatibilizer. Due to the high fluidity of the PP, which ensures a good embedding of the fibres, the tensile modulus increases up to 65 weight percent, tensile strength up to 50 weight percent of glass fibre content. Adding the MAH increases strength and impact properties, while the tensile modulus only shows an improvement at high fibre content. The influence of the compatibilizer effect diminishes at higher fibre contents, especially for the impact strength which could so far not be clarified exactly. Reasons could be the reduction of fibre length at higher fibre contents and the increasing influence of the brittle fibre component. With the adding of MAH the contrasting behaviour of the impact properties in comparison to strength and stiffness can be reduced and the optimum over all mechanical properties can be shifted to higher fibre contents.</p>
Journal of Materials Science Research, Feb 23, 2016
<p class="1Body&a... more <p class="1Body">Short glass fibre reinforcement is one of the most important measures to improve the mechanical properties of injection moulded parts. The need for increasing performance leads to high fibre contents which is a critical fact due to the contrasting behaviour of strength, stiffness and impact properties. In this study a high-fluidity polypropylene (PP) is compounded with short glass fibres up to 70 weight percent and comparatively investigated with the adding of maleic anhydride (MAH) as compatibilizer. Due to the high fluidity of the PP, which ensures a good embedding of the fibres, the tensile modulus increases up to 65 weight percent, tensile strength up to 50 weight percent of glass fibre content. Adding the MAH increases strength and impact properties, while the tensile modulus only shows an improvement at high fibre content. The influence of the compatibilizer effect diminishes at higher fibre contents, especially for the impact strength which could so far not be clarified exactly. Reasons could be the reduction of fibre length at higher fibre contents and the increasing influence of the brittle fibre component. With the adding of MAH the contrasting behaviour of the impact properties in comparison to strength and stiffness can be reduced and the optimum over all mechanical properties can be shifted to higher fibre contents.</p>
Key Engineering Materials
The present invention relates to a novel acrylates polymerization of (meth) at which the polymeri... more The present invention relates to a novel acrylates polymerization of (meth) at which the polymerization is initiated by isocyanates and special bases with the imine structure. With this new and targetable method and high molecular weight poly (meth) acrylates are made with partly narrow molecular weight distribution. In addition, using this new polymerization diverse polymer architectures, such as block, star or comb polymers available.
The International Journal of Advanced Manufacturing Technology, 2021
The paper describes a novel technological approach to influencing the rheological properties of t... more The paper describes a novel technological approach to influencing the rheological properties of thermoplastic materials exposed to acoustic energy. The flow behavior of polypropylene with different mass percentages of glass fibers is investigated in a parallel plate rheometer under high-frequency longitudinal excitation. The influence of oscillation frequency on the melt viscosity is explained by means of shear thinning criteria. The dependence of the oscillation shape using sinusoidal excitation on shear thinning as a function of different fiber reinforcement percentages is also investigated. A phenomenological view describes the mutually influencing parameters with regard to different material compositions and different excitation frequencies over the time course of the rheometric measurement. Interacting relationships are analyzed and discussed and the potential of the actuator system to influence the plastic melt is worked out. Based on this, a technological approach follows whi...
Journal of Materials Science Research, 2016
<p class="1Body&a... more <p class="1Body">Short glass fibre reinforcement is one of the most important measures to improve the mechanical properties of injection moulded parts. The need for increasing performance leads to high fibre contents which is a critical fact due to the contrasting behaviour of strength, stiffness and impact properties. In this study a high-fluidity polypropylene (PP) is compounded with short glass fibres up to 70 weight percent and comparatively investigated with the adding of maleic anhydride (MAH) as compatibilizer. Due to the high fluidity of the PP, which ensures a good embedding of the fibres, the tensile modulus increases up to 65 weight percent, tensile strength up to 50 weight percent of glass fibre content. Adding the MAH increases strength and impact properties, while the tensile modulus only shows an improvement at high fibre content. The influence of the compatibilizer effect diminishes at higher fibre contents, especially for the impact strength which could so far not be clarified exactly. Reasons could be the reduction of fibre length at higher fibre contents and the increasing influence of the brittle fibre component. With the adding of MAH the contrasting behaviour of the impact properties in comparison to strength and stiffness can be reduced and the optimum over all mechanical properties can be shifted to higher fibre contents.</p>
Journal of Materials Science Research, Feb 23, 2016
<p class="1Body&a... more <p class="1Body">Short glass fibre reinforcement is one of the most important measures to improve the mechanical properties of injection moulded parts. The need for increasing performance leads to high fibre contents which is a critical fact due to the contrasting behaviour of strength, stiffness and impact properties. In this study a high-fluidity polypropylene (PP) is compounded with short glass fibres up to 70 weight percent and comparatively investigated with the adding of maleic anhydride (MAH) as compatibilizer. Due to the high fluidity of the PP, which ensures a good embedding of the fibres, the tensile modulus increases up to 65 weight percent, tensile strength up to 50 weight percent of glass fibre content. Adding the MAH increases strength and impact properties, while the tensile modulus only shows an improvement at high fibre content. The influence of the compatibilizer effect diminishes at higher fibre contents, especially for the impact strength which could so far not be clarified exactly. Reasons could be the reduction of fibre length at higher fibre contents and the increasing influence of the brittle fibre component. With the adding of MAH the contrasting behaviour of the impact properties in comparison to strength and stiffness can be reduced and the optimum over all mechanical properties can be shifted to higher fibre contents.</p>
Key Engineering Materials