This thesis offers novel insights into the time-dependent structural evolution of polymers under deformation. In-situ tensile experiments at high-brilliance synchrotron sources allowed to characterize the material with unrivaled resolution in time and space. The strain-induced crystallization in natural rubber was studied by wide-angle X-ray diffraction. Special emphasis was put on the establishment of new structure-property relationships to give a more in-depth understanding of the mechanical performance of rubber parts, e.g. in tear fatigue loading. To this end, the kinetics of strain-induced crystallization were investigated, subjecting the material to high strain rates. The local structure around a crack tip was observed by scanning wide-angle X-ray diffraction. Ultra-small angle X-ray scattering served to study filled elastomers under deformation, from specially prepared model filler systems to industrially relevant carbon black filled rubbers. Other methods include electron microscopy coupled with in-situ tensile testing and optical dilatometry to examine cavitation in rubbers.The underlying theory as well as a literature review are covered by an extensive introductory chapter, followed by a description of the experimental techniques. The results are presented in more detail than in the original journal publications.
This thesis offers novel insights into the time-dependent structural evolution of polymers under deformation. In-situ tensile experiments at high-brilliance synchrotron sources allowed to characterize the material with unrivaled resolution in time and space. The strain-induced crystallization in natural rubber was studied by wide-angle X-ray diffraction. Special emphasis was put on the establishment of new structure-property relationships to give a more in-depth understanding of the mechanical performance of rubber parts, e.g. in tear fatigue loading. To this end, the kinetics of strain-induced crystallization were investigated, subjecting the material to high strain rates. The local structure around a crack tip was observed by scanning wide-angle X-ray diffraction. Ultra-small angle X-ray scattering served to study filled elastomers under deformation, from specially prepared model filler systems to industrially relevant carbon black filled rubbers. Other methods include electron microscopy coupled with in-situ tensile testing and optical dilatometry to examine cavitation in rubbers.
The underlying theory as well as a literature review are covered by an extensive introductory chapter, followed by a description of the experimental techniques. The results are presented in more detail than in the original journal publications.
Karsten Brüning
Cavitation Crystallization Kinetics Elastomer Deformation and Fracture Mechanical Properties of Polymers Natural Rubber Reinforcement Polymers Under Deformation Strain-induced Crystallization Synchrotron Small and Wide-Angle X-ray Scattering & Diffraction Synchrotron X-ray Radiation Time-dependent Structure Evolution in Polymers WAXD, SAXS, USAXS, SEM