“…Therein, the material composition, a brief description as well as a schematic drawing of the microstructure are given. To accomplish the various layer architectures, a microlayer co-extrusion technique was used [ 12 , 13 , 53 ]. All materials were supplied in the form of extruded sheets with a thickness of 4 mm.…”
Section: Methodsmentioning
confidence: 99%
“…Thus, each additional module doubles the number of layers, so the final number of layers is 2 n +1 , with n being the number of modules. This processing routine has proven to provide neatly stacked polypropylene multilayer materials with uninterrupted continuous layers [ 12 , 13 ]. Figure A1 Multilayer extrusion using a multiflux static mixer, adapted from [ 53 ].…”
Section: Appendix A1 Materialsmentioning
confidence: 99%
“…Alternatively, the soft phase can be incorporated as distinct domains, for example, as continuous layers in a co-extrusion process [ 12 , 13 ]. Studies on natural materials suggest great potential for alternating layers of stiff and compliant material [ 14 , 15 , 16 , 17 ].…”
Talcum reinforced polypropylene was enhanced with a soft type of polypropylene in order to increase the impact strength and damage tolerance of the material. The soft phase was incorporated in the form of continuous interlayers, where the numbers of layers ranged from 64 to 2048. A blend with the same material composition (based on wt% of the used materials) and the pure matrix material were investigated for comparison. A plateau in impact strength was reached by layered architectures, where the matrix layer thickness was as small or smaller than the largest talcum particles. The most promising layered architecture, namely, 512 layers, was subsequently investigated more thoroughly using instrumented Charpy experiments and tensile testing. In these tests, normalised parameters for stiffness and strength were obtained in addition to the impact strength. The multilayered material showed remarkable impact strength, fracture energy and damage tolerance. However, stiffness and strength were reduced due to the addition of the soft phase. It could be shown that specimens under bending loads are very compliant due to a stress-decoupling effect between layers that specifically reduces bending stiffness. This drawback could be avoided under tensile loading, while the increase in toughness remained high.
“…Therein, the material composition, a brief description as well as a schematic drawing of the microstructure are given. To accomplish the various layer architectures, a microlayer co-extrusion technique was used [ 12 , 13 , 53 ]. All materials were supplied in the form of extruded sheets with a thickness of 4 mm.…”
Section: Methodsmentioning
confidence: 99%
“…Thus, each additional module doubles the number of layers, so the final number of layers is 2 n +1 , with n being the number of modules. This processing routine has proven to provide neatly stacked polypropylene multilayer materials with uninterrupted continuous layers [ 12 , 13 ]. Figure A1 Multilayer extrusion using a multiflux static mixer, adapted from [ 53 ].…”
Section: Appendix A1 Materialsmentioning
confidence: 99%
“…Alternatively, the soft phase can be incorporated as distinct domains, for example, as continuous layers in a co-extrusion process [ 12 , 13 ]. Studies on natural materials suggest great potential for alternating layers of stiff and compliant material [ 14 , 15 , 16 , 17 ].…”
Talcum reinforced polypropylene was enhanced with a soft type of polypropylene in order to increase the impact strength and damage tolerance of the material. The soft phase was incorporated in the form of continuous interlayers, where the numbers of layers ranged from 64 to 2048. A blend with the same material composition (based on wt% of the used materials) and the pure matrix material were investigated for comparison. A plateau in impact strength was reached by layered architectures, where the matrix layer thickness was as small or smaller than the largest talcum particles. The most promising layered architecture, namely, 512 layers, was subsequently investigated more thoroughly using instrumented Charpy experiments and tensile testing. In these tests, normalised parameters for stiffness and strength were obtained in addition to the impact strength. The multilayered material showed remarkable impact strength, fracture energy and damage tolerance. However, stiffness and strength were reduced due to the addition of the soft phase. It could be shown that specimens under bending loads are very compliant due to a stress-decoupling effect between layers that specifically reduces bending stiffness. This drawback could be avoided under tensile loading, while the increase in toughness remained high.
“…Köpplmayr et al [ 104 ] studied the thermomechanical properties of βPP-multilayer films, which were prepared by the uniform alternation of 128 layers of PPR and βPPR. It was found that the single-layer interface showed a nucleation effect, and the content of β-crystals increased with an increase in the number of layers.…”
Section: Nucleating Efficiency Of β-Crystalsmentioning
The β-crystals of polypropylene have a metastable crystal form. The formation of β-crystals can improve the toughness and heat resistance of a material. The introduction of a β-nucleating agent, over many other methods, is undoubtedly the most reliable method through which to obtain β-PP. Furthermore, in this study, certain newly developed β-nucleating agents and their compounds in recent years are listed in detail, including the less-mentioned polymer β-nucleating agents and their nucleation characteristics. In addition, the various influencing factors of β-nucleation efficiency, including the polymer matrix and processing conditions, are analyzed in detail and the corresponding improvement measures are summarized. Finally, the composites and synergistic toughening effects are discussed, and three potential future research directions are speculated upon based on previous research.
“…The isotactic polypropylene (iPP) as a polymorphic semi‐crystalline polymer, could crystallize in the monoclinic α‐form, hexagonal β‐form, orthorhombic γ‐form, and mesomorphic smectic form . Each crystalline form with diverse supermolecular structure exhibits different mechanical properties.…”
The low impact strength of short carbon fiber (CF) reinforced polypropylene (PP) composites (PP/CF) restricts their practical application. Many studies focus on improving interfacial adhesion strength between PP and CF, while the essential properties of PP matrix are also significant, but rarely investigated for toughening PP/CF composites. In this work, the combination of β‐modification and annealing treatment were adopted to modify the intrinsic toughness of PP matrix, thereby enhancing the impact strength of PP/CF composites, meanwhile their flexural strength and modulus were almost maintained. From the XRD, DSC, POM, DMA and SAXS results, we observed that abundant β‐crystals with small size were produced in PP matrix after β‐modification. In addition, increased overall crystallinity, perfected crystals structure and looser amorphous region were generated after annealing treatment. These microstructure changes resulting from β‐modification and annealing treatment, together triggered the plastic deformation of PP matrix, which was the main reason for toughening PP/CF composites.
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