“…The tan δ value varied with the type of polymer. It is known that tan δ of polymer is greatly influenced by the structural properties of polymer (Choi et al, 2011). Figure 6.Tan delta as a function of polymer type.…”
The damping performance of lightweight steel/polymer/steel sandwich composites has been typically studied without considering the interface between the heterogeneous materials. Herein, the interface between the steel and polymer layers was investigated experimentally for various steels and polymers. Impact hammer tests revealed that the interfacial adhesion strength between steel and polymer did not significantly affect the loss factor of the sandwich cantilever beam composites. However, although very thin, the adhesive layer itself greatly influenced the vibration-damping performance of the composite. As such, previous three-layered (skin-core-skin) sandwich model without considering the properties of adhesive layer predicted different results from experiments. To accurately predict the loss factor of the sandwich, a five-layered sandwich model consisting of two skins, two adhesives, and a core layer was proposed and validated with experiments.
“…The tan δ value varied with the type of polymer. It is known that tan δ of polymer is greatly influenced by the structural properties of polymer (Choi et al, 2011). Figure 6.Tan delta as a function of polymer type.…”
The damping performance of lightweight steel/polymer/steel sandwich composites has been typically studied without considering the interface between the heterogeneous materials. Herein, the interface between the steel and polymer layers was investigated experimentally for various steels and polymers. Impact hammer tests revealed that the interfacial adhesion strength between steel and polymer did not significantly affect the loss factor of the sandwich cantilever beam composites. However, although very thin, the adhesive layer itself greatly influenced the vibration-damping performance of the composite. As such, previous three-layered (skin-core-skin) sandwich model without considering the properties of adhesive layer predicted different results from experiments. To accurately predict the loss factor of the sandwich, a five-layered sandwich model consisting of two skins, two adhesives, and a core layer was proposed and validated with experiments.
“…Therefore, a great deal of effort has been directed toward enhancing the melt strength and impact strength of PP. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] To improve its impact strength, impact modifiers have been added to PP, and ethylene propylene rubber has been considered the most effective among them due to its high impact strength over a wide temperature range. These blends, commonly referred to as thermoplastic polyolefin elastomers, have an increasingly important role in the polymer industry, especially in automotive applications.…”
Section: Introductionmentioning
confidence: 99%
“…The melt strength of PP can be improved by various methods such as controlling the molecular weight and distribution, 1,2 introducing long-chain branches (LCBs), [3][4][5][6][7][8][9][10][11] or forming polymer composites with inorganic nanofillers. [12][13][14][15] Among these approaches, the most efficient way to enhance the melt strength of PP is by introducing LCBs within the PP chain.…”
Long-chain branched-polypropylene (LCB-PP) was prepared by melt grafting, and LCB-PP/silicate composites were prepared by adding 1-7 wt% silicate using a mini-compounder at 190 1C. The chemical structure of the LCB-PP was confirmed by the existence of a-C ¼ C-H-stretching peak at 3100 cm À1 in the Fourier transform infrared spectrum. LCB-PP and the LCB-PP/ silicate composites exhibited unusual rheological properties, including high shear-thinning tendency and elasticity. Shearthinning tendency and elasticity were highest in the composite containing 5 wt% silicate. These effects were confirmed by oscillatory rheological measurements. The crystallization behavior of LCB-PP and the silicate composite were investigated using a non-isothermal process proposed by Ozawa. The exothermic pattern of the composite is narrower and sharper than those of PP and branched PP. The extending exponents were 3.6 for PP, 2.4 for LCB-PP and 1.5 for the composite. These behaviors can be interpreted by speculating that the silicate in the PP matrix functions as a seed for crystallization and alters the crystallization process.
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