화학공학소재연구정보센터
Journal of Polymer Science Part B: Polymer Physics, Vol.37, No.6, 523-530, 1999
Hardness and Young's modulus of transcrystalline polypropylene by Vickers and Knoop microindentation
A study of the anisotropic microhardness and Young's modulus of transcrystalline isotactic polypropylene grown from the surface of high modulus carbon fibers is described. Static microindentation experiments were performed with Knoop and Vickers tips. The Young's moduli of the transcrystalline region were estimated from Knoop microindentation data by using a method recently developed in our laboratory. Data for the different lamellar directions were generated using the Knoop tip, which is sensitive to material anisotropy. We found that the hardness and Young's modulus of the transcrystalline layer are higher by up to 30% when the longer diagonal of the probing Knoop tip is perpendicular to the transcrystalline growth direction, compared to when the diagonal is parallel to that direction.