TY - JOUR
T1 - Spherulite formation from microphase-separated lamellae in semi-crystalline diblock copolymer comprising polyethylene and atactic polypropylene blocks
AU - Ueda, Masaya
AU - Sakurai, Kazuo
AU - Okamoto, Shigeru
AU - Lohse, David J.
AU - MacKnight, William J.
AU - Shinkai, Seiji
AU - Sakurai, Shinichi
AU - Nomura, Shunji
N1 - Funding Information:
This work was supported in part by a research grant from Kinki Invention Center (granted to S.S.). The SAXS experiments were performed in the Photon Factory of the Research Organization for High Energy Accelerator with the approval number 99G241, and at SPring-8 (2000B0228-NOL).
PY - 2003/10/3
Y1 - 2003/10/3
N2 - The characteristics of crystallization in a semi-crystalline block copolymer have been experimentally examined using small-angle X-ray scattering and small-angle light scattering. For this purpose, a flow-oriented polyethylene-block-(atactic polypropylene) diblock copolymer with Mw = 113 kg/mol and apolyethylene volume fraction of 0.48 was used. First of all, the crystallization was found to be much suppressed as compared to that of polyethylene homopolymer (homo-PE), as evidenced by a crystallinity that was approximately one-third of homo-PE. Spherulite growth with rupturing the microphase-separated lamellae (micro-LAM) was found at crystallization temperatures in the range 95 ≤ Tc ≤ 101°C. That is, spherulites can grow even if the crystallization is initiated in the spatially confining micro-LAM structure. However, it was further found that the micro-LAM structure did not co-exist with a spherulite. On the other hand, at much lower crystallization temperatures (Tc < 95°C), the micro-LAM structure was retained whereas no spherulites formed. The suppression of spherulite formation can be accounted for by an auto-decelerating effect of nuclei in a confining microdomain space.
AB - The characteristics of crystallization in a semi-crystalline block copolymer have been experimentally examined using small-angle X-ray scattering and small-angle light scattering. For this purpose, a flow-oriented polyethylene-block-(atactic polypropylene) diblock copolymer with Mw = 113 kg/mol and apolyethylene volume fraction of 0.48 was used. First of all, the crystallization was found to be much suppressed as compared to that of polyethylene homopolymer (homo-PE), as evidenced by a crystallinity that was approximately one-third of homo-PE. Spherulite growth with rupturing the microphase-separated lamellae (micro-LAM) was found at crystallization temperatures in the range 95 ≤ Tc ≤ 101°C. That is, spherulites can grow even if the crystallization is initiated in the spatially confining micro-LAM structure. However, it was further found that the micro-LAM structure did not co-exist with a spherulite. On the other hand, at much lower crystallization temperatures (Tc < 95°C), the micro-LAM structure was retained whereas no spherulites formed. The suppression of spherulite formation can be accounted for by an auto-decelerating effect of nuclei in a confining microdomain space.
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U2 - 10.1016/S0032-3861(03)00697-9
DO - 10.1016/S0032-3861(03)00697-9
M3 - Article
AN - SCOPUS:0141643370
SN - 0032-3861
VL - 44
SP - 6995
EP - 7005
JO - polymer
JF - polymer
IS - 22
ER -