著者

岩崎 祥平 山崎 敦朗 畠山 広大 内山 陽平 井上 貴博 新田 晃平 山口 政之

出版者

一般社団法人 日本レオロジー学会

雑誌

日本レオロジー学会誌 (ISSN:03871533)

巻号頁・発行日

vol.50, no.2, pp.171-179, 2022-04-15 (Released:2022-05-15)

参考文献数

50

被引用文献数

2

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Microporous films were obtained from an extruded sheet of isotactic polypropylene (PP) containing N,N’-dicyclohexyl-2,6-naphthalene dicarboxamide as a crystal nucleating agent under suitable hot-stretching conditions. The crystalline structure before and after the stretching operations was evaluated by two-dimensional wide-angle X-ray diffraction, and it was found that the original sheet contains a large amount of β-form crystals oriented to the transversal direction (TD) by the extrusion at 200 °C, which is lower than the dissolution temperature of the nucleating agent in PP. During stretching of the sheet, α-form crystals oriented to the stretching direction appeared by the transformation from β- to α-form crystals. Moreover, numerous microvoids were generated by stretching around at 100 °C to the machine or flow direction (MD) of the sheet, although the microvoids were prolonged. The sequential TD stretching, however, expanded the area of voids, leading to a microporous film with a pronounced porosity.

著者

Khunanya Janchai 井上 貴博 岩崎 祥平 木田 拓充 山口 政之

出版者

一般社団法人 プラスチック成形加工学会

雑誌

成形加工 (ISSN:09154027)

巻号頁・発行日

vol.35, no.9, pp.318-323, 2023-08-20 (Released:2023-09-20)

参考文献数

38

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We investigated the effect of shear history on the crystallization behavior of isotactic polypropylene (PP) containing a fibrous nucleating agent, i.e., 1, 3 : 2, 4-bis-o-(4-methylbenzylidene)-Dsorbitol (MDBS), using a polarized optical microscope attached with a parallel-plate shear device. The addition of MDBS greatly enhanced the crystallization temperature of PP with an accelerated crystallization rate. Although shear history applied during cooling barely affected the crystallization temperature for the sample containing MDBS, it greatly enhanced the PP orientation, even with a low shear rate. This was attributed to the formation of a pseudo shish-kebab structure, in which MDBS acted as the shish. It was also found that the addition of MDBS reduced the amount of β -form crystals, while PP without MDBS exhibited β -form crystals after applying an appropriate shear history.

著者

山口 政之 木田 拓充

出版者

一般社団法人 日本レオロジー学会

雑誌

日本レオロジー学会誌 (ISSN:03871533)

巻号頁・発行日

vol.49, no.5, pp.361-363, 2021-12-15 (Released:2022-01-15)

参考文献数

10

著者

西川 理穂 山口 政之

出版者

一般社団法人 プラスチック成形加工学会

雑誌

成形加工 (ISSN:09154027)

巻号頁・発行日

vol.34, no.1, pp.25-28, 2021-12-20 (Released:2022-01-22)

参考文献数

17

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We investigated the structure and properties of extruded high-density polyethylene (HDPE) containing 03. wt.% of multi-walled carbon nanotubes (CNTs). It was found from differential scanning calorimetry measurements that the CNT addition raised the crystallization temperature of HDPE, suggesting that CNT acts as a nucleating agent for HDPE. Furthermore, two-dimensional X-ray diffraction measurements revealed that the CNT addition greatly enhanced the chain orientation of HDPE in the extruded strand, which was pronounced by melt-stretching after passing through the die. CNTs orientated parallel to the flow direction behave like extended chain crystals, and thus accelerate the formation of shish-kebab structure. As a result, the tensile modulus was enhanced by the CNT addition, which was pronounced especially in the high temperature region.

著者

山口 政之

出版者

日本学校教育学会

雑誌

学校教育研究 (ISSN:09139427)

巻号頁・発行日

vol.22, pp.95-108, 2007-08-04 (Released:2017-07-28)

著者

山口 政之

出版者

社団法人日本化学会

雑誌

化学と教育 (ISSN:03862151)

巻号頁・発行日

vol.58, no.7, pp.310-311, 2010-07-20