Perpendicular orientation between dispersed rubber and polypropylene molecules in an oriented sheet

Phulkerd, Panitha; Funahashi, Yoshiaki; Ito, Asae; Iwasaki, Shohei; Yamaguchi, Masayuki

doi:10.1038/s41428-017-0017-3

Cited by 8 publications

(8 citation statements)

References 37 publications

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“…Under the high‐temperature processing condition, that is, 240°C, fine MDBS crystals that existed in the pellets dissolved into the PP and consequently took some time to segregate/crystallize during the cooling process in the mold, leading to poor capability of MDBS as a nucleating agent for PP. This situation was especially pronounced in the skin layer because this layer was quenched in a very short time 43,44 . At 190°C, on the contrary, MDBS crystals did not dissolve in molten PP, at least when the MDBS content was 0.4 wt.%.…”

Section: Resultsmentioning

confidence: 95%

Modulus enhancement of polypropylene by sorbitol nucleating agent in flow field

Iwasaki

Inoue

Takei

et al. 2020

Polymer Crystallization

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The rigidity of an injection‐molded isotactic polypropylene (PP) containing 1,3:2,4‐bis‐o‐(4‐methylbenzylidene)‐D‐sorbitol (MDBS) as a crystal nucleating agent can be enhanced by selection of appropriate processing conditions. A new method by differential scanning calorimetry measurements showed that the dissolution temperature of 0.4 wt.% MDBS in molten PP is around 210°C. When injection molding was performed below the dissolution temperature, for example, 190°C, the molecular orientation of PP was greatly enhanced. Although this is an anomalous condition for the system to expect good transparency, the product obtained showed a high flexural modulus. In contrast, with high‐temperature processing at 240°C, that is, conventional condition, the modulus decreased because of poor molecular orientation. Transmission electron microscopy observation revealed that MDBS fibrils strongly orient to the flow direction under the low‐temperature processing, in which network structure of MDBS fibers is not detected. The oriented MDBS fibers led to a well‐developed shish‐kebab structure, which is responsible for the pronounced rigidity.

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Section: Resultsmentioning

confidence: 95%

Modulus enhancement of polypropylene by sorbitol nucleating agent in flow field

Iwasaki

Inoue

Takei

et al. 2020

Polymer Crystallization

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“…Numerous technologies are adopted to improve the performance of regular homopolypropylene (HPP), such as toughness, tensile strength, and transparency, and a series of PP-based polyolefins including isotacticity polypropylene (iPP), random copolypropylene (RPP), impact PP, PP-based block copolymer, functionalized PP, etc. are successfully commercialized by tailor-made catalysts and polymerization process [3][4][5][6][7][8]. Now these PP-based polyolefins are used in a wide range of industries such as packaging, electrical and electronics, construction, automobile, medical, equipment, and facilities industries [9,10].…”

Section: Introductionmentioning

confidence: 99%

Versatile Propylene-Based Polyolefins with Tunable Molecular Structure through Tailor-Made Catalysts and Polymerization Process

Wang¹,

Han²,

Xu³

2020

Polypropylene - Polymerization and Characterization of Mechanical and Thermal Properties

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Since the discovery of Ziegler-Natta catalysts for olefin polymerization in the 1950s, the production of polyolefins with a variety of properties has continuously grown with rapid development of catalyst technology combined with polymerization process innovation. For propylene-based polyolefin, various polyolefins with distinctive characteristic of mechanical and optical properties were made with specific catalysts in commercial industries owned especially by those large worldwide companies. In this chapter, Ziegler-Natta catalysts, metallocene catalysts, and post-metallocene catalysts for PP polymerization are discussed in detail. Gas phase, bulk, slurry, and solution polymerization processes, such as Spheripol (Basell), Hypol (Mitsui Chemicals), Unipol (Dow Chemical), Innovene (INEOS), Novelen (BASF), Spherizone (Basell), and Borstar (Borealis), developed by the industrial tycoons were reviewed. The molecular architecture of the PP-based polyolefins could be tailored precisely using specific high-performance catalyst in an appropriate polymerization process, and different types of PPs, including homopolypropylene (HPP), random copolypropylene (RPP), impact PP, PP-based block copolymer, functionalized PP, etc., are produced. The relationship between molecular structure and performance of the PP-based polyolefins is also discussed thereof.

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“…Polyolefins are undoubtedly one of the most robust fields in polymer production and consumption globally [ 1 , 2 , 3 ]. Along with continuously growing demand worldwide, there is the remarkable progress of polyolefin catalysts and polymerization process technologies [ 4 , 5 , 6 , 7 , 8 , 9 , 10 ]. The single-site metallocene catalysts have attracted extensive interest, both from academia and industry, due to their abilities to precisely control the polymer microstructure and stereospecificity by simply tailoring the ligands used [ 11 , 12 , 13 , 14 , 15 ].…”

Section: Introductionmentioning

confidence: 99%

Highly Flowable Nano TiO2/Porous Organic Polymer (POP) Supports for Efficient Metallocene Catalysts

et al. 2020

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Porous organic polymers (POPs) have proven to be an efficient support in the olefin polymerization catalyst field. In this paper, nano TiO2 beads were used to modulate the pore structure, bulk density, and surface morphology and flowability of the prepared POPs. With the incorporation of the hydrophilic nano TiO2 beads, the prepared TiO2/POP supports obtained reasonable specific surface area (100–300 m2/g) and higher bulk density (0.26–0.35 g/mL) and flowability than the pure POP supports. The results show that bulk density of the prepared TiO2/POP particles increased when adding an increased amount of TiO2, and when 37.5% TiO2 (weight percent to the total comonomers divinylbenzene (DVB) and 2-hydroxyethyl methacrylate (HEMA)) and 3:1 DVB/HEMA (molar ratio) were added, highly flowable TiO2/POP composites (POP-6 and POP-7) were obtained. With the modulation of the nano TiO2 template during the support synthesis, the prepared POP-7 particles successfully achieved a normal distribution with a narrow particle size distribution (PSD) of 0.717 and average particle size of 24.1 m, a specific surface area (SSA) of 279 m2/g, and relatively high bulk density of 0.30 g/mL. Furthermore, all the prepared TiO2/POP supports obtained higher ethylene polymerization activity than silica gel-supported commercial metallocene catalyst. The immobilized (n-BuCp)2ZrCl2/MAO@POP-7 catalyst exhibited the highest ethylene polymerization activity of 4794 kg PE/mol Zr.bar.h and productivity of 389 g PE/g cat, more than twice that of the commercial counterpart. Even higher catalyst productivity (3197 g PE/g cat) and bulk density of the produced PE (0.36 g/mL) could be obtained in higher ethylene partial pressure at 80 ∘C for 2 h, and the prepared TiO2/POP catalyst shows no obvious Zr+ active sites decay during the ethylene polymerization.

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Perpendicular orientation between dispersed rubber and polypropylene molecules in an oriented sheet

Cited by 8 publications

References 37 publications

Modulus enhancement of polypropylene by sorbitol nucleating agent in flow field

Modulus enhancement of polypropylene by sorbitol nucleating agent in flow field

Versatile Propylene-Based Polyolefins with Tunable Molecular Structure through Tailor-Made Catalysts and Polymerization Process

Highly Flowable Nano TiO2/Porous Organic Polymer (POP) Supports for Efficient Metallocene Catalysts

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