Separation and identification of ethylene-propylene block copolymer

Xu, Jun‐Ting; Feng, Linxian; Yang, Shilin; Wu, Yinan; Yang, Yiqing; Kong, Xiangming

doi:10.1016/s0032-3861(96)01021-x

Cited by 61 publications

(40 citation statements)

References 12 publications

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“…The peak assignments for the 13 C NMR spectra are given in Table 3. These assignments were made according to literature [41][42][43][44][45]. Assignments for the methylene carbons in Table 3 are identified by the letter S and a pair of Greek letters that indicate its distance in both directions from the nearest tertiary carbons.…”

Section: Resultsmentioning

confidence: 99%

Molecular composition and properties of impact propylene copolymers

Aj¹,

Nc²

2012

Express Polym. Lett.

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Abstract. Impact polypropylene copolymers (IPCs) are important commercial materials, but their morphology and molecular architecture are not yet fully understood. In this study the focus was on selectively removing specific fractions from the original IPC, recombining the remaining fractions, and studying the properties and morphology of these recombined polymers. It was found that some properties of the samples changed remarkably, depending on the fraction of material that was removed before recombination. In a similar fashion, morphological changes could be observed. For example, the degree of phase separation and the crystalline morphology of the recombined materials varied noticeably. It was further established that specific copolymer fractions present in the original polymer affect not only the morphology of the final polymer, but also the hardness and impact resistance.

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Section: Resultsmentioning

confidence: 99%

Molecular composition and properties of impact propylene copolymers

Aj¹,

Nc²

2012

Express Polym. Lett.

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“…Recently, many reports have been published on the temperature rising elution fractionation (TREF) analysis of various polyolefins, such as polypropene [1][2][3][4][5][6] , polyethene 7) , poly(1-octene) 8) , propene-butene copolymer 9) , ethene-1-hexene copolymer 10) , impact polypropene copolymer 11) , impact-resistant polypropene alloy 12) , etheneFull Paper: Microstructural heterogeneities of cyclopolymers of 1,5-hexadiene and polypropenes obtained by stopped-flow and conventional slurry polymerization methods were investigated by means of temperature rising elution fractionation (TREF) analysis. Both the cyclopolymer and polypropene obtained by the stopped-flow method showed two main peaks in the TREF profiles.…”

Section: Introductionmentioning

confidence: 99%

Microstructural heterogeneities of the cyclopolymer of 1,5-hexadiene obtained by stopped-flow and conventional methods: correlation to plural active sites for polypropene on MgCl2-supported Ziegler catalyst

Mori

Kono

Terano³

2000

Macromol. Chem. Phys.

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“…The technology involves bulk polymerization of propylene and gas-phase copolymerization of ethylene and propylene using spherical superactive TiCl 4 /MgCl 2 based catalyst systems. [11][12][13][14] The use of a spherical catalyst allows a wider range of rubber content in the alloy and better control over phase structure to be achieved. The resulting spherical granules can be directly processed, eliminating the need for pelleting.…”

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confidence: 99%

Effect of Copolymerization Time on the Microstructure and Properties of Polypropylene/Poly(ethylene-co-propylene) In-Reactor Alloys

et al. 2009

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Three Polypropylene/Poly(ethylene-co-propylene) (PP/EPR) in-reactor alloys produced by a two-stage slurry/gas polymerization had different ethylene contents and mechanical properties, which were achieved by controlling the copolymerization time. The three alloys were fractionated into five fractions via temperature rising dissolution fractionation (TRDF), respectively. The chain structures of the whole samples and their fractions were analyzed using high-temperature gel permeation chromatography (GPC), Fourier transform infrared (FT-IR), 13 C nuclear magnetic resonance ( 13 C NMR), and differential scanning calorimetry (DSC) techniques. These three in-reactor alloys mainly contained four portions: ethylenepropylene random copolymer (EPR), ethylene-propylene (EP) segmented and block copolymers, and propylene homopolymer. The increased copolymerization time caused the increased ethylene content of the sample. The weight percent of EPR, EP segmented and block copolymer also became higher. The more EPR content indeed improves the toughness of the alloy but lowers its stiffness. Increasing the ethylene content in the EPR fraction and EP segmented and block copolymer, as well as the suitable content of EPR, is believed to be the key factors resulting in the excellent toughnessstiffness balance of in-reactor alloys.KEY WORDS: PP/EPR In-Reactor Alloy / Fractionation / Microstructure / Isotactic polypropylene (iPP) is a thermoplastic material widely used as it offers interesting combinations of good mechanical performance, heat resistance, and fabrication flexibility. However, it has relatively poor impact resistance, especially at low temperatures. Its toughness could be improved by a variety of elastomers, 1-3 by adding a nucleating agent that reduces the average dimensions of the spherulites. 4The toughness could also be improved by copolymerization of propylene with ethylene or other olefins, 5-10 among which the copolymerization with ethylene is one of the most useful and effective methods. Polypropylene/poly(ethylene-co-propylene) (PP/EPR) in-reactor alloys have been industrialized on a large scale.The in-reactor blending technology was developed by Montell Company, hence opening up new horizons for polyolefin materials. The technology involves bulk polymerization of propylene and gas-phase copolymerization of ethylene and propylene using spherical superactive TiCl 4 /MgCl 2 based catalyst systems.11-14 The use of a spherical catalyst allows a wider range of rubber content in the alloy and better control over phase structure to be achieved. The resulting spherical granules can be directly processed, eliminating the need for pelleting.The mechanism of the two-stage in-reactor blending technology is very complicated, depending on the nature of active species in the catalysts and polymerization process. Xu et al. had proposed that the iPP with active center still can copolymerized with propylene and ethylene in the second stage.6 A previous investigation of the composition and chain structure of the PP/EPR in-reactor ...

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Separation and identification of ethylene-propylene block copolymer

Cited by 61 publications

References 12 publications

Molecular composition and properties of impact propylene copolymers

Molecular composition and properties of impact propylene copolymers

Microstructural heterogeneities of the cyclopolymer of 1,5-hexadiene obtained by stopped-flow and conventional methods: correlation to plural active sites for polypropene on MgCl2-supported Ziegler catalyst

Effect of Copolymerization Time on the Microstructure and Properties of Polypropylene/Poly(ethylene-co-propylene) In-Reactor Alloys

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