Polyolefin analysis by single-step crystallization fractionation

Britto, L. J. D.; Soares, João B. P.; Penlidis, Alexander; Monrabal, Benjamín

doi:10.1002/(sici)1099-0488(19990315)37:6<539::aid-polb6>3.0.co;2-o

Cited by 32 publications

(17 citation statements)

References 10 publications

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“…CRYSTAF and TREF analysis of the PE supported the above results. CRYSTAF and TREF can be used to measure chemical composition distribution (CCD) based on the continuous crystallization of polymer chains from a dilute solution [31][32][33][34]. The knowledge of a polymer's CCD is essential in investigations of structure-property relationships, polymerization kinetics and mechanisms, and polymer reaction engineering [33].…”

Section: Polymer Characterizationmentioning

confidence: 99%

Easy one-pot method to control the morphology of polyethylene/carbon nanotube nanocomposites using metallocene catalysts

Bahuleyan

Atieh

et al. 2012

J Polym Res

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An easy one pot method is demonstrated for the controlled periodical surface coating of polyethylene over multiwalled carbon nanotubes (MWCNT) by insitu polymerization of ethylene using highly active metallocene catalysts (Cp 2 ZrCl 2 and Cp 2 TiCl 2 ) in combination with methylalumoxane. The crystallinity of the nanocomposite was increased and its morphology could be tuned from "sausage" like to "shish-kebab" in the presence of CNT depending on the experimental condition and choice of metal atom.

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Section: Polymer Characterizationmentioning

confidence: 99%

Easy one-pot method to control the morphology of polyethylene/carbon nanotube nanocomposites using metallocene catalysts

Bahuleyan

Atieh

et al. 2012

J Polym Res

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“…The characterization techniques for measuring the CCD of semicrystalline copolymers have been continuously developed, especially crystallization-based techniques that fractionate polymers according to chain crystallizabilities in a dilute solution, such as temp erature-rising elution fractionation (TREF), crystallization analysis fractionation (CRYSTAF), and crystallization elution fractionation (CEF). [ 1,[3][4][5][6][7][8] Dynamic crystallization (DC) was recently introduced as a new CCD analysis tool using fractionation concepts similar to TREF and CRYSTAF, but with the fractionation step occurring under a constant solvent fl ow to enhance the physical separation of the polymer chains during the crystallization step. [ 7,8 ] DC consists of two consecutive steps: crystallization and elution steps.…”

mentioning

confidence: 99%

Effect of Operating Conditions on Dynamic Crystallization of Ethylene/1‐Octene Copolymers

Chokputtanawuttilerd

Anantawaraskul

Alghyamah

et al. 2013

Macro Chemistry & Physics

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Dynamic crystallization (DC) is a new characterization technique for measuring the chemical composition distribution (CCD) of semicrystalline copolymers. This technique fractionates polymers based on chain crystallizabilities under a constant cooling rate; a solvent is also fed through the column at a constant fl ow rate during the crystallization to enhance the physical separation of the polymer fractions. In this work, a DC model for ethylene/1-olefi n copolymers on the basis of population balance, crystallization kinetics, and axial dispersion is proposed. This model is found to describe the experimental DC profi les of an ethylene/1-octene copolymer at various operation conditions very well.

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“…Negligenciando a pequena influência do PM [14] , a cristalização em solução do PELBD irá segregar os cristais de acordo com a quantidade de co-monômero ou ramificação.…”

Section: Medida De Distribuição De Ramificações Curtas Dscbunclassified

Correlação entre propriedades reológicas e ópticas de filmes tubulares de polietileno linear de baixa densidade com diferentes distribuições de ramificações curtas

et al. 2006

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Resumo: Devido a suas excelentes propriedades mecânicas o polietileno linear de baixa densidade, PELBD, tem ganhado cada vez mais importância na indústria de embalagens. Essas propriedades são resultado de sua estrutura molecular, da existência de ramificações curtas, SCB, e da distribuição dessas ramificações, DSCB. Junto com o peso molecular, PM, e sua distribuição, DPM, as ramificações curtas também afetam o processo de sopro de filmes influenciando na solidificação do filme até a linha de neve, já que a cinética de cristalização é dependente da distribuição destas ramificações. Assim, este trabalho teve como objetivo verificar a influência da DSCB do PELBD nas propriedades reológicas e óticas de filmes tubulares. Para isso, três PELBD foram escolhidos; dois sintetizados com catalisador Ziegler-Natta e um com catalisador metaloceno, de peso molecular ponderal médio, M w , similar e DSCB diferentes.Observou-se que a DSCB exerce influência nas propriedades reológicas que refletem a elasticidade do material como a primeira diferença de tensões normais N 1 , o módulo de armazenamento G'(ω), e a deformação recuperável γ r ; entretanto na viscosidade em função da taxa de cisalhamento η( ), e no módulo de perda G"(ω), a diferença nessa distribuição não foi percebida. Observou-se também que quanto maior a deformação recuperável dos PELBD, menores foram as estruturas cristalinas formadas o que diminuiu a opacidade dos filmes. Porém essa proporcionalidade manteve-se até uma determinada γ r mínima, acima da qual a fratura do fundido se sobrepôs à recuperação da deformação e a opacidade voltou a aumentar. Palavras-chave: Polietileno linear de baixa densidade, filmes soprados, deformação recuperável, opacidade. Correlation Between Rheological and Optical Properties of LLDPE Blown Films with Different Distributions of Short Chain BranchingAbstract: Linear low-density polyethylene, LLDPE, has increased its market share in the packaging industry due to its excellent mechanical properties. These properties are the result of its molecular structure due to its short chain branching, SCB, and their distribution, DSCB. Together with the molecular weight and the distribution of molecular weights, the SCB affects the blown film process because it interferes in the film solidification and crystallization kinetics up to the freezing line. The objective of this work was to verify the influence of the DSCB of LLDPE in the rheological and optical properties of blown films. Three LLDPE, synthesized with Ziegler-Natta and metallocene catalysts, were studied, all with similar weight average molecular weight, M w , but with different DSCB. It was observed that the DSCB influenced the rheological properties that reflect the material elasticity, such as the first normal tension difference, N 1 ( ), the storage modulus G'(w) and the recoverable strain γ r ; however, the rheological properties that reflect the viscosity, such as the shear viscosity η( ) and the loss modulus G"(w), were not affected. In addition, the higher the γ r of the LLDPE,...

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Polyolefin analysis by single-step crystallization fractionation

Cited by 32 publications

References 10 publications

Easy one-pot method to control the morphology of polyethylene/carbon nanotube nanocomposites using metallocene catalysts

Easy one-pot method to control the morphology of polyethylene/carbon nanotube nanocomposites using metallocene catalysts

Effect of Operating Conditions on Dynamic Crystallization of Ethylene/1‐Octene Copolymers

Correlação entre propriedades reológicas e ópticas de filmes tubulares de polietileno linear de baixa densidade com diferentes distribuições de ramificações curtas

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