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Inter and intra-molecular branching distribution of tailored LLDPEs inferred by melting and crystallization behavior of narrow fractions

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Abstract

Here we report the melting and isothermal crystallization behavior of two sets of fractions obtained from a film-grade metallocene catalyzed ethylene-1-hexene resin with enhanced mechanical properties. One set of fractions was obtained by molecular weight fractionation, the second set was obtained fractionating by content of 1-hexene. The melting behavior, crystallization kinetics and supermolecular morphology of the fractions are analyzed in reference to the behavior of model systems with uniform inter-chain branching content and a random intra-chain distribution. While melting and crystallization kinetics of molecular weight fractions conforms to the bivariate (molecular weight-comonomer content) distribution of the original copolymer, the behavior of 1-hexene compositional fractions indicate a blockier branching distribution in the highly branched high molar mass fractions. Major differences with model random copolymers are also observed in the supermolecular morphology of the latter fractions.

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Acknowledgements

We are indebted to the ExxonMobil Co. for financial support and clearance for publication of this work. The assistance of undergraduate student Belen Kelly is also acknowledged.

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Authors and Affiliations

  1. Department of Chemical and Biomedical Engineering, FAMU/FSU College of Engineering, 2525 Pottsdamer St, Tallahassee, FL, 32310, USA

    Madhavi Vadlamudi & Rufina G. Alamo

  2. ExxonMobil Chemical Co, 5200 Bayway Drive, Baytown, TX, 77522, USA

    David M. Fiscus

  3. ExxonMobil Research and Engineering Co, Rt 22 East, Annandale, NJ, 08801, USA

    Manika Varma-Nair

Authors
  1. Madhavi Vadlamudi
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  2. Rufina G. Alamo
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  3. David M. Fiscus
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  4. Manika Varma-Nair
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Correspondence to Rufina G. Alamo.

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Vadlamudi, M., Alamo, R.G., Fiscus, D.M. et al. Inter and intra-molecular branching distribution of tailored LLDPEs inferred by melting and crystallization behavior of narrow fractions. J Therm Anal Calorim 96, 697–704 (2009). https://doi.org/10.1007/s10973-009-0020-9

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  • DOI: https://doi.org/10.1007/s10973-009-0020-9

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