Polyethylenes multimodal

Application To produce bimodal and multimodal high-density polyethylene (HOPE) using the stirred-tank, heavy-diluent Hostalen ACP process. 

Description The Hostalen ACP process is a slurry polymerization method with three reactors in series. The reaction in cascade enables producing top quality unimodal, bimodal and multimodal polyethylene (PE) from narrow to broad molecular weight distribution (MWD) with the same catalyst family. 

Piel C, Albrecht A, Neubauer C, Klampfl CW, Reussner J. Improved SEC-FTIR method for the characterization of multimodal high-density polyethylenes. Anal Bioanal Chem 2011 400 2607-13. 

The initial use of analytical TREF was to characterize polyethylene fractions [120]. Mirabella and Ford used TREF to fractionate LDPE and LLDPE for further characterization using SEC, X-ray C-NMR, DSC and viscosity measurements [121]. These investigators determined that the melting behavior of LLDPE correlated well with a multimodal SCB distribution and the distribution became narrower with increasing molecular weight. Mingozzi and collaborators [122] have applied both analytical and preparative TREF to the analysis of tacticity distribution in polypropylene. The results showed that both methods could be used successfully analytical TREF gave faster qualitative results on the polymer microstructure, while preparative TREF, with subsequent analysis of the fractions, could yield detailed quantitative tacticity information. Hazlitt has described an automatic TREF instrument to measure SCB distributions for ethylene/ a-olefin copolymers [123]. 

Deslauriers PJ, McDaniel MP, Roldfing DC, et al A comparative study of multimodal vs. bimodal polyethylene pipe resins for PE-100 apphcations, Polym Eng Sci 45(9) 1203-1213, 2005. 

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