Improving Visible‐Light Transparency of Drawn Melt‐Crystallized Linear Polyethylenes: Influence of Molecular Weight Distribution. Issue 6 (31st March 2017)

• Record Type: Journal Article
• Authors: Shen, Lihua; Severn, John; Bastiaansen, Cees W. M.
• Is Part Of: Macromolecular materials and engineering. Volume 302:Issue 6(2017)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-03-31
• Subjects: drawing -- linear polyethylenes -- molecular weight distribution -- transparency; Plastics -- Periodicals; Polymers -- Periodicals; Polymerization -- Periodicals; 547.705
• DOI: 10.1002/mame.201700003
• Languages: English
• ISSNs: 1438-7492

Abstract

Abstract : Visible‐light transparency of drawn melt‐crystallized LPEs highly depends on molecular weight distribution (MWD). At a low MWD < 10, transparent samples are produced only by incorporating appropriate amounts of high refractive index additives prior to drawing. The drawn samples with a comparatively high MWD = 25, however, are transparent, even without any additives. Abstract : A series of drawn melt‐crystallized linear polyethylenes (LPEs) with different molecular weight distributions (MWD = M w / M n ) ranging from 2 to 25 are investigated with respect to the visible‐light transparency. The results indicate that the MWD of the LPEs significantly influences the visible‐light transparency of drawn melt‐crystallized LPEs. At a high MWD, drawn melt‐crystallized LPEs films are transparent and glass‐like, this in contrast to the LPEs with a low MWD. A mechanism behind the observed results is proposed based on differential scanning calorimetry (DSC) analysis, small‐angle X‐ray scattering, wide‐angle X‐ray scattering, and small‐angle light scattering experiments. A correlation between the molecular characteristics, especially the MWD, and the visible‐light transparency of the drawn melt‐crystallized LPEs is proposed.