Skip navigation
  • Home
  • Browse
    • Communities
      & Collections
    • Browse Items by:
    • Publication Date
    • Author
    • Title
    • Subject
    • Department
  • Sign on to:
    • My MacSphere
    • Receive email
      updates
    • Edit Profile


McMaster University Home Page
  1. MacSphere
  2. Open Access Dissertations and Theses Community
  3. Open Access Dissertations and Theses
Please use this identifier to cite or link to this item: http://hdl.handle.net/11375/27411
Title: Investigating the Efficacy of Non-Ionic Surfactants as Compatibilizing Agents for Polyethylene-Polyamide Sintered Polymer Blends
Authors: Akhtar, Mohammad
Advisor: Thompson, Michael
Vlachopoulos, John
Department: Chemical Engineering
Publication Date: 2022
Abstract: A novel strategy was considered in this work to improve the physical properties of rotationally molded parts formed using a thermodynamically immiscible physical blend of high-density polyethylene (HDPE) and polyamide 11 (PA11). Morphology of the melted system of the two polymers dry-mixed in the mold was dictated by the selected non-ionic surface-active agents. Through a preliminary evaluation of numerous non-ionic surfactants, Span 85 and Tween 20 showed the most promise at concentrations between 0.1 - 1.0 wt% for influencing how the two polymers spread over the mold surface in a uniaxial rotational molding unit; the two surfactants demonstrated favourable interparticle cohesion at 235 °C and were chosen on the basis of investigating the hydrophilic-lipophilic balance (HLB) as a predictive metric for polymer migration during rotomolding. For a comparison to a more traditional (and expensive) approach of preparing a molded part with blends of these two polymers, extrusion-mixed blends were first compounded using a twin-screw extruder, pelletized, ground, and finally rotomolded. The good compatibility of the two constituent polymers with Tween 20 was demonstrated by decreasing zero-shear viscosities with increasing surfactant concentration. In the molded samples, porosity for 50/50 dry-mixed blends increased at low concentrations of Tween 20, but ultimately the surfactant demonstrated its beneficial nature on sintering with a downward trend observed in porosity with increasing surfactant concentration; molded samples with 1.0 wt% Tween 20 showed a 1% improvement in porosity relative to uncoated blends, whereas 1.0 wt% Span 85 coated blends showed an undesirable increase in porosity instead. Similar trends were observed for 75/25 dry-mixed blends, except that the porosities for all Tween 20 concentrations were lower than those of uncoated blends. Low porosities were observed for all extrusion-mixed blends (with or without 1.0 wt% Tween 20) relative to the dry-mixed blends. As more favourable results for this new approach, Tween 20 coated dry-mixed blends showed an increase in impact strengths for both blend ratios, whereas extrusion-mixed blends showed a drastic decrease instead. Conversely, the inverse trend was found with flexural strengths. The results were reconciled through morphological analysis of the molded samples which demonstrated that a moderate degree of polymer migration occurred (i.e. aggregation of PA11 at the wall boundaries and HDPE near the centre) in the presence of the surfactant for 50/50 dry-mixed blends, whereas observations for the 75/25 blends were inconclusive. Therefore, based on the observations for density/porosity, impact strength, flexural strength, and morphology (i.e. polymer migration) modifying the blend-ratio, mixing strategy, and surfactant concentration for rotomolded HDPE-PA11 physical blends enables us to reliably predict and control the polyblends’ resultant properties and cater them to meet the requirements of a wide range of unique and specific use-case scenarios.
URI: http://hdl.handle.net/11375/27411
Appears in Collections:Open Access Dissertations and Theses

Files in This Item:
File Description SizeFormat 
Akhtar_Mohammad_F_2022March_MASc.pdf
Access is allowed from: 2023-03-01
2.67 MBAdobe PDFView/Open
Show full item record Statistics


Items in MacSphere are protected by copyright, with all rights reserved, unless otherwise indicated.

Sherman Centre for Digital Scholarship     McMaster University Libraries
©2022 McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L8 | 905-525-9140 | Contact Us | Terms of Use & Privacy Policy | Feedback

Report Accessibility Issue