Effect of cross‐linking on the mechanical properties, degree of crystallinity and thermal stability of polyethylene vitrimers

• Published in: Polymer engineering and science Vol. 62; no. 12; pp. 4203 - 4213
• Main Authors: Montoya‐Ospina, Maria Camila, Verhoogt, Henk, Ordner, Mark, Tan, Xiao, Osswald, Tim A.
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.12.2022; Society of Plastics Engineers, Inc; Blackwell Publishing Ltd
• Subjects: Analysis; Crosslinked polymers; cross‐linking; Crystallinity; Damping; Degree of crystallinity; Density; Dynamic stability; Maleic anhydride; Materials research; Mechanical properties; Melt blending; Optical microscopy; Polyethylene; Polyethylenes; Reprocessing; Spherulites; Stiffness; structure–property relations; Thermal properties; Thermal stability; Thermodynamic properties; Thermogravimetric analysis; Vitrimers; Yield strength; United States; Canada
• ISSN: 0032-3888; 1548-2634
• DOI: 10.1002/pen.26178

Maleic anhydride‐grafted‐polyethylene was dynamically cross‐linked via reactive melt blending with 4,4′‐dithiodianiline. Thermal and mechanical properties of polyethylene vitrimers with different cross‐linking density were investigated. The results indicate that the degree of crystallinity decreased with increasing cross‐linking density. This behavior was directly related to short‐term and long‐term mechanical properties: vitrimers showed a decrease in yield strength and creep performance. The yield strength of PE vitrimers decreased linearly in relation to the degree of crystallinity. Polarized optical microscopy revealed that the cross‐links inhibit the growth of spherulites structure in polyethylene vitrimers. Thermogravimetric analysis indicated an increase in the onset degradation temperature and decomposition rate for vitrimers with increased cross‐linking density. The stiffness of the vitrimers decreased with increasing cross‐linking density which led to higher damping properties. Finally, it was demonstrated that reprocessing of polyethylene vitrimer was possible without significant impact in mechanical properties. Thermal and mechanical properties of polyethylene vitrimers with different cross‐linking density were investigated. The yield strength and crystallinity of the vitrimers decreased with increasing cross‐linking density following a linear relationship.