Processing and rheological behavior of cross-linked polyethylene containing disulfide bonds

SPE Polymers

article

Maria Camila Montoya-Ospina¹  Henk Verhoogt²  Tim A. Osswald¹ 

[1] Polymer Engineering Center, University of Wisconsin-Madison;SABIC Technology & Innovation

关键词: cross-linking density;    crystallinity;    dimensional stability;    disulfide bonds;    polyethylene;    rheology;    vitrimers;   

DOI  :  10.1002/pls2.10062

学科分类：社会科学、人文和艺术（综合）

来源: Wiley

【 摘 要 】

Vitrimers are a new class of materials that consist of chemically cross-linked networks that engage in thermoactivated associative exchange reactions. These exchange reactions can impart malleability, healing, and recyclability properties to thermosets. In this study, a one-step protocol to prepare linear low-density polyethylene (LLDPE) vitrimer-like materials with disulfide exchange bonds via reactive blending is presented. The cross-linking reaction of maleic anhydride-grafted-linear low-density polyethylene (LLDPE-MAH) and 4,4′-dithiodianiline was followed in a torque rheometer. The degree of MAH-functionalization and its impact on the melt rheology, dynamic mechanical properties, and thermal properties of the vitrimer was studied. The cross-linked LLDPE possessed a mostly elastic behavior, with storage modulus ( G ′ ) higher than loss modulus ( G ′ ′ ) in the entire frequency range. The complex viscosity of cross-linked LLDPE at high frequencies (>100 rad/s) was comparable to the thermoplastic LLDPE. The MAH-groups and formation of cross-links decreased the degree of crystallinity, which led to a decrease in the storage modulus at a temperature of 35°C. The storage modulus and dimensional stability of the materials improved with cross-linking density, suggesting potential benefits of LLDPE vitrimers in secondary manufacturing processes. Finally, the reprocessing ability was demonstrated via internal mixing and the rheological and mechanical properties were retained.

【 授权许可】

CC BY