Additive-Like Amounts of HDPE Prevent Creep of Molten LDPE: Phase-Behavior and Thermo-Mechanical Properties of a Melt-Miscible Blend

作者:Andersson Mattias G; Hynynen Jonna; Andersson Mats R; Hagstrand Per Ola; Gkourmpis Thomas; Mueller Christian
来源:Journal of Polymer Science Part B: Polymer Physics , 2017, 55(2): 146-156.
DOI:10.1002/polb.24262

摘要

Low-density polyethylene (LDPE) is the preferred type of polyolefin for many medical and electrical applications because of its superior purity and cleanliness. However, the inferior thermo-mechanical properties as compared to, for example, high-density polyethylene (HDPE), which arise because of the lower melting temperature of LDPE, constitute a significant drawback. Here, we demonstrate that the addition of minute amounts of HDPE to a LDPE resin considerably improves the mechanical integrity above the melting temperature of LDPE. A combination of dynamic mechanical analysis and creep experiments reveals that the addition of as little as 1 to 2 wt% HDPE leads to complete form stability above the melting temperature of LDPE. The investigated LDPE/HDPE blend is found to be miscible in the melt, which facilitates the formation of a solid-state microstructure that features a fine distribution of HDPE-rich lamellae. The absence of creep above the melting temperature of LDPE is rationalized with the presence of tie chains and trapped entanglements that connect the few remaining crystallites.

  • 出版日期2017-1-15