Improved balance between dimensional stability, mechanical properties and processability of linear low density polyethylene for rotational molding

Abstract

The linear low density polyethylene (LLDPE) products made by rotational molding (RM) usually involve two main problems of poor dimensional stability and insufficient mechanical properties. Although the decline in thermal expansion coefficient and rise in mechanical strength can be attained by filling with inorganic particles, the melt fluidity of LLDPE, which is of great importance for RM, would be significantly reduced. In this study, a combination of crosslinker low‐temperature blending and partial chemical crosslinking strategy is employed to enhance the dimensional stability and mechanical properties of LLDPE without sacrificing the melt fluidity. The structure–property relationships in the crosslinked specimens are analyzed based on X‐ray diffraction, differential scanning calorimetry, thermogravimetric analysis, scanning electron microscopy, and dielectric spectrometry. The results show that our simple, low‐cost and universal strategy not only contributes to a better dimensional stability and significantly improved mechanical properties, but also endow the samples with promising processability and thermal stability.

Melt‐reprocessablelinear low‐density polyethylene/cyclic olefin copolymerblends with low dielectric constant and low thermal expansion

“…Low‐density PE was later replaced by cross‐linked PE due to its improved properties. Cross‐linked PE exhibits better resistance to water treeing, better environmental stress cracking resistance, resistance to higher temperatures, and especially greater dimensional stability, all improvements over uncross‐linked PE 14–20 . However, crosslinking of thermoplastics alters the materials to those that no longer melt and lose melt processability or renewability.…”