Comparison in processability and mechanical and thermal properties of ethylene–octene copolymer crosslinked by different techniques

Abstract

ABSTRACT:The crosslinking of metallocene ethyleneoctene copolymer was investigated. The crosslinked polymers were prepared using two different techniques, i.e., peroxide crosslinking and silane-water crosslinking. In the former, the crosslinking reaction was conducted in a twinscrew extruder, in the presence of dicumylperoxide. In the latter, the polymer was first grafted with vinyl trimethoxysilane in the extruder and subsequently crosslinked with water. The paper aims at investigation of the differences between these two techniques, in terms of processing and product mechanical and thermal properties. The results showed that the silane-crosslinked polymers could be prepared with much higher gel contents than the peroxidecrosslinked samples. The silane-crosslinked polymers also retained the elastomeric characteristics of the pure polymer and showed remarkably higher extensibility, better thermal stability, and energy storage capacity. An explanation for the property differences between peroxide-crosslinked and silane-crosslinked polymers was proposed.

Properties of poly(ethylene 1‐octene)‐g‐maleic anhydride copolymers prepared via solvothermal process

“…Pure POE exhibited broad differential scanning melting endotherm, which could be due to the distribution in length of crystallizable ethylene sequence imposed by the placement of noncrystallizable units along the chain, leading to a broad distribution of crystal sizes in this polymer. 22 Different melting behaviors reflect from the melting temperature (T m ) of pure POE at 81.37 C that was much higher than those of POE-g-MAH ranging from 76.02 C to 67.32 C. The heat of fusion (DH f ) of pure POE (39.29 J/g) was also clearly higher than those of POE-g-MAH ranging from 25.81 J/g to 13.98 J/g in the order of increasing extent of grafting. In other words, T m and the heat of fusion decreased as the extent of grafting increased.…”

Properties and Characterization of Filled Poly(Propylene) Composites Crosslinked Through Siloxane Linkage

“…In the case of poly(propylene) (PP), it has been well established that PP mainly experiences chain scission reactions during peroxide modification, leading to a decrease in molecular weight and molecular weight distribution. Therefore, in order to perform crosslinking of PP, the silane-water crosslinking seems to be a promising technique.Silane-grafting and water-crosslinking of polyolefins have received much attention in recent years, [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] not only for industrial applications but also in fundamental research, because of its various advantages, such as easy processing, low capital investment, and favorable properties in the processed materials. The properties of silane-crosslinked products were reported earlier to differ from those of peroxide crosslinked materials, in which the silane-crosslinked polymers were found to exhibit better thermal stability and higher energy storage capacity.…”

Broader Spectrum: Examples

“…The metallocene ethylene -octene copolymer is prepared through two different techniques, i.e., peroxide and silane -water crosslinking [36] , and it is seen that the silane -crosslinked polymers retain the elastomeric characteristics of the pure polymer and show remarkably higher extensibility, better thermal stability, and energy storage capacity. Thermal stability also depends on the nature of the crosslinked moiety as well as on the environment.…”