Thermoplastic elastomers blends based on linear low density polyethylene, ethylene-1-octene copolymers and ground rubber tire

Abstract

Blends of linear low density polyethylene (LLDPE) ethylene-1-octene copolymers (EOC), with different 1-octene (OC) content, and ground rubber tire (GRT) were prepared by melt mixing in a twin screw extruder. Five different compositions of LLDPE/EOC/GRT blends were processed in the extruder to evaluate the effect of EOC addition to the LLDPE/GRT blends. The addition of EOC to LLDPE/GRT blends improves the mechanical properties. Besides, the replacement of 5% of GRT by EOC grades (OC = 20 or 30 wt %) in the 50/50 LLDPE/GRT blend, leads to a significant increase of ultimate tensile properties. The EOC comonomer content affects the properties of LLDPE/EOC and LLDPE/EOC/GRT blends. Dynamical-mechanical analyses showed that, with the addition of EOC to LLDPE/GRT blends, the Tg of GRT and the Tg of EOC are closer. This effect is more pronounced when the EOC with the highest content of comonomer (30 wt %) is added to LLDPE/GRT blend. In this case, only one peak related to the Tg of the rubber phase can be visualized in the amorphous region. These findings indicate that EOC may act as compatibilizer agent for LLDPE/GRT blends.

Elastic modulus measurements at variable temperature: Validation of atomic force microscopy techniques

“…The comparison between the two series of data for each material demonstrates the repeatability of the technique. As temperature increases in the analyzed range, which is comprised between the LDPE glass transition and melting temperatures (around -120°C and 100-140°C, respectively), LDPE indentation modulus roughly linearly decreases down to 50% of M 0 , in agreement with results reported in literature [38][39][40]. For temperature ranging from room condition to 50°C, an almost negligible decrease of indentation modulus is observed on PC, while a slightly more significant reduction down to 75 − 80% of the corresponding M 0 is observed as temperature increases to 70°C, which is well below the PC glass transition temperature (about 140°C).…”

Contact resonance atomic force microscopy for viscoelastic characterization of polymer-based nanocomposites at variable temperature

“…Conversely, tan δ measured on LDPE definitely increases with temperature from 0.1 at room temperature to about 0.2 at T = 70°C. These values are consistent with those (approximately from 0.13 to 0.23) obtained in the same range of temperature using DMA recently reported [41]. It should be explicitly noted, however, that the comparison among the results of mechanical characterizations obtained by different techniques on polymers reported in literature may be not significant and misleading.…”

Blends of ground tire rubber devulcanized by microwaves/HDPE - Part B: influence of clay addition

“…In general, the mechanical properties of the blends containing clay are not so good, especially the results of elongation at break, probably due to the poor adhesion between the phases [13,14,60,63] . According to the presented results, adhesion between the phases was not sufficient to promote good stress transference, resulting in the deterioration of the mechanical properties results.…”

“…In the production of thermoplastic vulcanized blends (TPVs) containing recycled rubbers, the addition of a virgin rubber or the promotion of the rubber devulcanization (at least partial) are pre-requisites to obtain resultant good mechanical properties [12] . The poor adhesion between the phases and the large particle size of the rubber phase facilitate the propagation of cracks and lead to a pronounced decline of the mechanical properties of the blends [13] . In order to improve the properties of blends containing recycled rubbers, some authors devulcanize the rubber phase [3,9,[14][15][16][17][18] , or add functional fillers [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] .…”