Rotomolding of Thermoplastic Elastomers Based on Low-Density Polyethylene and Recycled Natural Rubber

Abstract

In this study, regenerated and nonregenerated off-the-road (OTR) ground tire rubber (GTR) was blended with low-density polyethylene (LDPE) to produce thermoplastic elastomers (TPE) by rotational molding. In particular, blending was performed by two different methods: melt blending (extrusion) and dry blending (high shear mixer). Then, different GTR concentrations (0, 20, 35, and 50 wt %) were used to determine the effect of rubber content on the processability and properties of the rotomolded compounds. From the samples produced, a complete morphological (optical and scanning electron microscopy), physical (density and hardness), and mechanical (tension, flexion, and impact) characterization was performed. The results showed that increasing the rubber content decreased the mechanical rigidity and strength but increased the elasticity and ductility. Finally, although melt blending led to slightly better properties than dry blending, the latter is more interesting to limit possible material degradation (mechanical, thermal, and oxidative), while reducing processing cost and time.

Recycling Waste Tires into Ground Tire Rubber (GTR)/Rubber Compounds: A Review

“…Blending a polymer matrix and GTR (surface modified) with elasticity and impact resistance might result in improved blend properties, such as tensile strength and elongation at break, depending on the level of interfacial interaction between the GTR and the matrix [13,17,22,60]. The incorporation of even as little as 10 wt.% GTR into polymer matrices (thermosets, thermoplastics and rubbers) leads to large consumption of waste tires as a partial replacement of virgin polymers [38].…”

“…On the other hand, RTR is offering better mechanical strength, thermal stability and curing behavior compared to GTR. This is attributed to the soluble fraction of RTR responsible for a good interfacial adhesion with rubber molecules and possible co-crosslinking at the interphase between RTR and rubber matrix [17,22]. Recently, more research attention was directed to find the optimum GTR/RTR loading in rubber matrices with less property loss compared with virgin rubber properties.…”

“…In order to melt blend waste tires with polymers, grinding methods are used for downsizing the discarded tires and produce ground tire rubber (GTR) having small particle sizes (granulates in the range of 0.5-15 mm and powders with sizes less than 0.5 mm) [16]. However, poor bonding between GTR and most polymer matrices is leading to low mechanical strength and low durability of the resulting compounds, which is a significant challenge limiting the performances of the blends [17,18].…”

Product Design by Additive Manufacturing for Water Environments: Study of Degradation and Absorption Behavior of PLA and PETG

“…Likewise, the use of design tools for the AM of cellular structures allows the easy inclusion of a reinforcement assembly in the dome that improves its behavior on impact. In the manufacture of this type of flotation elements, it is common to create a skin of polyethylene or other thermoplastics by rotomolding processes [47,48] or blow molding [49] and fill the interior with expanded polystyrene or polyurethane to achieve structural consistency under hydrostatic pressure [50]. The product developed in this work has been designed to be produced in a single process and with a single material, through the AM FFF.…”

A New Multiparameter Model for Multiaxial Fatigue Life Prediction of Rubber Materials

“…Although there are works in the literature that study the fatigue phenomenon of these materials during the crack propagation stage [23], this paper establishes its objective in the crack nucleation stage. This is because, in general, stress [51]. Wang et al [52] used the finite element method to calculate stress-based fatigue damage parameters, including the logarithmic principal stress and the Cauchy principal stress.…”