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This paper extends previous studies by the authors that aimed to describe the effect of apparent cross-link density (CLD) of the rubber polymer networks on the fracture mechanism caused by cut and chip (CC) wear of natural rubber (NR), demonstrating the positive effect of conventional vulcanization (CV). This work is focused on the determination of the effect of CLD while keeping constant the accelerator-to-sulfur ratio A/S = 0.2, typical for CV systems. For this ratio, different sulfur quantities were chosen, and the concentration of the accelerator N-tert-butyl-benzothiazole sulphonamide (TBBS) was calculated to achieve CLDs in a range from 35 to 524 μmol·cm–3. Standard analyses such as tensile tests, hardness, rebound resilience and DIN abrasion were performed. From these analyses, the optimum physical properties of the NR-based rubber were estimated to be in the CLD range of approximately 60 to 160 μmol·cm–3. A CC wear analysis was performed with an Instrumented cut and chip analyzer (ICCA) and it was found that the highest CC wear resistance of the NR is in the CLD range of 35 to 100 μmol·cm–3. Furthermore, the effect of straininduced crystallization (SIC) of NR on CC wear and its dependence on the CLD region was discussed. For the first time, we determine a CLD range for a CV system in which the material achieves both optimal mechanical properties and CC wear resistance. [ABSTRACT FROM AUTHOR]

This investigation reports the synthesis of a new class of polyurethane (PU) based on bis(hydroxyalkyl) polydimethylsiloxane (PDMS) as diol and isophorone diisocyanate as diisocyanate followed by the preparation of PU/layered double hydroxide (PU/LDH) nanocomposite via ex-situ technique. Nuclear magnetic resonance and Fourier-transform infrared spectroscopy studies confirm the formation of PU and incorporation of PDMS into the PU backbone. Thermogravimetry analysis revealed that thermal stability of the composite improves significantly with incorporation of LDH into the PU matrix. This may be accredited to the barrier effect rendered by the LDH layers. Differential scanning calorimetry study reveals that with the incorporation of LDH, glass transition temperature ([T.sub.g]) of the composite increases for an optimum level of loading beyond which it remains constant. KEYWORDS composite, layered double hydroxide, polydimethylsiloxane, polyurethanes, thermal property, 1 | INTRODUCTION Polyurethanes (PUs) are one of the most significant class of polymeric materials which have wide spread applications due to its diversified properties. [1] Despite of several advancements [...]

With the assistance of the moving least‐squares (MLS) interpolation functions, a two‐dimensional finite element code is developed to consider the effects of a stationary or moving solid body in a flow domain. At the same time, the mesh or grid is independent of the shape of the solid body. We achieve this goal in two steps. In the first step, we use MLS interpolants to enhance the pressure (P) and velocity (V) shape functions. By this means, we capture different discontinuities in a flow domain. In our previous publications, we have named this technique the PVMLS method (pressure and velocity shape functions enhanced by the MLS interpolants) and described it thoroughly. In the second step, we modify the PVMLS method (the M‐PVMLS method) to consider the effect of a solid part(s) in a flow domain. To evaluate the new method's performance, we compare the results of the M‐PVMLS method with a finite element code that uses boundary‐fitted meshes. [ABSTRACT FROM AUTHOR]

Predicting the heat build-up in rubber under dynamic cyclic loading is still challenging due to its complexity. The simplest way to make such a prediction is to use numerical methods like the Finite Element Method (FEM), which is preferable especially for geometrically complex rubber components. However, for components with simple geometry, analytical methods may be more appropriate as they better reflect the physical background and allow an assessment of the accuracy of the FE methods through comparison. This paper deals with the detailed derivation of the analytical equations for predicting the heat generation from the heat equation in a rubber cylinder under dynamic cyclic loading. The work focuses exclusively on a thermal solution assuming known rubber material parameters and corresponding loading conditions of the cylinder. The results of the equations derived in this way are compared and discussed with the results of a Finite Element Analysis (FEA) in the radial and axial directions and in the time domain. The analytical expression represents a significant contribution to the effective prediction of the evolution of heat generation in rubber without meeting the requirements of the FEA implementation. [ABSTRACT FROM AUTHOR]

Stimuli–responsive mechanoadaptive materials, capable of reversibly changing their mechanical properties when exposed to an external stimulus, are the next generation of smart materials with immense transformative potential for various technological applications. Although the concept of adaptive mechanical properties has been proven for some materials, it remains very challenging for soft elastomeric materials. The aim of this review is to provide new ideas and strategies for the development of mechanoadaptive elastomeric composites using commercial rubber as the matrix polymer. The fundamental question addressed here is as follows: How do the phase‐responsive functional fillers alter the mechanical properties? For a given physical network environment, what is the mechanism that gives rise to the stimuli–responsive properties of the resulting composites? Herein, the preparation, structure, and properties of recently developed mechanoadaptive elastomeric materials are summarized. Furthermore, based on their structure–property relationships, plausible applications of these smart materials in various technology‐specific applications such as soft robotics, actuators, sensors, smart tires, automotive design, aerospace, etc. are demonstrated with representative examples. Finally, the article critically discusses the existing challenges in the field of mechanoadaptive elastomers in order to provide valuable insights in this area. [ABSTRACT FROM AUTHOR]