Reliability of Free Inflation and Dynamic Mechanics Tests on the Prediction of the Behavior of the Polymethylsilsesquioxane–High-Density Polyethylene Nanocomposite for Thermoforming Applications

Numerical modeling of the thermoforming process of polymeric sheets requires precise knowledge of the viscoelastic behavior under conjugate effect pressure and temperature. Using two different experiments, bubble inflation and dynamic mechanical testing on a high-density polyethylene (HDPE) nanocomposite reinforced with polymethylsilsesquioxane HDPE (PMSQ–HDPE) nanoparticles, material constants for Christensen’s model were determined by the least squares optimization. The viscoelastic identification relative to the inflation test seemed to be the most appropriate for the numerical study of thermoforming of a thin PMSQ–HDPE part. For this purpose, the finite element method was considered.

Viscoelastic Analysis of the Damping Asphalt Mixtures (DAMs) Made with a High Content of Asphalt Rubber (AR)

Damping asphalt mixtures (DAMs) have been developed to resist vibration and noise caused by traffic loads, and the ultimate design goal in this process is to increase damping. However, while optimizing its damping characteristics, the viscoelastic properties are not yet clear. In the present study, two DAMs are designed based on the open-graded (OG) aggregate structure, and the viscoelastic properties are evaluated subsequently by the dynamic mechanical testing. The results show that the proposed mix-design method for DAMs can meet the mechanical requirements specified in the standards; DAMs are detected to have higher phase angle and lower stiffness modulus compared with traditional mixtures, and the antifatigue performance is excellent but resistance to rutting may face challenges.

Reclaimed Rubber/Poly(ε-caprolactone) Blends: Structure, Mechanical, and Thermal Properties

The amount of elastomeric waste, especially from tires is constantly increasing on a global scale. The recycling of these residua should be considered a priority. Compounding the waste rubbers with other polymers can be an excellent alternative to reuse waste materials. This procedure requires solving the issue of the lack of compatibility between the waste rubber particles and other polymers. Simultaneously, there is a claim for introducing biodegradable plastics materials to reduce their environmental impact. In this work, reclaimed rubber/poly(ε-caprolactone) (RR/PCL) blends are proposed to enhance the recycling and upcycling possibilities of waste rubbers. The results show that the addition of PCL to the RR allows obtaining blends with improved mechanical properties, good thermal stability, and enhanced interfacial compatibility between the used components. Structure and properties of the proposed RR/PCL have been studied by means of static and dynamic mechanical testing, Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA)-FTIR analysis.

Discussion the Rheological Properties of Asphalt Rubber

To test the effects of crumb rubber's mesh and parameters to rubber asphalt to improve the performance of asphalt, we use different mesh rubber powder and asphalt to prepare rubber asphalt in the laboratory, and do dynamic mechanical testing to rubber asphalt sample. We find that different mesh rubber powder have obviously different action to improve the performance of asphalt. Under the same conditions, in order to make better use of modified bitumen. We propose how to use modified asphalt prepared by different mesh rubber powder for different paving.

Comparison of the Polymer/Composite Based on Polyurethane with Different –OH Backbone

Polyurethanes with two different types of –OH backbones castor oil (CO) and hydroxyl terminated polybutadiene (HTPB) were synthesized by using moderately reactive iso-phorone diiscocayante (IPDI) as curing agent. IR spectroscopy and mechanical property evaluations were carried out to elucidate the structure-property relationship of the polymer. It was found that the polymer, intersegment bonding had significant effects on the ultimate tensile properties. The CO based polymer exhibited far better mechanical properties than that of HTPB based polymer. However, a reverse behavior was observed in the composites. Composite fabricated with HTPB based polymer matrix showed four times the tensile strength of CO based composite. SEM comparison of the fractured composites revealed better wetting and adhesion properties with HTPB. Dynamic mechanical testing results indentified a relationship between the viscoelastic parameters and frequency of the applied load.