Mechanics of Time-Dependent Materials and Processes in Conventional and Multifunctional Materials

ABSTRACT The work described in this research focuses on the development of a single-component remendable polymer suitable for integration into aerospace composite structures. The structural polymer can be used as a replacement matrix material in fiber-reinforced composites and allows for in-situ site-specific healing of delamination and matrix cracking when combined with a small volume fraction […]

Study of the Effect of Interface Enthalpy on Nanocomposite Viscoelasticity

ABSTRACT Polymer Nanocomposites (PNC) are a fascinating category of material systems, in which nanoscopic fillers are found to induce remarkable improvements in the properties of the polymeric matrix. [1] This improvement is often determined by the interfacial energetic interactions which dictate the matrix chain mobility, filler dispersion, and distribution. The PNC community has widely studied […]

Sterilization effect on structure, thermal and time-dependent properties of polyamides

ABSTRACT This article studies the effect of different sterilization techniques on structure, thermal and time-dependent mechanical properties of polyamide 6 materials. We used two different types of polyamide 6 material: conventional polyamide 6 with monomodal molecular mass distribution and modified with bimodal one. Samples were prepared and properly shaped in order to observe the mentioned […]

Microstructural Evolution of Nafion During Uniaxial Deformation Monitored by X-ray Scattering

INTRODUCTION Fuel cells enable direct chemical to electrical conversion of fuel to electricity, providing an efficient and clean process. Proton Exchange Membrane Fuel Cells (PEMFC), in which protons from hydrogen or methane cross a membrane to react with oxygen producing electricity, are the preferred transportable fuel cell. Nafion is the membrane of choice for Proton […]

Coupled Non-Fickian Diffusion and Large Deformation of Hydrogels

ABSTRACT Solvent migration in swelling polymer shows complex behaviour, as the interface of wet (rubbery) region moves along with solvent diffusion into the dry (glassy) region, which is accompanied by local deformation. This extrinsic mechanism has led to novel three-dimensional (3D) polymer micro-actuators using direct solvent delivery via microfluidic channels. Here we present experimental techniques […]

Accelerated Testing Methods for Oxidative Aging of Polymeric Composites

Abstract Controlling damage progression in oxidative environments is critical for enhancing the long-term durability of polymeric resins and composites. Traditional methods for characterization of these materials for their practical service life require several thousands of hours of isothermal aging. Therefore, there is a need for accelerated testing methods in order to reduce the prohibitive cost […]

Degradation of Shape Memory Polymer Due to Water and Diesel Fuels Part 1

ABSTRACT Shape-Memory-Polymers (SMP) is smart materials have the ability to memorize original shape; and can be used as sensors, transplants, and structural materials in engineering applications. Despite its practical importance, limited work is available on its degradation behavior. This study has been carried out to evaluate degradation behavior of Veriflex-SMP on exposures to water and […]

Degradation of Shape Memory Polymer Due to Water and Diesel Fuels Part 2

Effect of Degradation due to Water and Diesel Fuel: In this study, the degradation of the SMP due to water and diesel fuel has been examined. At first, the intensity of degradation causes by water and diesel fuel has been compared. Then the progress of degradation with time due to water and diesel respectively, for […]

Structural Enhancement of Framing Members Using Polyurea Part 1

ABSTRACT This paper demonstrates the potential for using field applied structural coatings to reinforce traditional framing members and standard building ties, thereby providing an improved and continuous foundation to roof load pathway. Tension tests are performed on rafter top plate model joint connections, some of which were reinforced with a hurricane tie, to establish how […]

Structural Enhancement of Framing Members Using Polyurea Part 2

During forensic analysis of the weaker specimens, we discovered that the polyurea felt sticky and failure occurred in the polyurea itself as opposed to within the wood fibers. We attributed this problem to incomplete mixing which most likely occurred when one of the canisters in the spray gun ran dry before the other. The interesting […]