The present work describes pretreatment processes of thermoplastic polyurethane elastomer (TPU) material, used as an adhesive in powder form, that results in the increased peeling resistance of joints. The TPU in powder form is an environmentally-friendly adhesive and provides safer bonding conditions in the shoe manufacturing industry. TPU particles are soft and require an anti-blocking agent to prevent agglomeration. However, particles covered by such an anti-blocking agent may account for a low peeling resistance in the resulting joints. To overcome this disadvantage, two pretreatment processes for the TPU adhesive were evaluated. The results of a two-step wet washing process, representing a conventional solvent-based procedure that involves both the application of a solvent and a powder separation step, are compared to the performance of a one-step dry plasma treatment process. The process type did not affect the size and agglomeration behavior of the particles, and both processes were effective in improving joint strength according to peeling test results. Spectroscopic investigation of the particle surface after washing or plasma treatment indicated some zinc concentration, which is interpreted to result from the anti-blocking agent. The crystallinity of the TPU, investigated by thermal analysis, was higher after pretreatment. The obtained results indicate that TPU in powder form is a versatile adhesive for the shoe industry with a safer application compared to solvent based adhesive systems.
Classical molecular dynamics were carried out in order to obtain insights into proper conditions to perform chemical fixation of carbon dioxide (CO2) with epoxide molecules into cyclic carbonates. Two different molecules containing epoxide groups were investigated: 1,2–Epoxybutane (EB), called linear aliphatic epoxide molecule, and 3-Ethyl-7-oxabicyclo(4.1.0)heptane (EC), called cycloaliphatic epoxide molecule. The reaction systems involving carbon dioxide additionally were catalyzed by tetraethylammonium bromide (TEAB). The dynamics of the molecular groups were studied by taking into account known reaction mechanisms to investigate whether the optimal reaction conditions were observed. Radial distribution functions and self-diffusion coefficients were calculated and revealed that in case of the systems with cycloaliphatic epoxide groups as reagent the CO2 molecules were located far away from the agglomerate formed by the dispersed tetraethylammonium bromide catalyst and epoxide groups (EC), and they do not present enough mobility to overcome the long distances to react. Additionally, it was observed that, in the case of the linear aliphatic epoxide groups (EB), the dynamics of the groups tends to facilitate the reaction mechanisms by presenting a considerable amount of available CO2 molecules in the neighborhood of the epoxy rings. Thus, via the Molecular Dynamics insights, the systems containing linear aliphatic epoxide groups presented a much more accessible condition for the subsequent reaction steps of the carbon dioxide fixation to occur as compared to systems containing cycloaliphatic epoxide groups. The simulation results are in agreement with the experimental findings, which showed via infrared spectroscopy the successful conversion of epoxy rings from linear aliphatic epoxide molecules into five-membered cyclic carbonates after reacting with carbon dioxide.
In this chapter, we outline some perspectives on embracing the datasets gathered using Extended Non-destructive Testing (ENDT) during manufacturing or repair process steps within the life cycle of bonded products. Ensuring that the ENDT data and metadata are FAIR, i.e. findable, accessible, interoperable and re-usable, will support the relevant stakeholders in exploiting the contained material-related information far beyond a stop/go decision, while a shorter time-to-information will facilitate a prompter time-to-decision in process and product management. Exploiting the value of ENDT (meta)data will contribute to increased performance by integrating all defined, measured, analyzed and controlled aspects of material transformation across process and company boundaries. This will facilitate the optimization of manufacturing and repair operations, boosting their energy efficiency and productivity. In this regard, some aspects that are currently driving activities in the field of pre-process, in-process and post-process quality assessment will be addressed in the following. Furthermore, some requirements will be contemplated for harmonized and conjoint data transfer ranging from a bonded product’s beginning-of-life through its end-of-life, the customization of stand-alone or linked ENDT tools, and the implementation of sensor arrays and networks in joints, devices and structural parts to gather material-related data during a product’s middle-of-life application phase, thereby fostering structural health monitoring (SHM).
This paper presents insights into surfaces properties of sputter‐deposited titania modified with bisphosphonates, including zeta potential measurements in a pH range. Functionalization was investigated through simulation and experimental approaches to model the adsorbate and evaluate structure‐response relationships. Molecules of etidronic, alendronic, and risedronic acids were investigated through density functional theory. The molecules vary their reactivity through similar structures considering different scenarios. X‐ray photoelectron spectroscopy of titania/BP systems demonstrated that functionalization occurs in a short time and resulted in a predominantly “side‐on” adsorbate configuration after two hours of immersion. Zeta potential showed the predominancy of negative charges deprotonated free phosphonates. Water contact angle demonstrated that titania surfaces are hydrophilic after overnight functionalization. Atomic force measurements of bisphosphonates layers suggested that the molecular anions follow the surface topography, unchanging the surface roughness.
Following the vision of the European Commission, organisations and workers establishing Industry 5.0 approaches aspire to more future-proof, resilient, sustainable, and human-centred European industries. In this contribution, we explore how technological innovations that contribute to a “win–win” interaction with involved stakeholders may be advanced in a human-centred and transparent proceeding supported by impartial expert translators who provide information or knowledge-based guidance for decision-makers, initiators and implementers in manufacturing innovation driven by sustainability. We elaborate a stepwise procedure for agreeing on milestones and conjointly treading the path towards solving innovation challenges during a translation process. We exemplify the technological aspects of such a process using an innovation case aiming at identifying parameters for enhancements in a vacuum-bagging process applied to the manufacturing of composite parts from prepregs based on condensation-curing matrix resins made from renewable resources. In detail, we present a straightforward design of an experimental approach varying the dwelling temperature and the temperature ramps during the curing of stacked prepregs. In this way, we demonstrate that for cured composites comprising a poly(furfuryl alcohol)-based matrix, the porosity and connected mechanical properties achieved with autoclave-free curing processes sensitively depend on these process parameters. Applying the resulting data-based model is shown to support decision-making for sustainable composite manufacture.