Surface Treatment Applications Research Articles

Application of friction stir surface treatment for modification of peripheral coarse grain structure and mechanical properties of AZ31 Mg alloy

The presence of peripheral coarse grains (PCG) in the microstructure of extruded products is considered one of the causes of decreased mechanical properties. Such microstructure has been observed at the periphery of extruded AZ31 Mg alloy. This research aims to achieve a refined and homogeneous microstructure at the structure of extruded bars of AZ31 alloy using pinless friction stir processing (FSP). Up to six passes of FSP using pinless tools with different shoulder surface geometries were conducted. Tools with varying diameters of 12, 15, and 22 mm were used to investigate the effect of shoulder geometry. The rotational speed and traverse speed of the tool were set at 900 rpm and 70 mm/min, respectively. The tool tilt angle was also set to 3°. The effect of the tool geometry on the metallurgical and mechanical properties was investigated using metallography tests, microhardness testing, tensile testing, and fracture testing. According to the results, it was found that reducing the diameter of the tool and using featured tool can lead to homogenization and reduction of the average grain size in the processed samples, increasing the microhardness compared to the primary sample. It was also observed that mechanical properties were improved with the increase in the tool diameter due to the improved quality of the processing area. For samples processed with a 22 mm diameter tool, the final strength reached 242.7 and 248.81 MPa, respectively, for the simple and featured tools.

Improving the quality of the ultrasonic welded thermoset-based composites using laser surface treatment

In this article, ultrasonic welding of glass fiber-reinforced thermosetting polymers which were surface-treated by laser engraving, is investigated. Composite samples were prepared by hand lay-up method. In the next step, surface treatment of the composite samples was performed by means of a high-power laser confirming two grooved and circular patterns. Polymethylmethacrylate and polypropylene as the amorphous and semicrystalline thermoplastic intermediate layers were incorporated to create a joining between the two thermoset parts. Besides, the welding time was considered in the three different levels. In order to investigate the microstructure of the welding zone, scanning electron microscopy analysis were accomplished. Besides, lap-shear tests were performed so as to evaluate the mechanical performances of the welded parts. Morphological studies indicated that in the surface-treated samples, the penetration of the intermediate material into the welded parts is much higher than neat samples and this leads to the superior interaction between the coupling layer and the surface-treated parts. Confirming the morphological outcomes, the results of the lap-shear tests specified that the application of surface treatment using laser engraving has increased the laps-shear strength almost 5.5 times compared to the samples without preparation.

Color reproduction trueness of 3D-printed full-color dental casts with scans derived from an intraoral scanner.

To investigate the effects of shade tab color variations (tooth-colored vs. gingiva-colored) and surface treatment (application of mineral oil) on the trueness of color reproduction from dental shade tabs to 3D-printed full-color dental casts, using digital scans obtained from an intraoral scanner. Pristine tooth-colored (with 16 shade tabs) and gingiva-colored (with five shade tabs) shade guides were digitally scanned using an intraoral scanner, and subsequently, 3D-printed replicas were created using a full-color material jetting 3D printer. Three color measurements using a contact type digital spectrophotometer were recorded, including actual shade tabs (R0), dried 3D-printed study samples (RP1 ), and study samples with mineral oil application (RP2 ), in this study to calculate color differences between the actual shade tabs and 3D-printed ones. The CIEDE2000 formula was used to calculate the color differences (color reproduction trueness) between reference shade tabs and 3D-printed full-color study samples-without and with mineral oil, ∆E00 (RP1 ), and ∆E00 (RP2 ). ∆E00 (RP1 ) and ∆E00 (RP2 ) were compared with a 50:50% accessibility threshold (AT) and a 50:50% perceptibility threshold (PT). A grading system, based on the relative ranges of AT and PT, was employed. The percentage of samples falling into each color-matching category was then recorded. The data collected were subjected to statistical analysis, utilizing a mixed model ANOVA to evaluate the effects of shade tab color and mineral oil application on color differences, α = 0.05. The application of mineral oil significantly affected the ∆E00 [F(1, 378) = 19.1, p = < 0.0001]. However, this effect was only significant for the gingiva-colored study samples; the mineral oil application significantly decreased color difference, showing ∆E00 (RP1 ) of 8.71 ± 3.78 and ∆E00 (RP2 ) of 6.55 ± 2.14 (p < 0.0001). For the tooth-colored groups, the mineral oil application did not yield any color difference, showing ∆E00 (RP1 ) of 7.05 ± 2.35 and ∆E00 (RP2 ) of 6.94 ± 2.35 (p = 0.497). In the absence of mineral oil, gingiva-colored samples revealed a significantly larger ∆E00 (RP1 ) of 8.71 ± 3.78 compared to tooth-colored samples at 7.05 ± 2.35 (p = 0.017). Conversely, mineral oil application rendered comparable ∆E00 (RP2 ) values between gingiva-colored (6.55 ± 2.14) and tooth-colored (6.94 ± 2.35) samples (p = 0.558). All 3D-printed full-color samples showed Grade 1 (extremely unacceptable mismatch) and Grade 2 (clearly unacceptable mismatch), regardless of the shades or the presence of mineral oil. Utilizing an intraoral scanner to gather digital color data, along with an MJ 3D printer, offers the potential for producing 3D-printed full-color dental casts for prosthesis characterization in the dental laboratory. While mineral oil improves the color reproduction trueness of gingiva-colored objects, all 3D-printed full-color samples exhibited unacceptable mismatches when compared to their target objects. This underscores the need for future improvement in the digital color data acquisition process and color optimization protocols in 3D printing processes.

Investigation of Paralleled Inverters With Various-Order LC Resonant Tanks for Possible Surface Treatment Applications

Investigation of Paralleled Inverters With Various-Order LC Resonant Tanks for Possible Surface Treatment Applications

A combinatorial hollow cathode discharge/plasma polymerization system for silver containing plasma parylene coating

The conventional pyrolysis of parylene coating depends on a high vacuum environment and an expensive solid dimer precursor. Our previous study successfully demonstrated the feasibility of synthesizing plasma parylene (PP) coating using plasma polymerization with a liquid para-xylene precursor. The deposition conditions for plasma polymerization are compatible with the vacuum level of the hollow cathode discharge (HCD). This led to the idea of using an HCD gun as the metal source to incorporate metal into the plasma polymerized films, thereby achieving different coating functions and extending applications, such as active antibacterial purposes. In this study, an HCD gun was installed on the plasma polymerization reactor to synthesize a silver containing plasma parylene (Ag-PP) coating, where the silver HCD tube serves as the in situ source for incorporating silver.The experimental results demonstrate that the quantity of incorporated silver increases linearly with the power delivery level of the HCD device, and its content can be controlled during deposition to form an Ag-PP coating. Microstructural analysis reveals that the incorporated silver exhibits a crystalline and granular structure with a metallic state in the Ag-PP coating. Furthermore, the Ag-PP coating significantly resists both Staphylococcus aureus and Escherichia coli, with an antibacterial activity value exceeding 2.0 after 24 h of plate culture, corresponding to a silver metal ion release of 2–3 ppb. This quantitatively substantiates that the incorporated silver can impart an active antibacterial function to the PP coating for biomedical surface treatment applications.

Advancements in anode and cathode nanomaterials for high-performance Li-ion batteries

Commercially, lithium-ion batteries are the most popular batteries for electric devices, while energy density and stability have become more important for electric vehicles. Therefore, there is an increased interest in producing advanced lithium-ion batteries with a greater range of electric storage capability and improved electron transfer efficiency. Over the past few years, nanotechnology has been widely applied to enhance the physical properties of materials through the application of surface treatments or the modification of nanostructures. The significant development potential of nanotechnic applications for lithium-ion batteries is the reason for this discussion. There have been several advancements in graphene, carbon nanotubes, silicon-based and other metal-based anodes, lithium cobalt oxide, lithium iron phosphate, and nickel-based cathodes, their fabrication processes and understanding of mechanisms, as well as trends for further improvement of those previously discovered. These advancements have led to the development of batteries with greater capacity and greater performance, better stability, quicker charging times, and a longer cycle life.

Technical assessment of shear bond strength at ceramo-alloy interface after various surface treatment combinations and application of metal bonding agent.

Bonding between metal and ceramic is one of the most important aspects of a successful prosthesis. Various methods have been recommended for preparing the metal surface to enhance the bond between metal and ceramic including the use of a metal bonding agent. This study aims to evaluate and compare the shear bond strength of the metal-ceramic (M-C) interface after combinations of various surface treatments including the application of a metal bonding agent. 40 Ni-Cr alloy specimens were made and divided into 4 groups of 10 each based on the combination of surface treatments. Sandblasting, surface grinding, and Oxidation heat treatment (OHT) were performed on specimens from Group 1 (Control). In addition, Group 2 specimens received ultrasonic cleaning, Group 3 steam cleaning, and Group 4 metal bonding agent application. Following surface treatments on all specimens, porcelain build-up was performed, and shear bond strength was tested in a Digital Universal testing machine. The statistical tests used were independent t-test and ANOVA. Results revealed that Group 4 specimens had the highest mean value of shear bond strength of 39.087 MPa while Group 3 specimens showed the least mean shear bond strength of 18.154 MPa with highly statistically significant results (p< 0.001). The surface treatments and application of bonding agent to metal prior to porcelain application resulted in increased shear bond strength of the metal-ceramic interface.

Durability of concrete incorporating recycled coarse aggregates: carbonation and service life prediction under chloride-induced corrosion

The use of recycled aggregates (RA) is growing due to the environmental problems associated with extracting natural aggregates (NA) and the disposal of construction and demolition waste (CDW). However, the service-life prediction of recycled coarse aggregate concretes remains incipient. Thus, this study aimed to evaluate the effects of different replacement contents of NA by RA (25, 50, and 75 wt%) on physical (water absorption, porosity, and bulk density), mechanical properties (compressive strength and modulus of elasticity), microstructure (evaluated by X-ray microtomography), accelerated carbonation, and chloride penetration of concrete. A service life prediction analysis of RA concretes was conducted based on the chloride profile obtained and considering the application of different concrete surface treatments. The RA contents evaluated increased the carbonation and chloride diffusion coefficients by 75.7% and 43.0%, respectively, compared to the reference concrete. Nevertheless, reductions of approximately 50% on the critical chloride concentration depth of RA concretes are estimated considering the application of acrylic-based surface treatment. Therefore, applying surface treatments is promising to increase RA concretes' durability and service life, contributing to its wide use and dissemination feasibility.

The Impact of Riboflavin, Nd: YAG Laser, and Ceramic Primer Pretreatment on Surface Roughness, Bond Failure, and Adhesive Strength of Resin Composite to Lithium Disilicate Ceramics: A Scanning Electron Microscopy (SEM) Analysis

Aim: Adhesive bond integrity and surface roughness (Ra) of LDS ceramics following the application of various surface treatments. Material and Method: Forty disks of LDS ceramics were prepared and randomly distributed into different groups based on the method of pretreatment. Group 1: HF (hydrofluoric acid) + S (Silane), Group 2: RFP (riboflavin photosensitizer) S, Group 3: SECP (selfetch ceramic primer and Group 4: Nd: YAG laser. Following conditing LDS ceramic was assessed for Ra and Scanning electron micrographs. All LDS ceramics were bonded and the strength of the resin-ceramic interface was tested using a universal testing machine. The debonded samples were examined under a stereomicroscope. The failure modes were categorized as cohesive, admixed, and adhesive interfaces. Ra and bond integrity values were tested using, two-way ANOVA, and Tukey post hoc tests. (p = 0.05). Results: The highest Ra and bond values were exhibited by samples pretreated using HF + S. Nevertheless, group 2 (RFP + S) demonstrated the lowest bond integrity (12.37 ± 1.98 MPa). No significant differences in the bond integrity outcomes between group 1, group 3 (SECP), and group 4 (Nd: YAG laser + S) (p &gt; 0.05). Conclusion: Nd: YAG and SECP have the potential to be used as an LDS ceramic conditioner alternative to HFA for adequate bond scores.

Electrical and optical characteristics of radio-frequency atmospheric dielectric barrier discharge using anodic alumina barriers

It is widely accepted that dielectrically insulated electrodes can control plasma contraction in radio frequency atmospheric pressure glow discharge at very large currents. It is also known that thin dielectric barriers maximize the permissible discharge current, thus boosting the reactive plasma species and enhancing the application efficacy. An experimental investigation of radio-frequency atmospheric pressure dielectric barrier discharge (rf APDBD) using a thin layer of a novel dielectric, anodic alumina grown by a wet electrochemical process to insulate electrodes is presented in this paper to demonstrate that rf APDBD with anodic alumina barriers remains stable and retains volume without contraction over a wide current range in the γ-mode. The electrical characterization of the rf APDBD is performed using an equivalent electric circuit model based on the measured electrical parameters. In normal glow discharge, the measured impedance data closely matched the simulated data. Optical emission spectroscopy demonstrated that a higher discharge current facilitated active plasma chemistry. The estimated excitation, vibrational, and gas temperatures indicate that rf APDBD with anodized electrodes is well suited for surface treatment and decontamination applications in open air.

Bacterial Adhesion Strength on Titanium Surfaces Quantified by Atomic Force Microscopy: A Systematic Review.

Few studies have been able to elucidate the correlation of factors determining the strength of interaction between bacterial cells and substrate at the molecular level. The aim was to answer the following question: What biophysical factors should be considered when analyzing the bacterial adhesion strength on titanium surfaces and its alloys for implants quantified by atomic force microscopy? This review followed PRISMA. The search strategy was applied in four databases. The selection process was carried out in two stages. The risk of bias was analyzed. One thousand four hundred sixty-three articles were found. After removing the duplicates, 1126 were screened by title and abstract, of which 57 were selected for full reading and 5 were included; 3 had a low risk of bias and 2 moderated risks of bias. (1) The current literature shows the preference of bacteria to adhere to surfaces of the same hydrophilicity. However, this fact was contradicted by this systematic review, which demonstrated that hydrophobic bacteria developed hydrogen bonds and adhered to hydrophilic surfaces; (2) the application of surface treatments that induce the reduction of areas favorable for bacterial adhesion interfere more in the formation of biofilm than surface roughness; and (3) bacterial colonization should be evaluated in time-dependent studies as they develop adaptation mechanisms, related to time, which are obscure in this review.

Predicting the Friction Coefficient of High-Friction Surface Treatment Application Aggregates Using the Aggregates’ Characteristics

Providing sufficient pavement surface friction (i.e., skid resistance) between vehicle tires and pavement surface throughout the pavement service life is considered to be one of the main objectives of highway design. Moreover, vehicle safety, the amount of consumed fuel, and the wearing rate of vehicle tires generally are influenced by pavement surface friction. In this study, a comprehensive experimental testing program was conducted on different aggregate sources, including calcined bauxite and five alternative local sources, to assess their friction characteristics. The testing program included a British pendulum tester (BPT) and a dynamic friction tester (DFT), which were used to evaluate the friction characteristics of the proposed aggregates, along with basic and durability properties tests. The aggregate imaging measurement system (AIMS) technique was applied to evaluate the aggregate characteristics due to Micro-Deval degradation. This study provides two empirical models for the friction characteristics of high-friction surface treatment (HFST)-application aggregates based on the experimental results. The first model correlates the friction coefficient at 20 km/h (DFC20) with the British pendulum number (BPN). The second model expresses DFC20 as a function of polishing resistance of aggregates, which is represented by the initial and terminal aggregate texture and angularity values measured using the AIMS device with an overall coefficient of determination (R2) of 0.949. The aggregate characteristics (i.e., particle angularity and surface texture) align well with the microtexture characteristics of the investigated sources.

Tribological properties of hemp fiber reinforced polylactic acid bio-composites: effect of different types of modification methods

In this study, green composites are prepared with 30 wt.% hemp fibers reinforced polylactic acid (PLA) to enhance the impact and tribological properties. Different surface treatments of alkali and silane, compatibilizer of maleic anhydride (MA), and blends of thermoplastic polyurethane (TPU) and poly (butylene succinate) were applied to improve interfacial adhesion between fibers and matrix. Hemp-reinforced PLA bio-composites were fabricated and characterized by hardness, impact strength, wear, and friction properties. The tribological tests of the injection-molded components were performed under two different loads (10 N and 20 N) as dry-sliding linearly reciprocating motion per ASTM G133. Modified composites gave better tribological properties than unmodified composites. While no remarkable improvement was observed in the hardness value of untreated fiber-reinforced composite, alkali-treated composite reached up to 43% improvement in hardness value. In general, as the load increased, weight loss increase was observed in all composites. Unmodified bio-composite exhibited a very low weight loss and specific wear rate (SWR) compared to neat PLA under 10 N load. The SWR of the MA bio-composite had the lowest value for both loads (10 N and 20 N) compared to the other bio-samples. The TPU blended bio-composite exhibited the highest impact strength (22.96 kJ m−2) after pure PLA (26.5 kJ m−2). Therefore, due to surface treatments and blends applied to the fibers, some composites’ hardness and wear resistance were increased while the impact strength and friction coefficient was decreased. Especially silane surface treatment and MA compatibilizer application increased the wear resistance of composites. When the scanning electron microscope images were examined, it was revealed that the fiber and matrix interface bonding was good, and the fibers were firmly embedded in the matrix. Furthermore, forming a protective thin film layer formed by the polymer debris from the surface during dry-sliding increased the wear performance of the bio-composites.

Evaluation and thermal performance of cool pavement under desert weather conditions: Surface albedo enhancement and carbon emissions offset

Surfaces such as pavement, buildings, and other heat-absorbing surfaces that store more heat than natural vegetation generate the Urban Heat Island (UHI) effect. Temperatures are known to be significantly higher in urbanized areas compared to rural ones.The application of a reflective surface treatment to the pavement improves its solar reflectivity while lowering the warmth of its surface. The main objective of this study is to assess the performance of a cool pavement in an educational complex parking area, under desert climatic conditions to reduce heat islands. White and high reflective material was applied to the tested parking pavement area. Various experimental techniques were used to assess the performance of non treated (baseline) and treated (cool) pavements including spectral radiation, reflectance (albedo), solar irradiance, and pavement surface temperature. The results show that the coated pavement has a 15 % reflectance in ultraviolet A (UVA) and the untreated pavement has a 17 % solar reflectance (baseline basement). There are no potential dangers to human health posed by the coated pavement's reflection of UVA (For visible wavelengths, coated pavement has a reflectance of roughly 70 %, while uncoated pavement has a reflectivity of only 24 %. Under desert climatic conditions, the results show a net decrease in surface temperature of the coated pavement by up to 15 °C compared to the uncoated one. In the summer, for example, raising the albedo of the pavement surface from 24 % to 70 % lowered the surface temperature from 60 °C to 47 °C. This represents a 22 % decrease in pavement surface temperature. The thermal performance analysis of the cool pavement technology reveals that the pavement surface albedo enhancement will help to increase surface reflectance while lowering pavement surface temperature and offsetting CO2 emissions. Increasing the pavement surface albedo by 192 % (from 24 % to 70 %) for the total treated surface area (81,000 m2) in the educational complex will offset 28,350 tons of CO2. The application of a white coating with a high reflective value on concrete and asphalt pavements will help to extend the life of the pavement, reduce the energy consumption of buildings and the emissions of greenhouse gases, minimize the emissions of carbon dioxide caused by the enhancement of albedo (a strategy for mitigating the effects of climate change), improve parking lot visibility, and deal with the effects of heat islands.

Enhanced behaviour of a passive thermoelectric generator with phase change heat exchangers and radiative cooling

Heat exchangers are essential to optimize the efficiency of Thermoelectric Generators (TEGs), and heat pipes without fans have proven to be an advantageous design as it maintains the characteristic robustness of thermoelectricity, low maintenance and lack of moving parts. However, the efficiency of these heat exchangers decreases under natural convection conditions, reducing their heat transfer capacity and thus thermoelectric power production. This work reports on a novel heat exchanger that combines for the first time, phase change and radiative cooling in a thermoelectric generator to improve its efficiency and increase the production of electrical energy, specially under natural convection. For this, two thermoelectric generators with heat-pipes on their cold sides have been tested: one with the radiative coating and the other without it. Their thermal resistances have been determined and the electric power output was compared under different working conditions, namely, natural convection and forced convection indoors and outdoors. The experimental tests show a clear reduction of the heat exchanger thermal resistance thanks to the radiative coating and consequently, an increase of electric production 8.3 % with outdoor wind velocities of 1 m/s, and up to 54.8 % under free convection conditions. The application of the radiative surface treatment is shown to result in a more stable electrical energy production, suppressing the drastic decrease in the generated electric power that occurs in thermoelectric generators when they work under free convection.

Effect of local ‘over-growth’ on fracture behaviors of coated titanium fiber fabricated by plasma electrolytic oxidation

The local ‘over-growth’ behavior of plasma electric oxidation (PEO) coating plays a vital role in the fracture of alloy. In this work, the effect of the ‘over-growth’ on the fracture behavior of PEO coating on the titanium fiber substrate was investigated by the tensile and bending. The ‘over-dissolution’ on the surface of fiber occurred by concentrated plasma discharge during the discharge stage, which lead to the ‘over-growth’ behavior and formed a ‘zigzag’ region in the interface between fiber and coating. The ‘over-growth’ behavior induces the concentration of residual stress generated by PEO, which provides a driving force for the crack initiation and propagation. The cracks propagate from the ‘zigzag’ interface to the fiber substrate resulting in the reduction of the tensile strength for the coated fiber by 45%, compared with the original fiber. Besides, the cracks propagate from the ‘zigzag’ interface to the coating surface, which causes coating cracking and peeling off. This work provides a potential application in surface treatment on fibers and the theoretical basis for optimizing ceramic coating.

Investigation of Bonded Joints in Glass Fiber Reinforced Flat Profiles

Nowadays, raw material shortage is a characteristic problem that affects every sector of the industry. Composite materials reinforced with fiberglass, manufactured through the pultrusion process, have extremely favorable properties. In our research, we examined the application of surface treatments on pultruded profiles to enhance surface energy. We roughened the surfaces to be bonded using manual sanding and sandblasting techniques, and then performed wetting measurements using various degreasing agents. To demonstrate the occurrence of surface treatment and determine its magnitude, we inspected the surfaces with a roughness tester. The bonds were created using two different structural adhesives as well as epoxy resin. The shear strength values of the flat profiles were compared through tensile tests, and the effects of the surface treatments were determined. Based on the results, the appropriate surface treatment and adhesive type greatly influence the developed bond strength.

Development of Ultrasonic Pulsed Plasma Jet Source for Remote Surface Treatment

We have developed a supersonic pulsed plasma jet device capable of long-distance and high-speed processing, and investigated its basic characteristics for surface treatment applications, mainly in the material and medical fields. The developed apparatus is equipped with a mechanism to transport active species in the plasma to the object to be treated by jetting the generated high-density plasma outward with supersonic pulse jets, which allows the gas flow velocity to increase significantly during pulse jetting compared with plasma generation. This enables the active species in the plasma to reach the treatment target before deactivation, thereby realizing surface treatment at a distance. Measurements using the Schlieren method revealed that the velocity of the jet flow reached Mach 1.7.

Evaluation of the Bond Strength of Polyetherketoneketone to Dental Ceramic.

To evaluate the efficacy of different surface treatments on the bond strength of polyetherketoneketone (PEKK) to ceramic materials. PEKK test specimens were separated into four groups according to surface treatments (group S: sandblasting; group A: acid etching; group SA: sandblasting + acid etching; group C: control). Surface roughness values of PEKK specimens were measured before and after surface treatment. After the prepared PEKK specimens were bonded to lithium-disilicate glass-ceramic specimens with resin cement, they were kept in distilled water at 37°C for 24 h. Half of the specimens in each surface treatment group were thermocycled. All test specimens underwent shear bond strength testing. Failure modes were assessed using light microscopy and SEM. Statistical analysis demonstrated that surface treatments created significant roughness on the PEKK surfaces (p = 0.005). While group S showed the highest roughness values, group A showed the lowest. Of the thermocycled test groups, the sandblasting + acid etching group obtained the highest shear bond strengths. Among the non-thermocycled test groups, the sandblasting surface treatment group achieved the highest shear bond strengths. The application of surface treatments to enhance the bond strength of PEKK to ceramics has proven to be effective.

Cleaner technologies to minimise the environmental footprint of the footwear bonding process

Advances in cleaner technologies have a critical role in reaching Europe’s climate and environmental goals. More precisely, in the case of the footwear bonding process its environmental impact is mainly related to the VOCs emissions resulting from the use of organic solvents in the most common adhesives used, as well as during the application of some surface treatments such as halogenation. Moreover, the use of raw materials of fossil origin also contributes to its carbon footprint. The aim of this work is to deploy cleaner technologies to minimise the environmental footprint of the footwear bonding process through several approaches at different steps of the process life cycle, also to contribute to footwear circularity. This work focuses on the synthesis and application of reactive hot melt polyurethanes from CO2-based polyols as biobased adhesives, and the study of plasma-based surface treatments (low-pressure plasma and atmospheric pressure plasma) to improve adhesion properties, using styrene-butadiene vulcanised (SBR) rubber as a representative footwear soling material. The influence of CO2-based polyols on the polyurethane structure and the physicochemical effects of the plasma treatments on the rubber surface, as well as the final adhesion properties have been evaluated by means of different experimental techniques. The results showed that the values obtained for the T-peel strength of the adhesive joints studied, with the combination of the application of the plasma surface treatments and the biobased reactive hotmelt, exceed the minimum quality requirements for footwear according to the standardised tests. As a result, the deployment of such cleaner technologies regarding adhesives and surface treatments in the footwear bonding process will contribute to improving footwear carbon footprint and its circularity.