Interfacial Adhesion Mechanism Research Articles

Synthesis of adhesion promoter for lead frame bonding and application of epoxy composite materials

AbstractPolymer adhesion promoters were formulated to improve the adhesion strength of lead frame/epoxy composites. The poly(itaconic acid‐co‐acrylamide) (IAcAAM) was synthesized via free radical polymerization to improve the interfacial adhesion between Ni and Cu lead frames and epoxy composites. IAcAAM was synthesized by setting itaconic acid (IA) and acrylamide (AAM) at molar ratios of 7:3, 5:5, and 3:7. The interfacial adhesion mechanism was investigated by introducing IAcAAM with three different comonomer molar ratios. The adhesion strength between EMC and Cu and Ni substrates to which each IAcAAM was applied was measured using a universal testing machine, and the effect of IAcAAM with various IA:AAM molar ratios on the surface energy of EMC was closely studied. As a result, the adhesion properties of Ni lead frame/epoxy composite and Cu lead frame/epoxy composite were improved as small amounts of all IAcAAM samples were added to the epoxy mixture. We confirmed that IAcAAM with an appropriate molar ratio can be used in the EMC process and has the potential to increase the adhesion of epoxy composites and metal lead frames.Highlights A polymeric adhesive promoter was synthesized to enhance the adhesion strength of lead frame/epoxy composites. Poly(itaconic acid‐co‐acrylamide) (IAcAAM) was copolymerized from itaconic acid and acrylamide for this purpose. The adhesion strength of lead frame/epoxy composites was compared for different IAcAAM monomer contents and with a commercial adhesive promoter. IAcAAM showed superior adhesion strength in the Ni lead frame/epoxy composite material. The highest adhesion strength was achieved at a monomer composition of 5:5.

Soil conditioning of clay based on interface adhesion mechanism: Microscopic simulation and laboratory experiment

Clogging frequently occurs in the cutter head, excavation chamber or screw conveyor when an earth pressure balance (EPB) shield machine is tunneling in soft or silty clay ground with high clay mineral content. In this paper, montmorillonite, kaolinite, and illite were selected as research objects, and molecular dynamics (MD) simulation and laboratory experiment were adopted. At the microscopic scale, dynamic contact behavior and interfacial mechanical behavior of the interface between clay minerals and water/surfactant solution was simulated and the interfacial adhesion and conditioning mechanism between clay minerals and water/surfactant solution was revealed. Thus, sodium dodecyl benzene sulfonate (SDBS) surfactant was selected as the main composition of the soil conditioner. Then, the adhesion stress before and after soil conditioning and the contact angles between clay minerals and water/surfactant solution were tested and analyzed at the macroscopic scale. The result shows that the contact angle between droplet and clay mineral surface is an important parameter to characterize soil adhesion. The simulation rules of the microscopic contact angle are consistent with the experiment results. Furthermore, the adsorption energy between microscopic substances is dominated by electrostatic force, which can reflect the adhesion stress between macroscopic substances. Soil adhesion stress can be effectively decreased by adding the surfactant to the soil conditioner.

Study on the interfacial adhesion mechanism between polydopamine and coal: Experimental demonstration and molecular simulation

Understanding the adhesion mechanism between polydopamine (PDA) and coal surface is crucial for implementing the mussel strategy in self-adhesive gel for fire suppression. In this study, a combination of experiments and molecular simulations was utilized to explore the interfacial adhesion mechanism between PDA and coal. Initially, the adhesion potential of varying concentrations of PDA solutions was evaluated using a UV–Vis spectrophotometer, and in conjunction with contact angle/surface tension measurements, it was observed that adhesion strength did not show a direct correlation with PDA concentration. Subsequently, the adhesion sites of PDA on the coal surface were identified through spectroscopic analysis and confirmed using Dmol3 simulations. The study revealed that the amino and phenolic hydroxyl groups in the PDA structure could establish hydrogen bonds with oxygen-containing functional groups on the coal surface (e.g., COOH, OH, R-O-R'), while the aromatic rings in the molecules engaged in π-π stacking interactions. These non-covalent forces collectively facilitated the adhesion process. Molecular dynamics (MD) simulations were then employed to validate the relationship between PDA solution concentration and adhesion strength, which aligned with the experimental findings. Furthermore, the MD simulations elucidated how the concentration of PDA solution influenced its interfacial adhesion strength with coal by considering water molecule diffusion. Overall, this research offers a theoretical foundation for designing self-adhesive gel for fire suppression.

Strength evaluation of alkali treated Sabai Grass (Eulaliopsis binata) fibers and its reinforced composites

This investigation aims to use Sabai grass fiber as a substitute reinforcement in epoxy-based composite systems, which is environment friendly and performs similarly to other natural fibers. Composite laminates are prepared with treated and untreated Sabai fibers reinforcement layered in different orientations using vacuum resin transfer molding method. Fabricated composite laminates have been evaluated for their mechanical properties (tensile strength, flexural strength, and impact strength). The effect of varying concentrations (3%, 5%, 7%, and 9 wt.%) of NaOH treatment and fiber reinforcement angle on Sabai fiber-reinforced composite laminates on its physical and mechanical properties are experimentally evaluated. The specimen made with 5 wt.% of NaOH-treated has shown maximum tensile properties because of the higher fiber concentration in the composite laminate. The thickness of fibers gets reduced as the central voids contract after the treatment. The treated strand reinforced (0°/0°/0°/0°) composite laminate has maximum tensile (103.15 MPa) and flexural strength (143 MPa). In addition, it has a higher density (1.20 g/cm3) and less porosity contents (0.70%). The untreated reinforcement has a higher impact strength. The adhesion mechanism at the fiber matrix interface has been studied using field emission scanning electron microscopy by analyzing the fiber surface morphology after treatment and in the fractured samples. The correlation of the mechanical properties of the laminate has been discussed with consideration of interfacial adhesion mechanism, fiber pull-outs, and fiber-matrix cracking phenomenon. FTIR analyses confirm the removal of the peak at around 1735 cm−1 that belongs to the acetyl group of hemicellulose attributed to C=O stretching vibration, and the peak at 1253 cm−1 is associated with the lignin, which is in close agreement with chemical analysis.

Variation and mechanism of asphalt-aggregate interface features under ultraviolet aging based on meso- and micro-observations

Time-dependent variation and mechanism of asphalt-aggregate interface features under ultraviolet (UV) aging have not yet been illustrated. This study explored the time-dependent variation and mechanism of asphalt-aggregate interface features under UV aging. To this end, six asphalt binders were chosen and subjected to different durations of UV aging, and then the variation behaviors of their cohesion-adhesion ability with the changing UV radiation time were analyzed through surface energy theory. Further, the microscopic attributes of asphalt binders experiencing the various UV aging durations were measured and their varying rules were investigated with a series of micro observations. Finally, the relationship between cohesion-adhesion characteristics and microscopic properties were illustrated and thus the variation mechanism of interfacial cohesion and adhesion were revealed by mathematical statistics and image presentation. The results showed that UV aging weakened the cohesion and multi-working adhesion of asphalt binders and the moisture stability of asphalt-aggregate systems, and overall presented a gradually strengthened influence on them with the prolonged UV radiation time, especially the UV radiation exceeded 6 days. The variation of phase morphology of asphalt binders under UV aging depended on the asphalt types and neat asphalt oil sources, and there existed a favorable linear relationship between Catana phase of asphalt binders and surface roughness. Adhesion force, function group and four components (saturate (S), aromatics (Ar), resin (R) and asphaltene (As)) also exhibited a gradually increasing variation as the UV radiation duration went on, and among which, the UV aging reduced the adhesion force of asphalt binders. Adhesion force Fad demonstrated the highest Pearson relevance with the cohesion and aqueous-condition adhesion and the moisture stability of asphalt-aggregate system, and the cohesion-adhesion properties of asphalt binders under UV aging met the multivariate linear mathematical relationship with the microscopic attributes screened, with the goodness-of-fit greater than 0.7000.

Electronic characteristic, tensile cracking behavior and potential energy surface of TiC(111)/Ti(0001) interface: A first‑principles study

The preparation of TiC coating on Ti alloy surface to improve the wear resistance has attracted attention from researchers in aerospace field. The service life of TiC coating is related to the interfacial adhesion properties between TiC coating and Ti alloy substrate. However, it is difficult to explain its interfacial adhesion mechanism by experimental methods. Based on the termination of atoms on the TiC surface, two TiC/Ti interface models named as the C-terminated-TiC(111)/Ti(0001) and Ti-terminated-TiC(111)/Ti(0001) interface were constructed by first-principles. The interfacial electronic characteristic of C—Ti bond is a mixture of polar covalent and metal bonds, and that of Ti—Ti bond is the metal bond. The tensile strains of both C-terminated-TiC(111)/Ti(0001) and Ti-terminated-TiC(111)/Ti(0001) interface in the fracture stage are ranged from 12% to 14%. Their maximum tensile stresses are 16.201 GPa and 15.590 GPa, respectively. The sliding potential energy surface maximum of C-terminated-TiC(111)/Ti(0001) and Ti-terminated-TiC(111)/Ti(0001) interface are 5.387 J/m2 and 0.271 J/m2, respectively. And the sliding potential barriers on the minimum energy path are 2.094 J/m2 and 0.136 J/m2 with an ideal shear strength of 20.32 GPa and 1.61 GPa, respectively. In summary, the interfacial adhesion property of C-terminated-TiC(111)/Ti(0001) interface is better than that of Ti-terminated-TiC(111)/Ti(0001) interface.

Study of Interfacial Adhesion and Re-Ir Alloy Coating in Chalcogenide Glass Molding.

Precision glass molding (PGM) has become an efficacious technique to fabricate high-precision optics. Chalcogenide (ChG) glass is increasingly used in thermal imaging, night vision, etc., because of its excellent infrared optical properties. Nevertheless, glass-mold interfacial adhesion has emerged as a pivotal issue within the PGM process. The interfacial adhesion during PGM has the potential to significantly undermine the performance of molded optics and reduce the longevity of molds. It is important to investigate interfacial adhesion behaviors in the PGM. In this study, the interfacial adhesion mechanism between ChG glass and the nickel-phosphorus (Ni-P) mold is analyzed using the cylindrical compression test. The effect of ChG glass internal stress on physical adhesion is investigated by finite element method (FEM) simulation. The spherical preform is proven to be capable of reducing the stress concentration and preventing physical adhesion. More importantly, a rhenium-iridium (Re-Ir) alloy coating is deposited on the Ni-P mold surface by ion sputtering to prevent atomic diffusion and resolve the problem of chemical adhesion. Finally, ChG glass microstructures with high accuracy are fabricated using the spherical ChG glass preform and the Re-Ir-coated Ni-P mold by PGM.

High-performance thermoplastic polyaryletherketone/carbon fiber composites: Comparison of plasma, carbon nanotubes/graphene nano-anchoring, surface oxidation techniques for enhanced interface adhesion and properties

This investigation highlights the development and performance comparison of carbon fiber (CF)-polyaryletherketone (PAEK) thermoplastic laminates prepared using CF, surface-modified with plasma, multi-walled carbon nanotubes (MWCNT), graphene, acid, and rare earth elements. Analysis of surface-treated CF by Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) revealed development of functional groups and changes in elemental composition on the CF surface. Significant lowering of contact angle and improvement in wettability was achieved by plasma and MWCNT/graphene treatment on CF. Field emission scanning electron microscopy (FESEM) analysis gave insight into the surface irregularities caused by various surface treatment techniques. The CF-PAEK composites were prepared by film stacking and compression moulding. The plasma-treated PAEK-CF composites exhibited the highest tensile properties, flexural strength, fracture toughness, and interlaminar shear strength. The superior properties are credited to better interfacial adhesion between CF and PAEK arising from mechanical interlocking over the roughened surface and covalent bonds by functional groups grafted on CF surface by plasma. MWCNT and graphene-anchored CF-PAEK composites also showed significant improvement in mechanical properties attributed to the bridging effect and interfacial interaction arising from increased surface area and functional groups. The surface-treated CF-PAEK composites exhibited a positive shift in the glass transition temperature, which is evidence of better adhesion. In dynamic loading conditions, MWCNT anchored CF-PAEK composite presented the highest storage modulus and energy absorption characteristics. Examination of the tensile fracture surface and fiber pull-out gave insight into the failure pattern and interfacial adhesion mechanism for the individual surface modification techniques.

Effects of Different Surface Treatments of Woven Glass Fibers on Mechanical Properties of an Acrylic Denture Base Material

Silanized glass fibers are popular reinforcements of acrylic denture base materials. To increase the number of surface hydroxyl groups and to improve interfacial adhesion between the matrix and reinforcements, acid or base treatments of glass fibers are commonly performed before the silanization. However, limited data are available on the effect of these treatments on the mechanical properties of acrylic matrix composite materials used for denture base applications. In this work, before the silanization of a woven glass fiber fabric (GF) with 3-(trimethoxysilyl) propyl methacrylate, activation pretreatments using HCl and NH4OH aqueous solutions have been performed. To characterize the glass surface, FTIR spectroscopy was used. Specimens of cured acrylic denture base resin and composites were divided into five groups: (1) cured acrylic denture base resin-control group; (2) composite with non-silanized GF; (3) composite with silanized GF; (4) composite with NH4OH activated and silanized GF; (5) composite with HCl activated and silanized GF. The flexural and impact properties of specimens were evaluated by means of three-point-bending tests and Charpy impact testing, respectively. The residual reactivity of the samples was analyzed using differential scanning calorimetry. The results of mechanical testing showed that acid and base pretreatments of the glass fabric had a positive effect on the flexural modulus of prepared composites but a negative effect on their impact strength. Possible interfacial adhesion mechanisms and the diffusion control of isothermal cure reactions due to vitrification have been discussed.

Molecular insights into the interfacial adhesion mechanism between carbon nanotubes and epoxy resin.

In recent years, carbon nanotubes (CNTs) have garnered widespread attention and have been deemed the preferred option for the creation of epoxy composites, owing to their outstanding mechanical properties. Despite this, the interaction between pure CNTs and epoxy resin is primarily dependent on van der Waals forces and therefore, the interfacial forces are weak, making it challenging for effective load transfer. To enhance the mechanical properties of the composites, surface functionalization is often deemed a more favorable method for improving interfacial bond strength. This study employs molecular dynamics simulations to examine the interfacial bonding characteristics between functionalized CNTs and epoxy resin. The results demonstrate that functional group modification can significantly improve the interfacial adhesion between CNTs and epoxy resin, and the incorporation of functional groups can enhance the crosslinking degree of the epoxy resin at the interface. The hydrogen bond network established between the CNTs and epoxy resin after functional group modification, and the high stability of the bond cooperation, are factors contributing to the excellent interfacial performance.

Study on influence of heat treatment on interfacial adhesion of CF/PI composites

In order to improve the service performance of carbon fiber reinforced polyimide (CF/PI) composites, the interfacial adhesion and failure mechanism were investigated via micro-bond test. Composites were formed by carbon fiber (sized and unsized TG800) and PI matrix (KH308 and KH500), and various heat treatments were designed and performed on each system. The results of CF/PI composites after high-temperature treatments showed that the interfacial shear strength (IFSS) always increased and then decreased with the increasing temperate due to the change of failure modes, and the performance retention rate of composites formed by KH500 was much higher under the same treatment. While the IFSS results of composites formed by KH308 and KH500 after long-time treatments were completely different, reflecting the proper service temperature of CF/PI composites. Besides, although it would decompose during curing process, the sizing agents still increased the active functionality on fiber surfaces, contributing to the interfacial adhesion of CF/PI composites at high temperature.

Nanoscale analysis of the interface of dip layer/rubber in fiber/rubber composites

The reaction mechanism and the interfacial modulus gradient of the interfacial transition layer between the environmentally friendly dipping system (PAL) and the rubber have not been fully studied. In order to better understand the chemical structures and nano-mechanical properties of the interface between the dip layer and the rubber, we used advanced atomic force microscope (AFM) and nanoscale Fourier transform infrared spectroscopy (nano-FTIR) to perform detailed analysis in this article. The characterization of interfacial nano-mechanical properties and chemical structures is very significant for the illustration of interfacial adhesion mechanism. AFM can effectively characterize the detailed interfacial modulus gradient and the thickness of interface, while nano-FTIR can comprehensively measure the interfacial chemical structures and the distribution of chemical bonds. The results suggest that the thickness of the interface between the PAL dip layer and the rubber matrix is 175 nm, and the crosslinking density of the interfacial layer is high, which explains that the failure location of fiber/rubber composites after pull-out tests occurs on the side of the rubber matrix. Similarly, the microstructure of resorcinol-formaldehyde-latex (RFL) system was also characterized, and the preparation of RFL usually requires carcinogenic and toxic substances such as formaldehyde and resorcinol.

Adhesion, tensile and shear properties of a-C/TiC interface: A first-principles study

TiC nanocrystals in amorphous carbon (a-C) films can improve the adhesion property between a-C films and substrate. The service life of a-C films is related to the interfacial adhesion property between a-C films and TiC. However, it is difficult to explain its interfacial adhesion mechanism by experimental methods. In this paper, based on the stacking of the interface models, two a-C/TiC interface models named as the C(110)/C-edge-TiC(110) and C(110)/Ti-edge-TiC(110) interfaces were constructed by first-principles method. After relaxation, their interfacial adhesion work are 3.624 and 3.622 J/m2, and interfacial energy are 6.831 and 6.833 J/m2, respectively. The interfacial electronic characteristic of CC bond at the interface is a mixture of non-polar covalent bond and metal bond, and the CTi bond is a mixture of polar covalent bond and metal bond. The tensile strains of both the C(110)/C-edge-TiC(110) and C(110)/Ti-edge-TiC(110) interfaces in the fracture stage are ranged from 9 % to 14 %, and the fracture location of the interface models all occur in the inner of the TiC surface model near the interface. The maximum tensile stresses of the C(110)/C-edge-TiC(110) and C(110)/Ti-edge-TiC(110) interfaces are 36.873 and 36.955 GPa, respectively. Therefore, the tensile strength of the C(110)/Ti-edge-TiC(110) interface is stronger than that of the C(110)/C-edge-TiC(110) interface. The sliding potential energy maximum of the C(110)/TiC (110) interface is 0.335 J/m2, and the sliding potential barrier on the minimum energy path is 0.090 J/m2 with an ideal shear strength (τMEP) of 0.030 GPa.

Void distribution, interfacial adhesion and anti-cracking mechanisms of cold recycled asphalt mixture based on AFM and X-ray CT

To reveal the anti-cracking mechanisms of cold recycled mixture (CRM) prepared by waterborne epoxy resin/styrene butadiene rubber latex (WER/SBR) modified emulsified asphalt (EA), the void distributions in CRM were analyzed by X-ray computed tomography. Then a method for calculating the adhesion work of asphalt-aggregate interface was proposed based on atomic force microscope tests. Finally, the anti-cracking properties were discussed by low-temperature bending and semicircular bending fatigue tests. Results indicated that the surface void contents of CRM specimen were all smaller in the middle and larger at both ends along the height direction. The WER/SBR modifier exerted a significant filling effect on the voids, reducing the void content and size. Moreover, WER/SBR modified EA (WSEA) showed stronger adhesion property and deformation resistance. WSEA-fresh aggregate interface had the largest adhesion work of 267.25 mJ/m2. Further, the interfacial adhesion failure between EA and fresh aggregate, as well as the cohesive failure of the syncretic interface between EA and aged asphalt were the main cracking forms of CRM specimen. A three-dimensional network in the WSEA-aggregate interface was formed by the WER/SBR modifier, improving the interfacial adhesion property. The void distributions and interfacial adhesion property in CRM specimen significantly affected the cracking resistance.

Robust and dynamic underwater adhesives enabled by catechol-functionalized poly(disulfides) network.

Developing molecular approaches to the creation of robust and water-resistant adhesive materials promotes a fundamental understanding of interfacial adhesion mechanisms as well as future applications of biomedical adhesive materials. Here, we present a simple and robust strategy that combines natural thioctic acid and mussel-inspired iron-catechol complexes to enable ultra-strong adhesive materials that can be used underwater and simultaneously exhibit unprecedentedly high adhesion strength on diverse surfaces. Our experimental results show that the robust crosslinking interaction of the iron-catechol complexes, as well as high-density hydrogen bonding, are responsible for the ultra-high interfacial adhesion strength. The embedding effect of the hydrophobic solvent-free network of poly(disulfides) further enhances the water-resistance. The dynamic covalent poly(disulfides) network also makes the resulting materials reconfigurable, thus enabling reusability via repeated heating and cooling. This molecule-engineering strategy offers a general and versatile solution to the design and construction of dynamic supramolecular adhesive materials.

Interfacial adhesion mechanisms of ultra-highly filled wood fiber/polyethylene composites using maleic anhydride grafted polyethylene as a compatibilizer

To investigate whether the esterification reaction was the dominant factor that improved the interface compatibility of wood-plastic composites and accordingly their performances, ultra-highly filled wood fiber (WF)/polyethylene composites (UH-WPCs) was fabricated using maleic anhydride grafted polyethylene (MAPE) as compatibilizer or matrix with WF content of 60–85 wt%. The FTIR and TGA results confirm the absolute content of MAPE grafted on WF was 4.5% and 0.9% for the UH-WPCs with 80 wt% WF using MAPE as matrix and compatibilizer, respectively. The UH-WPCs using MAPE as matrix or compatibilizer exhibited considerable higher mechanical properties, better creep resistance, and lower water absorption compared to the uncompatibilized ones. Compared with the uncompatibilized composites with 80 wt% WF, the tensile and flexural strengths were increased by 187% and 186% for using MAPE as matrix, and 224% and 189% for using MAPE as compatibilizer, respectively. These results reveal that the mechanical properties of the UH-WPCs with MAPE were not positively correlated with the absolute content of MAPE grafted on WF. The above findings confirmed that the esterification was not the key determinant for interfacial adhesion mechanisms using MAPE as compatibilizer in UH-WPCs, and some other more important factors may exist.

Impact of Surface Topography, Chemistry and Properties on the Adhesion of Sodium Alginate Coatings Electrophoretically Deposited on Titanium Biomaterials

In this paper, we report on the electrophoretic deposition and characterisation of pure sodium alginate coatings on titanium biomaterials, the commercially pure titanium CP-Ti1 and Ti–13Nb–13Zr titanium alloy. Various solutions differing in the distilled water to ethanol volume ratio and sodium alginate concentration were used for coating deposition. Uniform, dense and continuous coatings with a thickness up to 1 µm were deposited. The effect of surface topography and morphology, wettability and surface free energy as well as surface chemistry on the coating adhesion to the titanium biomaterials were investigated. The coatings exhibited very good adhesion to the polished and then chemically treated alloy. The adhesion mechanisms were identified. The chemical bonding and interfacial adhesion mechanisms are plausible. The coatings exhibited low surface development, dependent on the applied substrate roughness. Sodium alginate coatings on both substrates showed moderate hydrophilicity and relatively high surface free energy, on average 30 pct higher in comparison with that of the substrate materials. The obtained results will be useful for the further development of composite sodium alginate coatings for enhancing the biological performance of titanium biomaterials.

A Sustainable Strategy for Medium-Density Fiberboards Preparation from Waste Hybrid Pennisetum Straws

The remaining waste residues of crops such as straws are considered a sustainable material that can be used in the manufacture of medium-density fiberboards (MDF). The hybrid Pennisetum straw has a high cellulose content, which gives it the potential to be used as a sustainable material in the manufacturing of MDF. In this study, a hot-pressing method was used to obtain MDF with a density of 650 kg m−3 and a thickness of 15 mm from hybrid Pennisetum straws. The effect of pressing temperatures on the thermal stability and physical properties of the obtained MDF was discussed. The results showed that the MDF obtained by hot pressing at 195 °C for 7.5 min had the optimum physical properties, which contained a static bending strength of 12.33 MPa, a nail holding force of 1313 N, and an elastic modulus of 2572 MPa. The mechanism of interfacial adhesion between fiber and resin was investigated. It was found that increasing the pressing temperature not only promoted the curing of the urea–formaldehyde resin, but also promoted the degradation of hemicellulose and lignin inside the straws.

Degradation Mechanism of Interfacial Adhesion between Screen-Printed Ag/Polyimide in Temperature/Humidity Environment

The effect of temperature/humidity (T/H) treatment at 85 ℃/85% relative humidity (R.H.) on the peel strength between screen-printed Ag/polyimide (PI) substrate was evaluated using a 180° peel test. Initial peel strength was 22.22 ± 1.00 gf/mm, and then decreased to 0.47 ± 0.22 gf/mm after 500 h at 85 ℃/85% R.H. treatment condition. And, the peeled locus was changed from Ag/PI interface to mixed mode of Ag/PI interface and shallow cohesive inside PI near Ag/PI interface. The decrease in peel strength during T/H treatment is related to formation of weak boundary layer inside PI near Ag/PI interface by hydrolytic degradation of PI due to long-term moisture penetration into the Ag/PI interface.

Importance of Interfacial Adhesion Condition on Characterization of Plant-Fiber-Reinforced Polymer Composites: A Review.

Plant fibers have become a highly sought-after material in the recent days as a result of raising environmental awareness and the realization of harmful effects imposed by synthetic fibers. Natural plant fibers have been widely used as fillers in fabricating plant-fibers-reinforced polymer composites. However, owing to the completely opposite nature of the plant fibers and polymer matrix, treatment is often required to enhance the compatibility between these two materials. Interfacial adhesion mechanisms are among the most influential yet seldom discussed factors that affect the physical, mechanical, and thermal properties of the plant-fibers-reinforced polymer composites. Therefore, this review paper expounds the importance of interfacial adhesion condition on the properties of plant-fiber-reinforced polymer composites. The advantages and disadvantages of natural plant fibers are discussed. Four important interface mechanism, namely interdiffusion, electrostatic adhesion, chemical adhesion, and mechanical interlocking are highlighted. In addition, quantifying and analysis techniques of interfacial adhesion condition is demonstrated. Lastly, the importance of interfacial adhesion condition on the performances of the plant fiber polymer composites performances is discussed. It can be seen that the physical and thermal properties as well as flexural strength of the composites are highly dependent on the interfacial adhesion condition.