Influence Of Interfacial Adhesion Research Articles

Large‐Area Transient Conductive Films Obtained through Photonic Sintering of 2D Materials

AbstractTransient electronics that can chemically or physically disappear after a period of stable operation have been achieved through various metal and semiconductor materials. Despite excellent properties and wide availability of 2D materials and van der Waals (vdW) thin‐film electronics, transient films and devices based on them have rarely been reported, not to mention large‐area production with high throughput. Here, a photonic sintering approach is developed to achieve large‐area transient vdW films that may be used for bioresorbable devices. The approach can process 2D materials such as graphite, graphene, and transition metal sulfide, resulting in continuous films that are 10 × 10 cm2 in area and ≈60 to ≈440 nm in thickness on transient substrates. The influence of interfacial adhesion and sintering conditions to the thickness and the electrical properties of transient graphite films is investigated. In addition, the transient films can yield conductive patterns such as biopotential electrodes, interdigital electrodes, and resistor arrays using complementary metal–oxide–semiconductor (CMOS) fabrication processes or a two‐step sintering method. The photonic sintering method may eventually lead to large‐area transient electronics for innovative applications in healthcare, data security, and consumer electronics, and enrich the category of transient electronics through achievement of more printable transient vdW electronics.

A comparative study on the tensile and impact properties of Kevlar, carbon, and S-glass/epoxy composites reinforced with SiC particles

Present study compares the tensile and impact characteristics of Kevlar, carbon and glass fiber reinforced composites with addition of microscale silicon carbide (SiC) within the common matrix of epoxy. The variation of tensile and impact strength values was explored for different content of SiC in the epoxy resin by weight (0, 5, 10, 15 and 20 wt%). Resulting failure characteristics were identified by assisting Charpy impact tests. The influence of interfacial adhesion between particle and fiber/matrix on failure and tensile properties was discussed from obtained results and scanning electron microscopy (SEM) figures. It is concluded from results that the content of SiC particles, and fiber types used as reinforcement are major parameters those effecting on tensile and impact resistance of composites as a result of different interface strength properties between particle-matrix and particle-fiber.

Influence of interfacial adhesion on the damage tolerance of Al6061/SiCp laminated composites

In this study, lamination as extrinsic mechanism was considered to enhance damage tolerance of three-layer Al6061-5%vol. SiCp/Al1050/Al6061-5%vol. SiCp composites. To fabricate laminates of dissimilar interfacial adhesion, different rolling strains were applied during hot roll-bonding. The discrepancy in interfacial strength of laminates was examined by shear test while toughness values were studied using three-point bending test. It was revealed that both interfacial adhesion and damage tolerance were influenced by rolling strain. Interfacial bonding played the major role in the energy absorption during fracture which was quantified as initiation, propagation and total toughness. The results declared that improving the interfacial adhesion elevated the energy consumed for emergence and growth of debonded area. Five different models based on genetic programming have been proposed in order to predict the toughness of composites. Also, corresponding mathematical correlations of introduced models were exhibited. To construct the models, experimental data were randomly divided and used as training and testing sets. The data used as inputs were comprised of five independent parameters such as “SiCp volume content”, “average SiCp volume in bulk laminates”, “specimen thickness”, “rolling strain” and experimented “shear strength”. The training and testing results were in good agreement and revealed strong capability for predicting the toughness of laminates.

The physical perspective on the solid and molten states associated with the mechanical properties of eco‐friendly HDPE/Pinus taeda wood‐plastic composites

ABSTRACTThe manufacture of wood plastic composites (WPCs) by reutilizing post‐consumed polymeric materials and post‐industry wood wastes contributes to reduce the environmental impact and the consumption of virgin plastics. In this work, the influence of interfacial adhesion on the solid and molten states of high density polyethylene (HDPE) containing WPCs wood dust of recycled Pinus taeda (PT) was evaluated. The composites were prepared by extrusion in a twin screw extruder using maleic anhydride as compatibilizer. The samples were analyzed by dynamic‐mechanical analysis (DMA), tensile and impact strength measurements, oscillatory rheometry, differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). DMA analysis showed increase in module and an improved interface with physical interaction between the WPCs phases. The higher molecular interactivity interface improved the mechanical properties relative to pure HDPE. Melting state analysis showed increased WPCs flow restriction, this feature being correlated with reduction in the molecular degree of freedom during flow, which consequently reduces the crystalline degree changes in microstructure as well as in processing parameters of the material. These results lead to consider the development of an eco‐friendly and economic effective technology to reuse abundant recycled solid wastes in a new market. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 42887.

Influence of interfacial adhesion on the mechanical response of magneto-rheological elastomers at high strain

This work investigates the interfacial adhesion between the iron fillers and the silicone matrix in magneto-rheological elastomers (MREs) at high strain. Carbonyl iron powder, composed of mechanically soft spherical particles with a median size of 3.5 μm and a volume fraction of 3.5 and 30 %, was mixed in a soft silicone matrix; the compound was then degassed and cured under temperature. The presence of a homogeneous magnetic field of 0.3 T during the curing process allowed the formation of particle chains. Tensile tests of these samples were conducted under scanning electron microscope to simulate and observe interfacial debonding between the two phases. To improve interfacial adhesion, a silane primer was applied to the iron particles, following two different procedures, before the mixing and crosslinking process, thus giving two additional types of samples for each volume fraction. In-situ scanning electron microscope measurements during tensile tests showed that a more elaborated particle–matrix interface was obtained with the primer additive. Furthermore, the structural response of the different types of samples were compared in tensile testing lengthwise to the particle alignment with engineering strains up to 150 %. An enhanced adhesion of the iron fillers to the silicone matrix resulting in a largely increased stiffness at high strain could be observed with the application of the primer. It was observed that the effect of the primer on the debonding of the particles from the silicone matrix has an impact on the macroscopic behavior of the composite only after 80 % deformation in the case of the 30 % volume fraction MRE.

Influence of interfacial adhesion and the nonequilibrium glassy structure of a polymer on the enthalpy of mixing of polystyrene-based filled composites

For composites based on polystyrene, the styrene-butadiene copolymer, and polybutadiene filled with various kinds of zinc oxide powder, the enthalpy of mixing is calculated in the entire range of filler contents on the basis of calorimetric measurements with the use of the thermochemical cycle. It is shown that, when the polymer is in excess in the composites based on polystyrene and its copolymer, the enthalpy of mixing is negative, whereas at a high content of the filler, this value is positive. The alternating-sign pattern of the concentration dependence of the enthalpy of mixing is interpreted in terms of the superposition of the negative contribution of the enthalpy of the interfacial-adhesion interaction of a polymer matrix with the filler and the positive contribution due to a gain in the level of nonequilibrium of the glassy matrix near the surface. A thermodynamic model that makes it possible to separate these contributions and to describe the experimental curves of the enthalpy of mixing for the composites is advanced.

Influence of interfacial adhesion on the structural and mechanical behavior of PP‐banana/glass hybrid composites

AbstractHybrid composites of polypropylene (PP), reinforced with short banana and glass fibers were fabricated using Haake torque rheocord followed by compression molding with and without the presence maleic anhydride grafted polypropylene (MAPP) as a coupling agent. Incorporation of both fibers into PP matrix resulted in increase of tensile strength, flexural strength, and impact strength upto 30 wt% with an optimum strength observed at 2 wt% MAPP treated 15 wt% banana and 15 wt% glass fiber. The rate of water absorption for the hybrid composites was decreased due to the presence of glass fiber and coupling agent. The effect of fiber loading in presence of coupling agent on the dynamic mechanical properties has been analyzed to investigate the interfacial properties. An increase in storage modulus (E′) of the treated‐composite indicates higher stiffness. The loss tangent (tan δ) spectra confirms a strong influence of fiber loading and coupling agent concentration on the α and β relaxation process of PP. The nature of fiber matrix adhesion was examined through scanning electron microscopy (SEM) of the tensile fractured specimen. Thermal measurements were carried out through differential scanning calorimetry (DSC) and the thermogravimetric analysis (TGA), indicated an increase in the crystallization temperature and thermal stability of PP with the incorporation of MAPP‐treated banana and glass fiber. POLYM. COMPOS., 31:1247–1257, 2010. © 2009 Society of Plastics Engineers

The use of a modified microindentation technique to evaluate enviro-mechanical changes in composite interphase properties

Fiber sizing can improve the performance of fiber-reinforced polymer composites. The focus of this work was to determine if the improvement in performance could be ascertained from a micromechanical test for interfacial adhesion on as-processed materials under hygrothermal exposure. Three types of sizings were examined: a carboxyl modified poly(hydroxyether), that is identified as low spread phenoxy (LSP), a poly(vinylpyrrolidone) (PVP) sample and a standard industrial sizing (G′). A nanoindenter was effectively used to obtain interfacial shear strength (IFSS) using a modified micro-indentation technique. The results showed that LSP outperforms the PVP and G′ materials in bulk composite properties, but showed equivalent interfacial shear strength to G′ and experienced hygrothermal degradation in interfacial adhesion that the PVP did not. The LSP composite loses 10% of its original interfacial shear strength after 576 h, while for PVP composite it improves by 25%. The tensile strengths for LSP and PVP composites decrease by 7% and 10%, respectively, at 576 h of hygrothermal exposure. The relationship between tensile strength and interfacial adhesion proved to be weak, but processing defects and other failure processes showed a strong influence of interfacial adhesion on tensile strength of compsites.

The Influence of Interfacial Adhesion on the Predicted Young's Modulus of Mica-Reinforced Nylon-6

ABSTRACT Particle-filled polymer composites have become attractive because of their wide applications and low cost. Various factors influence the mechanical properties of thermoplastic composites. Of these, the aspect ratio of the reinforcement, interfacial adhesion, and binder content are the most important. Other than these, the particle size and particle size distribution of the reinforcement also influence the mechanical properties. In this paper, injection molded mica composites were investigated, using nylon-6 as a binder. Many models are available to predict the Young's modulus of the composites. A theoretical model for Young's modulus by Lewis and Nielsen was used to predict the Young's modulus of the composites. Tetra isopropyl titanate (TYZOR® TPT) was used to modify the adhesion between the reinforcement and the binder by mixing it with the reinforcement prior to compounding. It was found that Young's modulus was greater than the predicted values.

Modeling of the mechanical behavior of HA/PEEK biocomposite under quasi-static tensile load

A cylindrical three-phase unit-cell model was established for predicting mechanical properties of hydroxyapatite (HA)-reinforced polyetheretherketone (PEEK) biocomposite. The model consists of an elastic–brittle HA spherical particle, an elasto-plastic matrix, and a very thin interphase region between the particle and the matrix. Perfect bonding was initially assumed among three phases before occurrence of particle–matrix debonding. For simulation of the particle–matrix debonding process of HA/PEEK, a damage evolution equation was incorporated into the material properties of the interphase region. A ductile damage evolution in the matrix was also taken into account, and was treated as a criterion for the failure of the biocomposite. A user subroutine for the damage-coupled material properties for the matrix and the interphase region was built and incorporated into a finite element code named ABAQUS. The influence of interfacial adhesion on the non-linear stress–strain relation of HA/PEEK has also been simulated by varying the tensile strength of the interphase region. The strength of the interphase region in the composite could be estimated by a comparison between the predicted and experimental results. By using the unit-cell modeling technique incorporated with the stress-based debonding and the composite failure criterion and selection of appropriate interphase strength, the numerical simulation was found to be close to the experimental results from available literatures. In vivo performance of HA/PEEK as implant materials was also discussed.

Investigation of deformation mechanism in polypropylene/glass fiber composite

A great amount of work has been done over the past few years to understand the structure–properties relationship in polypropylene/glass fiber composites. This is because of the very fast-growing rate of polypropylene applications in the automotive and other industries. This work focused on the role of glass fibers and fiber–matrix adhesion on deformation mechanism. Composites with different fiber content, with and without adhesion promoter, were fabricated. Tensile tests and microscopy techniques were conducted. Based on the results, a physical model has been proposed that illustrates the initiation and growth of the damage under static loading condition. According to this work, the introduction of glass fibers shifts the deformation mechanism from shear yielding to crazing. Although crazes propagate in a different manner in composites containing standard and treated fibers, no influence of interfacial adhesion was observed on craze thickening phenomenon. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2171–2176, 2003

The influence of interfacial adhesion, particle size and size distribution on the predicted mechanical properties of particulate thermoplastic composites

Various factors influence the mechanical properties of thermoplastic composites. Of these, the aspect ratios of the reinforcement, interfacial adhesion, porosity and binder content are most important. Other than these, the particle size and particle size distribution of the reinforcement also influence the mechanical properties. A previously developed model used micro-mechanical analysis to predict the Young's modulus and tensile strength of particulate composites. This model predicts that aspect ratio, rather than particle size, influences the Young's modulus and stress at break, assuming perfect adhesion between the reinforcement and binder. The model accounts for particle size distribution only in terms of the maximum packing fraction of the dry reinforcement.In this paper, compression-moulded phlogopite composites were investigated, using linear low density polyethylene (LLDPE) as a binder. The aspect ratio of the particles, binder content and processing conditions were kept constant. It was found that particle sizes between 60 and 300 μm had little effect on the Young's modulus. Particles smaller than 240 μm had lower tensile strengths than the particles above 240 μm. The results were, however, very close to the values predicted by the model.Acrylic acid was used to modify the adhesion between the reinforcement and the binder by blending it with the polymer prior to compression moulding. It was found that by using 100 mmol acrylic acid/100 g binder the tensile strength approached the value predicted by the micro-mechanical model and the Young's modulus was greater than the predicted value by a factor 5. No further improvement in the mechanical properties could be obtained by using more than 100 mmol acrylic acid/100 g binder.

Effects of interfacial adhesion on the rubber toughening of poly(vinyl chloride) Part 2. Low-speed tensile tests

The influence of interfacial adhesion on the tensile properties, including toughness, of poly(vinyl chloride) (PVC)–nitrile rubber (NBR) blends with the morphology of well-dispersed rubber particles has been investigated using two types of blends. The first type, which contains NBR26 (NBR with 26wt% acrylonitrile (AN)), has a higher interfacial adhesion strength than the second type that contains NBR18. The secant modulus and yield stress of the blends were found to be independent of interfacial adhesion. On the other hand, the elongation-at-break and toughness (defined as the area under the stress–strain curve to break) depend strongly on the interfacial strength. The effects of rubber particle size, size distribution and rubber volume fraction on the tensile properties have been combined into the effect of a single morphological parameter, the matrix ligament thickness T. Both the elongation-at-break and toughness increase as T decreases. At T<0.06μm the blends with stronger interfacial adhesion (PVC–NBR26) have much higher elongation-at-break and toughness. Stress whitening was observed in all deformed PVC–NBR18 blends. For PVC–NBR26 blends, however, stress whitening occurred only at T>0.06μm. Transmission electron microscopy studies revealed that debonding at the PVC–NBR interface is the sole microvoiding mechanism that causes stress whitening.

Effects of interfacial adhesion on the rubber toughening of poly(vinyl chloride) Part 1. Impact tests

The influence of interfacial adhesion on the impact toughness of poly(vinyl chloride) (PVC)–nitrile rubber (NBR) blends with the morphology of well-dispersed rubber particles has been investigated. The blend containing NBR 18 (NBR with 18wt% acrylonitrile (AN)) has medium interfacial adhesion strength, and exhibits a brittle–ductile transition at a critical matrix ligament thickness Tc=0.059μm while the blend containing NBR 26 (NBR with 26wt% AN) and having stronger interfacial adhesion exhibits the transition at Tc=0.041μm. The difference can be understood in terms of the deformation mechanisms. Debonding at the interface of the PVC–NBR 18 blend takes place upon impact, and this induces shear yielding of the matrix. For the PVC–NBR 26 blend, however, no microvoid is formed, so the occurrence of matrix shear yielding is delayed. In the investigated rubber particle size range (0.04−0.12μm), debonding followed by matrix shear yielding is a much more important toughening mechanism than internal cavitation of rubber particles.

Influence of interfacial adhesion on stress-strain properties of highly filled polyethylene

This paper studied the structure and properties of highly filled polyethylene/magnesium hydroxide composite. A third additive component was introduced to alter interfacial adhesion. Scanning electronic microscopy proved that the filler particles were totally surrounded by additive material. Interfacial adhesion played an essential role in determining the fracture mechanism and, consequently, the mechanical properties of the composites. The composites with good interfacial adhesion had high tensile strength and relatively low elongation at break. Conversely, a poor interfacial adhesion led to a composite with low tensile strength and high elongation. Struktur und Eigenschaften hochgefüllter Polyethylen/Magnesiumhydroxid-Komposite wurden untersucht. Zur Änderung der Grenzflächenadhäsion wurde jeweils eine dritte Additivkomponente zugegeben. Rasterelektronenmikroskopaufnahmen zeigen, daß die Füllstoffpartikel vollständig von Additiv umgeben waren. Die Grenzflächenadhäsion beeinflußte entscheidend den Bruchmechanismus und damit die mechanischen Eigenschaften der Komposite. Komposite mit guter Grenzflächenadhäsion besaßen eine gute Zugfestigkeit und relativ geringe Bruchdehnung. Umgekehrt führte eine schwache Grenzflächenadhäsion zu geringer Zugfestigkeit und hoher Bruchdehnung.

Influence of interfacial adhesion on toughening of polyethylene-octene elastomer/nylon 6 blends

Super-tough nylon 6 was prepared by using polyethylene–octene elastomer (POE) grafted with maleic anhydride as a toughener. The influences of maleating and a compatibilizer on interfacial adhesion and mechanical properties of nylon 6/POE blends were investigated in terms of mechanical testing, Molau tests, SEM observations, IR analyses, and rheological behavior. The results show that the unmodified POE has hardly any contribution to toughness of nylon 6, whereas the maleic anhydride-grafted POE (POE-g-MA) significantly improves the compatibility of POE with nylon 6 and sharply reduces its size in the nylon 6 matrix due to the in situ formation of a graft copolymer between POE-g-MA and nylon 6 during melt processing. With the POE-g-MA, a transition from brittle to ductile occurs. Besides, the use of a compatibilizer in nylon 6/POE-g-MA system shifts the brittle–ductile transition curve to a lower POE-g-MA content, which is attributed, in part, to the chain-extending effect of CE-96 on the nylon 6 matrix leading to further reduction of the sizes of POE-g-MA in the matrix, in part, to the coupling reaction of CE-96 between POE-g-MA and nylon 6. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 1711–1718, 1998

Influence of interfacial adhesion on the mechanical properties and fracture behaviour of short sisal fibre reinforced polymer composites

The mechanical properties of sisal fibre composites (randomly oriented) of several thermoset resin matrices, [polyester, epoxy, phenol-formaldehyde] and a thermoplastic matrix [low density polyethylene (LDPE)] were evaluated with respect to fibre length and fibre loading. All the composites showed a general trend of increase in properties with fibre loading. However, the optimum length of the fibre required to obtain an increase in properties varied with the type of matrix. Among polyester, epoxy and phenol-formaldehyde composites of sisal fibre, a phenolic type resin performed as a better matrix than epoxy and polyester resins with respect to tensile and flexural properties due to the high interfacial bonding in phenolic composites. However, as compared to thermoset resin composites, sisal fibre-LDPE composites showed a better reinforcing effect due to the high matrix ductility and high strength/modulus ratio of sisal as compared to that of LDPE matrix.

The influence of interfacial adhesion on the piezoelectric response of electroceramic/polymer composites

Abstract The nature of the interfacial adhesion in composites of electroceramics and polymers was found to exert a profound influence on the piezoelectric activity of PZT-polymer composites with 1–3 connectivity and perforated PZT-polymer composites with 3–1 and 3–2 connectivity patterns. Treatment of the electroceramic surface with coupling agents (e.g., organosilanes or organstitanates) apparently improves the interfacial adhesion sufficiently to provide more efficient stress transfer from the polymer to the PZT. The [gbar]h and [dbar]h coefficients of the composites with coupling agents are from 20 to 35% higher than those prepared without coupling agent.