Thick Resin Research Articles

First data on coniferous leaves from the Middle Jurassic of the Belgorod Region, Russia

Data on fossil coniferous leaves from the Middle Jurassic of the Stoilensky open mine in the Belgorod Region, Russia were obtained for the first time. These conifers are represented by the leaves of Mirovia, Podocarpophyllum, Elatocladus and Pityophyllum. A new species, Mirovia oskolica, sp. nov., is described based on the study of the morphology and epidermal features. Leaves of this species are characterized by the presence of thick resin ducts, stomata arranged in one stomatal zone, the short epidermal cells of the adaxial leaf side, the absence of papillae on the ordinary epidermal cells, and the rare presence of small proximal papillae on some subsidiary cells of the stomata. In addition, we have found leaves similar to the type leaves of M. eximia from the Middle Jurassic of the Kursk Region, Russia. We determine linear leaf fragments with longitudinally orientated stomata arranged in two stomatal bands and with narrow guard cells as Podocarpophyllum kazachstanicum, originally described from the Lower Jurassic of Kazakhstan. Besides these remains, there are numerous fragments of the narrower linear leaves with an acute apex, two stomatal bands and a very thin cuticle. These leaves are assigned to Pityophyllum sp. The only found sessile lanceolate leaf and several dispersed cuticle fragments with obliquely to transversely oriented stomata in the stomatal bands are determined as Elatocladus sp.

Effects of different treatment modalities on biomechanical behavior of maxillary incisors with external invasive cervical resorption at different progression levels.

This study aimed to evaluate the biomechanical behavior of maxillary incisors with external invasive cervical resorption (EICR) at different progression levels after receiving different modes of treatment under occlusal forces using finite element analysis (FEA). Three-dimensional (3D) models of intact maxillary central incisors were constructed and modified to include EICR cavities with different progression levels in the buccal cervical areas. The EICR cavities confined to dentin were repaired using Biodentine™ (Septodont Ltd., Saint Maur des Fausse ́s, France), resin composite, or glass ionomer cement (GIC) . Additionally, EICR cavities with pulp invasion requiring direct pulp capping were simulated as repaired using Biodentine only or 1 mm thick Biodentine and either resin composite or GIC for the rest of the cavity. Moreover, models with root canal treatment and EICR defects repaired using Biodentine, resin composites, or GIC were also generated. A force of 240 N was applied to the incisal edge. The principal stresses in the dentin were evaluated. GIC showed more favorable results than the other materials in EICR cavities confined to the dentin. However, Biodentine alone resulted in more favorable minimum principal stresses (Pmin ) compared to other materials in EICR cavities with close pulp proximity. Exceptionally, the models localized in the coronal third of the root with a circumferential extension of the cavity >90° showed more favorable results for GIC. The presence of root canal treatment had no significant effect on stress values. Based on this FEA study the use of GIC in EICR lesions confined to the dentin is recommended. However, Biodentine may be a better option for restoring EICR lesions close to the pulp with or without root canal treatment. Except when the circumferential extension of the cavity is >90°, the use of GIC may be more advantageous.

Comparison of Microhardness According to the Layered Thickness of 3D Printing Resin

Comparison of Microhardness According to the Layered Thickness of 3D Printing Resin

Cellular-structured carbon nanotube composite films with broadband microwave absorption and shape memory

Carbon nanotube (CNT) composite films consisting of a microcellular structure are prepared by layer-by-layer deposition and phase separation processing. Polyvinyl butyral (PVB) and CNTs form a continuous network of cell walls of less than 100 nm thick and epoxy resin (EP) spheres of 4–6 μm in diameter constitute the cell cores with Ba-ferrite lamella aggregated among the cells. The layer-by-layer deposition of CNTs ensures a uniform dispersion of CNTs, and the EP spheres separate CNTs and Ba-ferrite to form a dielectric-magnetic coupling network. The resultant cell structure is conducive not only to achieve electromagnetic impedance matching but also to induce wave attenuation by multiple mechanisms. The composite film with optimal electromagnetic loss and impedance matching has a broad effective bandwidth of 11.5 GHz in microwave absorption at a thickness of only 0.3 mm, superior over most carbon-based microwave absorbing materials reported so far. In addition, the composite film also shows good thermal response for shape memory. This study provides a microcellular strategy for developing materials with light weight, thin thickness, broadband absorption, and shape memory for applications in civil and military fields.

Pre-cementation treatment of glass-ceramics with vacuum impregnated resin coatings.

The study aimed to investigate the effectiveness of a vacuum impregnation process to eliminate the porosity at the ceramic-resin interface to optimize the reinforcement of a glass-ceramic by resin cementation. 100 leucite glass-ceramic disks (1.0±0.1mm thickness) were air-abraded, etched with 9.6% HF acid, and silanated. Specimens were randomly allocated to 5 groups (n=20). Group A received no further treatment (uncoated control). Groups B and D were resin-coated under atmospheric pressure, whereas groups C and E were resin-coated using vacuum impregnation. The polymerized resin-coating surfaces of specimens in groups B and C were polished to achieve a resin thickness of 100±10µm, while in groups D and E no resin-coating modification was performed prior to bi-axial flexure strength (BFS) determination. Optical microscopy was undertaken on the fracture fragments to identify the failure mode and origin. Comparisons of BFS group means were made by a one-way analysis of variance (ANOVA) and post-hoc Tukey test at α=0.05. All resin-coated sample groups (B-E) showed a statistically significant increase in mean BFS compared with the uncoated control (p<0.01). There was a significant difference in BFS between the ambient and vacuum impregnated unpolished groups (D and E) (p<0.01), with the greatest strengthening achieved using a vacuum impregnation technique. Results highlight the opportunity to further develop processes to apply thin conformal resin coatings, applied as a pre-cementation step to strengthen dental glass-ceramics.

Gaussian Model of Anti-Radar Properties for Coatings Based on Carbonyl Iron Powder.

The article presents the Gaussian model of the electromagnetic radiation attenuation properties of two resin systems containing 75% or 80% of a carbonyl iron load as an absorber in the 4-18 GHz range. For the attenuation values obtained in the laboratory, mathematical fitting was performed in the range of 4-40 GHz to visualize the full curve characteristics. The simulated curves fitted up to a 0.998 R2 value of the experimental results. The in depth analysis of the simulated spectra allowed a thorough evaluation of the influence of the type of resin, absorber load, and layer thickness on reflection loss parameters such as the maximum attenuation, peak position, half-height width, and base slope of the peak. The simulated results were convergent with the literature findings, allowing a much deeper analysis. This confirmed that the suggested Gaussian model could provide additional information, useful in terms of comparative analyses of datasets.

Delamination behaviors of an epoxy-impregnated REBCO pancake coil during a quench

For the epoxy-impregnated high-temperature superconducting (HTS) REBa2Cu3O7-x (REBCO) magnets, the quench cannot be still avoided in the operation, which may induce the mechanical damage of the magnets and even burning out. In this research, an electromagnetic-thermo-mechanical coupling model is proposed to explore the delamination mechanisms of an epoxy-impregnated REBCO pancake coil during a quench, and thereinto, a cohesive zone model (CZM) based on the mixed-mode traction-separation law is used to simulate the onset and growth of the delamination. The numerical results indicate that the delamination of the coil is mainly concentrated in the quenching turns. The reason is that localized high-temperature gradients are generated in these turns due to the large temperature increase during a quench, and thus the accumulated stress induced by the thermal mismatch stress locally leads to the cracking of the interface between the superconducting layer and Hastelloy substrate. Meanwhile, the delamination onset of the coil is predicted by mixed-mode delamination according to the quadratic failure criterion, and the delamination propagation is mainly determined by shear stress. Up to now, the delamination mechanisms of the epoxy-impregnated pancake coil during a quench are clarified in detail, which is different from those during cooling down. To further understand the delamination behaviors of the epoxy-impregnated pancake coil during a quench, the effects of the location and height of the heater, and the thickness of the epoxy resin on the interface delamination failure are discussed in the paper.

Ablation and mechanical properties of ZrC-reinforced PBI resin matrix composites

With the rapid development of laser technology, there is an increasing demand for laser protective materials. Thus, the mechanical and ablation properties of composite materials need to be further enhanced. Herein, solution impregnation and hot-press molding were used to develop composites containing various mass ratios of ZrC to polybenzimidazole (PBI) resin (thickness = 3 mm) for laser ablation applications. The results showed that adding short carbon fiber (SCF) to ZrC/PBI composites improves the ablation and mechanical properties. The ZrC/PBI/SCF composites were ablated using a high-energy continuous laser (7 kW cm−2), and the composites did not burn through. The composites did not peel off or split as the ablation process progressed. With the increase in the ZrC content in the composites, dense oxide layers are formed, enhancing the ablation properties of the composites. The ZrC/PBI/SCF composite (the ZrC/PBI mass ratio = 2:1) exhibited the lowest mass loss (2.24%), mass ablation rate (0.119 mg s−1) and linear ablation rate (0.032 mm s−1). This indicates that ZrC/PBI/SCF composites can be used as protective materials in high-energy continuous laser applications.

Degree of conversion and bond strength of resin cements through different thicknesses of lithium disilicate ceramic using different curing modes

Objectives: The aim of this in vitro study was to assess the physical and mechanical properties of resin cements to ceramic substrate using different curing modes by evaluating the degree of conversion and bond strength of these cements. &#x0D; Methods: Hundred twenty square lithium disilicate ceramic discs specimens of three thicknesses (0.5, 1 and 1.5 mm) and 10x10mm diameter were bonded to 120 bovine teeth using two resin cements (one light cure and one dual cure) and using two curing modes (ramp and continuous). As a result, 12 experimental groups were established for bond strength testing. degree of conversion of luting cements was evaluated using Fourier transform infrared spectroscopy (FTIR).&#x0D; Results: using the continuous mode compared to the ramp after controlling the type of resin and material thickness showed no significant difference(P&gt;0.001) in SBS and DC. the effect of changing the material thickness between 0.5mm, 1mm and 1.5mm after controlling the resin type and mode of light curing, showed significant difference (p&lt;0.001) from 1mm to 1.5mm using light-cured resin and continuous curing mode for SBS. while for the DC these correlations between different material thicknesses and both light cure type of resin and continuous light-curing mode was significant (p&lt;0.001), it was also significant with dual cure cement. This study also evaluated the effect of using dual-cured resin cement compared to the light-cured resin cement on the SBS and DC, for the SBS the effect was significant with higher thicknesses (p&lt;0.001 for the thickness of 1.5 mm) but not significant with thicknesses less than this such as 0.5mm and 1mm (P&gt;0.05).&#x0D; Conclusion: There is no change on the effect of changing light curing mode on the DC and SBS increasing the thickness decrease SBS and DC, dual-cured resin performed better when used for thickness of 1.5mm.

Magnetic properties of Fe soft magnetic composites with a double-insulating layer comprising Fe3O4 and silicone resin

In this study, we suggest a rotating closed reaction system for oxidizing Fe powder at 500 ℃. This rotation leads to the homogeneous oxidation of large amounts of Fe powder. The analysis of the oxygen content in the oxidized Fe powder shows that all oxygen gas supplied to the closed system is consumed for the oxidation of Fe powder. This indicates that the thickness of the Fe3O4 layer formed by oxidation increases proportionally with the amount of oxygen gas supplied to the reactor. It was observed that the loss of the toroidal core decreased as the thickness of the Fe3O4 layer increased. The change in hysteresis loss was negligible compared with the change in eddy current loss. The eddy current loss decreased from 364.2 W/kg to 139 W/kg (@ 1 T, 400 Hz) as the Fe3O4 layer thickened from 30 to 110 nm. Because the Fe3O4 layer did not provide sufficient insulation, another approach was attempted to coat the silicone resin (>1013 Ω∙cm) with a specific resistivity approximately 1015 times higher than that of Fe3O4 on the Fe3O4 layer. To observe this double-layer structure, a thermally evaporated Ni film was coated on top of the double-insulating layer. The energy-dispersive X-ray spectroscopy analysis of a cross-sectional transmission electron microscopy image showed that the Ni film successfully protected the silicone resin layer from the ion-beam irradiated during FIB sampling, making it possible to observe the double-layer structure. When a ∼30 nm thick silicone resin layer was coated on the ∼30 nm thick Fe3O4 layer, the eddy current loss was abruptly reduced from 364.2 W/kg to 8.6 W/kg (@ 1 T, 400 Hz). It was found that the silicone resin layer with high electrical resistivity contributed significantly in reducing eddy current loss, and a resin layer several of tens nanometers thick was sufficient to insulate Fe powder from each other.

Adaptive reversible composite-based shape memory alloy soft actuators

This research demonstrates how a combination of two-way shape memory alloy (SMA), low-temperature liquid epoxy cure composites, and fibre reinforced plastic (FRP) may be utilised to create a novel reversible actuator with built driven functionality. The novelty of this work is that the actuator can reverse its original shape and be mounted on different customized structures. The strategy is based on a knowledge of SMA wires and the manufacturing principle underlying composite structure, as well as experiments to see how soft SMA-FRP can be programmed to bend. The folding mechanism is studied in terms of fabrication factors such as SMA training and strong interfacial bonding between SMA and epoxy resin, which influence the programming process and shape change. The two-way SMA wires are trained using the pre-straining method to programme the SMAs. The technique has been used to assemble the SMA wires with bond reliability to enhance the actuator interface's thermal behaviour. The SMA elements are directly inserted into FRP strips and epoxy resin is used as an adhesive, resulting in dynamic hybrid composites. The module is actuated using an electrical board with a current value between 3 and 6 A. The robustness, controllability, mechanical properties, and 500 life cycles of the actuator are tested. Results indicate a bending angle of 58° with 30 mm of deflection in 7 s after actuating the module. Also, 3D printing is used to print a gripper inspired by human fingers and a structure to lift various weights. The actuator’s performance as a soft gripper is reliable in terms of grasping objects of different shapes. • Fabricating a novel fast responsive composite-based shape memory alloy actuator. • Developing reversible SMA-FRP soft actuators which can be mounted on various designs. • Adjusting current intensity and FRP/epoxy resin thickness, soft actuators demonstrated electrically reversible bending. • Programming of two-way shape memory alloy wires. • Grasping/release is achieved in an electrically-actuated gripper by 3D-printed structures.

A 4.5-mW 22-nm CMOS Label-Free Frequency-Shift 3 × 3 × 2 3-D Biosensor Array Using Vertically Stacked 60-GHz LC Oscillators

In this brief, a label-free <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mathbf {3\times 3\times 2}$ </tex-math></inline-formula> three-dimensional frequency-shift biosensor array with vertically-stacked 60-GHz on-chip LC oscillators is presented. The 60-GHz LC oscillators function as sensor front-end since the frequency downward shifts due to dielectric derived from biomedical sensing targets. The proposed array element consists of the two vertically-stacked LC oscillators and 15-stage dividers necessary for extracting high-frequency output signals with a long distance. The proposed circuit was designed with Spectre RF simulation and the test chip was fabricated in 22-nm CMOS technology. The whole and element chip size is 0.04 mm2 and 0.0035 mm2 respectively. The measurement with thick and thin silicon resin samples successfully demonstrated their vertical and horizontal detection on the same chip while the prior works only achieved two-dimensional detection. The 22-nm CMOS prototype also showed high spatial resolution <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$60 ~\mu {\mathrm{ m}} \times 60 ~\mu {\mathrm{ m}} \times 4 ~\mu {\mathrm{ m}}$ </tex-math></inline-formula> and high fill factor 73% while consuming 4.5 mW under 1.2 V per the single-element.

Experimental and Numerical Investigations of the Vibration and Acoustic Properties of Corrugated Sandwich Composite Panels

To explore the lightweight structures with excellent vibration and acoustic properties, corrugated composite panels with different fiber reinforcements, i.e., carbon and glass fibers, were designed and fabricated using a modified vacuum-assisted resin infusion (VARI) process. The vibration and sound transmission loss (STL) of the corrugated composite panels were investigated via mode and sound insulation tests, respectively. Meanwhile, finite element models were proposed for the verification and in-depth parametric studies. For the vibration properties of the corrugated composite panels, the results indicated that the resin layer on the panel surface, despite the extremely low thickness, showed a significant effect on the low-order bend modes of the entire structure. In addition, the difference in the mode frequency between the panels consisting of different fiber types became more and more apparent with the increase of the frequency levels. For the sound insulation property of the panel, the initial frequency of the panel’s resonant sound transmission can be conveniently increased by increasing the layer thickness of surface resin, and the fraction of fiber reinforcements is the most predominant factor for the sound insulation property, which was significantly improved by increasing the thickness of the fiber cloth. This work can provide fundamental support for the comprehensive design of vibration and acoustics of the composite sandwiched panel.

Experimental Study on Repairing Corroded Cracks by Electrophoretic Deposition

The corrosion of reinforced concrete could reduce its mechanical properties and cause concrete cracking. Electrophoretic deposition is a new method for repairing rust-cracked reinforced concrete. In this study, we observed the crack surface morphology, mass growth, epoxy resin film thickness, ultrasonic rate, and epoxy resin filling depth of rust-cracked reinforced mortar specimens during the repair process and investigated internal microstructure and phase composition of the repaired mortar, and clarified the principle behind the electrophoretic deposition of cationic epoxy resin and curing agent molecules in the repair solution. The result of research shows that longer repair times decreased the carbonization depth and water absorption of the specimens. After repair, the porosity of the surface mortar decreased, owing to the filling of epoxy resin, and the newly generated epoxy resin film had a dense structure. Thus, the carbonization resistance and waterproof performance of the repaired specimens improved. The repair process of electrophoretic deposition can be divided into the immersion, repair, and curing stages, and the physical and chemical principles of each stage were explained.

Masking Ability of Bleach Shade Composite Resins in Different Thicknesses.

Introduction In recent years, the use of bleach shade composite resins has increased due to the high esthetic demands. The aim of the present study was to investigate the masking ability and translucency of several bleach shade composite resins. Materials and Methods In this in vitro study, 180 discs from 9 bleach shade composite resins of 5 brands (G-aenial Anterior, Gradia Direct, Charisma Diamond, Estelite Sigma Quick, and Renamel Microfill) in thicknesses of 0.5, 1, 1.5, and 2 mm were prepared. The color parameters of the specimens were measured in a CIE l∗a∗b∗ system using a spectrophotometer. Masking ability and translucency parameters were calculated, and the influence of thickness, shade, and composite resin brand on these variables was analyzed using the Kruskal–Wallis and Mann–Whitney U tests. Results Both masking ability and translucency differed significantly among groups (p < 0.001), but only MA was different between different brands (p < 0.001). Higher thicknesses showed lower translucency in all pairwise comparisons (p < 0.001). 0.5 mm-thick specimens had lower masking ability than 1.5 mm- (p=0.016) and 2 mm- (p=0.035) thick ones. However, masking ability of other thickness pairs did not show a significant difference (p > 0.05). G-aenial Anterior and Renamel Microfill had the highest and lowest masking ability. Bleach white shades had lower masking ability and higher translucency than extrawhite bleach shades. Conclusion Translucency and masking ability of bleach shade composite resins differed in different thicknesses, composite resin brands, and shade groups.

A new light transmission method to evaluate the through thickness fibre alignment in transparent resin

This work presents a new method to analyse vertical alignment of short fibres inside transparent resin layers using in situ measuring of light transmission through the layer. In this method, a light source is placed on one side of the composite layer and on the opposite side, a phototransistor measures the transmitted light intensity. A feature of the alignment process causes increased light transmission with increased fibre alignment. Using this technique, alignment of short nickel coated carbon fibres inside epoxy resin layers under magnetic field were evaluated and the effect of fibre content, field strength, fibre length and resin thickness on the alignment quality were characterised. An important finding is that the ratio of fibre length and resin thickness showcases a limit to the alignment degree. Finally, an analytical model is introduced which aims to predict average fibre angles based on the sample configuration, showcasing good agreement with experimental results.

Numerical analysis of delamination degradation of epoxy-impregnated superconducting coils wound with REBCO tapes caused by thermal stress

REBa2CuOy (REBCO) superconducting wires are expected to be used in coil applications owing to their excellent magnetic field properties. However, their weak delamination strength may deteriorate the superconducting characteristics of an epoxy-impregnated REBCO coil during cooling. In general, degradation is unlikely to occur if the outer-to-inner diameter ratio is less than 1.4; however, degradation has been reported in single pancake coils with an inner diameter of 560 mm and an outer diameter of 670 mm. A thermal stress analysis study is conducted to investigate the cause of this problem. Considering the non-uniformity of the epoxy resin thickness at the top and bottom of the coil, coil warping during cooling is simulated. When an FRP reinforcement plate is attached to the coil to suppress warpage, a high radial stress generated in the coil owing to the thermal contraction difference between the coil and FRP plate. The maximum local radial stress exerting in the delamination direction is 30 MPa, which is believed to degrade the superconducting characteristics of the REBCO single pancake coils.

Effect of Thermal Shrinkage of Extruded Sheet on Mouthguard Thickness: Influence of Model Undercut

The effectiveness and safety of the mouthguard are greatly affected by its thickness. The aim of this study was to investigate the effect of thermal shrinkage of the extruded sheet on the mouthguard thickness depending on the amount of undercut of the model. Mouthguard sheet was used a 4.0 mm thick ethylene-vinyl acetate resin manufactured by extrusion molding. The sheets were placed in the vacuum forming machine with the sheet extrusion direction either vertical (condition V) or parallel (condition P) to the model’s centerline. The working models were three hard plaster models trimmed so that the angles of the anterior teeth to the model base were 90?, 100?, and 110? (Models A, B, and C). The sheet was softened until it sagged 15 mm, and then suction was continued for 30 s. Measurement points of the mouthguard were the incisal portion (incisal edge and labial surface) and molar portion (cusp and buccal surface). The differences in the reduction rate of the thickness due to model form and extrusion direction were analyzed using two-way ANOVA and Bonferroni’s multiple comparison tests. Differences in thickness depending on the extrusion direction of the sheet were observed in Models B and C on the labial surface and in all models on the buccal surface, and the thicknesses obtained under condition P were significantly thinner than those obtained under condition V. The thicknesses of the incisal edge and the cusp were not affected by the extrusion direction. The result of this study was suggested that the labial and buccal thickness of the mouthguard was secured by placing the sheet in the extrusion direction vertical to the model’s centerline. Furthermore, it was clarified that the presence of the undercut of the model tends to increase the influence of the extrusion direction of the sheet on the thickness of the mouthguard.

Effect of dent defects on the collapse pressure of sandwich pipes

This paper aims to assess the effect of dent defects on the collapse pressure of sandwich pipes under external pressure. A new pipe-making process is proposed, and its ability to resist external loads is investigated. The result shows that the collapse pressure of the sandwich pipe is 76.46%–99.95% higher than that of a single-wall pipe in the same dent defect, and the buckling propagation pressure is 100% higher than the sum of the inner and outer pipes. Otherwise, the influence of the dent on the sandwich pipe is weakened. The pipe consists of two steel pipes and a polypropylene pipe bonded together by one-millimetre thick epoxy resin to form a sandwich pipe. Seven specimens with varying degrees of defects were investigated to obtain their collapse pressure, where four specimens are sandwich pipes. Additionally, a numerical model was established and validated, and systematic parametric studies were carried out to supplement the test results. The experimental and numerical results show that the collapse pressure of the sandwich pipe is significantly influenced by the dent defect. Based on the parametric study, the main parameters that affect the collapse pressure of sandwich pipes are obtained. The relationship between the collapse pressure and the geometry of the sandwich pipes was analysed. The research shows that dent defects have a significant effect on the collapse pressure of sandwich pipes and that reducing the thickness-to-ratio of the inner pipe and the friction between layers is an effective method to improve the collapse pressure of defective sandwich pipes.

In Situ Neutron Reflectometry Analysis of Interfacial Structure Formation between Phenolic Resin and Silica during Curing.

The structural formation mechanism of phenolic resin-silica interfaces was investigated in situ by neutron reflectometry during curing. There was a 4 nm thick novolac resin adsorption layer on the silica surface before curing. The curing reaction of the novolac resin with hexamethylenetetramine (HMTA) increased the coherent neutron scattering length density of the resin due to the cure shrinkage accompanied by the volatilization of ammonia, which is a byproduct of HMTA decomposition. As curing proceeded at 180 °C, the thickness of the bulk layer increased despite the cure shrinkage, and the thickness of the interfacial layer decreased from 4 to 1 nm. This is attributed to the diffusion of decomposed HMTA fragments generated in the bulk layer into the interfacial novolac adsorption layer during diffusion throughout the bulk layer, incorporating the upper part of the interfacial layer reacting with the fragment into the bulk layer. On the other hand, the fragments could not diffuse into the tightly bound immobile segments of novolac resin in direct contact with the silica surface, retaining the 1-2 nm thick interfacial layer in the cured resin. This structural formation mechanism caused interfacial cross-link inhomogeneity in the cured resin on the silica surface.