Silica Filler Content Research Articles

In Situ Monitoring of the Curing of Highly Filled Epoxy Molding Compounds: The Influence of Reaction Type and Silica Content on Cure Kinetic Models.

Monitoring of molding processes is one of the most challenging future tasks in polymer processing. In this work, the in situ monitoring of the curing behavior of highly filled EMCs (silica filler content ranging from 73 to 83 wt%) and the effect of filler load on curing kinetics are investigated. Kinetic modelling using the Friedman approach was applied using real-time process data obtained from in situ DEA measurements, and these online kinetic models were compared with curing analysis data obtained from offline DSC measurements. For an autocatalytic fast-reacting material to be processed above the glass transition temperature Tg and for an autocatalytic slow-reacting material to be processed below Tg, time-temperature-transformation (TTT) diagrams were generated to investigate the reaction behavior regarding Tg progression. Incorporating a material containing a lower silica filler content of 10 wt% enabled analysis of the effects of filler content on sensor sensitivity and curing kinetics. Lower silica particle content (and a larger fraction of organic resin, respectively) favored reaction kinetics, resulting in a faster reaction towards Tg1. Kinetic analysis using DEA and DSC facilitated the development of highly accurate prediction models using the Friedman model-free approach. Lower silica particle content resulted in enhanced sensitivity of the analytical method, leading, in turn, to more precise prediction models for the degree of cure.

Epoxy–Silica Functionally Graded Materials: A Review

This article provides an overview of the studies that have been conducted on the characteristics of epoxy resins containing various types of silica nanoparticles and microparticles, as well as their performance in the industrial application of functionally graded materials (FGMs). Silica nanoparticles and microparticles are used to create epoxy resins in order to improve various properties, such as thermal stability, adhesiveness, electrical conductivity, strength, modulus, and toughness. This review examines the literature that has been published in the last decade, compares the results, focuses on the mechanical and thermal properties, and discusses the changes that have resulted in improvements in those properties. Previous experimental findings are presented and contrasted to demonstrate the extent to which silica filler content contributes to improving the properties of composite materials. The findings reveal that the characteristics of epoxy compounds can be improved by adding a particular amount of silica particles. There is a correlation between an increase in the silica amount and an increase in the Young modulus of epoxy compounds, this correlation becomes stronger as the silica amount increases. Additionally, the tensile strength of epoxy compounds increases to a certain limit as the amount of silica nanoparticles increases. In contrast, the hardness of the material increases as the silica amount increases. The density of the material also increases steadily as the silica amount in the material increases. According to thermal analysis results from calorimetric research on epoxy–silica systems, the glass transition temperature increases as the silica amount increases.

UV-Curable, Low-Viscosity Resin with a High Silica Filler Content for Preparing Ultrastiff, 3D-Printed Molds

UV-Curable, Low-Viscosity Resin with a High Silica Filler Content for Preparing Ultrastiff, 3D-Printed Molds

Evaluation of thermal fatigue crack propagation in underfill resin materials for electronic packages

AbstractTo improve the fatigue life of electronic packages, it is necessary to clarify thermal fatigue characteristics of underfill resin materials. In this study, a new setup for measuring thermal fatigue crack growth was developed, and the effects of thermal cycle conditions and silica filler contents on fatigue crack propagation were investigated. The results show that the likelihood of crack initiation increased with the filler content and the temperature of the thermal cycles. Comparing the results with those from mechanical fatigue tests, crack initiation and propagation occurred at lower ΔK and the crack growth rates were higher for thermal fatigue. Observations of the fracture surface revealed that the cracks propagated inside the underfill resin, which resulted in smaller crack growth resistance than that in mechanical fatigue. The addition of fillers introduced a crack propagation path at the interface between fillers and resins and enhanced the crack propagation resistance in thermal fatigue.

Mesopore silica effect on chemical, thermal and tribological properties of polyimide composites

Abstract In this experimental study, the effects of mesoporous silica filler content on the chemical, thermal and tribological properties of polyimide composites were investigated. For that purpose, Pi/mesoporous silica composites were produced by in situ polymerization with various mesoporous silicas. After fabrication, thermal stability and chemical characterization were determined using TGA and FTIR. Morphological alterations were monitored with a scanning electron microscope (SEM). Texture structure (pore size and pore volume) were determined by the BJH method. Friction and wear properties were investigated by using a pin-on-disc arrangement. At the end of the study, minor shifts of Pi/mesoporous silica composites were observed. Thermal stability, as well as pore size and pore volume, was decreased with mesoporous silica. The coefficient of friction and specific wear rate decreased with the addition of mesoporous silica. Abrasive wear behaviors were seen for both neat Pi and Pi–Si composites. Hence, this study evidenced that the properties of Pi are influenced by mesoporous dimensions and content of Si employed.

Effect of Strain Rate and Silica Filler Content on the Compressive Behavior of RTM6 Epoxy-Based Nanocomposites.

The aim of this paper is to investigate the effect of strain rate and filler content on the compressive behavior of the aeronautical grade RTM6 epoxy-based nanocomposites. Silica nanoparticles with different sizes, weight concentrations and surface functionalization were used as fillers. Dynamic mechanical analysis was used to study the glass transition temperature and storage modulus of the nanocomposites. Using quasi-static and split Hopkinson bar tests, strain rates of 0.001 s−1 to 1100 s−1 were imposed. Sample deformation was measured using stereo digital image correlation techniques. Results showed a significant increase in the compressive strength with increasing strain rate. The elastic modulus and Poisson’s ratio showed strain rate independency. The addition of silica nanoparticles marginally increased the glass transition temperature of the resin, and improved its storage and elastic moduli and peak yield strength for all filler concentrations. Increasing the weight percentage of the filler slightly improved the peak yield strength. Moreover, the filler’s size and surface functionalization did not affect the resin’s compressive behavior at different strain rates.

Investigation of the Sharkskin melt instability using optical Fourier analysis

ABSTRACTAn optical method allowing the characterization of melt flow instabilities typically occurring during an extrusion process of polymers and polymer compounds is presented. It is based on a camera‐acquired image of the extruded compound with a reference length scale. Application of image processing and transformation of the calibrated image to the frequency domain yields the magnitude spectrum of the instability. The effectiveness of the before mentioned approach is shown on Styrene‐butadiene rubber (SBR) compounds, covering a wide range of silica filler content, extruded through a Göttfert capillary rheometer. The results of the image‐based analysis are compared with the results from the sharkskin option, a series of highly sensitive pressure transducers installed inside the rheometer. A simplified version of the code used to produce the optical analysis results is included as supplementary material. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48806.

In vitro/in silico investigation of failure criteria to predict flexural strength of composite resins.

The aim of this study was to investigate a failure criterion to predict flexural strengths of composite resins (CR) by three-dimensional finite element analysis (3D-FEA). Models of flexural strength for test specimens of CR and rods comprising a three-point loading were designed. Calculation of Young's moduli and Poisson's ratios of CR were conducted using a modified McGee-McCullough model. Using the experimental CR, flexural strengths were measured by three-point bending tests with crosshead speed 1.0 mm/min and compared with the values determined by in silico analysis. The flexural strengths of experimental CR calculated using the maximum principal strain significantly correlated with those obtained in silico amongst the four types of failure criteria applied. The in silico analytical model established in this study was found to be effective to predict the flexural strengths of CR incorporating various silica filler contents by maximum principal strain.

Foaming of trans‐polyisoprene using N2 as the blowing agent

Foaming of trans‐1,4‐polyisoprene (TPI) polymer was carried out through a batch process using nitrogen (N2) as the blowing agent. TPI vulcanizates having varying crosslink densities were prepared by varying crosslinking agent content and curing time. The vulcanizates were then saturated with N2 inside a pressure vessel at a pressure of 14 MPa and varying temperatures for 5 hours before effecting the foaming by rapidly quenching the pressure. The effects of varying the crosslinking agent content, silica filler content, and precuring time of the vulcanizates and the effects of varying the gas saturation temperature of foaming on the cell characteristics and physical properties of the foam prepared were investigated. The cells of the TPI foams had a spherical, closed structure. The density, expansion ratio, cell size, cell density, and tensile properties of the foams varied with varying crosslink density of the TPI vulcanizates as well as the saturation temperature of foaming. The important effects of crosslink density and saturation temperature on the N2 solubility in the TPI matrix and thus on the foam expansion were discussed. The silica filler was found to be acting as a cell nucleating agent and reinforcing filler for the TPI foams.

THERMAL AND THERMOPHYSICAL PROPERTIES OF EPOXY-SILICA NANOCOMPOSITES OF CATIONIC POLYMERIZATION

The polymer and composites were received using epoxy resin EPONEX 1510 – diglycidyl ether of dicyclohexylolpropane and 15 % solution of boron trifluoride in diethylene glycol. The silica particles were formed in situ via the sol-gel method using hydrolytic polycondensation of tetraethoxysilane. The silica sol was obtained in acetone as the organic solvent. Silica filler content in the composites varied from 0.5 to 3 wt%. The effect of the nanofiller on the thermophysical and thermal properties of the obtained polymers was studied. Thermophysical characteristics were determined by differential scanning calorimetry on a TA Instruments DSC Q2000 apparatus at a rate of heating of 20 °С/min in the temperature range from 5 to 190 °C. With the objective of decreasing the influence of the technological (kinetic) and thermal prehistory of the sample on its thermophysical characteristics, the scanning was done twice. The glass transition temperature and heat capacity jump of the composite coatings based on epoxy-silica prepared by cationic polymerization were studied. It was established that with an increase of filler content the glass transition temperature of composites increases, and the value of the heat capacity jump remains almost unchanged. Parameters of thermostability of polymer and composites were determined by thermogravimetric analysis on a TA Instruments Q50 apparatus at a rate of heating of 20 °С/min in the temperature range from 20 to 1000 °C in an atmosphere of oxygen. The destruction process of epoxy-silica composites proceeds in several stages. In the deep stages of the thermo-oxidative destruction of obtained composites the effect of the silica filler is insignificant. The obtained polymer coatings were subjected to a long-term (100 hours) isothermal aging at 160 °C in an atmosphere of oxygen. It was determined that the maximum rate of mass loss rate of epoxy-silica composites is 1.5 times lower than that of unmodified polymer.

Degradation of optical and surface properties of resin-based composites with distinct nanoparticle sizes but equivalent surface area

ObjectiveTo determine the optical and surface properties of model resin-based composites made with distinct nanoparticle sizes but equalized surface area, among them, before and after ageing. MethodsModel resin-based composites based on BisGMA/TEGDMA (50:50mol%) were loaded with three different fumed silica filler content (7nm/examethyldisilazane, 12nm/octylsilane, and 16nm/dimethylchlorosilane), but with equivalent surface area (BET method). The optical and surface properties of the disk-shaped specimens were measured in 24h after photoactivation (baseline) and repeated after water storage (90days at 37°C), and after abrasion (20,000 cycles of brushing). CIELAB individual parameters, color difference (ΔE*ab), translucency parameter (TP), gloss (G.U.) and roughness (Ra parameter) were measured. Data were statistically analyzed at α=0.05 significance level. ResultsCIE L* and TP were not affected by ageing in any group. CIE a* was increased and CIE b* decreased for the 12nm and 16nm groups and did not show any difference for the 7nm group. After ageing, the lowest ΔE*ab was observed for the 7nm group. Gloss and roughness were statistically equivalent for all groups, before and after ageing. The water storage didn’t show any significant difference while the abrasion decreased gloss and increased the roughness. ConclusionThe optical properties of the tested materials were not dependent of the fillers’ surface area, while the surface properties were. Clinical significanceSeveral factors influence the ageing resistance of the resin-based composites, including the surface area of the fillers and the amount and coupling treatment of them. The improvement of the material’s physical stability could avoid the premature replacement of dental restorations.

Bonding resin thixotropy and viscosity influence on dentine bond strength

ObjectivesTo investigate the influence of bonding resin thixotropy and viscosity on dentine tubule penetration, blister formation and consequently on dentine bond strength as a function of air-blowing pressure (air-bp) intensity. MethodsTwo HEMA-free, acetone-based, one-bottle self-etch adhesives with similar composition except disparate silica filler contents and different bonding resin viscosities were investigated. The high-filler-containing adhesive (G-Bond) featured a lower viscous bonding resin with inherent thixotropic resin (TR) properties compared to the low-filler-containing adhesive (iBond) exhibiting a higher viscous bonding resin with non-thixotropic resin (NTR) properties. Shear bond strength tests for each adhesive with low (1.5bar; 0.15MPa; n=16) and high (3.0bar; 0.30MPa; n=16) air-bp application were performed after specimen storage in distilled water (24h; 37.0±1.0°C). Results were analysed using a Student’s t-test to identify statistically significant differences (p<0.05). Fracture surfaces of TR adhesive specimens were morphologically characterised by SEM. ResultsStatistically significant bond strength differences were obtained for the thixotropic resin adhesive (high-pressure: 24.6MPa, low-pressure: 9.6MPa). While high air-bp specimens provided SEM images revealing resin-plugged dentine tubules, resin tags and only marginally blister structures, low air-bp left copious droplets and open dentine tubules. In contrast, the non-thixotropic resin adhesive showed no significant bond strength differences (high-pressure: 9.3MPa, low-pressure: 7.6MPa). ConclusionsA pressure-dependent distinct influence of bonding resin thixotropy and viscosity on dentine bond strength has been demonstrated. Stronger adhesion with high air-bp application is explained by improved resin fluidity and facilitated resin penetration into dentine tubules. Clinical significanceFiller particles used in adhesive systems may induce thixotropic effects in bonding resin layers, accounting for improved free-flowing resin properties. In combination with high air-bp this effect allows an easy plugging of dentine tubules and elimination of blister structures, both resulting in superior dentine bond strength.

Large-area dielectric breakdown performance of polymer films – Part II: Interdependence of filler content, processing and breakdown performance in polypropylene-silica nanocomposites

In this study, large-area dielectric breakdown performances of various bi-axially oriented polypropylene (BOPP)-silica nanocomposite films are studied by utilizing the self-healing multi-breakdown method presented in the Part I of this publication. In particular, the effects of silica filler content, pre-mixing method, co-stabilizer content and film processing on the large-area breakdown performance are analyzed. Nanostructural and film cross-sectional analyses are correlated to the breakdown responses. The optimum silica filler content is found to reside at the low fill fraction level (~1 wt-%) and automatic pre-mixing of the raw materials and the optimization of the orientation temperature are found to be preferable. The co-stabilizer Irgafos 168 is found to have a significant effect on the breakdown distribution homogeneity of the reference BOPP films. The breakdown response of the silica nanocomposites is found to be not only dependent on the active measurement area but also on the voltage ramp rate, indicating that the silica nanocomposites exhibit altered internal charge behavior under DC electric field. The area- and ramp-rate-dependence results exemplify the importance of careful breakdown strength evaluation of dielectric polymer nanocomposites. Above all, the results emphasize the fact that a thorough understanding and the optimization of the film processing parameters are crucial for achieving improved breakdown response in dielectric polymer nanocomposite films.

Antibacterial Efficacy and Mechanical Properties of Silica Reinforced Natural Rubber (NR) with HPQM Based Neusilin

This work studied the antibacterial performance and mechanical properties of natural rubber (NR) compound reinforced with commercial silica at various silica loadings form 0, 20, 40 and 60 parts per hundred rubber (phr). 2-Hydroxypropyl-3-Piperazinyl-Quinoline carboxylic acid Methacrylate (HPQM) based Neusilin at loadings of 0, 3 and 5 phr were used as anti-bacterial agent against Escherichaia coli (E.coli) ATCC 25923 and Staphylococcus aureus (S.aureus) ATCC 25922. The antibacterial performance was reported as a clear zone radius by diffusion test and a percentage reduction of bacteria by Plate-Count-Agar (PCA) method. The results suggested that the increasing silica loading in the NR vulcanizates improved the tensile modulus and hardness, but decreased elongation which had optimal tensile strength at 20 phr of silica. Additionally, the HPQM based Neusilin did not affect the mechanical properties of the rubber vulcanizates. The antibacterial results showed that the inhibition zone radius and the percentage reduction increased with increasing HPQM based Neusilin, but decreased with silica filler content. The antibacterial efficacy was inversely related to the reinforcement level of the NR vulcanizates by the silica. The percentage reduction of bacteria of NR compound filled with 5 phr of HPQM based Neusilin achieved 99.9%.

Biphenyl liquid crystalline epoxy resin as a low-shrinkage resin-based dental restorative nanocomposite

Low-shrinkage resin-based photocurable liquid crystalline epoxy nanocomposite has been investigated with regard to its application as a dental restoration material. The nanocomposite consists of an organic matrix and an inorganic reinforcing filler. The organic matrix is made of liquid crystalline biphenyl epoxy resin (BP), an epoxy resin consisting of cyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (ECH), the photoinitiator 4-octylphenyl phenyliodonium hexafluoroantimonate and the photosensitizer champhorquinone. The inorganic filler is silica nanoparticles (∼70–100nm). The nanoparticles were modified by an epoxy silane of γ-glycidoxypropyltrimethoxysilane to be compatible with the organic matrix and to chemically bond with the organic matrix after photo curing. By incorporating the BP liquid crystalline (LC) epoxy resin into conventional ECH epoxy resin, the nanocomposite has improved hardness, flexural modulus, water absorption and coefficient of thermal expansion. Although the incorporation of silica filler may dilute the reinforcing effect of crystalline BP, a high silica filler content (∼42vol.%) was found to increase the physical and chemical properties of the nanocomposite due to the formation of unique microstructures. The microstructure of nanoparticle embedded layers was observed in the nanocomposite using scanning and transmission electron microscopy. This unique microstructure indicates that the crystalline BP and nanoparticles support each other and result in outstanding mechanical properties. The crystalline BP in the LC epoxy resin-based nanocomposite was partially melted during exothermic photopolymerization, and the resin expanded via an order-to-disorder transition. Thus, the post-gelation shrinkage of the LC epoxy resin-based nanocomposite is greatly reduced, ∼50.6% less than in commercialized methacrylate resin-based composites. This LC epoxy nanocomposite demonstrates good physical and chemical properties and good biocompatibility, comparable to commercialized composites. The results indicate that this novel LC nanocomposite is worthy of development and has potential for further applications in clinical dentistry.

Nonconductive Films (NCFs) With Multifunctional Epoxies and Silica Fillers for Reliable NCFs Flip Chip on Organic Boards (FCOBs)

Nonconductive films (NCFs) have become one of the promising interconnection adhesives for flip-chip assembly. Because NCFs have many advantages such as low cost, easy handling, and fine-pitch application. However, effects of the material properties of NCFs on the reliability of NCFs flip-chip assemblies have not been fully understood. In this paper, effects of multifunctional epoxy and the addition of silica fillers on thermomechanical properties of cured NCFs and thermal cycling reliability of NCFs flip-chip-on-organic board (FCOB) assemblies were investigated. For the NCF materials, two kinds of thermosetting polymers, di-functional and multifunctional epoxies, and silica fillers of various contents (0 wt%, 10 wt%, and 20 wt%) were used. The curing behavior and thermomechanical properties of NCFs were measured for the NCF materials characterization. According to the results, NCFs using multifunctional epoxy had higher glass transition temperature ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Tg</i> ), lower coefficient of thermal expansion (CTE), and higher storage modulus (E <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">'</sup> ) in high-temperature regions than NCFs using di-functional epoxy. As the silica filler content increased, the CTE and the storage modulus of cured NCFs decreased and increased, respectively. Thermal cycling test (-40degC - 150degC, 1000 cycles) was performed to investigate effects of thermomechanical properties of cured NCFs on thermal cycling reliability of NCF FCOB assemblies. According to the results, NCF FCOB assemblies using NCFs with multifunctional epoxy had better thermal cycling reliability than those using NCFs with di-functional epoxy, and 10 wt% and 20 wt% silica added NCFs showed the best thermal cycling reliability in the electroplated Au bump application and the stud Au bump application, respectively. Consequently, thermal cycling reliability of NCFs FCOB assemblies could be enhanced with the increased <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Tg</i> and the improved thermomechanical properties of NCFs by using multifunctional epoxy and the addition of silica fillers.

Filler size and content effects on the composite properties of anisotropic conductive films (ACFs) and reliability of flip chip assembly using ACFs

Flip chip assembly on organic board using anisotropic conductive films (ACFs) is gained more attention because of its many advantages. But to obtain more reliable flip chip assembly, it is necessary to have low coefficient of thermal expansion (CTE) value of ACFs. To control the CTE of ACF materials, non-conductive silica fillers were incorporated into ACFs. The effect of non-conductive silica filler content and size on cure kinetics and thermo-mechanical properties of ACFs was studied. Furthermore, filler content and size effects on reliability of flip chip assembly using ACFs were also investigated. In accordance with increasing filler content, curing peak temperature and storage modulus ( E′) increased. But CTE decreased as the filler content increased. The effect of filler size on composite properties and assembly reliability showed similar tendency with the filler content effect. The smaller filler size was applied, the better composite properties and reliability were obtained. Conclusively, incorporation of non-conductive fillers, particularly in case of smaller size and higher content, in ACFs improves the material properties significantly, and as a result, flip chip assembly using ACFs is resulted in better reliability.

Preparation and mechanical properties of novel polyimide/T-silica hybrid films

Polyimide/silica tube (PI/T-silica) hybrid films were successfully prepared from solution of polyamic acid (polyimide precursor) and silica tubes modified by coupling agent (γ-aminopropyltriethoxy silane, KH 550). Silica tubes were obtained by hydrolyzing tetraethyl orthosilicate (TEOS) using d, l-tartaric acid as a template. The morphology of silica tubes was investigated by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The results showed that the silica tubes were rectangle and 100–500 nm in width and their aspect ratio was 10–500. The effects of coupling agent and silica filler content on the mechanical properties were studied. The results showed that there existed the optimal coupling agent and silica contents leading to the highest mechanical properties. When the weight ratio of KH 550/T-SiO 2 was equal to 1/10 and the T-silica content was 1 wt%, the mechanical properties of PI/T-SiO 2 hybrids were markedly improved.

Synthesis and Characterization of Transparent Hydrophobic Sol-Gel Hard Coatings

It is challenging to make a transparent hydrophobic hard coating when soft hydrophobic additives are added into the coating system. Material non-homogeneity due to phase separation, non-durable hydrophobicity and deteriorated transparency are the main issues. In this paper, we describe a chemical formulation, which contains a pre-linked hydrophobic cluster and a silica hard matrix with silica hard fillers so that the hydrophobic property and hardness can be tuned separately and optimized. The transparency of the coating is found to be related to the effective modification of the reactive titanium tetraisopropoxide (TIP) precursor by ethyl acetoacetate (EacAc) and the right ratio between TIP and polydimethylsiloxane (PDMS) (≤0.5). The water contact angle is increased to a maximum of 133° when 50 Vol% of PDMS is added into the silica matrix. The hardness of coating is proportional to silica filler content and curing temperature, and inversely proportional to PDMS Vol%. 30 Vol% silica filler in silica matrix and curing temperature at 300°C result in the best hardness in this study. Hardness at 50 Vol% PDMS dropped to 0.2 GPa from 0.85 GPa of pure silica coating. The Vol% of PDMS and silica filler will be further optimized in our next stage experiments.

Effects of Silica Filler and Diluent on Material Properties and Reliability of Nonconductive Pastes (NCPs) for Flip-Chip Applications

In this paper, thermomechanical and rheological properties of nonconductive pastes (NCPs) depending on silica filler contents and diluent contents were investigated. And then, thermal cycling (T/C) reliability of flip chip assembly using selected NCPs was verified. As the silica filler content increased, thermomechanical properties of NCPs were changed. The higher the silica filler content was added, glass transition temperature (T/sub g/) and storage modulus at room temperature became higher while coefficient of thermal expansion (CTE) decreased. On the other hand, rheological properties of NCPs were significantly affected by diluent content. As the diluent content increased, viscosity of NCP decreased and thixotropic index increased. However, the addition of diluent deteriorated thermomechanical properties such as modulus, CTE, and T/sub g/. Based on these results, three candidates of NCPs with various silica filler and diluent contents were selected and used as adhesives for reliability test of flip chip assemblies. T/C reliability test was performed by measuring changes of NCP bump connection resistance. Results showed that flip chip assembly using NCP with lower CTE and higher modulus exhibited better T/C reliability behavior because of reduced shear strain in NCP adhesive layer.