Resin Research Articles

Biosystematic Studies, Distribution and Conservation Status of Guaiacum officinale L. in Karnataka State

Guaiacum L. is an evergreen tree indigenous to South America, West Indies and USA. It was introduced during British period. The stem is hard, abundant resin wood, ash- grey-green bark and paripinnate leaves. The flowers are blue-purple in colour and occur in axillary clusters. The fruit is a capsule. Anomocytic, Paracytic and tertacytic types of stomata present only on abaxial surface of the leaf, trichomes absent on both surface. Pollen monad, radialy sysmmetric, tricolporate. The secondary veins are joined to form a loop at the margin. Phenolic test, alkaloid test etc. gave positive results. This plant is having commercial as well as medicinal value. In Karnataka state this plant found only in two places, one in Lalbagh, Bangalore and another in Karnataka College, Dharwad. Silviculture experiments were conducted but not succeeded. In both the places flowers are many, but fruit setting is negligible. It inhibits the spreading of the species in Karnataka.

Dielectric Behavior Characterization of RE/BaTiO3 Using Time Domain Spectroscopy: Application on High-Performance Dielectric Resonator Antennas

We are working to design dielectric resonator antennas based on binary composites made of epoxy resin (RE) and barium titanate (BaTiO3 or BT). The composite samples are prepared at room temperature and under atmospheric pressure. The dielectric properties of these composites were assessed using time domain spectroscopy (TDS). The antennas structure are designed, simulated, and optimized using electromagnetic software Ansys, HFSS. Two types of antennas are studied. The first type consists of a cylindrical dielectric resonator that gives three antenna models in terms of bandwidths, the antennas having a single frequency band, the antennas having dual-band, and the antenna covering three frequency bands, with peak gains varying between 3.68 and 8.15 dB achieved. The second type consists of dielectric resonators composed of two adjacent identical shapes each consisting of a rectangular joined with a cylindrical with the same height. The proposed antenna achieves ultra-wideband with a relative bandwidth of 97% covering the range of 6 to 17.32 GHz, and dual-band circularly polarized ( AR<3dB ), the range of the lower band is 9.62 to 10.14 GHz and the range of the upper band is 16.74 to 16.94 GHz. The focus of this research is on creating novel antennas for applications in wireless communications systems.

Dielectric Characterization of Heterogeneous Composites Using Time Domain Spectroscopy and Microwave Test Benches in Microwave Frequency

Dielectric composite materials made of polymers and ferroelectric ceramics have recently emerged as one of the important components for applications involving the generation, transformation, and storage of sustainable energy. Because there is a trade-off between dielectric permittivity, dielectric loss, and dissipation factor, the end use is the energy storage capacity. In the present study, epoxy resin (RE)/barium titanate (BaTiO3) composite samples are prepared using the mixture cast method with new molds. The dielectric properties, such as dielectric permittivity, dielectric loss, electrical modulus, static conductivity and dissipation factors due to the concentration of barium titanate and frequency effect on the composites, are examined using two characterization methods. The objective of this study is to determine the dielectric permittivity of the material using two microwave methods, the first is time domain spectroscopy (TDS) and the second is on the X-band microwave test bench (MTB). Additionally, different empirical mixture laws are used to estimate the dielectric permittivity of our composites. It is found that an increase in filler concentration (BaTiO3) increases the effective dielectric permittivity, which is confirmed with different empirical mixture models. The findings of this research can be used for electrical devices, including sensors, wave absorbers, resonators, and antennas.

Characterization, Modeling, Experimental Validation and Dielectric Properties Studies of a Ternary Composite (RE-BaTiO3-SiO2) Using Time Domain Spectroscopy

This study aim is to investigate the ternary composites dielectric behavior and experimentally validate the predictive model that simplifies ternary models into binary ones using time domain spectroscopy (TDS). The scattered white silicon dioxide (SiO2) powder was evenly mixed with barium titanate (BaTiO3 or BT) powder in the same epoxy resin (RE) matrix. Over a frequency range from DC to 30 GHz, the dielectric behavior of these composite samples is examined, adding in particular a low frequency study at 500 MHz. The BT addition grew the mixture dielectric permittivity from 3.6063 to 8.2313 and moving the resonance frequency (ƒr) in the direction of the low frequency from 26.245 GHz until 17.09 GHz. By improving the shape factor smoothing and bringing theoretical and experimental results closer together, this seeks to optimize the modified Lichtenecker's law (MLL). These findings comparison demonstrates that the MLL model applies to ternary composites (RE-BT-SiO2) with an acceptable accuracy level. Another numerical method was used to evaluate the RE-[RE-BT-SiO2] composites employing a binary mixing model based on an MLL equation that is identical to the former ternary. This model results correlate well with binary composites experimental values as well as ternaries that are modeled using this law. This research perspective lies on the production of new materials for use in microelectronics and particularly on the MOS structure oxides improvement.

Separation and direct-indirect analysis of six group components from liquids of kerosene co-refining

The composition and structure of kerosene co-refining products (KCR) need to be studied to promote their further processing and utilization besides for making fuels. In this paper, their composition and structure were analyzed layer by layer from top to bottom in the form of “Surface (KCR)-Line (six group components, SGCs)-Point (compounds)”. SGCs combine extraction and column chromatography to provide a method for highly efficient separation of heavy hydrocarbons. Insoluble components (asphaltene, ASP) and n-heptane soluble (HS) were obtained from light and heavy liquids (LP and HP) of KCR by Soxhlet extraction. HS was gradient eluted by chromatographic column with different solvents and α-Al2O3, and separated into other five group components: saturates (SA), aromatics (AR), heteroatoms (HE), phenolics (PH) and resins (RE), wherein the results show that the extraction yields of LP-SA, LP-AR, LP-PH, LP-RE are 68.53 wt%, 7.28 wt%, 3.55 wt% and 1.20 wt%, and the extraction yields of HP-SA, HP-AR, HP-HE, HP-PH, HP-RE are 36.06 wt%, 25.13 wt%, 6.27 wt%, 4.53 wt% and 2.37 wt%, respectively. Physical and chemical characterization of the raw materials and SGCs were analyzed by TG, FTIR, 13C NMR, GC/MS, and Py-GC/MS, in which the combination of GC/MS and Py-GC/MS can fully detect the light and heavy components in LP and HP, including those difficult to detect above 300 °C. The final thermal mass loss rates of these components follow the order of LP-SA > LP-AR > LP-PH > LP-RE and HP-SA > HP-AR > HP-PH > HP-HE > ASP > HP-RE. The aromatic carbon mass ratio (fa) of LP and HP is 15.27% and 19.45%, respectively. n-Alkanes (C11–32) are the main compounds in LP and HP, followed by polycyclic aromatics with 3–4 R. Aromatics are rich in -CH2- bridge bond to generate light aliphatics and aromatics at 500 °C, especially the ASP generates many monocyclic aromatics with the increase of temperature by Py-GC/MS. In addition to aliphatics and aromatics, alkyl phenols, esters, pyridines and thiophenes are the main compounds in LP and HP.

Molecular Characteristics of Jimusaer Shale Oil from Xinjiang, China.

Increasing attention is currently obtained by the exploitation and utilization of unconventional energy sources globally. Jimusaer shale oil (JSO) was prepared by dry distillation from oil shale in Jimusaer, Xinjiang, China. Using n-heptane and toluene as solvents, saturate (SA), aromatic (AR), resin (RE), and asphaltene (AS) samples were produced from JSO. Samples were subsequently analyzed by elemental analysis (EA), thermogravimetric analysis (TG-DTG), infrared analysis (FT-IR), high-performance gel chromatography (GPC), and nuclear magnetic resonance (1H-NMR and 13C-NMR). In terms of basic properties, element content, classification of combustible minerals, and refining performance, JSO, which has a high H/C value, low carbon residue yield, low metal content, and excellent refining-processing performance, is considered a high-quality shale oil compared with the shale oil produced in other areas. The refining performance of JSO is even comparable with petroleum. According to column chromatography, the contents of SA, AR, RE, and AS in JSO are 54.32, 18.86, 25.81, and 1.01%, respectively. The results of FT-IR and NMR (1H-NMR and 13C-NMR) demonstrated that the chain alkane or aromatic cycloalkyl substituents of SA, AR, and RE decrease sequentially, while the number of aromatic rings and cycloalkane rings and the degree of condensation increase sequentially. These results indicate that the chain alkanes with a small number of cycloalkanes are the main component of SA. The AR and RE contain more thick-ring aromatic hydrocarbons. According to GPC, the molecular weight (Mn) of JSO is 845 g·mol–1, and those of SA, AR, and RE are 702, 1107, and 2218 g·mol–1, respectively. The estimated molecular formulas (Maf) of JSO, SA, AR, and RE, which were calculated based on the combined results of GPC and EA, are C57.91H115.60O1.38N0.79S0.04, C48.02H101.79O0.69N0.85S0.03, C76.96H137.16O1.08N1.87S0.09, and C156.24H247.75O1.46N4.42S0.32.

Dielectric Characterization and Modeling of Composite Materials Based on Epoxy Resin/Black Iron Oxide/Titanates in Several Frequency Ranges

The purpose of this article is to study the dielectric dispersion of two different ternary composites made of epoxy resin (RE), black iron oxide (Fe3O4) with one of the two titanates (calcium titanate (CaTiO3) or strontium (SrTiO3)) on several frequency bands. Additionally, the effect of the two titanates and the (Fe3O4) on the permittivity and conductivity of these ternary composites is investigated. These composite materials were characterized using time domain spectroscopy (TDS). The inclusion of the two titanates increased the real permittivity and conductivity of the two composites, shifting the resonance frequency (ƒR) towards the low frequency range and causing the opposite phenomenon for the static permittivity (ε s). The frequency dispersion behavior model for the complex permittivity has been proposed to improve the effectiveness of the predictive frequency model through a better choice of the damping factor and to bring theoretical and experimental findings closer together. Comparing these data shows that the proposed model is applicable to ternary combinations with high accuracy. The values of the quality factor (Q) obtained are encouraging in microwave applications. These composite materials witch containing CaTiO3 and SrTiO3 inclusions have contributed to the development of dielectric permittivity that suits very well frequency communication systems.

Impact energy absorption of block copolymer/tackifier blends: Effect of compatibility, viscoelasticity, and laminate structures

AbstractThis work studied the effects of tackifiers on the impact energy absorption properties of block copolymers (BCPs) comprising poly(styrene)‐b‐poly(isoprene)‐b‐poly(styrene) (SIS) and poly(methyl methacrylate)‐b‐poly(n‐butyl acrylate)‐b‐poly(methyl methacrylate) (MAM). A rosin ester resin (RE) and an aliphatic petroleum resin (C5PR) were compared as the tackifiers. Analyses of Hansen solubility parameters and observations using electron microscopy indicated that both tackifiers were highly compatible with the poly(isoprene) component of the SIS, while the RE also showed good compatibility with the poly(n‐butyl acrylate) phase of the MAM. The impact energy absorption characteristics of laminates made by applying layers of BCP/tackifier blends to cured epoxy substrates were evaluated using a pendulum impactor. The extent of energy absorption by these laminates was found to increase within specific tackifier concentration ranges. However, the C5PR showed poor compatibility with the MAM and had almost no effect on the energy absorption of the laminates. The energy absorption of the laminates could be described based on the calculated loss factor,η, determined using the RUK equation including the viscoelastic parameters (both tanδand storage modulus) for the BCP/tackifier blends, considering the time–temperature superposition principle, and for the laminate structures.

Resin infiltrant protects deproteinized dentin against erosive and abrasive wear.

ObjectivesThis study aimed to investigate the anti-erosive/abrasive effect of resin infiltration of previous deproteinized dentin.Materials and MethodsDentin slabs were randomly assigned to 3 groups (n = 15): Control (no deproteinization; no resin infiltrant applied), RI (no deproteinization; resin infiltrant applied), and DRI (deproteinization; resin infiltrant applied). After undergoing the assigned treatment, all slabs were subjected to an in vitro cycling model for 5 days. The specimens were immersed in citric acid (0.05 M, pH = 3.75; 60 seconds; 3 times/day) and brushed (150 strokes). Between the challenges, the specimens were exposed to a remineralizing solution (60 minutes). The morphological alterations were analyzed by mechanical profilometry (µm) and scanning electron microscopy (SEM). Data were submitted to one-way analysis of variance (ANOVA) and Tukey tests (p < 0.05).ResultsControl and RI groups presented mineral wear and did not significantly differ from each other (p = 0.063). DRI maintained a protective layer preserving the dentin (p < 0.001). After erosive/abrasive cycles, it was observed that in group RI, only 25% of the slabs partially evidenced the presence of the infiltrating, while, in the DRI group, 80% of the slabs presented the treated surface entirely covered by a resin-component layer protecting the dentin surface as observed in SEM images.ConclusionsThe removal of the organic content allows the resin infiltrant to efficiently protect the dentin surface against erosive/abrasive lesions.

Adsorption of Scandium and Yttrium from Aqueous Solutions by Purolite C100Na Resin: Equilibrium and Kinetic Modeling

ABSTRACT: Adsorption of Sc from single and bi-component Sc-Y solutions by Purolite C100Na was studied experimentally and kinetic and thermodynamic characteristics are described. The extended Freundlich isotherm was found to be successful in validating the experimental results. Moreover, curve fitting the time-dependent data into different kinetics mechanisms showed a satisfactory correlation with the pseudo-second-order model. Binary system results show a decrease in Sc adsorption capacity of the absorbent in the presence of secondary ions because of competition for adsorption sites. Furthermore, thermodynamic parameters indicate similarity of reaction mechanisms for both single and binary systems, with Sc absorption adversely affected by temperature. Data from experiments on synthetic electrolytes with Y/Sc ratio of 5 found in actual mining copper leach solution were used for extracting scandium by circulating mine-leach solution through a resin column. The results demonstrate a preferential collection of Sc ions despite the fivefold concentration of Y over Sc. The elusion studies showed that the yttrium desorption peak occurs before that of Sc which, corroborates the adsorption isotherm findings. This results in a 180 mgL-1 Sc rich solution or 60:1 concentration ratio over the original copper leach solution.

Mechanisms of arsenic removal from simulated surface water based on As(III) retention on thiol chelating resins

A novel system for arsenic speciation in the aqueous environment has been developed based on the high affinity of As(III) for the sulfhydryl groups present in thiol resins (R-S). The performance of tailor-made cartridges filled with the thiol resin was then compared with a commercial silica-based anion exchange cartridge with a quaternary ammonium group (R-N) typically used for As(V) speciation. Both were able to separate arsenic species efficiently, As(V) and As(III), within a broad pH range using flow rates of up to 5 ml min−1. The R-S resin was shown to be suitable for the inorganic arsenic speciation in aqueous systems containing calcium, magnesium, ferrous and ferric ions. The R-S selectivity for As(III) was affected only at sulfate or phosphate/As mass ratio > 500, in a behavior similar to R-N for As(V). The thiol resin's selectivity for As(III) and its immobilization mechanism were investigated through X-ray Absorption Spectroscopy. At pH 5, each arsenic atom bounds to three sulfur atoms, with an As-S inter-atomic distance of 2.26 ± 0.01 Å, and a coordination number (CN) of 2.8 ± 0.3. The separation of the neutral As(III) species by a thiol resin presents itself as an alternative to the available anion exchange methods. The sorption of As(III) on the thiol resin followed a pseudo-second-order kinetic model and can be described by the Langmuir isotherm.

Effect of Ionic Liquid on the Properties of Nanocomposites Based on Epoxy/CNT Hardened with MCDEA

Thermosetting systems based on epoxy resin (RE) with the dispersion of carbon nanotubes (CNT), have been extensively studied by the development of high-performance materials with interesting mechanical, thermal and electrical properties that the thermo-rigid system achieves with the addition of CNT, and thus contribute to obtain composites with excellent performance in low amounts of this filler. However, ensuring a good dispersion of these systems is not easy, as CNTs have a great tendency to cluster due to Van der Waals interactions. To assist in the dispersion of the systems, a phosphonium-based ionic liquid, tributyl (ethyl) -phosphonium diethyl phosphate, acted with a double role, as a dispersion agent and catalyst in systems hardened with MCDEA (4,4’-methylenebis (3 - chloro-2,6-diethylaniline), which is a solid compound giving the systems high viscosity, and with the addition of LI improved the dispersion of the systems, as well as the processability in the preparation of the nanocomposites.

Phase structure and adhesion properties of acrylic block copolymer/tackifier blends as nanocomposite‐like pressure‐sensitive adhesives

AbstractIn a blend of acrylic block copolymer consisting of poly(methyl methacrylate) and poly(n‐butyl acrylate) blocks and a special rosin ester resin (RE) tackifier as a model pressure‐sensitive adhesive (PSA), RE exists in two states: as nm‐sized agglomerated particles (A) and as dissolved molecules (B). The effect of A and B ratio on the PSA properties were investigated using REs with four different weight‐average molecular weights (Mws) in the range from 680 to 1700. The formation of A increased with increasing of Mw because of lowering of miscibility. The glass transition temperature increased with increasing of Mw. The tack at lower temperatures and the fracture energy were improved by B, whereas the tack at higher temperatures was improved by A. A and B enhanced the cohesive strength and the wettability of PSA, respectively. However, the improvement of cohesive strength by the RE with highest Mw was remarkably low. This seems to be caused by the larger size of agglomerated particles. 1H pulse nuclear magnetic resonance analysis was useful for estimating the degree of A formation. The model PSA investigated in this study was nanocomposite‐like.

Parámetros genéticos de caracteres de crecimiento en un ensayo de progenies de Pinus oocarpa

Pinus oocarpa Schiede ex Schltdl. es una de las especies forestales en México de mayor importancia ecológica (por su amplia distribución geográfica) y económica (por la extracción de su resina en poblaciones naturales). Una resinación más intensiva requerirá de plantaciones comerciales, que podrían ser multipropósito: resina y madera. El objetivo del presente trabajo fue conocer el control genético (heredabilidad) de caracteres de crecimiento (altura total, ALT), diámetro a la base del tallo (DIAM) y diámetro a la altura del pecho (DAP), de progenies de medios hermanos de árboles originalmente seleccionados para producción de resina. Esto con la finalidad de valorar la factibilidad de un programa de mejoramiento genético multipropósito. Se estableció un ensayo de progenies en el año 2011 en Michoacán, México con 27 familias de medios hermanos en un diseño de 10 bloques completos al azar. A los cinco años después de la plantación, los promedios fueron ALT = 5.5 m, DIAM = 13.4 cm y DAP = 10.4 cm. Hubo diferencias significativas entre familias para todos los caracteres. La heredabilidad a nivel individual (h2i) fue: ALT = 0.15, DIAM = 0.22 y DAP = 0.17; a nivel media de familias (h2f) fue de 0.44, 0.54 y 0.47, respectivamente. A una intensidad de selección de mejores individuos de i=1.4, las ganancias genéticas para ALT, DIAM y DAP fueron de 3.9%, 5.2% y 5.0%, respectivamente. De demostrarse posteriormente asociación entre diámetro y producción de resina, sería factible incrementar ambos, mediante selección de individuos con mayores diámetros.

Qualidade das juntas coladas de madeira de cinco espécies de Eucalyptus com adesivos acetato de polivinila e resorcina-formaldeído

O objetivo deste trabalho foi avaliar o potencial das madeiras de Eucalyptus benthamii, Eucalyptus dunnii, Eucalyptus grandis, Eucalyptus saligna e Eucalyptus urophylla, para produção de painéis colados lateralmente (EGP) e madeira laminada colada (MLC). As propriedades físicas e químicas das madeiras foram determinadas com base nas normas COPANT 461/459:1972 e TAPPI 204/252:2002. Foram confeccionadas juntas coladas com adesivo acetato de polivinila (PVA), com gramaturas de 150 g m-2 e 200 g m-2, e resorcina-formaldeído (RF), com 200 g m-2 e 300 g m-2. A qualidade de colagem foi avaliada por meio de ensaios de cisalhamento, com base na norma EN 13354:2008. Todas as espécies apresentaram densidade básica de média a baixa e anisotropia de contração de média a alta. O teor de extrativos totais e pH estão dentro da faixa referenciada na literatura. As avaliações dos resultados com base nos requisitos da norma EN 15353:2008 para 5º percentil inferior indicaram que as espécies E. benthamii, E. dunnii, E. grandis e E. saligna, apresentam potencial para produção de painéis EGP com adesivo PVA, para o uso interno, e externo com cobertura. Para a colagem com adesivo RF, o E. dunni apresentou melhores resultados, sendo indicativo do seu bom potencial para a produção de madeira laminada colada, visando aplicações estruturais em ambientes interno úmido e externo. Para os dois tipos de adesivos o aumento na gramatura não afetou os resultados de cisalhamento das juntas coladas.

Polymerization shrinkage of resin mixtures used in dental composites

Polymerization shrinkage of resin mixtures used in dental composites

The mechanical properties of the expandable polyurethane resin based on its volumetric expansion nature

The mechanical properties of the expandable polyurethane resin based on its volumetric expansion nature

Crosslinking Density Control and Its Carbonization Characteristics of Spherical Phenolic Resin Particles by Using Cresol as Comonomer

구형 페놀수지 입자 및 상대적으로 가교밀도가 낮은 구형 페놀-크레졸 공중합체 수지를 페놀, ortho-크레졸, 및 포름 알데히드로부터 염기성 촉매인 트리에틸아민(triethylamine)의 존재 하에 98 ℃에서 현탁중합을 통하여 합성하였다. 페놀은 두 개의 ortho 및 한 개의 para 위치에서 포름알데히드와 반응하여 가교구조를 형성하지만 ortho-크레졸은 선점된 하나의 ortho 위치의 methyl 기로 인하여 공중합 시 가교 밀도를 저하시킨다. 그 영향으로 700 ℃ 질소 환경에서의 탄화 시 구형 페놀수지 비드에 비해 구형 페놀-크레졸 공중합체 수지의 경우 겉보기 밀도의 감소와 함께 수축율의 증가 현상이 일어나는 것을 확인할 수 있었다. 크레졸 올리고머의 분자량이 증가함에 따라 탄화 된 공중 합체 비드의 기공 반경이 감소하여 밀도 및 수축 결과와 일치 하였으며, 크레졸을 이용하여 구형 페놀수지 입자의 가교도를 조절함으로써 탄화과정에서의 밀도 감소율이 약 3~6%포인트 증가되고, 수축율은 약 6~20%포인트 증가함을 확인하였다.

Profundidade de cura das resinas bulk fill variando a fonte de luz

Analisar a profundidade de cura das resinas do tipo Bulk Fill (Fluida e Pasta) alterando a fonte de luz. 10 tipos de resinas foram analizadas: (P) Pasta: FiltekTM One Bulk Fill (F1), Tetric N-Ceram Bulk Fill (T1); Aura Bulk Fill (A1); OPUS Bulk Fill (O1) e (F) Fluida: FiltekTM Bulk Fill Flow (F2); Tetric N-Flow Bulk Fill (T2); SDR® Plus Bulk Fill Flowable (S2); OPUS Bulk Fill Flow (O2). Foram confeccionados três discos para cada grupo seguindo ISO 4049/2000, através de molde (4x10mm), que foi totalmente preenchido com resina e fotoativado num tempo de 20s, sendo variado a fonte de luz entre Gnatus (G) e Kavo (K). Imediatamente depois as amostras foram removidas e a parte não polimerizada foi retirada com espátula de plástico. A mensuração foi realizada com um micrômetro de precisão ± 0,1mm. Os dados foram analisados usando ANOVA One-Way e ANOVA Two-Way e teste-t com significância de 0,05. Os grupos T1-K, S1-K, F1-K, F1-G, F2-G e T1-G mostraram resultados de profundidade de polimerização compatíveis com recomendações de fabricante. As fontes de luz G e K não apresentaram diferença (p = 0,068), mas entre os grupos (O2-G) (O2-K) (p = 0,004) houve diferença. Não foram encontradas diferenças entre as resinas (P-K p = 0,059), mas houve: grupo (F-K p =&lt; 0,050), entre resinas-K (p =&lt; 0,050), entre grupos (P-G) (F-G) e resinas-G (p =&lt; 0,050). Resinas fluidas (S2 e T2) apresentaram resultados de profundidade de cura superior a outras. A composição do material, assim como o comprimento de onda, pode ter influenciado nos resultados.

Effect of bioactive glass pretreatment on the durability of dentin bonding interface

To study the effect of bioactive glass (BG) on the dentin bond strength and the microleakage of hybrid layer. In the study, 30 dentin planes were prepared from the third molars with no caries and equally assigned to the control group, BG group, and sodium trimetaphosphate (STMP)-polyacrylic acid (PAA)-BG group (S-P-BG group), randomly. After etched with 35% phosphoric acid, the dentin planes of BG group were pretreated with 0.5 g/L BG, and the dentin planes of S-P-BG group were pretreated with 5% STMP, 5% PAA and 0.5 g/L BG. No additional pretreatment was done to the dentin planes of control group. Then the dentin planes were bonded using 3M Single Bond 2 adhesive to 3M Z350XT composite resin, and cut into 0.9 mm×0.9 mm column samples, which were stored at 37 ℃ artificial saliva (AS). After 24 hours, 1 month, and 3 months, the microtensile bond strength test was performed. The data were analyzed using one-way ANOVA and LSD method. The morphology of the bond fracture interface was observed with scanning electron microscope. Other 27 teeth were collected and the enamel layer and roots cut off, with the pulp chamber exposed. 0.1% rhodamine B was added to the 3M Single Bond 2 adhesive, and then the adhesive was applied to complete the bonding procedures as above. The teeth were stored in 37 ℃ AS for 24 hours, 1 month, 3 months, and then 0.1% sodium fluorescein solution was placed in the chambers and stained for 1 hour. Confocal laser scanning microscopy was used to observe the interface morphology and microleakage of the hybrid layer. At the end of 24 hours and 1 month, there was no significant difference in the microtensile bond strength among the three groups (P>0.05). After 3 months of soaking, the S-P-BG group [(36.91±7.07) MPa] had significantly higher microtensile bond strength than the control group [(32.73±8.06) MPa] (P=0.026); For the control group and the BG group, the microtensile bond strength significantly decreased at the end of 3 months compared with 24 hours (control group: P=0.017, BG group: P=0.01); The microtensile bond strength of S-P-BG group af the end of 3 months had no significant difference in compared with 24 hours [(37.99±7.98) MPa] (P>0.05). Observation of the fracture surface at the 24 hours showed no obvious mineralization in all the three groups. After 1 and 3 months, mineral formation was observed in BG group and S-P-BG group, and no obvious collagen exposure was observed in S-P-BG group. Confocal laser scanning microscopy revealed no obvious differences in the morphology and quantity of the resin tag in the control group, BG group and S-P-BG group. At the end of 24 hours, leakage was found in all the three groups. The microleakage of the control group increased at the end of 3 months, while the microleakage of the BG and S-P-BG groups decreased. BG pretreatment of dentin bonding interface can induce mineralization at the bonding interface and reduce the microleakage of the hybrid layer; pretreating the dentin bonding interface with STMP, PAA and BG may enhance the maintaining of the dentin bonding durability.