• Title/Summary/Keyword: adhesive thickness

Search Result 356, Processing Time 0.021 seconds

Failure Mode and Strength of Unidirectional Composite Single Lap Bonded Joints I. Experiments (일방향 복합재료 Single Lap접합 조인트의 파손 모드 및 강도 I. 실험)

  • Kim Kwang-Soo;Yoo Jae-Seok;An Jae-Mo;Jang Young-Soon
    • Composites Research
    • /
    • v.17 no.6
    • /
    • pp.14-21
    • /
    • 2004
  • Failure process, mode and strength of unidirectional composite single lap bonded joints were investigated experimentally with respect to bonding methods, those are, co-curing with and without adhesive and secondary bonding. The co-cured joint specimens without adhesive had the largest failure strength. Progressive failures along the adhesive layer occurred in the secondary bonded specimens. In the co-cured specimens with adhesive film which had better material strength and adhesion performance, delamination failure occurred and the joint strengths were less than those of secondary bonded specimens. Delamination failure did not occur in the secondary bonded specimens because of earlier crack growth and progressive failure in the adhesive layer. Therefore, failure strength of composite bonded Joints were not always proportionate to material strength and adhesion performance of the adhesive due to the weakness of delamination in composite materials. The effects of surface roughness, bondline thickness and fillets were also studied on secondary bonded specimens.

Influence of cement thickness on resin-zirconia microtensile bond strength

  • Lee, Tae-Hoon;Ahn, Jin-Soo;Shim, June-Sung;Han, Chong-Hyun;Kim, Sun-Jai
    • The Journal of Advanced Prosthodontics
    • /
    • v.3 no.3
    • /
    • pp.119-125
    • /
    • 2011
  • PURPOSE. The aim of this study was to evaluate the influence of resin cement thickness on the microtensile bond strength between zirconium-oxide ceramic and resin cement. MATERIALS AND METHODS. Thirty-two freshly extracted molars were transversely sectioned at the deep dentin level and bonded to air-abraded zirconium oxide ceramic disks. The specimens were divided into 8 groups based on the experimental conditions (cement type: Rely X UniCem or Panavia F 2.0, cement thickness: 40 or 160 ${\mu}m$, storage: thermocycled or not). They were cut into microbeams and stored in $37^{\circ}C$ distilled water for 24 h. Microbeams of non-thermocycled specimens were submitted to a microtensile test, whereas those of thermocycled groups were thermally cycled for 18,000 times immediately before the microtensile test. Three-way ANOVA and Sheffe's post hoc tests were used for statistical analysis (${\alpha}$=95%). RESULTS. All failures occurred at the resin-zirconia interface. Thermocycled groups showed lower microtensile bond strength than non-thermocycled groups (P<.001). Differences in cement thickness did not influence the resin-zirconia microtensile bond strength given the same resin cement or storage conditions (P>.05). The number of adhesive failures increased after thermocycling in all experimental conditions. No cohesive failure was observed in any experimental group. CONCLUSION. When resin cements of adhesive monomers are applied over air-abraded zirconia restorations, the degree of fit does not influence the resin-zirconia microtensile bond strength.

Light and electron microscopic morphology of the fertilized egg and fertilized egg envelope of Poropanchax normani, Poeciliidae, Teleostei

  • Dong Heui Kim
    • Applied Microscopy
    • /
    • v.52
    • /
    • pp.6.1-6.5
    • /
    • 2022
  • We examined the morphology of the fertilized egg and the fine structure of fertilized egg envelopes of Poropanchax normani belonging to the family Poeciliidae, also known as Norman's lampeye using light and electron microscopes. The fertilized eggs with narrow perivitelline space were found to be spherical and demersal, additionally containing small oil droplets in the vitelline membrane. Further, a bundle of adhesive filaments was observed to be present on one side of the fertilized egg. These filaments possessed remarkably high elasticity and were approximately 1-3mm in length. The size of the fertilized egg was determined to be about 1.49 ± 0.07mm (n=30). The outer surface appeared smooth, and adhesive filaments originating at different location of the surface of the envelope were found to be distributed around the egg envelope and were joined together to form a single long bundle in scanning electron microscopic observation. A peak-like structure formed of several straight wrinkles was observed around the micropyle. However, the complete structure of the micropyle could not be studied due to the depth at which it was located. Additionally, the total thickness of the egg envelope was ascertained to be approximately12.5-14.5㎛. The egg envelope consisted of two distinct layers, an outer electron dense layer and an inner lamellar layer, further consisting of 10 sublayers of varying thicknesses. Collectively, it was observed that the morphological characteristics of the fertilized egg, fine structures surrounding the micropyle, outer surface, adhesive structure consisting adhesive filaments, and sections of fertilized egg envelope displayed species specificity.

SHEAR BOND STREGNTHS OF ONE-BOTTLE DENTIN ABHESIVE SYSTEMS (One-Bottle system 상아질접착제의 전단결합강도 해석)

  • Cho, Byeong-Hoon;Lim, Sung-Sam;Kwon, Hyuck-Choon;Um, Chung-Moon;Son, Ho-Hyun;Bae, Kwang-Sik
    • Restorative Dentistry and Endodontics
    • /
    • v.24 no.4
    • /
    • pp.546-553
    • /
    • 1999
  • In Older to evaluate the effectiveness of 'One-bottle dentin adhesive system', the shear bond strengths of two fourth generation dentin adhesive systems and two One-bottle systems to the occlusal dentin of the freshly extracted third molars were measured by the regulation of the ISO TR 11405. The fourth generation dentin adhesive systems used in this study were Scotchbond Multi-Purpose Plus and All-Bond 2, and the One-bottle systems were Single Bond and One-Step. The effects of the thickness of hybrid layer and adhesive layer, the diameter of resin tag and the ratio between the diameter of resin tag and that of dentinal tubule were analyzed as the contributing factors of the shear bond strength of dentin bonding systems from the Scanning Electron Microscopic images. The results were as follows: 1. The shear bond strengths of Scotchbond Multi-Purpose, All-Bond 2, and Single Bond were 16.98${\pm}$3.40 MPa, 15.10${\pm}$2.77 MPa and 15.05${\pm}$3.18 MPa, respectively. There were no statistical differences(p>0.05). 2. But, the shear bond strength of One-Step were significantly lower than those of the other groups (11.81${\pm}$1.95 MPa, p<0.05). 3. The thicknesses of hybrid layer and adhesive layer of One-Step were significantly thinner than those of the other groups(p<0.05). The differences of the diameter of resin tag(p=0.0685) and the ratio between the diameter of resin tag and that of dentinal tubule(p=0.2401) were not significant among all the material groups. 4. The thickness of hybrid layer and adhesive layer might be considered as contributing factors of the she at bond strengths of dentin bonding systems, but the diameter of resin tag and the ratio between the diameter of resin tag and that of dentinal tubule might not.

  • PDF

Clinical Outcome after Arthroscopic Capsular Release for Adhesive Capsulitis of the Shoulder

  • Yoo, Jae Chul;Koh, Kyoung Hwan;Shon, Min Soo;Bae, Kyu Hwan;Lim, Tae Kang
    • Clinics in Shoulder and Elbow
    • /
    • v.21 no.3
    • /
    • pp.127-133
    • /
    • 2018
  • Background: This study was undertaken to evaluate the outcome of the arthroscopic capsular release for adhesive capsulitis of the shoulder. Methods: This study retrospectively investigated thirty shoulders in 29 patients who presented with recalcitrant adhesive capsulitis and underwent arthroscopic treatments. Other than typical findings of adhesive capsulitis, combined pathologies in the glenohumeral joint and subacromial space were evaluated by arthroscopy. Clinical evaluations were performed using the Constant's score and ranges of motion (ROM) at preoperative, 6 months postoperatively and at the final follow-up. Results: Our study included 17 women and 12 men with a mean age of 53.8 years (range, 34-74). Mean follow-up duration was 24 months (range, 12-40 months). Assessment of combined pathologies revealed that partial rotator cuff tear of less than 25% thickness, was most common (overall 83.3%; with bursal 57% and articular 23%). Subacromial synovitis and adhesion were also frequent (53.3%). The Constant score and ranges of motion significantly improved at the final follow-up, compared with preoperative levels. However, clinical results at 6 months postoperatively were found to be significantly inferior to those observed at the final follow-up ($p{\leq}0.001$ for all factors). Functional impairment was the major complaint in 59.3% patients at the 6 months follow-up. Conclusions: Although arthroscopic capsular release yielded favorable outcome at the mean 24 months follow-up, pain and motion limitations at 6-month postoperatively persisted in more than 50% of our patients. While combined pathologies were commonly encountered during arthroscopy, although their effects on surgical outcome in adhesive capsulitis remains unclear in this study.

Fluoride Release of Giomer and Compomer Through the Dental Adhesive Layer (자이오머와 컴포머의 치과용 접착제를 통한 불소 유리에 관한 연구)

  • Hwang, Minseon;Park, Howon;Lee, Juhyun;Seo, Hyunwoo
    • Journal of the korean academy of Pediatric Dentistry
    • /
    • v.44 no.2
    • /
    • pp.180-187
    • /
    • 2017
  • The aim of this study was to investigate and compare fluoride release of giomer (Beautifil Injectable), compomer ($Dyract^{(R)}$ XP), and composite resin ($Filtek^{TM}$ Z350XT) through adhesive (Scotchbond Multi-Purpose) layer. A total of 20 cylindrical specimens (7 mm in diameter and 2 mm in thickness) of giomer, compomer and composite resin were prepared according to the manufacturers' instruction (10 with adhesive and 10 without adhesive). These specimens were immersed individually in 2 mL of deionized water at $37^{\circ}C$. The amount of fluoride release was measured on the $1^{st}$, $3^{rd}$, $7^{th}$, $14^{th}$, $21^{st}$, and $28^{th}$ day. To confirm uniform application of the adhesive layer, additional 18 specimens with adhesive were prepared and evaluated by scanning electron microscope. The giomer and compomer groups with adhesive applied showed no fluoride release until the $3^{rd}$ day. However, from the $7^{th}$ day, fluoride was detected. The application of dentin adhesive did not completely prevent fluoride release from giomer or compomer. Fluoride release was significantly (p < 0.05) reduced through the adhesive layer. The reduction of fluoride release was more remarkable on the giomer.

Adhesive bonding using thick polymer film of SU-8 photoresist for wafer level package

  • Na, Kyoung-Hwan;Kim, Ill-Hwan;Lee, Eun-Sung;Kim, Hyeon-Cheol;Chun, Kuk-Jin
    • Journal of Sensor Science and Technology
    • /
    • v.16 no.5
    • /
    • pp.325-330
    • /
    • 2007
  • For the application to optic devices, wafer level package including spacer with particular thickness according to optical design could be required. In these cases, the uniformity of spacer thickness is important for bonding strength and optical performance. Packaging process has to be performed at low temperature in order to prevent damage to devices fabricated before packaging. And if photosensitive material is used as spacer layer, size and shape of pattern and thickness of spacer can be easily controlled. This paper presents polymer bonding using thick, uniform and patterned spacing layer of SU-8 2100 photoresist for wafer level package. SU-8, negative photoresist, can be coated uniformly by spin coater and it is cured at $95^{\circ}C$ and bonded well near the temperature. It can be bonded to silicon well, patterned with high aspect ratio and easy to form thick layer due to its high viscosity. It is also mechanically strong, chemically resistive and thermally stable. But adhesion of SU-8 to glass is poor, and in the case of forming thick layer, SU-8 layer leans from the perpendicular due to imbalance to gravity. To solve leaning problem, the wafer rotating system was introduced. Imbalance to gravity of thick layer was cancelled out through rotating wafer during curing time. And depositing additional layer of gold onto glass could improve adhesion strength of SU-8 to glass. Conclusively, we established the coating condition for forming patterned SU-8 layer with $400{\mu}m$ of thickness and 3.25 % of uniformity through single coating. Also we improved tensile strength from hundreds kPa to maximum 9.43 MPa through depositing gold layer onto glass substrate.

Studies on the Vibration Controllability of Smart Structure Depending on the Interfacial Adhesion Properties of Composite Materials (복합재료내의 계면 접착 특성에 따른 지능형 구조물의 진동제어에 관한 연구)

  • 한상보;박종만;차진훈
    • Journal of KSNVE
    • /
    • v.8 no.6
    • /
    • pp.1093-1102
    • /
    • 1998
  • The success of controllability of smart structures depends on the quality of the bonding along the interface between the main structure and the attached sensing and acuating elements. Generally, the analysis procedures neglect the effect of the interfacial bond layer or assume that this bond layer behaves like viscoelastic material. Three different bond layers. two modified epoxy adhesives, and one isocyanate adhesive were prepared for their toughness and moduli. Bond layer of the chosen adhesive provides an almost perfect bonding condition between the composite structure and the PZT while bended significantly like arrow-shape. The perfect bonding condition is tested by considering various material properties of the bond layers. and based on this perfect bonding condition, the effects of the interfacial bond layer on the dynamic behavior and controllability of the test structure is experimentally studied. Once the perfect bonding condition is achieved. dynamic effects of the bond layer itself on the dynamic characteristics of the main structure is negligible. but the contribution of the attached PZT elements on the stiffness of the multi-layered structure becomes significant when the thickness of the bond layer increased.

  • PDF

Strain Transmission Characteristics of Packaged Fiber Bragg Grating Sensors for Structural Health Monitoring

  • Cho, Sung-In;Yoo, Seung-Jae;Kim, Eun-Ho;Lee, In;Kwon, Il-Bum;Yoon, Dong-Jin
    • Journal of the Korean Society for Nondestructive Testing
    • /
    • v.30 no.3
    • /
    • pp.236-243
    • /
    • 2010
  • Fiber Bragg grating(FBG) sensor arrays can be used to monitor the mechanical behavior of the large composite structures such as wind turbine rotor blades and aircrafts. However, brittle FBG sensors, especially multiplexed FBG sensors are easily damaged when they are installed in the flexible structures. As a protection of brittle FBG sensors, epoxy packaged FBG sensors have been presented in this paper. Finite element analysis and experiments were performed to evaluate the effects of adhesives, packaging materials and the bonding layer thickness on the strain transmission. Two types of epoxy were used for packaging FBG sensors and the sensor probes were attached with various bonding layer thickness. It was observed that thin bonding layer with high elastic modulus ratio of the adhesive to packaging provided good strain transmission. However, the strain transmission was significantly decreased when elastic modulus of the adhesive was much lower than the packaged FBG sensor probe's one.