Volume change and viscoelastic properties of UV-curable adhesives for precise positioning during curing process and their formulation

Takahashi, Atsushi; Sekiguchi, Yu; Sato, Chiaki

doi:10.1080/00218464.2021.1950538

Cited by 6 publications

(3 citation statements)

References 22 publications

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“…The polymerization of microlenses was performed in approximately 30 min using an ultraviolet (UV) lamp operating at a wavelength of around 365 nm and a power density of 65 mW/cm 2 (on a lens sample). A constant shrinkage ratio of 7.69% in volume was identified for the fully polymerized microlenses, which kept almost unchanged contact angle and lens profile as those before polymerization 34,35 (see Fig. 2f and Materials and methods).…”

Section: Resultsmentioning

confidence: 83%

Liquid-shaped microlens for scalable production of ultrahigh-resolution optical coherence tomography microendoscope

Xu,

Guan,

Abbasi

et al. 2024

Commun Eng

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Endoscopic optical coherence tomography (OCT) is a valuable tool for providing diagnostic images of internal organs and guiding interventions in real time. Miniaturized OCT endoscopes are essential for imaging small and convoluted luminal organs while minimizing invasiveness. However, current methods for fabricating miniature fiber probes have limited ability to correct optical aberrations, leading to suboptimal imaging performance. Here we introduce a liquid shaping technique for the rapid and scalable fabrication of ultrathin and high-performance OCT microendoscopes suitable for minimally invasive clinical applications. This technique enables the flexible customization of freeform microlenses with sub-nanometer optical surface roughness by regulating the minimum energy state of curable optical liquid on a wettability-modified substrate and precisely controlling the liquid volume and physical boundary on a substrate. Using this technique, we simultaneously fabricated 800-nm OCT microendoscopes with a diameter of approximately 0.6 mm and evaluated their ultrahigh-resolution imaging performance in the esophagus of rats and the aorta and brain of mice.

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Section: Resultsmentioning

confidence: 83%

Liquid-shaped microlens for scalable production of ultrahigh-resolution optical coherence tomography microendoscope

Xu,

Guan,

Abbasi

et al. 2024

Commun Eng

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“…The heat flow detected by DSC associated with the transition in adhesives is a function of time and temperature, 9 which gives a quantitative measurement of the extent of reaction 10,11 . Using the DSC technique to understand the curing of epoxy resins has been reported in several works and the autocatalysis mechanism has also been discussed 12–16 …”

Section: Introductionmentioning

confidence: 99%

“…10,11 Using the DSC technique to understand the curing of epoxy resins has been reported in several works and the autocatalysis mechanism has also been discussed. [12][13][14][15][16] During the curing process of adhesives, complex chemical and thermal reactions take place. To achieve expected physical and mechanical properties, the nature of these reactions has to be understood, and an accurate kinetics model should be found for the used adhesive.…”

Section: Introductionmentioning

confidence: 99%

Modeling the curing kinetics of two thermoset adhesives under varying temperature conditions

Zhang,

Liu,

Xia

et al. 2023

J of Applied Polymer Sci

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This paper presents detailed curing kinetics models for two thermoset adhesives. The cure kinetics were characterized using differential scanning calorimetry in both anisothermal and isothermal modes. The Sestak–Berggren autocatalytic model was applied to describe the anisothermal cure kinetics of the two adhesives with the Malek and undetermined coefficients methods determining their kinetic parameters. The Kamal autocatalytic model was adopted for the isothermal curing processes with the Kenny analytical‐graphical method determining the kinetic parameters. A modified Kamal model was developed by introducing a concept of the maximum degree of cure (DOC) and temperature‐depended kinetic parameters to describe the isothermal cure kinetics of the adhesive with a typical exothermic peak, and an extended Kamal model was further proposed by adding an initial‐phase‐control term to the modified Kamal model to describe the isothermal cure kinetics of the adhesive with two exothermic peaks. The results showed that the presented curing kinetics models with the determined parameters can precisely predict the evolutions of the DOC of the two thermoset adhesives in both anisothermal and isothermal modes.

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Influence of the cure state on mechanical properties of an epoxy‐based adhesive: Experimental characterization and numerical simulation

Teixeira

Akhavan‐Safar

Carbas

et al. 2021

Polymers for Advanced Techs

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Heat curing epoxy‐based adhesives are extensively used in primary bonded structures. The manufacturing process of joints with heat curing adhesives is commonly made with isothermal processes where a large curing time is set to guarantee the complete curing of the adhesive. The aim of the current study is to investigate the influence of the curing state on the tensile mechanical properties of a structural one‐component epoxy based adhesive. To achieve this, tensile tests on bulk adhesive dog‐bone coupons with incomplete curing were performed. The process cycle was adjusted to achieve the desired curing degree for testing. The curing process was simulated by using the Kamal kinetics model calibrated with differential scanning calorimetry (DSC) tests. The results show that the curing process is very sensitive to the curing temperature, requiring a low curing temperature to control process duration. A good correlation between the estimated curing degree and the final obtained curing measured with the Fourier‐transform infrared spectroscopy FTIR was found. Regarding the mechanical properties, the elastic modulus and the tensile strength are reduced at lower curing degrees making the material softer and more ductile. The loss in the mechanical properties shows to be consistent with the measurements performed with dynamical mechanical analyses (DMA) by measuring the evolution of the elastic modulus with the curing degree. In this way, the numerical simulation of the curing process seems to be a valuable tool to predict the final performance of adhesive, and design the curing cycle.

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Volume change and viscoelastic properties of UV-curable adhesives for precise positioning during curing process and their formulation

Cited by 6 publications

References 22 publications

Liquid-shaped microlens for scalable production of ultrahigh-resolution optical coherence tomography microendoscope

Liquid-shaped microlens for scalable production of ultrahigh-resolution optical coherence tomography microendoscope

Modeling the curing kinetics of two thermoset adhesives under varying temperature conditions

Influence of the cure state on mechanical properties of an epoxy‐based adhesive: Experimental characterization and numerical simulation

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