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Biomaterials of Natural Origin in Regenerative Medicine
Published in Severian Dumitriu, Valentin Popa, Polymeric Biomaterials, 2020
Vijay Kumar Nandagiri, Valeria Chiono, Piergiorgio Gentile, Franco Maria Montevecchi, Gianluca Ciardelli
In another approach, Segura et al. have shown the construction of hydrogels based on cross-linked HA with poly (ethylene glycol) diglycidyl ether. They also have incorporated collagen into the cross-linked network in order to support cellular adhesion in vitro. This construct possessed low water content and low degradation rate and it could be topographically patterned during gelation. The authors have also functionalized HA and HA/collagen scaffolds by introducing biotin into the HA backbone before cross-linking reaction in order to introduce avidin-streptavidin and neutravidin molecules on the surface of hydrogel which can be widely employed for tissue engineering applications (Segura et al. 2005).
Structural Adhesives: Today’s State of the Art
Published in Gerald L. Schneberger, Adhesives in Manufacturing, 2018
Resorcinol diglycidyl ether (RDGE) and the triglycidyl ether of p-amino phenol (Ciba’s Araldite 0500) are two low-molecular-weight, polyfunctional epoxy resins used in many high-performance tape and liquid adhesives. As expected from their compact structure, the resins are able to reduce viscosity, improve hot strength, and increase reaction rates. Surprisingly, these two high-functionality resins also increase shock resistance. But Araldite 0500 is relatively expensive and has a limited shelf life even in the absence of catalysts. Resorcinol diglycidyl ether is also expensive but, more importantly, it is a toxic and very dangerous liquid, causing skin burns, nausea, and severe “poison ivy” reactions to personnel manufacturing or using adhesives containing even small quantities of this resin.
Inhalation of polycarbonate emissions generated during 3D printing processes affects neuroendocrine function in male rats
Published in Journal of Toxicology and Environmental Health, Part A, 2023
Kristine Krajnak, Mariana Farcas, Walter McKinney, Stacey Waugh, Kyle Mandler, Alycia Knepp, Mark Jackson, Diana Richardson, MaryAnne Hammer, Joanna Matheson, Treye Thomas, Yong Qian
Bisphenol A and bisphenol A diglycidyl ether were also assessed in the 3DP-generated emissions. Sampling for these substances occurred under the same conditions used to generate the animal exposures, except the animals were not in the chamber. The total concentration of particulate in each sample was approximately 600 µg/m3. The emissions were collected onto glass fiber filters (SKC lot #21600-7E5-274; n = 6 samples) and filters analyzed by BVNA labs (Novi, MI). Once received by BVNA, the filters were placed in separate glass test tubes and each sample cassette was wiped with a glass fiber filter wetted with 100% ethanol. Sample filters and wipes were extracted in 3 ml acetonitrile and then placed on a mechanical flatbed shaker for 30 min. An aliquot (18 µl) was transferred to individual auto-sampler vials for analysis by HPLC (Thermo Fisher Vanquish UHPLC with a Zorbax ODS C18, 5 µM 250 mm x 4.4 mm internal diameter). Samples were analyzed using a wavelength of 230 nm and read time of 22 min/sample. The average level of bisphenol in the samples was 5.3 ± 0.18 µg/m3. Using a mass particle distribution model to determine particle deposition in the nose, trachea, alveola and lung (where the tidal vol is 1.7 ml, the breathing rate is 120 breaths/min and the exposure time is 240 min), the estimated cumulative deposition of bisphenol A in the entire respiratory tract was 36 ng on day 1, 536 ng on day 15 and 1.072 µg on day 30. Bisphenol A diglycidyl ether was not detectable in any of the samples.
Estimating Moisture Resistance of asphalt mixture containing epoxy resin using Surface Free Energy Method and Modified Lottman test
Published in International Journal of Pavement Engineering, 2022
Hossein Bahmani, Hamed Khani Sanij, Farideddin Peiravian
Epoxy resins are a group of polymers that require another component, named ‘hardener’, to enhance their properties. The required percentages of hardeners vary among different epoxy resins and are specified by their manufacturers. The reaction process between an epoxy resin and its hardener is called ‘curing’. The time during which the reactions between epoxy resin and its hardener is completed under specified conditions is called ‘curing time’, also specified by its manufacturer (Augustsson 2004). The epoxy resin used in this study was a type of Bisphenol-A Diglycidyl Ether (commercially known as YD128), produced by Kukdo Chemical Company. The hardener used in this study was Cyloalphatic Amine (commercially known as KH-816), also produced by the same company. Properties of the epoxy resin and its hardener are presented in Tables 4 and 5, respectively (the information has been provided by the producer). According to the producer, 60 g of hardener was needed for every 100 g of the epoxy resin, with a curing time of 1 h at 110 °C, and then 1 day at 25°C.
EUROCORR 2020: ‘closing the gap between industry and academia in corrosion science and prediction’: part 4
Published in Corrosion Engineering, Science and Technology, 2021
L. Traverse (University of Manchester, UK) spoke on, ‘Solvent uptake, plasticisation and carbamation: the effects upon the resistance characteristics of a model epoxy amine coating.’ ‘Carbamation’ is a process that competes with the amine-epoxy reaction by the amine reacting with carbon dioxide and water, giving poor inter-coat adhesion. Epoxy amine polymer films were synthesised using Meta-xylylenediamine and bisphenol F diglycidyl ether, then exposed to water, methanol or dichloromethane. Solvent resistance was determined by differential scanning calorimetry (DSC), optical microscopy and gravimetric measurements. Destructive effects from solvent interaction were determined by comparison with an unexposed sample. In all cases, solvent interaction resulted in a lower Tg value with variable reversibility upon drying. Water diffusion was assessed by dynamic vapour sorption (DVS), showing consistent kinetics of water uptake over multiple ageing cycles; diffusion rates being more environmental humidity dependent than plasticisation. Possible carbamation of amine hardeners during polymerisation, disrupting the stoichiometry, was investigated. Environmental effects during polymerisation were identified using DVS, DSC and gravimetric uptake. Carbamation was observed by optical microscopy and IR spectroscopy. As expected, both water and CO2 were detrimental, humidity playing a greater role in deterioration than CO2 alone.