Explore chapters and articles related to this topic
Electron-beam initiated cationic polymerization
Published in Y. Yagci, M.K. Mishra, O. Nuyken, K. Ito, G. Wnek, Tailored Polymers & Applications, 2020
James V. Crivello, Thomas C. Walton, Ranjit Malik
Silicone-epoxy monomers VI-VIII were prepared as previously described [12, 13] from the corresponding silane and 4-vinylcyclohexene oxide (3-vinyl-7-oxabicyclo[4.1.0]heptane) using the hydrosilation reaction. The resins were characterized by various techniques. Infrared spectra were obtained on a Buck Model 500 Infrared Spectrometer. 1H NMR spectra were recorded on a Varian 500 MHz Nuclear Magnetic Resonance Spectrometer. Elemental analyses were performed by Quantitative Analysis, Bound Brook, NJ. Other epoxy resins, Tactix 123, Epon resins (Epon 862; bisphenol-A diglycidyl ether and Epon 825; bisphenol-F diglycidyl ether) and 3,4-epoxycyclohexylmethyl 3′,4′-epoxycyclohexanecarboxylate (UVR 6105) were obtained respectively, from the Dow Chemical, Shell Chemical and the Union Carbide corporations and used without further purification. The onium salt initiators (4-n-octyloxyphenyl)phenyliodonium hexafluoroantimonate (IOC-8) [14] and S,S-diphenyl-S(4-thiophenoxyphenyl)sulfonium hexafluoroantimonate (SS) [15], were prepared as previously reported. AG193P plain weave 3K (AS-4) carbon fiber fabric was supplied by the Hercules Corporation.
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.