Bio-Based Epoxy Adhesives with Lignin-Based Aromatic Monophenols Replacing Bisphenol A

A bio-epoxy surface adhesive for adherence of the metal component species to glass substrate with desirable adhesion strength, converted controlled removal upon request, and bio-based resource inclusion was developed. For the development of resin, three different lignin-based aromatic monophenols, guaiacol, cresol, and vanillin, were used in the chemical epoxidation reaction with epichlorohydrin. The forming transformation process was studied by viscoelasticity, in situ FTIR monitoring, and Raman. Unlike other hydroxyl phenyls, guaiacol showed successful epoxide production, and stability at room temperature. Optimization of epoxide synthesis was conducted by varying NaOH concentration or reaction time. The obtained product was characterized by nuclear magnetic resonance and viscosity measurements. For the production of adhesive, environmentally problematic bisphenol A (BPA) epoxy was partially substituted with the environmentally acceptable, optimized guaiacol-based epoxy at 20, 50, and 80 wt.%. Mechanics, rheological properties, and the possibility of adhered phase de-application were assessed on the bio-substitutes and compared to commercially available polyepoxides or polyurethanes. Considering our aim, the sample composed of 80 wt.% bio-based epoxy/20 wt.% BPA thermoset was demonstrated to be the most suitable among those analyzed, as it was characterized by low BPA, desired boundary area and recoverability using a 10 wt.% acetic acid solution under ultrasound.

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Epoxy Adhesives Modified With Nano- and Microparticles for In Situ Timber Bonding: Effect of Environment on Mechanical Properties and Moisture Uptake

Journal of Engineering Materials and Technology ◽

10.1115/1.4001836 ◽

2010 ◽

Vol 132 (3) ◽

Cited By ~ 1

Author(s):

Z. Ahmad ◽

M. P. Ansell ◽

D. Smedley

Keyword(s):

Room Temperature ◽

Environmental Stability ◽

Moisture Uptake ◽

Adhesively Bonded ◽

Block Shear ◽

Epoxy Adhesives ◽

Bonding Effect ◽

Timber Connections ◽

C 30

The environmental stability of three room temperature cure epoxy adhesives was evaluated following exposure to temperatures of 20°C, 30°C, and 50°C at 95%RH, to 50°C in air and soaked in water for up to 90 days. The adhesives contained nano- and microparticles and were especially formulated for bonded-in timber connections, and the properties of bulk adhesives and adhesively bonded block shear specimens were evaluated. After 90 days of aging the results demonstrate critical temperature effects controlled by the glass transition temperature. The apparent free volume for all the adhesives remains constant as moisture is absorbed but plasticization takes place at high temperature and relative humidity, evidenced by the increased elongation and yield observed by strain values and scanning electron microscope. Exposure at 50°C in air causes the adhesives to postcure enhancing strength but high humidity causes degradation. Nanofiller additions enhance environmental stability but the addition of microparticles provides better moisture resistance.

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Epoxy Adhesives Modified With Nano- and Microparticles for In Situ Timber Bonding: Fracture Toughness Characteristics

Journal of Engineering Materials and Technology ◽

10.1115/1.4003776 ◽

2011 ◽

Vol 133 (3) ◽

Cited By ~ 2

Author(s):

Z. Ahmad ◽

M. P. Ansell ◽

D. Smedley

Keyword(s):

Fracture Toughness ◽

Room Temperature ◽

Charpy Impact ◽

Charpy Impact Test ◽

Single Edge ◽

Notched Specimens ◽

Epoxy Adhesives ◽

Adhesive Formulation ◽

Made In

Adhesives used for bonded-in steel or composite pultruded rods and plate to make connections in timber structures are commonly room temperature cure adhesives. The room temperature cure, applied without pressure, thixotropic, and shear thinning characteristics of the adhesives, is for ease of application when repairs and reinforcement are being made in situ in the field. The room temperature cure adhesive may not fully cross-link and this may cause brittleness. Therefore to improve the toughness properties of such adhesives, nanoparticles can be added. This paper reports the experimental investigation carried out on the fracture toughness of three thixotropic and room temperature cured epoxy-based adhesives formulated specifically for in situ timber bonding, namely, CB10TSS (standard adhesive), Albipox is CB10TSS with the addition of nanodispersed carboxyl-terminated butadiene acrylonitrile (CTBN), and Timberset is an adhesive formulation containing ceramic microparticles. The fracture toughness behavior of the adhesives was investigated using the Charpy impact test on unnotched and notched specimens conditioned at 20∘C/65%RH to evaluate notch sensitivity, and a single-edge notched beam (SENB) test was performed to evaluate the stress intensity factor KIC. The fracture surfaces were investigated using scanning electron microscopy. Under high impact rate, toughness was in the order of CB10TSS, Albipox, and Timberset. CB10TSS and Albipox were found to be ductile in the unnotched state and brittle when notched. Timberset was brittle in both unnotched and notched states. Under low strain rate (SENB) conditions the addition of CTBN significantly improved the fracture toughness of Albipox compared with CB10TSS and Timberset. Examination of the topography of the fractured surface revealed marked changes in crack propagation due to the addition of nano- or microfillers accounting for the variation in toughness properties.

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Otoconia perfect/imperfect crystals

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100167949 ◽

1994 ◽

Vol 52 ◽

pp. 42-43

Author(s):

César D. Fermin ◽

Dale Martin

Keyword(s):

Image Processing ◽

Room Temperature ◽

Phosphotungstic Acid ◽

Gallus Domesticus ◽

Crystal Matrix ◽

Organic Templates ◽

Image Processing Algorithms ◽

Processing Algorithms ◽

Diffraction Patterns

Otoconia of higher vertebrates are interesting biological crystals that display the diffraction patterns of perfect crystals (e.g., calcite for birds and mammal) when intact, but fail to produce a regular crystallographic pattern when fixed. Image processing of the fixed crystal matrix, which resembles the organic templates of teeth and bone, failed to clarify a paradox of biomineralization described by Mann. Recently, we suggested that inner ear otoconia crystals contain growth plates that run in different directions, and that the arrangement of the plates may contribute to the turning angles seen at the hexagonal faces of the crystals.Using image processing algorithms described earlier, and Fourier Transform function (2FFT) of BioScan Optimas®, we evaluated the patterns in the packing of the otoconia fibrils of newly hatched chicks (Gallus domesticus) inner ears. Animals were fixed in situ by perfusion of 1% phosphotungstic acid (PTA) at room temperature through the left ventricle, after intraperitoneal Nembutal (35mg/Kg) deep anesthesia. Negatives were made with a Hitachi H-7100 TEM at 50K-400K magnifications. The negatives were then placed on a light box, where images were filtered and transferred to a 35 mm camera as described.

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In Situ Localization of PPAR Gamma and Uncoupling Protein in Mouse Embryo Sections Using Digoxigenin-Labeled Riboprobes

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100162624 ◽

1996 ◽

Vol 54 ◽

pp. 32-33

Author(s):

C. Jennermann ◽

S. A. Kliewer ◽

D. C. Morris

Keyword(s):

Alkaline Phosphatase ◽

Room Temperature ◽

Uncoupling Protein ◽

Ppar Gamma ◽

Nuclear Hormone Receptor ◽

Full Length ◽

Northern Analysis ◽

Peroxisome Proliferator

Peroxisome proliferator-activated receptor gamma (PPARg) is a member of the nuclear hormone receptor superfamily and has been shown in vitro to regulate genes involved in lipid metabolism and adipocyte differentiation. By Northern analysis, we and other researchers have shown that expression of this receptor predominates in adipose tissue in adult mice, and appears first in whole-embryo mRNA at 13.5 days postconception. In situ hybridization was used to find out in which developing tissues PPARg is specifically expressed.Digoxigenin-labeled riboprobes were generated using the Genius™ 4 RNA Labeling Kit from Boehringer Mannheim. Full length PPAR gamma, obtained by PCR from mouse liver cDNA, was inserted into pBluescript SK and used as template for the transcription reaction. Probes of average size 200 base pairs were made by partial alkaline hydrolysis of the full length transcripts. The in situ hybridization assays were performed as described previously with some modifications. Frozen sections (10 μm thick) of day 18 mouse embryos were cut, fixed with 4% paraformaldehyde and acetylated with 0.25% acetic anhydride in 1.0M triethanolamine buffer. The sections were incubated for 2 hours at room temperature in pre-hybridization buffer, and were then hybridized with a probe concentration of 200μg per ml at 70° C, overnight in a humidified chamber. Following stringent washes in SSC buffers, the immunological detection steps were performed at room temperature. The alkaline phosphatase labeled, anti-digoxigenin antibody and detection buffers were purchased from Boehringer Mannheim. The sections were treated with a blocking buffer for one hour and incubated with antibody solution at a 1:5000 dilution for 2 hours, both at room temperature. Colored precipitate was formed by exposure to the alkaline phosphatase substrate nitrobluetetrazoliumchloride/ bromo-chloroindlylphosphate.

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Cross-linked nonwoven fibers produced by room temperature cure blowing and in situ photopolymerization: 'Greener' approach to high performance nonwovens

10.1021/scimeetings.0c01646 ◽

2020 ◽

Author(s):

Aditya Banerji ◽

Kailong Jin ◽

Mahesh Mahanthappa ◽

Christopher J Ellison

Keyword(s):

High Performance ◽

Room Temperature ◽

Nonwoven Fibers

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Single Crystal Growth of High-Pressure Phases of Ice and Salt Hydrate Far Below the Original Melting Point by Mixing Alcohol: Crystal Structure Determination of Magnesium Chloride Heptahydrate

10.26434/chemrxiv.11345063.v2 ◽

2020 ◽

Author(s):

Keishiro Yamashita ◽

Kazuki Komatsu ◽

Hiroyuki Kagi

Keyword(s):

Crystal Structure ◽

High Pressure ◽

Crystal Growth ◽

Single Crystal ◽

Room Temperature ◽

Growth Technique ◽

Salt Hydrate ◽

X Ray

An crystal-growth technique for single crystal x-ray structure analysis of high-pressure forms of hydrogen-bonded crystals is proposed. We used alcohol mixture (methanol: ethanol = 4:1 in volumetric ratio), which is a widely used pressure transmitting medium, inhibiting the nucleation and growth of unwanted crystals. In this paper, two kinds of single crystals which have not been obtained using a conventional experimental technique were obtained using this technique: ice VI at 1.99 GPa and MgCl<sub>2</sub>·7H<sub>2</sub>O at 2.50 GPa at room temperature. Here we first report the crystal structure of MgCl2·7H2O. This technique simultaneously meets the requirement of hydrostaticity for high-pressure experiments and has feasibility for further in-situ measurements.

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Faculty Opinions recommendation of Induction of mammary gland ductal hyperplasias and carcinoma in situ following fetal bisphenol A exposure.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1058742.510659 ◽

2006 ◽

Author(s):

Ruth Keri

Keyword(s):

Mammary Gland ◽

Bisphenol A ◽

Carcinoma In Situ

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Lithium-mediated Ferration of Fluoroarenes

CHIMIA International Journal for Chemistry ◽

10.2533/chimia.2020.866 ◽

2020 ◽

Vol 74 (11) ◽

pp. 866-870

Author(s):

Lewis C. H. Maddock ◽

Alan Kennedy ◽

Eva Hevia

Keyword(s):

Hydrogen Atom ◽

Organometallic Chemistry ◽

Room Temperature ◽

Structural Elucidation ◽

Side Reactions ◽

Metal Base ◽

Lithium Amide ◽

Mixed Metal ◽

Important Challenge

While fluoroaryl fragments are ubiquitous in many pharmaceuticals, the deprotonation of fluoroarenes using organolithium bases constitutes an important challenge in polar organometallic chemistry. This has been widely attributed to the low stability of the in situ generated aryl lithium intermediates that even at –78 °C can undergo unwanted side reactions. Herein, pairing lithium amide LiHMDS (HMDS = N{SiMe3}2) with FeII(HMDS)2 enables the selective deprotonation at room temperature of pentafluorobenzene and 1,3,5-trifluorobenzene via the mixed-metal base [(dioxane)LiFe(HMDS)3] (1) (dioxane = 1,4-dioxane). Structural elucidation of the organometallic intermediates [(dioxane)Li(HMDS)2Fe(ArF)] (ArF = C6F5, 2; 1,3,5-F3-C6H2, 3) prior electrophilic interception demonstrates that these deprotonations are actually ferrations, with Fe occupying the position previously filled by a hydrogen atom. Notwithstanding, the presence of lithium is essential for the reactions to take place as Fe II (HMDS)2 on its own is completely inert towards the metallation of these substrates. Interestingly 2 and 3 are thermally stable and they do not undergo benzyne formation via LiF elimination.

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Enhanced room temperature ionic conductivity of the LiBH4·1/2NH3–Al2O3 composite

Chemical Communications ◽

10.1039/d0cc07296f ◽

2021 ◽

Author(s):

Ruixue Zhang ◽

Wanying Zhao ◽

Zhenzhen Liu ◽

Shanghai Wei ◽

Yigang Yan ◽

...

Keyword(s):

Ionic Conductivity ◽

Room Temperature ◽

Ion Conductivity ◽

Al2o3 Composite

In situ formed amorphous LiBH4·1/2NH3 on the surface of Al2O3 nanoparticles results in an enhanced ion conductivity of 1.1 × 10−3 S cm−1 at room temperature.

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