Room Temperature-Stable, One-Component, Flexible Epoxy Adhesives

2017 ◽  
pp. 161-174
Keyword(s):  
Room Temperature ◽  
Epoxy Adhesives

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

2010 ◽  
Vol 132 (3) ◽  
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.

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

2011 ◽  
Vol 133 (3) ◽  
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.

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

Polymers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3879
Author(s):  
Nigel Van de Velde ◽  
Saška Javornik ◽  
Tilen Sever ◽  
Danaja Štular ◽  
Matic Šobak ◽  
...  
Keyword(s):  
Bisphenol A ◽  
Room Temperature ◽  
Acetic Acid Solution ◽  
Transformation Process ◽  
Metal Component ◽  
Boundary Area ◽  
Epoxy Adhesives ◽  
Epoxidation Reaction ◽  
Temperature Optimization

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.

Room Temperature Curing Epoxy Adhesives for Elevated Temperature Service

1987 ◽  
Vol 22 (3) ◽  
pp. 227-251 ◽  
Author(s):  
H. Dodiuk ◽  
S. Kenig ◽  
I. Liran
Keyword(s):  
Elevated Temperature ◽  
Room Temperature ◽  
Epoxy Adhesives

High Temperature Resistance of Epoxy Adhesives under the Room-Temperature Curing

2011 ◽  
Vol 284-286 ◽  
pp. 1804-1807 ◽  
Author(s):  
De Long Ran ◽  
Jian Jun Xie ◽  
Kai Huang ◽  
Shui Ping Yin ◽  
Sheng Ming Chen ◽  
...  
Keyword(s):  
High Temperature ◽  
Absorption Band ◽  
Epoxy Resin ◽  
Room Temperature ◽  
Loss Modulus ◽  
Technological Parameters ◽  
Temperature Resistance ◽  
Epoxy Adhesives ◽  
High Temperature Resistance ◽  
Long Chain

High-temperature resistant epoxy adhesives cured under room-temperature becomes more and more important in many industries such as aerospace and aviation, the locomotive and diesel, etc. In this paper three self-made amine-based mannich-amide was mixed with E-44 epoxy resin under the same technological parameters, and the epoxy adhesives cured by the three amine-based mannich-amides under room-temperature are tested by FTIR, TGA and DMA. Results of TGA show a quicker drop in weight occurrence within 150-250°C for epoxy networks cured by multiamine-based mannich amides than the long-chain alkyl one. Results of FTIR show completely curing of epoxy adhesives cured by mannich amides under room temperature and the height of absorption band 1502cm-1(C-N) is much lower after 12h under 150°C,200°C atmosphere than 25°C. Results of DMA show that the Tg determined by DMA has an order EP AN2(89.9°C) >EP AN1(89.7°C)>EP AN3(80.8°C). In the rest results of DMA, the EP-AN3 system has the biggest storage modulus (E’) within 100-150°C while the EP-AN3 system has the smallest loss modulus(E”) within 100-150°C. As a whole, the epoxy adhesives cured by AN3 under room-temperature have the best high temperature resistance.

Dependence of Intergranular Fracture on Boundary Topography and Cohesion

1973 ◽  
Vol 31 ◽  
pp. 150-151
Author(s):  
J. E. Doherty ◽  
A. F. Giamei ◽  
B. H. Kear ◽  
C. W. Steinke
Keyword(s):  
Grain Boundary ◽  
Room Temperature ◽  
Nickel Base Superalloy ◽  
Boundary Shear ◽  
Room Temperature Ductility ◽  
Solid Solution Matrix ◽  
Nickel Base ◽  
Solution Matrix ◽  
Different Levels ◽  
Base Superalloy

Recently we have been investigating a class of nickel-base superalloys which possess substantial room temperature ductility. This improvement in ductility is directly related to improvements in grain boundary strength due to increased boundary cohesion through control of detrimental impurities and improved boundary shear strength by controlled grain boundary micros true tures.For these investigations an experimental nickel-base superalloy was doped with different levels of sulphur impurity. The micros tructure after a heat treatment of 1360°C for 2 hr, 1200°C for 16 hr consists of coherent precipitates of γ’ Ni3(Al,X) in a nickel solid solution matrix.

Hepatocyte Alterations in Guinea Pigs FED Polychlorinated Biphenyls (PCBs), Dibenzodioxins (PCDD), AND DIBENZOFURANS (PCDF)

1982 ◽  
Vol 40 ◽  
pp. 56-57
Author(s):  
J. N. Turner ◽  
D. N. Collins
Keyword(s):  
Guinea Pigs ◽  
Room Temperature ◽  
Dose Group ◽  
Methyl Cellulose ◽  
Uranyl Acetate ◽  
Target Organ ◽  
Office Building ◽  
Lead Citrate ◽  
Control Groups ◽  
Cooling Fluid

A fire involving an electric service transformer and its cooling fluid, a mixture of PCBs and chlorinated benzenes, contaminated an office building with a fine soot. Chemical analysis showed PCDDs and PCDFs including the highly toxic tetra isomers. Guinea pigs were chosen as an experimental animal to test the soot's toxicity because of their sensitivity to these compounds, and the liver was examined because it is a target organ. The soot was suspended in 0.75% methyl cellulose and administered in a single dose by gavage at levels of 1,10,100, and 500mgm soot/kgm body weight. Each dose group was composed of 6 males and 6 females. Control groups included 12 (6 male, 6 female) animals fed activated carbon in methyl cellulose, 6 males fed methyl cellulose, and 16 males and 10 females untreated. The guinea pigs were sacrificed at 42 days by suffocation in CO2. Liver samples were immediately immersed and minced in 2% gluteraldehyde in cacadylate buffer at pH 7.4 and 4°C. After overnight fixation, samples were postfixed in 1% OsO4 in cacodylate for 1 hr at room temperature, embedded in epon, sectioned and stained with uranyl acetate and lead citrate.

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