scholarly journals Tailoring Epoxy Resin Foams by Pre-Curing with Neat Amine Hardeners and Its Derived Carbamates

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1348
Author(s):  
Christian Bethke ◽  
Sebastian Manfred Goller ◽  
Uy Lan Du Ngoc ◽  
Simon Tino Kaysser ◽  
Volker Altstädt ◽  
...  
Keyword(s):  
Epoxy Resin ◽  
High Performance ◽  
Cell Structure ◽  
Dual Function ◽  
Curing Time ◽  
Blend Ratio ◽  
Homogeneous Cell ◽  
Curing Agents ◽  
Amine Curing ◽  
Blend Ratios

The use of amine-based carbamates with their dual function, acting as amine curing agents and CO2 blowing agents after their decomposition without by-products, are promising for ecofriendly epoxy foams as high-performance materials. However, controlling cell morphology requires a proper adjustment of the viscosity at the foaming step. The viscosity is altered not only by blending neat amine and its derived carbamate at a fixed pre-curing time, but also by changing the pre-curing time at a fixed blend ratio. Within this study, diglycidylether of bisphenol A (DGEBA) epoxy resin is mixed with different blend ratios of isophorone diamine (IPDA) and its derived carbamate (B-IPDA). The systems are characterized by DSC and rheology experiments to identify the pre-curing effects on the derived epoxy foams. Epoxy foams at a blend ratio of 30/70w IPDA/B-IPDA showed the best foam morphology and an optimum Tg compared to other blend ratios. Furthermore, it was found that both pre-curing times, 2 h and 3 h, for the 30/70w IPDA/B-IPDA system reveal a more homogeneous cell structure. The study proves that the blending of neat amine and carbamate is beneficial for the foaming performance of carbamate systems.

Studies of the Physical Properties of Cycloaliphatic Epoxy Resin Reacted with Anhydride Curing Agents

2017 ◽  
Vol 737 ◽  
pp. 248-255 ◽  
Author(s):  
Tae Hee Kim ◽  
Dae Yeon Kim ◽  
Choong Sun Lim ◽  
Bong Kuk Seo
Keyword(s):  
Physical Properties ◽  
Reaction Kinetics ◽  
Epoxy Resin ◽  
High Performance ◽  
Industrial Applications ◽  
Scanning Calorimetry ◽  
Low Viscosity ◽  
High Performance Polymer ◽  
Curing Agents ◽  
The Impact

The preparation of high performance epoxy composites for industrial applications has been extensively researched. In this report, we study the change in physical properties and reaction kinetics between epoxy resin and curing agents of similar geometry. For the experiments, celloxide 2021P, an epoxy resin having low viscosity, was blended with three different curing agents: methylhexahydropthalic acid, methyltetrahydropthalic acid, and 5-norbornene-2, 3-dicarboxylic anhydride. The amount of 1, 2-dimethylimidazole catalyst was controlled, and the highest heat flow temperature (Tpeak) was observed at around 145 °C. The impact on reaction kinetics relative to the change in heating rate was studied with differential scanning calorimetry (DSC) for each of the curing agents. The glass transition temperature (Tg) of each composition was measured with a second DSC cycle. The prepared epoxy compositions were thermally cured in a metallic mold to provide pure epoxy resins without fillers. Finally, the flexural strengths of these resins were compared to each other. The authors believe that insights into choosing an appropriate epoxy binder are useful when it comes to the overall preparation of high performance polymer composites.

Multifunctional β-amino alcohols as bio-based amine curing agents for the isocyanate- and phosgene-free synthesis of 100% bio-based polyhydroxyurethane thermosets

2016 ◽  
Vol 18 (8) ◽  
pp. 2406-2415 ◽  
Author(s):  
H. Blattmann ◽  
R. Mülhaupt
Keyword(s):  
Epoxy Resin ◽  
Amino Alcohols ◽  
Cyclic Carbonate ◽  
Raw Material ◽  
Curing Agents ◽  
Amine Curing

Novel 100% bio-based NIPU thermosets by employing bio-based epoxy resin feedstocks as raw material for cyclic carbonate monomers and amine curing agents.

scholarly journals Influence of epoxy resin curing systems and aluminium surface modification on selected properties of adhesive joints

2018 ◽  
Vol 20 (4) ◽  
pp. 26-31
Author(s):  
Małgorzata Szymiczek ◽  
Błażej Chmielnicki
Keyword(s):  
Surface Modification ◽  
Epoxy Resin ◽  
Adhesive Joints ◽  
Matrix Composites ◽  
Cycle Number ◽  
Lap Shear ◽  
Curing Agents ◽  
Amine Curing ◽  
Resin Curing ◽  
Composite Samples

Abstract The aim of the present study was to investigate the effect of epoxy resin curing agents and aluminium surface modification on the properties of adhesive joints which were subjected to aging under thermal shock conditions. Composites containing reinforced aramid and carbon fibres with aluminium flat profiles (alloy Al 5754) were tested under shear conditions. Epoxy resin (Araldite LY 1564) with amine curing agents (Aradur 3486, Aradur 3487 and Aradur 3405) was used as a matrix. Composites were made using vacuum-assisted contact lamination. The degree of degradation was assessed on the basis of lap shear strength of adhesive joints in accordance with EN ISO 1465:2009. The research showed that epoxy composite samples based on Aradur 3405 (accelerated aliphatic polyamine) and sanded surface of aluminium presented the best lap shear adhesive strength, because this composite has the largest roughness. The hardness of the used adhesive is slightly increased with the cycle number.

Effect of Fly Ash on Creep of High Performance Concrete Used in Bridge

2012 ◽  
Vol 204-208 ◽  
pp. 2192-2195 ◽  
Author(s):  
Liang Liang Zhang ◽  
Li Qun Wu ◽  
Jian Xin Yang ◽  
Kang Zhang
Keyword(s):  
Fly Ash ◽  
High Performance ◽  
High Performance Concrete ◽  
Class I ◽  
Blend Ratio ◽  
Blend Ratios

W/C ratio and the quantity of fly ash added have obvious influence on creep of high performance concrete. Effect of different quantities of fly ash on creep of high performance concrete of different W/C ratios used in bridge is studied in this research whose results reflect that creep value reduces along with reduction of W/C ratio at a certain quantity of fly ash added. Adding fly ash restrains creep on the whole, however, the degree depends on the quantity of fly ash added. Creep value of high performance concrete mixed with class-I fly ash at blend ratio of 12~40% is lower than that of standard concrete and fly ash at blend ratio of 18% has the best effect. Creep value in 365d is 51% of that of standard concrete at fly ash blend ratio of 18%, while at fly ash blend ratio of 40%, creep value in 365d is lower than that of standard concrete but higher than that of concrete at other blend ratios. It is generally considered that inhibition of creep of high performance concrete begins to fall beyond blend ratio of 30%.

scholarly journals Early-Age Tensile Bond Characteristics of Epoxy Coatings for Underwater Applications

Coatings ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 757 ◽  
Author(s):  
Kim ◽  
Hong ◽  
Han ◽  
Kim
Keyword(s):  
Bond Strength ◽  
Surface Treatment ◽  
Epoxy Resin ◽  
Coating Thickness ◽  
Experimental Results ◽  
Early Age ◽  
Curing Time ◽  
Bond Performance ◽  
Coating Type ◽  
Bond Characteristics

In this study, coating equipment for the effective underwater repair of submerged structures was developed. The tensile bond characteristics of selected epoxy resin coatings were investigated by coating the surface of a specimen using each of the four types of equipment. Using the experimental results, the tensile bond strength and the coating thickness were analyzed according to the type of equipment, coating, and curing time. The results show that the type of coating equipment used had the greatest effect on the measured bond strength and coating thickness of the selected coatings. However, the effect of coating type and curing time on the bond strength and the thickness was observed to be insignificant. Compared with the developed equipment, the surface treatment of the coating was observed to be more effective when using the pre-existing equipment, and thus the bond performance of the coating was improved compared to using the pre-existing equipment. Based on the experimental results, improvements and needs involving the equipment for further research were discussed.

scholarly journals Effect of Curing Agents on Electrical Properties of Low-Temperature Curing Conductive Coatings and Thermodynamic Analysis

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 656
Author(s):  
Junjie Shu ◽  
Yang Wang ◽  
Bei Guo ◽  
Weihua Qin ◽  
Lanxuan Liu ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Low Temperature ◽  
Surface Resistance ◽  
Advanced Manufacturing ◽  
Curing Time ◽  
Conductive Coatings ◽  
Exponential Factor ◽  
Design Expert ◽  
Surface Method ◽  
Curing Agents

Silver-based high-conductivity coatings are used in many advanced manufacturing equipment and components, and existing coatings require high-temperature curing. This paper studies the effects of different curing agents on the electrical properties of low-temperature curing (<100 °C) conductive coatings, and analyzes the effects of different curing temperatures and curing time on the surface resistance, square resistance and resistivity of conductive coatings. The response surface method in Design Expert was used to construct the model, and the curing thermodynamics of different curing agents were analyzed by DSC. It was found that curing agents with lower Tm and activation energy, higher pre-exponential factor and more flexible segments are beneficial to the preparation of highly conductive coatings.

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