Model studies on the cross-linking of epoxy resins with amines at room temperature

1987 ◽  
Vol 7 (1) ◽  
pp. 33-38 ◽  
Author(s):  
A. Groβ ◽  
H. Brockmann ◽  
H. Kollek
Keyword(s):  
Epoxy Resins ◽  
Room Temperature ◽  
Cross Linking ◽  
Model Studies ◽  
The Cross

scholarly journals Investigation of the functional network modifier loading on the stoichiometric ratio of epoxy resins and their dielectric properties

2021 ◽  
Author(s):  
Istebreq A. Saeedi ◽  
Sunny Chaudhary ◽  
Thomas Andritsch ◽  
Alun S. Vaughan
Keyword(s):  
Glass Transition ◽  
Dielectric Properties ◽  
Electrical Properties ◽  
Epoxy Resins ◽  
Functional Network ◽  
Cross Linking ◽  
Network Modifier ◽  
Epoxy Resin System ◽  
The Cross ◽  
The Impact

AbstractReactive molecular additives have often been employed to tailor the mechanical properties of epoxy resins. In addition, several studies have reported improved electrical properties in such systems, where the network architecture and included function groups have been modified through the use of so-called functional network modifier (FNM) molecules. The study reported here set out to investigate the effect of a glycidyl polyhedral oligomeric silsesquioxane (GPOSS) FNM on the cross-linking reactions, glass transition, breakdown strength and dielectric properties of an amine-cured epoxy resin system. Since many previous studies have considered POSS to act as an inorganic filler, a key aim was to consider the impact of GPOSS addition on the stoichiometry of curing. Fourier transform infrared spectroscopy revealed significant changes in the cross-linking reactions that occur if appropriate stoichiometric compensation is not made for the additional epoxide groups present on the GPOSS. These changes, in concert with the direct effect of the GPOSS itself, influence the glass transition temperature, dielectric breakdown behaviour and dielectric response of the system. Specifically, the work shows that the inclusion of GPOSS can result in beneficial changes in electrical properties, but that these gains are easily lost if consequential changes in the matrix polymer are not appropriately counteracted. Nevertheless, if the system is appropriately optimized, materials with pronounced improvements in technologically important characteristics can be designed.

scholarly journals Synthesis of epoxy resins derivatives of naphthalene-2,7-diol and their cross-linked products

2019 ◽  
Vol 138 (6) ◽  
pp. 4349-4358 ◽  
Author(s):  
K. Fila ◽  
M. Gargol ◽  
M. Goliszek ◽  
B. Podkościelna
Keyword(s):  
Fourier Transform ◽  
Epoxy Resins ◽  
Attenuated Total Reflectance ◽  
Cross Linking ◽  
Total Reflectance ◽  
Before And After ◽  
Ft Ir ◽  
The Cross ◽  
Derivatives Of ◽  
Epoxy Groups

Abstract The aim of this study was the synthesis of three different epoxy compounds based on naphthalene-2,7-diol (2,7-NAF.EP, 2,7-NAF.WEP, 2,7-NAF.P.EP) and then their cross-linking by triethylenetetramine (TETA). All epoxides were prepared by the reaction of naphthalene-2,7-diol with epichlorohydrin but under different conditions and with other catalysts. The structures of the obtained compounds before and after the cross-linking reactions were confirmed by the attenuated total reflectance Fourier transform infrared spectroscopy (ATR/FT-IR). The ATR/FT-IR spectra of cross-linked compounds show disappearance of the C–O–C bands (about 915 cm−1) derived from the epoxy groups. DSC and TG/DTG measurements indicated that the obtained materials possess good thermal resistance; they are stable up to about 250 °C. The hardness of the cross-linked products was determined using the Shore D method. The highest value of hardness was obtained for the 2,7-NAF.EP-POL. Additionally, the UV–Vis absorption spectra of the obtained polymers were registered and evaluated.

Chemiluminescence measurement of gel times for amine-cured epoxy resins

1995 ◽  
Vol 7 (2) ◽  
pp. 219-236 ◽  
Author(s):  
K A Kozielski ◽  
N C Billingham ◽  
G A George ◽  
D C L Greenfield ◽  
J M Barton
Keyword(s):  
Chemical Reactions ◽  
Epoxy Resins ◽  
Physical State ◽  
Glycidyl Ether ◽  
Cross Linking ◽  
Gel Time ◽  
The Matrix ◽  
Effect Of Impurities ◽  
The Cross

The cross-linking reactions of 4,4'-diaminodiphenyl sulphone (DDS) with stoichiometric quantities of glycidyl ether- or tetraglycidyl amine-based epoxy resins were monitored using chemiluminescence (CL) and rheometry. It was found that, when a sample was cured isothermally in air, the CL profile increased to a maximum, then decreased again. The maximum was found to correspond well with the gel time (tgel), as measured by rheometry. This observation is discussed in relation to the chemical reactions occurring within the material and the physical state of the matrix. The effect of impurities in DDS on the gel time of these epoxy resins is reported.

The radiation chemistry of dihydromyrcene

1967 ◽  
Vol 45 (2) ◽  
pp. 101-108 ◽  
Author(s):  
John L. Brash ◽  
Morton A. Golub
Keyword(s):  
Hydrogen Evolution ◽  
Pure State ◽  
Room Temperature ◽  
Benzene Solution ◽  
Radiation Chemistry ◽  
Cross Linking ◽  
Double Bonds ◽  
Trans Isomerization ◽  
The Cross ◽  
G Value

Dihydromyrcene was irradiated with 1-MeV electrons at room temperature both in the pure state and in benzene solution. The main reactions observed, and their G-values for the pure diisoprene, were loss of unsaturation (~7.8–9.9), cross-linking (or dimerization) (2.4–2.6), evolution of hydrogen (0.81), and trans → cis isomerization (< 0.5). As with squalene, the loss of double bonds in dihydromyrcene occurred only in the cross-linked residue, obtained on distillation of the irradiated isoprenoid. Although the residue (mainly dimer, with some trimer) was considered to be partially cyclized, no cyclization of uncross-linked (monomeric) dihydromyrcene was observed. Dihydromyrcene in 10% benzene solution (by weight) showed trans → cis and cis → trans isomerization with G-values of 0.63 and 1.2, respectively, hydrogen evolution with a G-value of 0.08, and a higher rate of loss of original unsaturation than in the pure state.

Mechanical Properties of Epoxidized Palm Oil/Epoxy Resin Blend

2014 ◽  
Vol 695 ◽  
pp. 655-658 ◽  
Author(s):  
Zyad Salem Alsagayar ◽  
Abdul Razak Rahmat ◽  
Agus Arsad ◽  
Alireza Fakhari ◽  
Wan Nurhayati binti Wan Tajulruddin
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Epoxy Resin ◽  
Palm Oil ◽  
Room Temperature ◽  
Flexural Properties ◽  
Cross Linking ◽  
Impact Tests ◽  
Epoxidized Palm Oil ◽  
The Cross

In this paper, a blend of epoxy resin and epoxidized palm oil (EPO) was prepared to investigate its mechanical properties. Epoxy and EPO were mixed for 20 minutes at room temperature before mixed with hardener and followed by curing for 2 hours at 100 °C. Tensile, flexural and impact tests were conducted to characterize the blend. In general, the tensile and flexural properties of epoxy resin/EPO decreased when the amount of EPO increased. However, strain at break, toughness and impact strength was slightly increased when the amount of EPO was increased up to 20%.The mechanical properties were reduced due to the reduction of the cross linking density and effect of plasticizer.

A Delayed-Curing Cotton Fabric Based on an Internally Catalyzed Cotton Cellulose and Divinyl Sulfone

1969 ◽  
Vol 39 (2) ◽  
pp. 173-180 ◽  
Author(s):  
Stanley P. Rowland ◽  
Mary Ann F. Brannan
Keyword(s):  
Elevated Temperature ◽  
Room Temperature ◽  
Cotton Cellulose ◽  
Cross Linking ◽  
Cure Reaction ◽  
Divinyl Sulfone ◽  
Cross Links ◽  
The Cross ◽  
Catalyzed Reactions ◽  
Recovery Angle

2-(Diethylamino)ethyl cotton celluloses in the form of print cloth and at three levels of nitrogen have been quaternized and converted to the strong bases. Studies were made of internally catalyzed reactions of these cotton cellulose quaternary ammonium hydroxides with divinyl sulfone at room temperature in a “wet-cure” and with bis-(2-hydroxyethyl) sulfone in a “bake-cure.” Moderate levels of conditioned wrinkle-recovery angles and high levels of wet wrinkle-recovery angles result from the “wet-cure” reaction. The wrinkle-recovery angles of these modified cotton celluloses are compared to those of the corresponding cotton celluloses cross-linked by conventional external catalysis. The internally catalyzed fabrics from the “wet-cure” are particularly interesting among these compositions with regard to (a) the developed levels of wrinkle-recovery angle, (b) the capability of these compositions to develop high conditioned wrinkle-recovery angles as a result of recure in a “bake-cure” in the absence of external catalysis, and (c) the evidence of mobility of the cross links (i.e., reversibility of the cross-linking reaction followed by reformation of new or old cross linkages) at elevated temperature.

scholarly journals The Use of the ATD Technique to Measure the Gelation Time of Epoxy Resins

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6022
Author(s):  
Jakub Smoleń ◽  
Piotr Olesik ◽  
Paweł Gradoń ◽  
Mateusz Chudy ◽  
Bogusław Mendala ◽  
...  
Keyword(s):  
Carbon Fibers ◽  
Epoxy Resins ◽  
Gelation Time ◽  
Graphite Powder ◽  
Cross Linking ◽  
Gel Point ◽  
Curing Process ◽  
Carbon Particles ◽  
The Cross ◽  
The Stability

In this paper, we investigated the thermodynamics of the resin curing process, when it was a part of composition with graphite powder and cut carbon fibers, to precisely determine the time and temperature of gelation. The material for the research is a set of commercial epoxy resins with a gelation time not exceeding 100 min. The curing process was characterized for the neat resins and for resins with 10% by weight of flake graphite and cut carbon fibers. The results recorded in the analysis of temperature derivative (ATD) method unequivocally showed that the largest first derivative registered during the test is the gel point of the resin. The innovative approach to measuring the gelation time of resins facilitates the measurements while ensuring the stability of the curing process compared to the normative tests that introduce mechanical interaction. In addition, it was found during the research that the introduction of 10% by weight of carbon particles in the form of graphite and cut carbon fibers rather shortens the gelation time and lowers the temperature peak due to the effective absorption and storage of heat from the cross-linking system. The inhibiting (or accelerating) action of fillers is probably dependent on chemical activity of the cross-linking system.

scholarly journals The Effect of Surfactant-Modified Montmorillonite on the Cross-Linking Efficiency of Polysiloxanes

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2623
Author(s):  
Monika Wójcik-Bania ◽  
Jakub Matusik
Keyword(s):  
Total Pore Volume ◽  
Cross Linking ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
The Cross ◽  
Chain Lengths ◽  
First Time ◽  
Substituent Influence ◽  
Benzyl Substituent

Polymer–clay mineral composites are an important class of materials with various applications in the industry. Despite interesting properties of polysiloxanes, such matrices were rarely used in combination with clay minerals. Thus, for the first time, a systematic study was designed to investigate the cross-linking efficiency of polysiloxane networks in the presence of 2 wt % of organo-montmorillonite. Montmorillonite (Mt) was intercalated with six quaternary ammonium salts of the cation structure [(CH3)2R’NR]+, where R = C12, C14, C16, and R’ = methyl or benzyl substituent. The intercalation efficiency was examined by X-ray diffraction, CHN elemental analysis, and Fourier transform infrared (FTIR) spectroscopy. Textural studies have shown that the application of freezing in liquid nitrogen and freeze-drying after the intercalation increases the specific surface area and the total pore volume of organo-Mt. The polymer matrix was a poly(methylhydrosiloxane) cross-linked with two linear vinylsiloxanes of different siloxane chain lengths between end functional groups. X-ray diffraction and transmission electron microscopy studies have shown that the increase in d-spacing of organo-Mt and the benzyl substituent influence the degree of nanofillers’ exfoliation in the nanocomposites. The increase in the degree of organo-Mt exfoliation reduces the efficiency of hydrosilylation reaction monitored by FTIR. This was due to physical hindrance induced by exfoliated Mt particles.

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