CC BY
1CHEMISTRY
CURING OF DIGLYCIDAL ESTERS OF BISPHENOLS WITH ACID HARDENERS
Givi Papava, Professor, Doctor, Chief Scientific researcher, Petre Melikishvili Institute of Physical and Organic Chemistry of Ivane Javakhishvili Tbilisi State University, Tbilisi, Georgia, ORCIDID: https://orcid.org/0000-0002-8837-4909
Nora Dokhturishvili, Doctor, Research worker, Petre Melikishvili Institute of Physical and Organic Chemistry of Ivane Javakhishvili Tbilisi State University, Tbilisi, Georgia, ORCID ID: https://orcid.org/0000-0002-6021-H20
Nazi Gelashvili, Doctor, Research worker, Petre Melikishvili Institute of Physical and Organic Chemistry of Ivane Javakhishvili Tbilisi State University, Tbilisi, Georgia
Ia Chtrekashvili, Doctor, Senior researcher, Petre Melikishvili Institute of Physical and Organic Chemistry of Ivane Javakhishvili Tbilisi State University, Tbilisi, Georgia, ORCID ID: https://orcid.org/0000-0002-6673-191X
Ketevan Papava, Doctor, Petre Melikishvili Institute ofPhysical and Organic Chemistry of Ivane Javakhishvili Tbilisi State University, Tbilisi, Georgia, ORCID ID: https://orcid.org/0000-0002-5212-9362
Ketevan Archvadze, Doctor, Research worker, Petre Melikishvili Institute of Physical and Organic Chemistry of Ivane Javakhishvili Tbilisi State University, Tbilisi, Georgia, ORCID ID: https://orcid.org/0000-0002-7796-4137
DOI: https://doi.org/10.31435/rsglobal_ws/30072021/7631
ARTICLE INFO ABSTRACT
Received: 04 May 2021 The unique properties of epoxy polymers have led to their wide application
Accepted: 17 June 2021 in various fields of modern technology. The influence of the structure of
Published: 3° July 2021 bisphenols on the properties of epoxy polymers, especially thermal ones, is
known. However, the chemical structure of the hardener also affects the
KEYWORDS properties of cured epoxy polymers. As hardeners, we used acid hardeners of
polymer, oligomer, bisphenol, various structures: anhydrides of maleic, phthalic, pyromellite,
norbornan, diaminodiphenylsulphon, methyltetrahydrophthalic and other acids. The following hardeners give high
thermomechanicalcurves, glycidic, results in heat resistance: pyromellite and methyltetrahydrophthalic
polycyclic, anhydride, anhydrides. Polymers obtained by curing with these hardeners are deformed
thrrmogravimetric, analysis, in the temperature range of 220-245°C. The use of these hardeners gives
itema^ heat stabU^ structure, high results in terms of thermal stability. These polymers are formed by
hardener, cyclic. curing these components.
It is known that the properties of epoxy polymers depend on the chemical structure of the glycide ether. There was some interest in investigating the influence on the properties of epoxy polymers as a chemical structure, as well as the nature of hardeners. For this purpose, diglycidal esters based on bisphenols were synthesized.
Citation: Givi Papava, Nora Dokhturishvili, Nazi Gelashvili, Ia Chtrekashvili, Ketevan Papava, Ketevan Archvadze. (2021) Curing of Diglycidal Esters of Bisphenols with Acid Hardeners. World Science. 7(68). doi: 10.31435/rsglobal_ws/30072021/7631
Copyright: © 2021 Givi Papava, Nora Dokhturishvili, Nazi Gelashvili, Ia Chtrekashvili, Ketevan Papava, Ketevan Archvadze. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
It is known that the properties of epoxy polymers depend on the chemical structure of the glycide ether [1-7]. There was some interest in investigating the influence on the properties of epoxy polymers as a chemical structure, as well as the nature of hardeners. For this purpose, diglycidal esters based on bisphenols were synthesized. Table 1 shows the characteristics of diglycidal esters.
Table 1. Characteristics of diglycidal esters of bisphenols
№ Structure of glycide ether Temperature softening, °C Content groui of epoxy ps, % Molecular weight
calculated found Intheory Determine dbyebullios copy
1 (/ |— CH—k A—OCH2—CH— CH2| ^ V ^ 61 21.23 19.00 405 424
2 /CH3 —H— CH—^ OCH2— CH — CH2\ \<J ^ V1 69 20.04 18.86 429 406
3 f^T" CH—^ OCH2— CH — CH2\ CIch^ ^ 71 20.62 20.02 419 422
4 /h3 c^^k 0ch2— ch— ch2^ (ix [Vj v 1 ^-v/ nch3 75 19.23 18.6 449 505
5 (0(O~OCH"VH) 55 21.9 17.0 392 480
6 /CH3 75 20.4 17.5 420 505
7 65 19.9 15.1 432 612
8 /ch3 Q;£j"(O"0ch"cH/cH2)2 65 18.6 17.4 460 472
9 83 18.7 14.0 458 508
10 _/ch3 [QQO^v i 75 17.9 15.3 486 530
Table 2 and Figures 1 - 3, as an example, show the properties of polymers obtained on the basis of the glycide ether 4,4'-(2-norbornylmethylene)diphenol and various acid hardeners.
Table 1. Properties of structured polymers obtained on the basis of 4 4'-(2-norbornylmethylene)diphenol glycide ether and various acid hardeners_
№
Structure of the hardener
Name of the hardener
The amount of hardener per 100 glycide ether, is prepared
10% deformation according to the thermomechanical curve, °C
The temperature of mass reduction by 10%, °C**
2
3
4
5
6
CH-CO\ II
CH — CO'
O
Maleic anhydride
39,2
322
270
_CO\ -CO'
Phthalicanhydride
54,0
170
O
310
/
CO-~CO"
CO\ '- CO'
Pyromelliteanhydride
83,5
215
O
410
CH2
Methyltetrahydrophthalicanhydride
62,2
200
H3C
,-CH-CO\ -CH-CO^
CH2
320
*Here and in the following tables] the conditions for curing glycide ether are as follows: 120°C-2 hours, 160°C-3 hours, 180°C-3 hours, 200°C-5 hours.
** Here and in the following table, the temperature of mass reduction by 10% is determined from the thermogravimetric curve at a temperature rise rate of 4.50 S/min.
1
1
2
3
O
4
Temperature,°C
Fig. 1. Thermomechanical curves of epoxy polymers based on glycide 4,4'-(2norbornylmethylene)diphenol ether, hardeners: 1. methyltetrahydrophthalic anhydride, 2. pyromellite anhydride, 3. Phthalic anhydride, 4. maleic anhydride.
s? 100-§ ■
•e
5
O
60-
40-
20-
0
0
100
200
300
400
Temperature, °C
500
Fig. 2. Thermomechanical curve of an epoxy polymer based on glycide ether 4,4'-(3-methyl-2-norbomylmethylene)diphenol The hardener is methyltetrahydrophthalic anhydride.
Fig. 3. Thermogravimetric curve of an epoxy polymer based on the glycide ether of 4,4'-(3-methyl-2-norbomylmethylene)diphenol The hardener is methyl tetrahydrophthalic anhydride.
As can be seen from the data in the table and figures, cured epoxy polymers are characterized by a fairly high heat resistance. High results in heat resistance are given by the following hardeners:pyromellite and methyltetra-hydrophthalic anhydrides. Polymers obtained by curing with these hardeners are deformed in the temperature range of 220-245°C. It should be particularly noted that the polymers formed during curing with maleic anhydride are deformed at 310°C. This can obviously be explained by the formation of additional crosslinking due to the disclosure of the double bonds present in maleic anhydride.
The use of the hardeners listed in Table 2 gives high results in terms of heat resistance. In all cases, the polymers formed by curing these components decrease in mass by 10% in the temperature range of 340-400°C.
From the hardeners listed in Table 2, based on the results obtained by us, some were selected for the purpose of curing the glycide esters of 4,4'-(2-norbornylmethylene)diphenol and 4,4'-(3-methyl-2-norbornylmethylene)diphenol. Table 3 and Figures 2 and 3 show the properties of polymers obtained by curing the above glycide esters with methyltetrahydrophthalic anhydride.
0
100
0 100 200 300 400 500 600 700
Temperature, 0C
Based on these data, the thermal heat resistance of the cured polymers does not change significantly compared to the polymers obtained by curing the glycide ether of 4,4'-(3-methyl-2-norbornylmethylene)diphenol. Obviously, the change in the structure of the cyclic group does not affect these indicators.
As the study showed, the epoxy polymers obtained by curing the glycide esters listed in Table 1 of cyclic bisphenols with these hardeners are characterized by high heat and heat resistance, which causes some practical interest. It is only necessary to pay attention to the fact, the ester of 4,4'-(3-methyl-2-norbornylmethylene)diphenol is slightly higher than that of polymers based on other bisphenols.
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