CURING OF DIGLYCIDAL ESTERS OF BISPHENOLS WITH AMINE 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
Ketevan Ebralidze, Doctor, Chief Scientific researcher, Petre Melikishvili Institute of Physical and Organic Chemistry of Ivane Javakhishvili Tbilisi State University, Tbilisi, Georgia, Eter Gavashelidze, Doctor, Senior researcher, Petre Melikishvili Institute of Physical and Organic Chemistry of Ivane Javakhishvili Tbilisi State University, Tbilisi, Georgia,
Marina Gurgenishvili, Doctor, Chief Scientific researcher, Petre Melikishvili Institute of Physical and Organic Chemistry of Ivane Javakhishvili Tbilisi State University, Tbilisi, Georgia, Shalva Papava, Doctor, Petre Melikishvili Institute of Physical and Organic Chemistry of Ivane Javakhishvili Tbilisi State University, Tbilisi, Georgia,
Nanuli Khotenashvili, Research worker, Petre Melikishvili Institute of Physical and Organic Chemistry of Ivane Javakhishvili Tbilisi State University, Tbilisi, Georgia
DOI: https://doi.org/10.31435/rsglobal_ws/30072021/7633
ARTICLE INFO
Received: 05 May 2021 Accepted: 25 June 2021 Published: 30 July 2021
KEYWORDS
polymer, oligomer, bisphenol, norbornan, diaminodiphenylsulphon, thermomechanical curves, glycidic, polycyclic, anhydride, thrrmogravimetric, analysis, thermal, heat stability, structure, hardener, cyclic.
ABSTRACT
The effect of hardeners on the properties of cured epoxy polymers is studied. For the purpose of synthesis of polymers with increased thermal properties. Theglycide esters of polycyclic bisphenols synthesized by us were used as a diol component. Since the thermal and heat resistance of polymers, in addition to the chemical structure of bisphenols, also depend on the structure of the hardener used, amine hardeners of different chemical structure are used to improve the thermal parameters of polymers, both heat resistance and heat resistance. The influence of the chemical structure of these hardeners on the properties of epoxy polymers is studied. Cured epoxy polymers are characterized by high heat resistance. High heat resistance results are obtained by 4,4'-diaminodiphenylsulfone, benzidine, 4,4'-diaminodiphenyloxide and other aromatic diamines. Polymers obtained by curing with these hardeners are deformed in the temperature range of 220-245°C.
The use of the above hardeners gives high results in terms of heat resistance. In all cases, the polymers obtained on the basis of these hardeners decrease in weight by 10% in the temperature range of 340-400°C.
Citation: Givi Papava, Ketevan Ebralidze, Eter Gavashelidze, Marina Gurgenishvili, Shalva Papava, Nanuli Khotenashvili. (2021) Curing of Diglycidal Esters of Bisphenols with Amine Hardeners. World Science. 7(68). doi: 10.31435/rsglobal_ws/30072021/7633
Copyright: © 2021 Givi Papava, Ketevan Ebralidze, Eter Gavashelidze, Marina Gurgenishvili, Shalva Papava, Nanuli Khotenashvili. 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.
In works [1-7], epoxy polymers based on various bisphenols are described. Continuing research in the field of this interesting, practically important class of polymers, it was considered interesting to synthesize polymers with increased thermal properties. It was found that the presence of cyclic groups in the diol component, both aromatic and alicyclic in nature, largely determines the properties of the structured polymer, contributing to the growth of thermal parameters of polymers. Components containing various cyclic groups were used as hardeners. Since the thermal and heat resistance of polymers, in addition to the chemical structure of bisphenols, also depend on the
structure of the hardener used, amine hardeners of different chemical structure were used to improve the thermal properties of polymers, both heat resistance and heat resistance. The influence of the chemical structure of hardeners on the properties of epoxy polymers was studied.
The structure of the final product obtained by curing the glycide ester of bisphenol with amine can be represented as follows:
.-OArOCH2-CH-CH2 + H2N-Ar-NH2 -►
O
...-OArOCH-CH-CHo-N-Ar-N-C^-CH-C:^-0^-....
OH
I
OH
CH2 - CH - CH2 - OAr
.... — ArO — CH2 - CH - CH
I 2 I
OH OH
Where Ar1 - is a residue of a diamine molecule,
Ar - is the remainder of the bisphenol molecule.
Table 1 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 amine hardeners.
Table 1. Properties of structured polymers based on glycide ether
№ 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**
1 no - 300 PolyethylenePolyamine 27.1 - 250
2 nh2 o M-phenylenediamine 13.0 210 360
3 nh2 0 1 nh2 P-phenylenediamine 14.0 170 220
4 NH2~^ CH.-Q - NH2 4,4' - diaminophenylmethane 19.0 145 390
5 qch, ^och3 h2n-( j- nh2 4,4'-diamino-3,3' -dimethoxydiphenylmethane 25.0 150 340
6 H2N-O-S02-O-NH2 4,4' - diaminodiphenylsulfone 24.8 235 400
7 „^Q-Q-Q-NH, 4,4' - diaminodiphenyloxide 21.5 205 330
8 H2N-Q-0-NH2 benzidine 18.1 195 325
9 H2N-Qx />"NH2 O^O AnilineFluorene 17.1 200 295
*Here and in the following table, 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.
Fig. 1. Thermomechanical curves of epoxy polymers based on 4,4'-(2-norbornylmethylene)diphenol. Hardeners: 1.4,4'-diaminodiphenylsulfone, 2. Benzidine, 3. 4,4'-diaminodiphenylmethane, 4. Aniline fluorene, 5. M-phenylenediamine, 6. P-phenylenediamine
Temperature, 0C
Fig. 2. Thermogravimetric curves of epoxy polymers based on the glycide ether 4,4'-(2-norbornylmethylene)diphenol. Hardeners: 1. 4,4'-diaminodiphenylsulfone, 2. Benzidine, 3. Aniline fluorene, 4. Polyethylene polyamine.
Fig. 3. Thermomechanical curves of epoxy polymers based on 4,4-(3-methyl-2-norbornylmethylene)diphenol. Hardeners: 1. 4,4'-diaminodiphenylsulfone, 2. 4,4'-diaminodiphenyloxide, 3. Benzidine
As can be seen from the data in the table and figures, cured epoxy polymers are characterized by a fairly high heat resistance. The exception is polymers obtained by curing 4,4'-diamino-3,3'-
dimethoxydiphenylmethane and 4,4'-diaminodiphenyl-methane, whose heat resistance is equal to 145 and 150°C. This is obviously due to the structure of the above - mentioned diamines, namely, the presence of methoxy-and methylene groups in their molecules. 4,4'-diaminodiphenylsulfone gives high results in heat resistance. Polymers obtained by curing with these hardeners are deformed in the temperature range of 220-245°C.
The use of the hardeners listed in Table 1 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 340-400°C. The only exception is the polymer obtained by curing the glycide ether with polyethylene polyamine. The temperature of reduction in mass by 10% for it is 260°C. The use of 4,4'-diaminodiphenylsulfone for curing glycide ether gives a high result. The temperature of the mass reduction by 10% at the same time increases to 400°C.
Temperature, 0C
Fig. 4. Thermogravimetric curves of epoxy polymers based on the glycide ether 4,4'-(3-methyl-2-norbomylmethylene)diphenol Hardeners: 1. 4,4'-diaminodiphenylsulfone, 3. 4,4'-diaminodiphenyloxide, 4. Benzidine
Table 2. Properties of structured compounds based on glycide esters
4,4'-(2-norbornylmethylene)diphenol (1) and 4,4'-(3-methy -2-norbornylmethylene)diphenol (2).
№ Structure 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**
1 2 1 2 1 2
1 H2n"0"0-NH2 20,0 17,3 195 260 325 300
2 H2n_q_o.0_nh2 19,7 16,2 205 210 330 300
3 h2n-0-so2-0- nh2 24,5 25,9 225 235 400 280
Based on the results obtained, some of the hardeners listed in Table 1 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 2 and Figures 4 show the properties of polymers obtained by curing the above glycide esters with the following hardeners: 4,4'-diaminodiphenyl-sulfone, benzidine and 4,4'-diaminodiphenyl oxide.
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.
Epoxy polymers obtained by curing glycide esters of cyclic bisphenols with these hardeners are characterized by high heat and heat resistance, which causes some practical interest. You should only pay attention that the heat and heat resistance of ester of 4,4'-(3-methyl-2-norbornylmethylene)diphenol is slightly higher than polymers based on other bisphenols.
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