The study of the curing of the polyurethane coating by method of IR spectroscopy

The results of the study of the curing process of polyurethane compositions with participation of two different catalysts by the method of IR spectroscopy are given. The time dependences of curing of polyurethane coatings from concentrations of catalysts were determined, on the basis of which the most effective catalyst was selected.

One of the most common plastic materials today is polyurethane. The widespread use of this polymer is due to the wide scope and high rates of physicalmechanical properties as strength, wear resistance, resistance to swelling in vari-ous oils and solvents and ozone-and radiation resistance and others [1,2].
The combination of high elasticity with wide range of hardness defines the excellent operational properties of the products based on them. The polymer is able to withstand heavy loads, less subject to aging than other substances. It is resistant to temperature extremes, sunlight, salts, solvents on organic base. Therefore, the establishment of the protective anti-corrosion polyurethane coatings, used in large industrial objects (bridges, overpasses, etc.) is an actual task today.
The obtaining of the polyurethane occurs by the reaction of di-and polyfunctional isocyanates with di-and polyfunctional alcohols: Since the curing time of the composition is sufficiently large, there is a need for its acceleration, while maintaining the properties of the very protective coating. In many experiments thermal processing is used for acceleration of curing of polyu-rethane, which is difficult to implement in a coating outdoor environments [3][4][5]. In this case it seems more profitable variant of use of a catalyst which initially is added to the reaction mixture, accelerating the process of chemical curing of the coating. One of the most common catalytic systems is the combination of organometallic compounds and tertiary amines. Often this combination is due to the synergistic effect of these compounds.
The purpose of work is the determination of the influence of the concentration of tertiary amine as a catalyst on the rate of binding process of the components in the reaction for producing the polyurethane at room temperature by the method of IR spectroscopy.

Materials and methods of study
Spectra of prepared samples were recorded on a IR-Fourier spectrometer Bruker Alpha prefix diffusive reflection.
As starting components for the preparation of the samples were taken:* Aliphatic polyisocyanate on the basis of isocyanurate hexamethylenediisocyanate (Desmodur N3390 of firm Bayer) 90 % Solution in n-butyl acetate with a mass content of isocyanate groups of 19.6 % was represented in the sale: Therefore, the establishment of the protective anti-corrosion polyurethane coatings, use in large industrial objects (bridges, overpasses, etc.) is an actual task today.
The obtaining of the polyurethane occurs by the reaction of di-and polyfunction isocyanates with di-and polyfunctional alcohols: Since the curing time of the composition is sufficiently large, there is a need for i acceleration, while maintaining the properties of the very protective coating. In man experiments thermal processing is used for acceleration of curing of polyurethane, which difficult to implement in a coating outdoor environments [3][4][5]. In this case it seems mo profitable variant of use of a catalyst which initially is added to the reaction mixture, acceleratin the process of chemical curing of the coating. One of the most common catalytic systems is th combination of organometallic compounds and tertiary amines. Often this combination is due the synergistic effect of these compounds.
The purpose of work is the determination of the influence of the concentration of tertia amine as a catalyst on the rate of binding process of the components in the reaction for producin the polyurethane at room temperature by the method of IR spectroscopy.

Materials and methods of study.
Spectra of prepared samples were recorded on a IR-Fourier spectrometer Bruker Alph prefix diffusive reflection.
As starting components for the preparation of the samples were taken:* the hydroxyl-bearing polyacrylate (Setalux DA 160X) with a mass content of hydroxyl groups of 1.6 % in the sale form. Represented as 60 % solution in xylene: As organometallic catalyst was used 1 % solution of dilaurate dibutylamine in butyl acetate, the tertiary amines are variable amounts of triethanolamine and diazobicycloundezen.
Therefore, the establishment of the protective anti-corrosion polyurethane coatings, used in large industrial objects (bridges, overpasses, etc.) is an actual task today.
The obtaining of the polyurethane occurs by the reaction of di-and polyfunctional isocyanates with di-and polyfunctional alcohols: Since the curing time of the composition is sufficiently large, there is a need for its acceleration, while maintaining the properties of the very protective coating. In many experiments thermal processing is used for acceleration of curing of polyurethane, which is difficult to implement in a coating outdoor environments [3][4][5]. In this case it seems more profitable variant of use of a catalyst which initially is added to the reaction mixture, accelerating the process of chemical curing of the coating. One of the most common catalytic systems is the combination of organometallic compounds and tertiary amines. Often this combination is due to the synergistic effect of these compounds.
The purpose of work is the determination of the influence of the concentration of tertiary amine as a catalyst on the rate of binding process of the components in the reaction for producing the polyurethane at room temperature by the method of IR spectroscopy.

Materials and methods of study.
Spectra of prepared samples were recorded on a IR-Fourier spectrometer Bruker Alpha prefix diffusive reflection.
As starting components for the preparation of the samples were taken:* experiments thermal processing is used for acceleration of curing of polyurethane, difficult to implement in a coating outdoor environments [3][4][5]. In this case it see profitable variant of use of a catalyst which initially is added to the reaction mixture, ac the process of chemical curing of the coating. One of the most common catalytic syste combination of organometallic compounds and tertiary amines. Often this combination the synergistic effect of these compounds.
The purpose of work is the determination of the influence of the concentration amine as a catalyst on the rate of binding process of the components in the reaction for p the polyurethane at room temperature by the method of IR spectroscopy.

Materials and methods of study.
Spectra of prepared samples were recorded on a IR-Fourier spectrometer Bruk prefix diffusive reflection.
As starting components for the preparation of the samples were taken:*

The experimental part
In advance 12 metal dies of a given size of 25.5×4,5×6,0 mm had been prepared. The sizes of dies were determined by measuring of the geometric parameters of the set of elements of the sample preparation for the recording of spectra of diffuse reflection. Metal dies on one side were mirror polished. Half the polished side was covered with the prepared sample using a special device enabling the thickness of the polyurethane coatings of 0.01-0.03 mm, the other half surface was used as a standard of comparison.
The ratio was calculated by the following formula (calculated to anhydrous polyol): where P A is the number of polyol, g; P B is the number of isocyanate derivatives, g; M 1 is the molecular weight of isocyanate groups 42.e.m.; M 3 is the molecular weight of the hydroxyl groups 17.e.m.; b is the content of hydroxyl groups in the polyol, 1,6 %; с is the content of isocyano groups in the isocyanate, 19,6 %. The founding ratio of isocyanate derivatives was to poliol by mass is 30,63:100. Given the content of solvents the mass ratio used 20,47:100.
The experiment was conducted in 4 parallel: without catalyst of tertiary amine, with content of catalyst of tertiary amine, 0.50 %, 0.75 %, 1.00 % of the mass of the mixture. Isocyanate and polyol were mixed in a specific ratio, were added 1 % by mass of the mixture dilaurate dibutylamine 1 % solution in butyl acetate and the variable number of catalyst of tertiary amine was poured. So 4 parallels were got, where as the catalyst there was used triethanolamine, and 4 parallels, where the catalyst was diazobicycloundecen. The reaction mixture was prepared by stirring for 10 minutes at room temperature.
IR spectra were recorded with the frequency of once per day for 25 days. Additional treatment except correction of base line was not carried out.

Results and discussion
The assessment of chemical bonding of the components was based on changes in the concentration of isocyanate, which is determined by the intensity of the absorption band of the isocyanate group at 2291 cm -1 [6]. The process of formation of polyurethane was considered complete when the absorption band is not visible in the spectrum (Fig. 1). In Fig. 2 and 3 show graphs of the content of the absorption band of NCO-groups in time are shown.
As can be seen in the graphs, the speed of curing increases with increasing concentration of catalyst. Isocyanate groups  b is the content of hydroxyl groups in the polyol, 1,6%; с is the content of isocyano groups in the isocyanate, 19,6%.
The founding ratio of isocyanate derivatives was to poliol by mass is 30,63:100. Given the content of solvents the mass ratio used 20,47:100.
The experiment was conducted in 4 parallel: without catalyst of tertiary amine, with content of catalyst of tertiary amine, 0.50 %, 0.75 %, 1.00 % of the mass of the mixture.
Isocyanate and polyol were mixed in a specific ratio, were added 1 % by mass of the mixture dilaurate dibutylamine 1 % solution in butyl acetate and the variable number of catalyst of tertiary amine was poured. So 4 parallels were got, where as the catalyst there was used are extremely reactive and rapidly interact with substances that contain hydroxyl and amino groups. This interaction of isocyanate groups and hydroxyl or amino groups of agents of chain growth leads to the formation of a larger number of urethane linkages. Therefore, the time for chemical curing of the reaction mixture of the polymer requires less at higher content of the catalyst. It should be noted that the physical curing is observed within hours after applying of the sample, whereas chemical curing was leaking much longer. Physical curing was evaluated by leaving of the nail strip on the sample of polyurethane isocyanate group at 2291 cm [6]. The process of formation of polyurethane was c complete when the absorption band is not visible in the spectrum (Fig. 1). In Fig. 2 graphs of the content of the absorption band of NCO-groups in time are shown. In the resulting study the chemical curing of the polymer composition was observed faster when used as a catalyst triethanolamine. It should be noted also that the triethanolamine is cheaper than diazobicycloundecen, which explains its wide spread in industrial production.
The obtained experimental data can be used to optimize the technology of applying of polyurethane protective coatings and will predict the time to complete bonding of the components of the reaction mixture to achieve optimal physical-mechanical indicators. * The authors thank the Head of R@D Division Prof. Kozhevnikov D. N of JSC SIH VMP for scientific and innovative work. for the objects of study and their interest in scientific research activity of students, hit UrFU.
The obtaining of the polyurethane occurs by the reaction of di-and polyfunction isocyanates with di-and polyfunctional alcohols: Since the curing time of the composition is sufficiently large, there is a need for acceleration, while maintaining the properties of the very protective coating. In man experiments thermal processing is used for acceleration of curing of polyurethane, which difficult to implement in a coating outdoor environments [3][4][5]. In this case it seems mo profitable variant of use of a catalyst which initially is added to the reaction mixture, acceleratin the process of chemical curing of the coating. One of the most common catalytic systems is t combination of organometallic compounds and tertiary amines. Often this combination is due the synergistic effect of these compounds.
The purpose of work is the determination of the influence of the concentration of tertia amine as a catalyst on the rate of binding process of the components in the reaction for produci the polyurethane at room temperature by the method of IR spectroscopy.

Materials and methods of study.
Spectra of prepared samples were recorded on a IR-Fourier spectrometer Bruker Alp prefix diffusive reflection.
As starting components for the preparation of the samples were taken:*  Since the curing time of the composition is sufficiently large, there is a need acceleration, while maintaining the properties of the very protective coating. In experiments thermal processing is used for acceleration of curing of polyurethane, w difficult to implement in a coating outdoor environments [3][4][5]. In this case it seem profitable variant of use of a catalyst which initially is added to the reaction mixture, acce the process of chemical curing of the coating. One of the most common catalytic system combination of organometallic compounds and tertiary amines. Often this combination is the synergistic effect of these compounds.
The purpose of work is the determination of the influence of the concentration of amine as a catalyst on the rate of binding process of the components in the reaction for pro the polyurethane at room temperature by the method of IR spectroscopy.

Materials and methods of study.
Spectra of prepared samples were recorded on a IR-Fourier spectrometer Bruke prefix diffusive reflection.
The obtaining of the polyurethane occurs by the reaction of di-and polyfunctional isocyanates with di-and polyfunctional alcohols: Since the curing time of the composition is sufficiently large, there is a need for its acceleration, while maintaining the properties of the very protective coating. In many experiments thermal processing is used for acceleration of curing of polyurethane, which is difficult to implement in a coating outdoor environments [3][4][5]. In this case it seems more profitable variant of use of a catalyst which initially is added to the reaction mixture, accelerating the process of chemical curing of the coating. One of the most common catalytic systems is the combination of organometallic compounds and tertiary amines. Often this combination is due to the synergistic effect of these compounds.
The purpose of work is the determination of the influence of the concentration of tertiary amine as a catalyst on the rate of binding process of the components in the reaction for producing the polyurethane at room temperature by the method of IR spectroscopy.

Materials and methods of study.
Spectra of prepared samples were recorded on a IR-Fourier spectrometer Bruker Alpha prefix diffusive reflection.
As starting components for the preparation of the samples were taken:*