Synthesis and research of photocurable protective coatings on the basis of olygoesteracrylates 229 D O I: 1 0. 15 82 6/ ch im te ch .2 02 0. 7. 4. 16 Karsakova O. A., Kuzmin M. V. Chimica Techno Acta. 2020. Vol. 7, no. 4. P. 229–232. ISSN 2409–5613 Synthesis and research of photocurable protective coatings on the basis of olygoesteracrylates O. A. Karsakova*, M. V. Kuzmin Chuvash State University named after IN Ulyanov, 15 Moskovsky pr., Cheboksary, 428015, Russia *email: karsakova.lesya@yandex.ru Abstract. In this work, photocurable protective coatings based on methacrylic acid esters have been developed and their physical and mechanical properties have been investigated. The photocurable compositions were obtained by mixing at different ratios the following methacrylic acid esters: polyethylene glycol dimethacrylate 400 and triethylene glycol dimethacrylate ether, polyethylene glycol dimethacrylate 400 and oligourethane dimethacrylate, polyethylene glycol dimethacrylate 400 and pentae- rythritol tetraacrylate. For the obtained compositions, the viscosity was studied using a Brookfield rotary viscometer. To initiate polymerization, a mixture of initiators was used: benzoyl peroxide and benzoin. Curing of the obtained compositions was carried out under the influence of UV rays for 2–5 minutes. For photo-cured compositions, their physical and mechanical properties have been studied. It was found that the composition based on polyethylene glycol dimethacrylate modified with triethylene glycol dimethacrylate at a ratio of 70:30 has the highest strength. Keywords: photocuring; protective coatings; polyethylene glycol dimethacrylate 400; tri- ethylene glycol dimethacrylate ether; pentaerythritol tetraacrylate; oligourethane dimethacrylate; benzoyl peroxide; benzoin Received: 30.10.2020. Accepted: 09.12.2020. Published:30.12.2020. © Karsakova O. A., Kuzmin M. V., 2020 Introduction Currently, photoinitiated po- lymerization is really relevant; this is due to  the  fact that the  field of  application of  photo-cured materials is  increasing. This method of curing is used in the man- ufacture of  lacquers, paints, adhesives, coatings, in  stereolithography, 3D print- ing, dentistry, laser image printing, and microelectronics [1]. An important component of photopo- lymerizing compositions (photopolymers) are oligomers, which determine the main characteristics of the photo-cured mate- rial  — chemical resistance, abrasion re- sistance, hardness, elasticity, tensile and flexural strength. Under the  influence of UV rays, three-dimensional insoluble polymer systems are formed from the con- tained functional groups of the oligomer. For radical photopolymerization initiated by ultraviolet radiation, unsaturated poly- ethyracrylates are used: epoxyacrylates, complex polyester acrylates, simple poly- ester acrylates, aminomodified polyester acrylates, urethanacrylates [2]. Another component is  monomers and diluents. They are used to  regulate the viscosity of the system. The meaning 230 of the mechanism of action of monomers in the process of ultraviolet curing is em- bedded in the polymer structure. Acrylic acid esters are considered more popular: tripropylene glycol diacrylate, hexadiol diacrylate and dipropylene glycol dia- crylate. Also widely used are glycidylmeth- acrylates, low-viscosity derivatives of gly- cidylmethacrylate or methyl methacrylate and polyatomic alcohols, polyphenols, polyether polyols, polycarboxylic acids, their esters or anhydrides. When the func- tionality of  acrylic monomers increases, their reactivity increases, but the elasticity of the product decreases [3]. The  third component of  the  photo- cured composition is the initiators (photo- initiators). In  the  composition you need to  enter the  matter, that the  absorption radiation of a certain wavelength will go into an excited state, followed by molecu- lar breakdown, leading to the emergence of radicals and initiate thereby the polym- erization reaction of the monomer and oli- gomer, providing a transition of the com- position from liquid to solid, with a spatial mesh stitched structure. Thus, due to  the  intensive develop- ment of  new technologies for the  use of photo-cured polymers, it became nec- essary to create new special compositions based on materials with lower cost for 3D printers. In this regard, the purpose of this work is to develop and study the physical and mechanical properties of photo-cured compositions based on methacrylic acid esters. Experimental Polymer binders were prepared on the basis of acrylic monomers by mixing at a certain ratio of polyethylene glycol-400 dimethacrylate and triethylene glycol dimethacrylate, polyethylene glycol 400 dimethacrylate and oligourethandimeth- acrylate, polyethylene glycol-400 dimeth- acrylate and pentaerythritol tetraacrylate. To  initiate polymerization, benzoyl per- oxide and benzoin were used. Benzoyl peroxide and benzoin were dissolved in polyethylene glycol-400 dimethacrylate. Next, to the obtained solution was added olygoethyleneamines, dimethacrylates ether of  triethylene glycol, tetraacrylate of pentaerythritol and permissively until smooth. For the obtained compositions, the vis- cosity was studied using a rotational Brook- field viscometer. Compressive strength was tested according to  GOST 4651–82 on a tensile testing machine REM-10-A-2. Results and discussion The initialization mechanism is shown in Fig. 1. The  results of  studying the  viscos- ity of the photocurable compositions ac- cording to the Brookfield viscometer and the compressive strength of the obtained photocurable protective coatings are given in Table 1 and Table 2. From Table  1 it can be seen that the highest viscosity at room temperature is the composition obtained on the basis of polyethylene glycol dimethacrylate and triethylene glycol dimethacrylate ether at a ratio of 70:30. Curing of the binder obtained was car- ried out under the action of UV light for 2–5 min. Then the cured samples were kept for 14 days and their physical and mechanical properties were studied. 231 From Table.  2 it can be seen that the  composition based on polyethylene glycol dimethacrylate modified with trieth- ylene glycol dimethacrylic ether at a ratio of 70:30 has the greatest strength. Table 1 The viscosity of the photocurable compositions on the basis of olygoesteracrylates at room temperature № The name of the modifier The content of the modifier, % 0 10 20 30 Viscosity ηср, mPa∙s 1 Dimethacrylic triethylene glycol ether 13262 15003 14755 13964 2 Oligourethandimethacrylate 13262 34896 33268 35194 3 Tetraacrylate of pentaerythritol 13262 12647 14945 21669 Table 2 Physical and mechanical properties of photocurable formulations, based on olygoesteracrylates № The name of the modifier The content of the modifier, % 0 10 20 30 Uniform compressive strength δ, MPa 1 Dimethacrylic triethylene glycol ether 44.41 47.37 90.19 140.96 2 Oligourethandimethacrylate 44.41 48.96 54.62 73.94 3 Tetraacrylate of pentaerythritol 44.41 56.19 71.75 81.98 O OH C O + OH O+ O + N R1 R2 CH2 R hv hv O N+ R2 R1 CH2 R n C+ OH + R CH+ N R1 R2 Fig. 1. The mechanism of photoinitiation 232 Conclusions Thus, in this work we have developed a photocurable coating based on the amal- gam of  polyethylene glycol and various cooligomers. It was found that the com- positions modified with triethylene glycol dimethacrylic ether have the highest curing rate and maximum strength. Acknowledgements The research was carried out under a grant for students from the Foundation for Support of  Youth Startups of  the  FSBEI HE “Chuvash State University named after I. N. Ulyanov”. References 1. Deng L, Tang L, Qu  J.  Synthesis and photopolymerization of  novel UV-curable macrophotoinitiators. Progress in Organic Coatings. 2020;141:105546. doi:10.1016/j.porgcoat.2020.105546 2. Quan H, Zhang T, Xu H, Luo Sh, Nie J, Zhu X. Photo-curing 3D printing technique and its challenges. Bioactive Materials. 2020;5(1):110–5. doi:10.1016/j.bioactmat.2019.12.003 3. Babkin O. E. Polimernye pokrytiya UF-otverzhdeniya [Polymer coatings of UV- curing]. Saint-Petersburg: Spbgukit, 2012. 39 p. Russian.