KINETICS OF FORMATION AND PROPERTIES OF PHOTOCURED SIMULTANEOUS EPOXY-ACRYLATE IPNS WITH THE PREVAILING CONTENT OF AN EPOXY COMPONENT

2021 ◽  
Vol 43 (4) ◽  
pp. 287-294
Author(s):  
N.V. YAROVA ◽  
◽  
T.F. SAMOILENKO ◽  
L.M. YASHCHENKO ◽  
O.O. BROVKO ◽  
...  

The distinct features of UV induced polymerization of epoxy-acrylate blends leading to the formation of simultaneous interpenetrating polymer networks (IPNs) have been studied. Different ratios of components within a prevailing content of an epoxy one have been used for the synthesis. Such a content of epoxy monomer is required to create a barrier preventing oxygen diffusion into a curing sample. It allows retardation of the well-known oxygen-inhibition effect, which acrylate monomers are susceptible to. Hence, the conduction of their polymerization in open-air conditions is possible. The proceeding of the polymerization reactions of acrylate (TEGDM) via free radical mechanism and of epoxy (UP-650D) via cationic one have been monitored by FTIR-spectroscopy. Namely, the conversion degrees have been calculated for double bonds of TEGDM and for epoxy groups of UP-650D respectively. A mixture of triphenylsulfonium hexafluorophosphate salts, which is capable of generating both free radical and cationic reactive species, have been used as a single photoinitiator for the formulations being investigated. Almost complete conversion of acrylate double bonds was reached after 60 min of UV irradiation irrespective of epoxy content. On the contrary, conversion of epoxy groups of aliphatic epoxy, which is known to be rather unreactive towards cationic photopolymerization, when mixed may be either higher or lower compared to the neat epoxy network. Such results are attributed to dual influence of acrylate network on the formation of epoxy one. Firstly, cationic polymerization of epoxy component is sensitized by acrylate macroradicals in terms of free radical promoted cationic polymerization. On the other hand, the mobility of epoxy macrocations is restricted by the rapid build-up of acrylate network. At the weight ratio of UP-650D and TEGDM 70/30 the sensitizing effect of acrylate is revealed to be dominant, so the given composition may be considered as optimal. Regardless of low conversion of epoxy groups, the content of the estimated gel fraction is high, and the epoxy component is found not to be leached in the process of extraction in acetone. Furthermore, physicomechanical properties of obtained UV-cured IPNs have been investigated. The results of the measurements, namely, impact resistance by the Gardner test, crosshatch adhesion test to different substrates (including silicon), and accelerated weathering test in a climatic chamber, show that all the samples exhibit good operational properties essential for effective protecting coatings of outdoor exposure.

Author(s):  
Oleksandr O. Brovko ◽  
◽  
Natalia V. Yarova ◽  
Tetiana F. Samoilenko ◽  
Larysa M. Yashchenko ◽  
...  

Using the method of IR spectroscopy, the kinetic features of the course of photoinitiated cationic and free radical polymerization in simultaneous epoxyacrylate interpenetrating polymer networks were investigated. The degree and rate of conversion of epoxy groups in the epoxy component (aliphatic diepoxide UP-650D, aliphatic-alicyclic triepoxide UP-650T, and diane epoxides ED-20 and Epicot 828), and the opening of double bonds in acrylate component (triethylene glycol dimethacrylate) were determined. The sensitizing effect of the acrylate component on the degree of conversion of epoxy groups in IPNs with aliphatic diepoxide or aliphatic-alicyclic triepoxide with an epoxy/acrylate ratio of 50/50 wt. % was revealed. For diane epoxies, the opposite regularity of conversion of epoxy groups in the composition of epoxy-acrylate IPNs is observed: in comparison with initial polymer networks, the degree of conversion of epoxy groups was significantly reduced. In the first case of low-viscosity aliphatic and cycloaliphatic epoxides such a sensitization is occurred due to the fact that the simultaneous polymerization of acrylate via a free radical mechanism promotes the decomposition of the photoinitiator and the formation of more macrocations quantity. In second case of more viscous diane epoxy resins, the spatial restriction imposed by the rapidly formed acrylate networks is predominate. That is why the conversion of epoxy groups is reduced and this effect is neutralized.


2014 ◽  
Vol 2 (1) ◽  
pp. 5-9
Author(s):  
Tetiana Samoilenko ◽  
Nataliia Iarova ◽  
Halyna Menzheres ◽  
Oleksandr Brovko

The paper discuses the phenomenon of the sensitization of the aliphatic epoxy photopolymerization in the presence of acrylate oligomers while forming epoxy-acrylate interpenetrating polymer networks. The photopolymerization process was studied by IR spectroscopy and the properties of the final products – by the Gardner test, crosshatch adhesion test, and the pencil hardness test. The epoxy groups conversion, which is rather low in aliphatic epoxy polymers, was found to alter with the increase of acrylate compounds content. The materials synthesized on the base of interpenetrating polymer networks were shown to reveal fine properties and may have a potential application as coatings.


e-Polymers ◽  
2016 ◽  
Vol 16 (6) ◽  
pp. 429-435
Author(s):  
Tetiana F. Samoilenko ◽  
Natalia V. Iarova ◽  
Svitlana M. Ostapiuk ◽  
Maksym H. Tkalich ◽  
Liubov O. Vorontsova ◽  
...  

AbstractPhotocured simultaneous epoxy-acrylate interpenetrating polymer networks (IPNs) were formed both under irradiation by UV-lamp and natural sunlight. The conversion degrees of functional groups were calculated by using data obtained from Fourier transform infrared (FTIR) spectroscopy. The influence of N-vynilcarbazole (NVC) as a photosensitizer on the kinetics of IPN photopolymerization was investigated. The conversion degrees of epoxy groups were revealed to increase significantly with the addition of NVC to the given systems. The phase morphology of IPNs was analyzed by optical and scanning electronic microscopy as well as by dynamic mechanical analysis (DMA). The data obtained using DMA method, which was used for analyzing the IPN samples with different component ratios, indicate the formation of both phase-separated and single-phase IPNs. The phase separation is occurred only in NVC-containing 50:50 IPN.


2010 ◽  
Vol 174 ◽  
pp. 385-388
Author(s):  
Fu Qiang Chu

Water-based UV-curable prepolymers are novel environmentally friendly materials. The blending property of two kinds of the prepolymers, water-based UV-curable polyurethane acrylate (UVPU) and water-based UV-curable epoxy acrylate (WEA), was studied in this paper. Blending compatibility, curing rate, optical and mechanical properties, and the cross-section morphology of the cured films of UVPU and WEA were investigated by Fourier transform infrared (FTIR), UV-visible spectrophotometer (UV-vis) and Environmental scanning electron microscopy (ESEM). Results indicated that the two prepolymers had good blending compatibility and high curing rate under UV radiation. The elongation at break of the cured film by WEA mixed with 20 wt% UVPU had 1.5 times increase compared to pure WEA, and the gloss increased 23% compared to pure UVPU, but the tensile strength decreased slightly. The morphology showed that the molecules of the two prepolymers polymerized each other and formed a network similar to the structure of Interpenetrating Polymer Networks (IPN). The comprehensive properties of the film were improved by blending of WEA and UVPU, and could be widely applied in the fields of coating varnish or printing ink.


e-Polymers ◽  
2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Mehdi Ghafghazi ◽  
Masoud Esfandeh ◽  
Jalil Morshedian

AbstractThis paper describes the preparation of Epoxy/Urethane (EP/PU) graft interpenetrating polymer networks (g-IPNs) and investigates the effect of EP/PU weight ratio and urethane's prepolymer molecular weight on the mechanical, morphological and thermal properties of the IPN system. Here, g-IPN was prepared by thorough mixing of an isocyanate-terminated urethane prepolymer with an epoxy resin followed by simultaneous curing of the resins. Polytetra hydrofuranate (PTHF), molecular weights (Mw) 1000, 2000 and 3000 g/gmol, was used to prepare urethane prepolymers. EP/PU weight ratios were 75/25, 50/50, 30/70 and 15/85. Disappearance of epoxide and isocyanate functional groups was followed by Fourier Transform Infrared spectroscopy (FT-IR), showing curing of the resins. Differential Scanning Calorimetry (DSC) was used to investigate the glass transition temperature (Tg) of the IPNs. Thermal Gravimetric Analysis (TGA), Dynamic Mechanical Thermal Analysis (DMTA), tensile measurements and Scanning Electron Microscopy (SEM) were used to study thermal, mechanical and morphological properties of the prepared systems. The best mechanical properties were obtained at EP/PU weight ratio 75/25 which also shows a fine and uniformly dispersed morphology. Moreover, at this ratio, with increasing PTHF Mw in the urethane prepolymer, the mechanical properties were improved whereas a decrease was observed in Tg and thermal degradation temperature of g-IPNs.


2016 ◽  
Vol 38 (1) ◽  
pp. 40-46
Author(s):  
T.F. Samoilenko ◽  
◽  
N.V. Iarova ◽  
S.M. Ostapiuk ◽  
M.H. Tkalich ◽  
...  

e-Polymers ◽  
2002 ◽  
Vol 2 (1) ◽  
Author(s):  
Stefano Fiori ◽  
Alberto Mariani ◽  
Laura Ricco ◽  
Saverio Russo

AbstractInterpenetrating polymer networks made of dicyclopentadiene and methyl methacrylate or tri(ethylene glycol) dimethacrylate have been successfully prepared by non-interfering frontal polymerization. The role of catalyst and free radical initiator relative amounts, as well as of monomer ratio, has been thoroughly studied. The conditions under which a pure frontal polymerization occurs, and the related values of both front velocity and maximum temperature reached by the reaction, are presented and discussed.


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