• Journal of Adhesion and Interface
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• v.23 no.4
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• pp.137-143
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• 2022

In this study, the polyurethane acrylates (PUA) resin with good adhesive and flexibility for adhesive for shoes and clothing were synthesized using that poly(tetramethylene adiphate glycol) (PTAd), poly(tetramethylene ether glycol) (PTMG) as polyester polyol and polyether polyol respectively, including 4,4'-methylene diphenyl diisocyanate (MDI), isophorone diisocyanate (IPDI), 1,4-butandiol (1,4-BD), 2-hydroxyethyl methacrylate (2-HEMA) and dibutyl amine (DBA). The effect of polyol blend in the polyurethane acrylate on thermal and mechanical properties, adhesion strength and flexural strength were studied. The glass transition temperature (T_g) of PUA was confirmed in range of -70~-40 ℃. In addition, the glass transition temperature (T_g), decomposition temperature (T_d), tensile strength adhesion strength and heat resistance were increased as increasing of PTAd amount while the elongation, water resistance and flexural properties were decreased. The synthesized polyurethane acrylate with 5:5 ratio of PTAd and PTMG indicated the highest adhesion strength and flexural properties.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.4
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• pp.463-469
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• 2015

Purpose: A hydrogel including alginate and $CaCl_2$ extracted from seaweed was manufactured, and their physical properties were investigated. Also, its applicability as contact lenses was examined. Methods: A film-type sample used in this experiment was manufactured using 2-hydroxyethyl methacrylate (HEMA), which is the raw material of hydrogel contact lenses; azobisiobutyonitile (AIBN), which is an initiator and ethylenglycoldimethacrylate (EGDMA), which is a cross-linking agent. It was hydrated in a PBS solution for 24 hours, and an interpenetrating polymer network (IPN) was formed in 1% and 2% alginate and 1%, 3%, and 5% $CaCl_2$ solutions for 24 hours, respectively. Results: The measurement of the physical properties of the film after the IPN showed that the moisture content was 30.89~36.89%, the refractive index was 1.431~1.441, the contact angle was $62.98{\sim}80.45^{\circ}$, and the tensile strength was 2.378~4.215 ($gf/mm^2$). Also, the physical properties hardly changed as the content of alginate increased, and the moisture content decreased as the content of $CaCl_2$ increased. As a result of the IPN, the moisture content and contact angle decreased compared to those of basic HEMA, but the tensile strength increased. The tensile strength of the second IPN was higher than that of the first IPN. In the case of $CaCl_2$, for the sample polymerized for 24 hours and the second IPN sample with 2% alginate, the contact angle decreased as the content of $CaCl_2$ increased. Conclusions: In this study, the tensile strength increased as the content of $CaCl_2$ increased, and the wettability increased as a result of IPN of alginate and $CaCl_2$. The hydrogel containing the alginate and $CaCl_2$ was confirmed possible utilization as contact lens material.

• Knowledge Management Research
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• v.21 no.3
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• pp.249-269
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• 2020

Recently, as the online market has matured, it is facing many problems to prevent the growth. The most common problem is the homogenization of online products, which fails to increase the number of customers any more. Moreover, although the portion of the online market has increased significantly, it now becomes essential to expand offline for further development. In response, many online firms have recently sought to expand their businesses and marketing channels by securing offline spaces that can complement the limitations of online platforms, on top of their existing advantages of online channels. Based on their competitive advantage in terms of analyzing large volumes of customer data utilizing information technologies (e.g., big data and artificial intelligence), they are reinforcing their offline influence as well through this online for offline (O4O) business model. On the other hand, most of the existing research has primarily focused on online to offline (O2O) business model, and there is still a lack of research on O4O business models, which have been actively attempted in various industrial fields in recent years. Since a few of O4O-related studies have been conducted only in an experience marketing setting following a case study method, it is critical to conduct an empirical study on O4O selection attributes and their impact on customer satisfaction and loyalty. Therefore, focusing on China's representative O4O business model, 'Fresh Hema,' this study attempts to identify some key selection attributes specialized for O4O services from the customers' viewpoint and examine the impact of these attributes on customer satisfaction and loyalty. The results of the structural equation modeling (SEM) with 300 O4O (Fresh Hema) experienced customers, reveal that, out of seven O4O selection attributes, four (mobile app quality, mobile payment, product quality, and store facilities) have an impact on customer satisfaction, which also leads to customer loyalty (reuse intention, recommendation intention, and brand attachment). This study would help managers in an O4O area well adapt to rapidly changing customer needs and provide them with some guidelines for enhancing both customer satisfaction and loyalty by allocating more resources to more significant selection attributes, rather than less significant ones.

• Textile Coloration and Finishing
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• v.22 no.4
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• pp.293-299
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• 2010

A methacrylate monomer having phospholipid polar group and cell membrane structure is known as highly biocompatible. Based on these properties, new biocompatible multi-functional textile finishing agent was developed using phospolipid copolymer. 2-Methacryloyloxyethyl phosphorylcholine (MPCE) was synthesized using 2-hydroxyethyl methacrylate (HEMA), 2-chloro-2-oxo-1,3,2-dioxaphospholane (COP) and triethylamine (TEA), and then polymerized to prepare MPCE copolymer by radical polymerization using azobisisobutyronitrile(AIBN). The structures of MPCE was characterized by FT-IR and 1H NMR and will be evaluated as textile finishing agent in further study.

• Journal of the Korean Applied Science and Technology
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• v.34 no.3
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• pp.650-656
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• 2017

The water-swollen hydrogels containing silicone or fluorine were prepared by copolymerization of 2-hydroxy ethyl methacylate (HEMA) with 3-(trimethoxysilyl)propyl methacrylate(SM) or 2,2,2-trifluoroethyl acrylate(FA). When the content of SM or FA increased in copolymers, there was tendency of water absorbance to decrease, whereas contact angles to increase. The hydrogels containing FA showed 2 ~ 4% higher water content and 4 ~ 5% lower contact angles compared to that of SM. Tensile strengths decreased as the content of SM increased. However, FA exhibited strength of $2.2Mpa/cm^2$ which is similar to $2.3Mpa/cm^2$ of B. FA, which implies comparatively low adherence, hence, showed better protein resistance properties than SM-based hydrogel. The photo-polymerization was also applied instead of thermal polymerization to enhance the energy efficiency. As a result, the reaction yield reached over 95% within 1 minute.

• 순환기질환의공학회:학술대회논문집
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• 2004.11a
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• pp.15-16
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• 2004

In summary, we have demonstrated soft lithographic application of HA (or polysaccharides in general) by means of ${\mu}CP$ and molding and constructed well-defined patterns of proteins and cells of various substrates including glass, silicon dioxides, poly(HEMA), polystyrene culture dishes, and biodegradable PLGA. These results suggest that HA could be used as a general platform on hydrophilic substrates.

• Journal of the Korean Chemical Society
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• v.61 no.3
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• pp.97-103
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• 2017

In this study, the functional hydrogel ophthalmic lens containing tungsten oxide nanoparticles, 2,4-dihydroxy benzophenone and 2-hydroxy-4-(methacryloyloxy) benzophenone were manufactured. HEMA (2-hydroxyethyl methacrylate), MMA (methyl methacrylate), AA(acrylic acid), the cross-linker EGDMA (ethylene glycol dimethacrylate), the initiator AIBN (azobisisobutyronitrile) and the functional additives including tungsten oxide nanoparticles, 2,4-dihydroxy benzophenone, and 2-hydroxy-4-(methacryloyloxy) benzophenone were used respectively. The measurements of water content and refractive index of the sample was decreased and increased, respectively. And also, the UV transmittance of produced lens containing 2,4-dihydroxy benzophenone, 2-hydroxy-4-(methacryloyloxy) benzophenone and tungsten oxide nanoparticles was measured. Based on the results of this study, it is judged that the performance improvement increased over time when 2-hydroxy-4-(methacryloyloxy) benzophenone was used as an additive, while the use of tungsten oxide nanoparticles influenced on blue-ray-blocking effect of the hydrophilic lens.

• Bulletin of the Korean Chemical Society
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• v.32 no.12
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• pp.4239-4243
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• 2011

Biocompatible hydrogels from 2-hydroxyethyl methacrylate (HEMA) monomer containing various amount of alginate in the presence and absence of hydrophilic methacrylic acid (MAA) were synthesized in order for biomedical application. The antimicrobial effect and interaction with proteins for hydrogels were investigated in this study. MAA was introduced because it was expected to increase the amount of water content in the polymer which is an important factor for biocompatibility, and alginate was expected to enhance the antimicrobial activity. The antimicrobial effect against S. aureus and E. coli increased for all hydrogels as the amount of alginate and MAA contained. Presence of MAA further enhances the antimicrobial effect. Amount of adsorption of bovine serum albumin (BSA) increased with increasing concentration of alginate whether MAA was present or not. Contrarily, the amount of lysozyme was not affected with increasing alginate concentration in the absence of MAA, while it decreased in the presence of MAA.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2009.03a
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• pp.160-161
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• 2009

A methacrylate monomer having phospholipid polar group and cell membrane structure is known as highly biocompatible. Based on these properties, new biocompatible multi-functional textile finishing agent was developed using phospolipid copolymer. 2-Methacryloyloxyethyl phosphorylcholine (MPC) was synthesized using 2-hydroxyethyl methacrylate (HEMA), 2-chloro-2-oxo-1,3,2-dioxaphospholane (COP), trimethylamine (TMA) and triethylamine (TEA), and then polymerized to prepare MPC copolymer by radical polymerization using AIBN. The structures of MPC and MPCE were characterized by FTIR and 1H NMR and will be evaluated as textile finishing agent in further study.

• Journal of Biomedical Engineering Research
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• v.8 no.1
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• pp.13-28
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• 1987

Crosslinked poly(2-hydroxyethylmethacrylate) has been prepared by polymerizing 2-hydroxyethyl methacrylate(HEMA) with crosslinkers such as ehyleng glycol dime- thacrylate(EGDMA), tetraethylene glycol dimethacrylate(TEGDMA), tetraethylene glycol diacrylate(TEGDA), divinyl benzene(DVB), and N, N-methylenebisacry- lamide(MAB) in the presence of initiator $\alpha$ , $\alpha$ -azobisisobutyronitrile at 60。C, The synthesized copolymers were identified by FT-lR spectrophotomether. The swelling properties of the crosslinked copolymers in various solvents such as water, methanol, ethanol, n-propanol, and n-butanol were investigated at different temperatures. The thermal properties of the crosslinked coplymers were also measured by differential scanning calorimetry(DSC) and thermogravimetry(TG)