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Ethylene oxide functionalized vegetable oil based polyol for waterborne polyurethane dispersion
( Alagi Prakash Kallappa ),최예진,홍성철 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.1
Due to growing concerns on environmental issues and volatile organic compounds, waterborne polyurethanes (WPUs) have drawn attentions in polymer industry. Ethylene oxide (EO) has been widely used as soft segment for the WPUs because of its hydrophilic nature. In this study, preparation of hyperbranched polyols with EO functionalities were attempted through thiol-ene click reaction between soybean oil (SO) and thiol-containing EO compounds. The resulting SO-based polyols were successfully incorporated into WPUs, exhibiting hyperbranched chain architectures. Proton nuclear magnetic resonance spectroscopy and gel permeation chromatography were employed to investigate the functionalities and structural characteristics of the EO-functionalized SO-based polyols and WPUs. Thermal and mechanical properties of the WPUs were evaluated, along with their dispersion stability behaviors.
( Alagi Prakash Kallappa ),최예진,홍성철 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.1
Photoinduced thiol-ene click chemistry was investigated for efficient preparation of vegetable oil (VO)-based polyols with primary hydroxyl groups. To evaluate the efficiency of the thiol-ene reaction, experimental parameters such as thiol concentration, reaction time, and reaction temperature were studied. For the first time, nearly complete and quantitative transformation of carbon-carbon double bonds of castor oil and soybean oil to hydroxyl groups were demonstrated. The VO-based polyols were successfully incorporated into thermoplastic polyurethane (TPU), affording TPU with good elastomeric properties, high toughness, excellent transparency and improved hysteresis behaviors. The study demonstrated efficient synthetic pathway for the preparation of VO-based TPU through thiol-ene reaction to modulate their mechanical and optical properties.
Characteristics of polycarbonate polyol from carbon dioxide for thermoplastic polyurethane
( Alagi Prakash Kallappa ),최예진,홍성철,( Ghorpade Ravindra ) 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.1
Carbon dioxide (CO<sub>2</sub>) is becoming an increasingly crucial synthetic feedstock for chemicals and polymers, since it is abundant, cheap, and non-toxic. In present study, commercially available polyols from CO<sub>2</sub> and polyether polyol were successfully incorporated into thermoplastic polyurethanes (TPUs). The thermal, mechanical, and shape memory properties of the TPUs were compared with those of traditional TPUs from petroleum-based polyether polyol such as poly(tetrahydrofuran). Compared with the petroleum-based polyol TPUs, the CO<sub>2</sub>-based TPUs exhibited increased glass transition temperature, moduli, and favorable shape memory properties, demonstrating harder and tougher elastomers. In addition, TPUs from CO<sub>2</sub>-based polyols exhibited enhanced electrochemical corrosion resistance at room temperature compared with that of polyether-based polyol. These findings suggested that CO<sub>2</sub>-based TPUs are promising alternatives to conventional TPUs.
( Alagi Prakash Kallappa ),최예진,장정현,홍성철 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.1
Depletion of fossil resources and environmental issues has triggered the search for renewable feedstocks for sustainable polymers. In this study, controlled preparation of polyols with predetermined hydroxyl functionalities ranging from 2 to 4 were attempted using thiol-ene click reaction between soybean oil (SO) and 2-mercaptoethanol (ME). A series of thermoplastic polyurethanes (TPUs) were carefully prepared from the SO-based polyols and their polymerization characteristics were investigated. SO-based polyols with three and four ME units afforded TPUs with hyperbranched architectures. The SO-based TPUs exhibited improved mechanical and thermal properties, demonstrating hard and tough elastomers. The TPUs also exhibited excellent shape memory properties and film transparencies. This technique affords an efficient synthetic path way for the controlled preparation of polyols and TPUs from renewable resources.
Polycarbonate polyol from sustainable feedstock for thermoplastic polyurethane
( Alagi Prakash Kallappa ),최예진,홍성철 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.0
Carbon dioxide (CO2) is becoming increasingly important synthetic feedstock for chemicals and polymers, since it is abundant, low-cost, and non-toxic. Utilization of CO2 as a sustainable precursor for polyurethane (PU) is becoming a prime attention in polymer industry. In present study, commercially available polyol from CO2 and polyether polyol were successfully incorporated into thermoplastic polyurethanes (TPUs). The thermal and mechanical properties of the TPUs were compared with those of traditional TPUs from petroleum based polyols such as poly(tetrahydrofuran) and polypropylene glycol. The TPUs exhibited increased glass transition temperature and moduli with the CO2 based polyols, demonstrating harder and tougher elastomers in comparison with that from petroleum based polyols. These findings suggest that CO2 based TPUs will be promising alternative to conventional TPUs, enabling new applications of the ecofriendly material in high value added technologies.
Vegetable Oil-Based Polyols for Sustainable Polyurethanes
Prakash Alagi,홍성철 한국고분자학회 2015 Macromolecular Research Vol.23 No.12
Vegetable oils (VOs) are one of the most important bio-renewable resources in the chemical industry due to their biodegradability, universal availability and low price. Using VO-based polyols to substitute petroleum-based polyols is considered a prime and novel route towards preparing sustainable polyurethane (PU). In this context, recent progress on preparing VO-based polyols and PUs is briefly summarized in this article. Especially, thiol-ene reactions allow for the synthesis of VO-based polyols with different functionalities in keeping with efficient click chemistry principles. The studies indicated that VO-based polyols and the resulting PUs can be eco-friendly families of industrially important polymers with a low environmental footprint.
Prakash Alagi,Ravindra Ghorpade,장정현,Chandrashekhar Patil,Harishchandra Jirimali,Vikas Gite,홍성철 한국고분자학회 2018 Macromolecular Research Vol.26 No.8
One of the major challenges in current polymer industry is to develop renewable and sustainable alternatives to petroleum-based raw materials. In this study, soybean oil (SO) was adopted as a renewable resource to afford polyols (MSO) with predetermined primary hydroxyl values (OHVs). The MSOs were prepared through a simple thiol-ene click reaction between the SO and 2-mercaptoethanol. The OHVs of the MSOs were adjusted simply by controlling the conversion of carbon-carbon double bonds of SO to OH groups. To explore their potential applications, series of polyurethane (PU) coatings were prepared from the MSOs. The MSOs with increased OHVs afforded PU coatings with higher glass transition temperature and improved adhesion strength values. Notably, increased OHVs of MSOs afforded PU coatings with improved anticorrosion properties in 3.5 wt% NaCl corrosive medium, which was attributed to the strong adhesion and blocking characteristics of the PU coatings. This study demonstrated that the number of hydroxyl functionality of the bio-based polyols played a crucial role in controlling the characteristics of the PU coatings.