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991.
Photo‐curing behaviors of bio‐based isosorbide dimethacrylate by irradiation of light‐emitting diodes and the physical properties of its photo‐cured materials
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Bio‐based isosorbide (1,4:3,6‐dianhydroglucitol), which was obtained from biomass‐derived carbohydrates, has recently attracted much attention as an alternative to bisphenol A (BPA) because of its rigidity and transparency. BPA is still widely used for a variety of chemical applications even though it is known to be an endocrine‐disrupting chemical. BPA is a key precursor to most photo‐curable materials ranging from encapsulants of electronic devices to dental sealants. In this study, photo‐curable isosorbide dimethacrylate (ISDM) was synthesized from bio‐based isosorbide as a substitute for BPA, and the photo‐curing behaviors of ISDM by irradiation with light‐emitting diode (LED) light were investigated. The photo‐curing conversion and rates of ISDM formation were determined based on the change in the peak corresponding to the double bond within the methacrylate groups using attenuated total reflectance Fourier transform infrared (ATR–FTIR) spectroscopy. The effects of initiators and the wavelength of LED light on the photo‐curing conversion and rates of ISDM formation were examined, and a comparative study was carried out with 2,2‐bis[4(2‐hydroxy‐3‐methacryloyloxy‐propyloxy)phenylpropane] (Bis‐GMA), which is a photo‐curing material bearing a BPA moiety. In addition, the mechanical properties, such as surface hardness, adhesion strength, and transparency, after photo‐curing of ISDM were evaluated. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42726. 相似文献
992.
Jaewon Jeong Bora Kim Seunghan Shin Baekjin Kim Jae‐Soung Lee Sang‐Hyeup Lee Jin Ku Cho 《应用聚合物科学杂志》2013,127(4):2483-2489
Bio‐based compounds (FmHPM and FdHPM) with a furan backbone and photo‐polymerizable 2‐hydroxypropyl methacrylate (HPM) group(s) were synthesized from carbohydrate‐derived furanyl alcohols (furan‐2‐methanol and furan‐2,5‐dimethanol) and their photo‐polymerizing behaviors and mechanical properties after photo‐polymerization were investigated. Half time values (t1/2) of bio‐based FmHPM and FdHPM were 10.4 s and 3.0 s and their shrinkage ratios were 3.0 and 6.1% during photo‐polymerization, respectively. Tensile‐shear strength of glass and polycarbonate joints bonded by bio‐based furanic compounds appeared in range of 0.2–0.6 MPa and pencil hardness of film coated by bio‐based furanic compounds after photo‐polymerization showed 2H–3H. Newly synthesized bio‐based furanic compounds allowed the feasibility to alternate petroleum‐based Bis‐GMA/TEGDMA, photo‐polymerizable composition widely utilized in a variety of applications. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献
993.
994.
Aluminium appears to be a promising material for on-board hydrogen generation in fuel cell applications given the comparatively large amount of hydrogen produced per gram of aluminium in a safe system. A microfuel processor with aluminium and water as reactants is developed in a flow reactor for application in portable power sources. Two types of reactor are used. One reactor permits the direct feeding of liquid water in channels containing aluminium pellets, whereas the other utilizes the heat produced from the reaction to vapourize liquid water before entry into the reactor. Two additives, namely, calcium oxide (CaO) and sodium hydroxide (NaOH), are used to enhance the reaction rate. A maximum conversion of 78.6% with respect to aluminium is achieved when the water entering in the reactor is vapourized partially. In the case of liquid water entering the reactor, the conversion is 74.4%. 相似文献
995.
Han-Na Jang Hyo Jin No Ju-Yeon Lee Bum Ku Rhee Ki-Ho Cho Hee-Dok Choi 《Dyes and Pigments》2009,82(2):209-215
A novel, Y-type polyurethane containing 1-(2,4-dioxyethoxy)phenyl-2-{5-(2,2-dicyanovinyl)-2-thiophenyl}ethenes as nonlinear optical chromophores present within the polymer backbone, was prepared and characterized. The compound was soluble in common organic solvents and displayed thermal stability up to 260 °C and a glass transition temperature (Tg) of 163 °C. The second harmonic generation coefficient (d33) of poled polymer films at the compound's fundamental wavelength of 1560 nm was ~3.72 × 10?9 esu. Dipole alignment exhibited high thermal stability up to the Tg, and there was no decay in d33 below 148 °C owing to the partial main-chain character of the polymer structure. 相似文献
996.
This letter presents a complementary codes pilot-based space-time block code/orthogonal frequency division multiplex (STBC/OFDM) system. In this system, a pair of complementary codes transmitted in a pre-defined order with the OFDM data signals is used as the pilot signals in a two-antenna transmitter diversity system, and used to estimate the channels for optimal data detection at the receiver side. A complete receiver architecture has been designed and Monte Carlo simulations have been used to verify the performance of the system in mobile radio fading channels. 相似文献
997.
Yohan Kim Janghoon Yang Dong Ku Kim 《Communications Letters, IEEE》2008,12(5):365-367
In this letter, a closed form expression of the sum rate upperbound is derived for random beamforming. The proposed analytic solution provides a good approximation of the 'actual' sum rate performance, for which the conventional asymptotic analysis is less meaningful. Moreover, our result leads to an implication of the asymptotic growth rate of M log log K. 相似文献
998.
T. A. Chiang A. J. C. Trappey C. C. Ku 《The International Journal of Advanced Manufacturing Technology》2006,31(5-6):421-433
Traditional computer-aided design (CAD) and product lifecycle management (PLM) tools have their limitations in supporting quick-to-market, mass-customized product development environments. The present paper proposes a general integrated framework of design knowledge representation and develops a knowledge-based intelligent system (KBIS) to facilitate dynamic design reasoning. Owing to the increasing complexity of product design, the traditional design (knowledge) rules can no longer help facilitate complex product development, which requires flexible design knowledge adoption and collaborators’ interaction during design inference processes. Therefore, this research enhances the abilities of smart collaborative design reasoning. A conceptual architecture for the KBIS is presented to enable a collaborative design community to reason feasible design parameters and to integrate all sub-system designs of a product. Finally, a case study of designing an air compressor and its sub-system (V-type belt) is presented to demonstrate the unique features of the KBIS. 相似文献
999.
This study is focused on the application of a highly‐doped layered perovskite, La2Ti2O7, as the photocatalyst for the photocatalytic decomposition of isopropanol (IPA). The La2Ti2O7 powder prepared by solid state reaction was characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM), UV‐Vis diffuse reflectance spectrophotometry (UV‐DRS), X‐ray photoelectron spectroscopy (XPS), and zeta potential. The temporal behavior of the photocatalytic decomposition of IPA in aqueous solution by the UV/La2Ti2O7, with a photoreactor operated in a recirculation mode, was studied under various conditions including solution pH, light intensity, and La2Ti2O7 loading. The decomposition of IPA in aqueous solution by La2Ti2O7 photocatalytic processes was found to be technically feasible. A kinetic equation was developed for modeling the photocatalytic decomposition of IPA by the UV/La2Ti2O7 photocatalytic processes. 相似文献
1000.
M. Oberžan J. Holc M. Buh D. Kuščer I. Lavrač M. Kosec 《Journal of the European Ceramic Society》2009,29(11):2143-2152
We have studied the influence of increasing the amount of β-spodumene (LiAlSi2O6), as a Li2O-containing flux, on the phase composition, the microstructure evolution and the physical properties of high-alumina porcelain. Quartz reacts with β-spodumene in the temperature range 1150–1250 °C, forming lithium aluminium silicates with a larger amount of SiO2. The presence of lithium minerals contributes to a lower CTE for the fired bodies. At 1300 °C an improved flexural strength is achieved with compositions containing 1.0 or 1.2 wt.% of Li2O, as a result of a more uniform microstructure. With increasing amounts of Li2O the overfiring effect is greatly enhanced. The most favourable characteristics from an industrial perspective with regard to flexural strength and deformation during firing were attained by using a high-alumina porcelain composition containing 1.0 wt.% Li2O. 相似文献