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  • Open Access

    ARTICLE

    Renewable Bis-benzoxazine Monomers from Lignin Derivatives: Synthesis, Characterization and Studies on Curing Behavior

    CHUNYAN LIU*, YUNHE LIU, ZIHAN PAN, QIUTING LI, HAN XU, TAO LIU

    Journal of Polymer Materials, Vol.36, No.1, pp. 87-99, 2019, DOI:10.32381/JPM.2019.36.01.7

    Abstract In this work, a series of novel lignin-based bis-benzoxazine monomers were efficiently synthesized by the reaction of renewable phenols: guaiacol, vanillyl alcohol, eugenol, vanillin with ethylene diamine and paraformaldehyde. The chemical structures of these lignin-based bis-benzoxazine monomers were confirmed by 1H-NMR, 13C-NMR and FTIR, indicating the formation of benzoxazine ring. The obtained bis-benzoxazine monomers were cured via thermal treatment. The curing behavior of these lignin-based bis-benzoxazine monomers were compared and analyzed via differential scanning calorimetry (DSC), showing that Va-e possessed higher ring-opening polymerization activity than G-e, while E-e and V-e had lower curing activity than G-e. More >

  • Open Access

    ARTICLE

    Synthesis and Physico-chemical Studies on Chalcone Based Epoxy Resin of (2E, 6E)-Bis (4-hydroxybenzylidene) cyclohexanone

    DHARMESH B. SANKHAVARA, JALPA CHOPDA, JIGNESH P. PATEL, P. H. PARSANIA*

    Journal of Polymer Materials, Vol.36, No.1, pp. 13-21, 2019, DOI:10.32381/JPM.2019.36.01.2

    Abstract Chalcone based epoxy resin (EBHBC) of (2E, 6E)- bis(4-hydroxybenzylidene) cyclohexanone (BHBC) was synthesized by condensing 0.5 mol BHBC and 2.5 mol epichlorohydrin in 500 mL isopropanol as a solvent and 1.0 mol NaOH in 50 mL water as a catalyst at 80o C. The structure of EBHBC is supported by spectral techniques. Molecular weights and molecular weight distribution of EBHBC were determined by gel permeation chromatography. DSC thermogram of EBHC showed one endothermic transition (146.1°C) and two endothermic transitions (253.52°C and 397.34°C) due to melting, some physical change and decomposition transitions, respectively. EBHBC is thermally More >

  • Open Access

    ARTICLE

    Curing Study of Epoxy Resin of (2E, 6E)-Bis (4-hydroxybenzylidene)-4-methylcyclohexanone with Different Aromatic Diamines and Anhydrides Hardeners: Spectral and Thermal Analysis

    JALPA V. CHOPDA, DHARMESH B. SANKHAVARA, JIGNESH P. PATEL, P. H. PARSANIA*

    Journal of Polymer Materials, Vol.38, No.1-2, pp. 35-48, 2021, DOI:10.32381/JPM.2021.38.1-2.4

    Abstract Conventional curing study of epoxy resin of (2E, 6E)-bis (4-hydroxybenzylidene)-4-methyl cyclohexanone (EMBHBC) was conducted at 140 0 /150 0 C by using 4,4’-diaminodiphenylmethane (DDM),4,4’-diaminodiphenylsulphone (DDS),4-4’-diaminodiphenyl ether (DDE), p-phenylenediamine (PDA), 1,2,3,6-tetrahydrophthalic anhydride(THPA), maleic anhydride (MAH) and pyromellitic dianhydride (PMDA). The gel time for DDS, THPA and DDM hardeners are found considerably longer than those of DDE, PDA, MAH and PMDA systems indicated different reactivity towards curing of EMBHBC. Sol–gel analysis of cured resins was carried out in DMF at room temperature. Diamines cured samples showed 76.3-97.5% gel fractions, while anhydrides cured samples showed 84.6-99.6% gel fractions.… More >

  • Open Access

    ARTICLE

    Fabrication and Comparative Properties of Sustainable Epoxy Methacrylate of Bisphenol-C-Jute/Treated JuteNatural Fibers Sandwich Composites: Part-2

    RITESH D. BHATT, JIGNESH P. PATEL, PARSOTAM H. PARSANIA*

    Journal of Polymer Materials, Vol.39, No.3-4, pp. 223-239, 2022, DOI:10.32381/JPM.2022.39.3-4.4

    Abstract Compression-molded epoxy methacrylate of bisphenol-C-jute/treated jute-banana/groundnut/ cane sugar/pineapple leaf/rice husk/wheat husk sandwich composites were fabricated under 5 MPa pressure at room temperature for 3 h. Alkali treated jute-natural fiber sandwich composites displayed considerably improved mechanical properties over untreated jute-natural fiber sandwich composites due to surface modification of the jute fibers. Both types of sandwich composites showed high water uptake tendency, excellent hydrolytic stability against acids, alkali, and salt solutions, and also a longer equilibrium time at 30o C. Alkali treated sandwich composites revealed a considerably lower water uptake tendency than untreated sandwich composites. Observed water More >

  • Open Access

    ARTICLE

    Fabrication and Comparative Properties of Sustainable Epoxy Methacrylate of Bisphenol-C-Jute/Treated JuteNatural Fibers Sandwich Composites: Part-1

    RITESH D. BHATT, JIGNESH P. PATEL, PARSOTAM H. PARSANIA*

    Journal of Polymer Materials, Vol.39, No.3-4, pp. 205-221, 2022, DOI:10.32381/JPM.2022.39.3-4.3

    Abstract Epoxy methacrylate of bisphenol-C-jute/treated jute and their sandwich composites of white coir, brown coir, wild almond, bamboo, betel nut, and palmyra were prepared by a compression molding technique under 5MPa pressure and at room temperature for three h. The neat sample showed almost double tensile strength than its jute composite, while it is comparable for treated jute. The composites revealed substantially improved flexural strength compared to neat. The neat, jute/treated jute and their sandwich composites indicated good impact strength, pretty good Barcol hardness, and fairly good electric strength. The neat sample showed excellent volume resistivity, More >

  • Open Access

    REVIEW

    A Brief Review of Surface Modification of Carbonyl Iron Powders (CIPs) for Magnetorheological Fluid Applications

    THIRUMALAISAMY SURYAPRABHAA, CHUNGHYUN CHOIA, ZUBAIR AHMED CHANDIOB, LAWRENCE ROBERT MSALILWAB, TAEGWANG YUNC,*, JUN YOUNG CHEONGB,*, BYUNGIL HWANGA,*

    Journal of Polymer Materials, Vol.40, No.3-4, pp. 191-204, 2023, DOI:10.32381/JPM.2023.40.3-4.5

    Abstract Magnetorheological fluids (MRFs) is a smart fluid system that exhibits swift and reversible alterations in their rheological characteristics when exposed to an external magnetic field. MRFs are used for applications in various areas, including automotive systems, robotics, aerospace, and civil engineering. The performance of MRFs depends on the behavior of the dispersed magnetic particles, necessitating thoughtful consideration of particle traits to optimize fluid performance. Carbonyl Iron Powders (CIPs), high purity iron (>98%) reduced from penta carbonyl iron, are widely employed in MRFs due to their exceptional magnetic characteristics. Nevertheless, the innate surfaces of CIPs tend… More >

  • Open Access

    ARTICLE

    Fabrication and Comparative Properties of Sustainable Epoxy Methacrylate of Bisphenol-C-Jute/Treated JuteNatural Fibers Sandwich Composites: Part-II

    RITESH D. BHATT, JIGNESH P. PATEL, PARSOTAM H. PARSANIA*

    Journal of Polymer Materials, Vol.39, No.1-2, pp. 37-53, 2022, DOI:10.32381/JPM.2022.39.1-2.3

    Abstract Compression-molded epoxy methacrylate of bisphenol-C-jute/treated jute-banana/groundnut/ cane sugar/pineapple leaf/rice husk/wheat husk sandwich composites were fabricated under 5 MPa pressure at room temperature for 3 h. Alkali treated jute-natural fiber sandwich composites displayed considerably improved mechanical properties over untreated jute-natural fiber sandwich composites due to surface modification of the jute fibers. Both types of sandwich composites showed high water uptake tendency, excellent hydrolytic stability against acids, alkali, and salt solutions, and also a longer equilibrium time at 30o C. Alkali treated sandwich composites revealed a considerably lower water uptake tendency than untreated sandwich composites. Observed water More >

  • Open Access

    REVIEW

    Mini Review on PEDOT:PSS as a Conducting Material in Energy Harvesting and Storage Devices Applications

    HYUNGSUB YOONa,*, HEEBO HAa, CHUNGHYEON CHOIa, TAE GWANG YUNb, BYUNGIL HWANGa

    Journal of Polymer Materials, Vol.40, No.1-2, pp. 1-17, 2023, DOI:10.32381/JPM.2023.40.1-2.1

    Abstract Poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), one of the conducting polymers, is widely used as a conducting material in various applications. PEDOT:PSS possesses high electrical conductivity, optical transparency in visible light range, good chemical and physical stability in ambient state, etc. Furthermore, PEDOT:PSS offers the advantages of flexibility and possibility of solution-based process, which makes it suitable for use in flexible electronic devices. In this mini review, the applications of PEDOT:PSS as a conductive parts in energy harvesting and storage technologies are discussed and summarized. More >

  • Open Access

    ARTICLE

    Linear and Non-Linear Dynamics of Inertial Waves in a Rotating Cylinder with Antiparallel Inclined Ends

    Mariya Shiryaeva1, Mariya Subbotina2, Stanislav Subbotin1,*

    FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.4, pp. 787-802, 2024, DOI:10.32604/fdmp.2024.048165

    Abstract This work is devoted to the experimental study of inertial wave regimes in a non-uniform rotating cylinder with antiparallel inclined ends. In this setting, the cross-section of the cylinder is divided into two regions where the fluid depth increases or decreases with radius. Three different regimes are found: inertial wave attractor, global oscillations (the cavity’s resonant modes) and regime of symmetric reflection of wave beams. In linear wave regimes, a steady single vortex elongated along the rotation axis is generated. The location of the wave’s interaction with the sloping ends determines the vortex position and More >

  • Open Access

    ARTICLE

    Research on the Stability Analysis Method of DC Microgrid Based on Bifurcation and Strobe Theory

    Wei Chen, Nan Qiu*, Xusheng Yang

    Energy Engineering, Vol.121, No.4, pp. 987-1005, 2024, DOI:10.32604/ee.2023.045475

    Abstract During the operation of a DC microgrid, the nonlinearity and low damping characteristics of the DC bus make it prone to oscillatory instability. In this paper, we first establish a discrete nonlinear system dynamic model of a DC microgrid, study the effects of the converter sag coefficient, input voltage, and load resistance on the microgrid stability, and reveal the oscillation mechanism of a DC microgrid caused by a single source. Then, a DC microgrid stability analysis method based on the combination of bifurcation and strobe is used to analyze how the aforementioned parameters influence the More >

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