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

Journal of Polymer Materials, Vol.36, No.4, pp. 391-399, 2019, DOI:10.32381/JPM.2019.36.04.8

Abstract The epoxymethcrylate resin (EMBHBCMA) of (2E, 6E)-bis(4-hydroxybenzylidene)-4- methylcyclohexanone(EMBHBC) was synthesized by condensing EMBHBC and methacrylic acid (1:2 mole ratio) by using 1,4-dioxane as a solvent and triethylamine as a catalyst at reflux temperature for 1-5 h to get acid value < 10. The structure of EMBHBCMA was supported by UV-Vis, FTIR, ¹ HNMR and ¹³CNMR spectroscopic techniques. Molecular weights and molecular weight distribution of EMBHBCMA were determined by gel permeation chromatography. EMBHBCMA is thermally stable up to about 300°C and followed two step degradation reactions. Kinetic parameters such as n, Ea, A and ΔS* were determined according to Anderson-Freeman method… More >

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

Journal of Polymer Materials, Vol.36, No.4, pp. 371-379, 2019, DOI:10.32381/JPM.2019.36.04.6

Abstract The epoxy methacrylate of (2E,6E)-2, 6-bis(4-hydroxybenzylidene)cyclohexanone (EBHBCMA) was synthesized by condensing 0.02 equi. EBHBC, 0.04 equi. methacrylic acid, 50 mL THF as a solvent and 0.2 mL triethylamine as a catalyst at reflux temperature for 1-5 h to get acid value < 10. EBHBCMA showed good solubility in common solvents. The structure of EBHBCMA was supported by UV-Vis., FTIR, 1 H NMR, and 13C NMR spectroscopic techniques. DSC thermogram of EBHBCMA exhibited two endothermic peaks (86.4 and 117.1 °C) and one exothermic peak (142.6°C) due to moisture release, melting and curing of the resin, respectively. EBHBCMA is thermally stable up… More >

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

Journal of Polymer Materials, Vol.36, No.1, pp. 101-109, 2019, DOI:10.32381/JPM.2019.36.01.8

Abstract The epoxy resin (EMBHBC) of (2E,6E)-bis (4-hydroxybenzylidene)-4-methyl cyclohexanone (MBHBC) was synthesized by condensing 0.5 mol MBHBC and 2.5 mol epichlorohydrin in 500 mL isopropyl alcohol as a solvent and 1.0 mol NaOH in 50 mL water as a catalyst at 80°C for 3 h. The structure of EMBHBC was supported by UV-Vis, FTIR, ¹ HNMR and ¹³CNMR spectroscopic techniques. Molecular weights and molecular weight distribution of EMBHBC were determined by gel permeation chromatography. DSC thermogram of EMBHC showed one endothermic transition (95.9°C) and two exothermic transitions (317.7°C and 382.2°C) due to melting and decomposition transitions, respectively. EMBHBC is thermally stable… More >

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 stable up to about 300o… More >

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. DDM, PDA and THPA are… More >

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

Journal of Polymer Materials, Vol.38, No.1-2, pp. 11-19, 2021, DOI:10.32381/JPM.2021.38.1-2.2

Abstract The curing of epoxy resin of (2E, 6E)-2,6-bis(4-hydroxy benzylidene) cyclohexanone (EBHBC) was carried out at four different heating rates in the nitrogen atmosphere by using 4,4’-diamino diphenylmethane (DDM), 4,4’-diamino diphenyl sulfone (DDS), and 1,2,3,6-tetrahydrophthalic anhydride (THPA) as hardeners. From DSC curves onset, peak exotherm and end set temperatures, as well as heat release, were derived. The energy of activation was derived following Kissinger and Ozawa methods. Observed trend in Ea is EBHBC-THPA > EBHBCDDS > EBHBC-DDM > EBHBC. Nature and chemical structure of the hardeners affected the curing of EBHBC. More >

SORAYA SEGHIER^1,2,*, MOHAMMED BELBACHIR¹

Journal of Polymer Materials, Vol.38, No.3-4, pp. 205-218, 2021, DOI:10.32381/JPM.2021.38.3-4.3

Abstract In the present paper, we report the synthesis of a new amino polymer made of oxazolidinone using an efficient ecocatalyst called Maghnite-H⁺. The synthesis process contains two steps: the first consists to the preparation of an amino oxiran 3-(oxiran-ylmethyl) oxazolidin- 2-one (OMO) by a substitution reaction of epichlorhydrin by 2-oxazolidinone, the second step concerns a green polymerization of the resultant oxiran by a ring opening reaction catalysed by Maghnite-H⁺. The polymer have been successfully prepared and characterized by various techniques, such as ¹H NMR, ¹³C NMR, IR, which were used to elucidate the structural characteristics of the resulting polymers. The… More >

Morteza Eslamian^*

Frontiers in Heat and Mass Transfer, Vol.2, No.4, pp. 1-20, 2011, DOI:10.5098/hmt.v2.4.3001

Abstract Recent advances in thermodiffusion (Soret effect) in binary and higher multicomponent liquid mixtures are reviewed. The mixtures studied include the hydrocarbon, associating, molten metal and semiconductor, polymer, and DNA mixtures. The emphasis is placed on the theoretical works, particularly models based on the nonequilibrium thermodynamics, although other approaches such as the statistical, kinetic and hydrodynamic approaches are discussed as well. For each mixture, the major theoretical and experimental works are discussed and the research trends and challenges are addressed. Some of the challenges include a need for combining various methods to develop a comprehensive theoretical model or at least to… More >

BOWEN PENG¹, YUN GE¹, GANG YIN^2,3,*

BIOCELL, Vol.47, No.7, pp. 1519-1535, 2023, DOI:10.32604/biocell.2023.027026

Abstract Background: Tanshinone IIA, one of the main ingredients of Danshen, is used to treat hepatocellular carcinoma (HCC). However, potential targets of the molecule in the therapy of HCC are unknown. Methods: In this study, we collected the tanshinone IIA targets from public databases for investigation. We screened differentially expressed genes (DEGs) across HCC and normal tissues using mRNA expression profiles from The Cancer Genome Atlas (TCGA). Univariate Cox regression analysis and least absolute shrinkage and selection operator (LASSO) Cox regression models were used to identify and construct the prognostic gene signature. Results: Finally, we discovered common genes across tanshinone IIA… More >

Crisanto Velázquez-Becerra^1,*, Gu Yen Ambriz-Ortiz¹, Rafael Torres-Martínez², Mauro Manuel Martínez-Pacheco³

Phyton-International Journal of Experimental Botany, Vol.92, No.7, pp. 2165-2181, 2023, DOI:10.32604/phyton.2023.026954

Abstract Wood is a lignocellulosic material that, because of its organic nature, is a source of nutrients for bacteria, fungi, and insects. Incisitermes marginipennis (Latreille) is an interesting dry wood-boring termite. Because it is an extremely destructive pest, difficult to control due to its cryptic lifestyle, and for its role in the biogeochemical cycle of carbon and other elements; it is a fundamental organism. The use of less toxic and eco-friendly substances is important for protecting domestic, cultural, and historical heritage made of wood or lignocellulosic materials. The aim of this study was to evaluate the biological activity of various naphthoquinones… More >