RAVI KUMAR, VISHWA PRATAP SINGH, MADHUKAR PRAJAPATI, ASHWITH, PRIYANKA SINGH, SATYAJIT SAMANTA, SAIKAT BANERJEE^*

Journal of Polymer Materials, Vol.36, No.4, pp. 323-335, 2019, DOI:10.32381/JPM.2019.36.04.3

Abstract Types of nucleating agents and their dosage level play an important role on the crystallinity of the polymer which controls the final properties like optical clarity, stiffness and reduced cycle time during molding. In this study, the efficiency of two different types of commercially available nucleating agents, phosphate ester and dicarboxylic acid based, have been studied. Both the nucleating agents were compounded with molding grade polypropylene homopolymer having melt flow index (MFI) of 12 g/10min at 2.16 Kg and 230°C, in a co-rotating twin screw extruder at two different dosage level, i.e. 300 ppm and 600 ppm. The effectiveness of… More >

AYÇA BAL ÖZTÜRK^1,2,*, ZEHRA ÖZBA޳, BENGİ ÖZKAHRAMAN⁴, SERKAN EMİK⁵

Journal of Polymer Materials, Vol.36, No.2, pp. 161-173, 2019, DOI:10.32381/JPM.2019.36.02.5

Abstract A functionalized hydrogel composed of 2-(hydroxyethyl) methacrylate (HEMA) and acrylamide (AAm) was synthesized by amination and saponification reactions, respectively, and its functionality was examined for the elimination of copper(II) ions. The maximum adsorption capacity for copper(II) ions was 0.617 mmol g^-1 before saponification, whereas it was 1.2225 mmol g^-1 after saponification. The adsorption data was analyzed with pseudo-first-order (r² =0.8867), intra-particle diffusion (r² =0.9453), Elovich (r²=0.9489) and pseudo-secondorder(r² =0.9999) kinetic models. Based on the adsorption equilibrium experimental data Freundlich(r² =0.9964), Langmuir(r²=0.998) and Dubinin–Radushkevich (D-R) (r² =0.9960) adsorption isotherms provided good fits for all of experimental results. Finally, the datas of… More >

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 >

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 >

DIBYENDU S. BAG^*, SHILPI TIWARI, AKANSHA DIXIT, KM. MEENU

Journal of Polymer Materials, Vol.40, No.1-2, pp. 105-123, 2023, DOI:10.32381/JPM.2023.40.1-2.9

Abstract In this paper, we report the microstructural investigation and influence of H-bonding on the thermal behavior e.g., glass transition (T_g ) and thermal degradation of chiral copolymers of (R)- N-(1-phenyl-ethyl) methacrylamide (R-NPEMAM) and 2-hydroxy ethyl methacrylate (HEMA). The T_g increases with the increase of chiral unit content in the copolymers and then attains optimum at around 25 mole % of chiral content. Thereafter it decreases with the increase of chiral content. The effect of copolymer composition and secondary interaction associated with the Hbonding on the thermal properties of these copolymers was also studied. Secondary interaction, specifically H-bonding has been interpreted… More >

R. J. Johnson^∗, R. Pitchumani^†

Frontiers in Heat and Mass Transfer, Vol.1, No.1, pp. 1-9, 2010, DOI:10.5098/hmt.v1.1.3007

Abstract Much research is currently being performed with carbon nanotube additives to neat resin systems to enhance properties such as thermal and electrical conductivity, strength, modulus and damping. Fabrication of parts based on carbon nanotube filled resin systems requires information on their cure kinetics and rheology, which has been relatively less studied so far. This work presents an extensive experimental study that systematically characterizes the cure kinetics and viscosity as a function of degree of cure and temperature of EPON 815C/EPICURE 3274 epoxy resin system laden with carbon nanotubes. Studies are conducted to determine the effects of the carbon nanotube loading… More >

Haodong Li¹, Huiling Du^1,*, Le Kang¹, Yewen Zhang¹, Tong Lu¹, Yuchan Zhang¹, Lan Yang², Shijie Song²

Journal of Renewable Materials, Vol.11, No.12, pp. 4161-4174, 2023, DOI:10.32604/jrm.2023.028877

Abstract The large accumulation of coal gangue, a common industrial solid waste, causes severe environmental problems, and green development strategies are required to transform this waste into high-value-added products. In this study, low-cost ceramsites adsorbents were prepared from waste gangue, silt coal, and peanut shells and applied to remove the organic dye methylene blue from wastewater. We investigated the microstructure of ceramsites and the effects of the sintering atmosphere, sintering temperature, and solution pH on their adsorption performance. The ceramsites sintered at 800°C under a nitrogen atmosphere exhibited the largest three-dimensional-interconnected hierarchical porous structure among the prepared ceramsites; further, it exhibited… More > Graphic Abstract

Jiaojiao Yuan¹, Su Tuo¹, Yangyang Liu¹, Jing He¹, Shao-Hwa Hu¹, Junling Tu^2,*

Journal of Renewable Materials, Vol.11, No.8, pp. 3371-3385, 2023, DOI:10.32604/jrm.2023.028046

Abstract

Due to the existence of poly-hydroxyl structures, the temperature may have an effect on the thermal stability of oleuropein for its applications. In the current study, the thermal decomposition process and kinetics behavior of oleuropein from the olive resource were researched by thermogravimetric theoretical analysis methods and non-isothermal kinetics simulation. The results of thermogravimetry analysis showed the whole thermal decomposition process of oleuropein involved two stages, with 21.22% of residue. It was also revealed that high heating rates of more than 20 K min⁻¹ led to significant thermal hysteresis and inhibited the whole thermal decomposition behavior of oleuropein. Moreover, an… More > Graphic Abstract

A.D.S.M.R. Pascoal^a , P.M. da Silva^b,c, M.N.C. Coelho Pinheiro^a,d,*

Frontiers in Heat and Mass Transfer, Vol.12, pp. 1-7, 2019, DOI:10.5098/hmt.12.29

Abstract Efforts have been made to obtain new drug formulations in ophthalmologic applications to replace eye drops that are inefficient. Soft contact lenses have been using as an ophthalmic drug delivery device. Several hydrogels were used to prepare solid matrices with the drug impregnated. Assuming drug diffusion within polymeric devices as the dominant mechanism in the mass transfer process, simple models were developed to describe drug release from an ocular delivery device. The timolol maleate (medicine for glaucoma treatment) dissolution profile in the release medium for methacrylate hydrogels based contact lenses were obtained experimentally and compared with predictions considering one-dimensional and… More >

M.A. Waheed^a, C.A. Komolafe^b,*

Frontiers in Heat and Mass Transfer, Vol.12, pp. 1-7, 2019, DOI:10.5098/hmt.12.8

Abstract The drying kinetics of three varieties of cocoa beans (N38, F and WA) at 40, 50 and 60 degree centigrade was investigated experimentally. The three different varieties were dried using laboratory air oven UF Memmert and the moisture content determined according to AOAC standards. The results show that drying processes occur mainly in the range of the falling-rate period and the drying rates were observed to be faster at higher drying temperature. The effective diffusivities of the three cocoa beans varieties determined at 40, 50 and 60 degree centigrade ranged between 9.9269 x 10^-11 and 4.4671 x 10^-10 metre square… More >