Jamal N. Al Abbasi¹, Ahmed Z. Afify^2,*, Badr Alnssyan^3,*, Mustafa S. Shama^4,5

CMES-Computer Modeling in Engineering & Sciences, Vol.140, No.1, pp. 513-536, 2024, DOI:10.32604/cmes.2024.046533

Abstract This study proposes a new flexible family of distributions called the Lambert-G family. The Lambert family is very flexible and exhibits desirable properties. Its three-parameter special sub-models provide all significant monotonic and non-monotonic failure rates. A special sub-model of the Lambert family called the Lambert-Lomax (LL) distribution is investigated. General expressions for the LL statistical properties are established. Characterizations of the LL distribution are addressed mathematically based on its hazard function. The estimation of the LL parameters is discussed using six estimation methods. The performance of this estimation method is explored through simulation experiments. The usefulness and flexibility of the… More >

Liliane Nga¹, Benoit Ndiwe^1,2, Achille Bernard Biwolé¹, Antonio Pizzi^3,*, Jean Jalin Eyinga Biwole¹, Joseph Zobo Mfomo¹

Journal of Renewable Materials, Vol.12, No.3, pp. 553-568, 2024, DOI:10.32604/jrm.2023.046568

Abstract Extracts of plant origin, particularly tannins, are attracting growing interest for the sustainable development of materials in the industrial sector. The discovery of new tannins is therefore necessary. The aim of this work was to contribute to the understanding of the properties of Paraberlinia bifoliolata tannin by Matrix Assisted Laser Desorption Ionization Time of Flight Mass Spectroscopy MALDI-TOF/MS and Carbon 13 Nuclear Magnetic Resonance (¹³C NMR). The chemical composition of tannin extracted from Paraberlinia bifoliolata bark was determined, as was the mechanical strength of the resin hardened with Acacia nilotica extracts. Yield by successive water extraction was 35%. MALDI-TOF/MS analysis… More >

Verônica Távilla Ferreira Silva, Adriane Maria Ferreira Milagres^*

Journal of Renewable Materials, Vol.12, No.3, pp. 539-551, 2024, DOI:10.32604/jrm.2023.045726

Abstract This study was conducted to evaluate the effectiveness of enzymes in purifying and reducing the degree of polymerization of cellulose for the production of dissolving pulp. Our goal was to determine the contributions of xylanase (X) and endoglucanase (EG) in the treatment of pulp, specifically by quantifying the formation of soluble and insoluble reducing sugars using the dinitrosalycilic acid (DNS) test. Predominantly, the release of soluble reducing sugars (RSSol) was enhanced after xylanase treatment, while endoglucanase (EG) treatment led to changes in insoluble reducing sugars (RSIns). The maximum synergism was observed for RSIns when a high ratio of endoglucanase to… More > Graphic Abstract

Liting Jia¹, Xiao Han¹, Cuixia Qiao², Gang Zhao², Yanzhi Xia¹, Zhixin Xue^1,*

Journal of Renewable Materials, Vol.12, No.3, pp. 427-441, 2024, DOI:10.32604/jrm.2023.044310

Abstract Ba²⁺ pre-crosslinked carrageenan fiber (Ba/CAF) was prepared by adding a small amount of Ba²⁺ to the carrageenan (CA) solution as the spinning solution. Ba/CAF-n/A, Ba/CAF-n/B and Ba/CAF-n/C were prepared with ethanol solution (combine A), high concentration BaCl₂ solution (combine B) and low concentration BaCl₂ solution (combine C), as coagulation bath and stretch bath, respectively. The combination of coagulation bath and stretch bath suitable for Ba²⁺ pre-crosslinking wet spinning was screened. The results showed that Ba²⁺ can induce the birefringence of the CA molecular chain, and the Ba²⁺ pre-crosslinking effect is the best when the CA mass fraction is 8.0 wt%.… More > Graphic Abstract

KAVITA^*, R.K. TIWARI

Journal of Polymer Materials, Vol.36, No.2, pp. 195-205, 2019, DOI:10.32381/JPM.2019.36.02.7

Abstract The effect of poly (vinyl butyral) and acid functionalized multiwalled carbon nanotubes (f-MWCNT) on the thermal and mechanical performance of Kevlar fiber reinforced novolac epoxy nanocomposites was investigated and presented in this paper. Nanocomposite containing 1.5 wt. % poly (vinyl butyral) and 0.5 wt. % f-MWCNT exhibited best thermal and mechanical properties (except flexural strength) among all the nanocomposites reported here. It showed ~5%, 27% and 126 % improvement in tensile strength, young’s modulus and impact strength respectively as compared to the neat novolac epoxy Kevlar composite.Nanocomposite containing 0.5 wt. % f- MWCNT and 2 wt. % poly (vinyl butyral)… More >

D. MURALI MANOHAR^1,*, B.C. CHAKRABORTY², S. SHAMSHATH BEGUM³

Journal of Polymer Materials, Vol.37, No.1-2, pp. 91-107, 2020, DOI:10.32381/JPM.2020.37.1-2.7

Abstract In search of improved materials for efficient shock and vibration mounts for machineries, graphite loaded NBR and NBR/PVC blend were made and investigated. The scorch time was seen to be reduced and vulcanization rate was enhanced due to graphite inclusion. Scanning electron microscopy images have shown homogenous dispersion of graphite powder. NBRgraphite showed a gradual increase in the hardness, tensile strength, Young’s modulus, and tear values with increasing graphite loading. In the case of NBR/PVC-graphite composition, a drop in the tensile strength and increase in the Young’ modulus and tear strength was observed. Various mathematical models were used to investigate… More >

R.M. MISHRAA, R. VIJAYVARGIYAA, K.N. PANDEYA, J.S.P. RAIB

Journal of Polymer Materials, Vol.37, No.3-4, pp. 179-188, 2020, DOI:10.32381/JPM.2020.37.3-4.5

Abstract The present investigation is targeted to prepare nanocomposites based on binary blends of polyetherimide (PEI)-silicone rubber incorporated with varied loadings of nanotitanium dioxide particles. Nanocomposites have been prepared by melt blending process using twin screw extruder. Thermal properties of the developed nanocomposites have been investigated with the help of thermogravimetric analyzer (TGA) and dynamic mechanical analyzer (DMA). Scanning electron microscopy (SEM) is used to analyze the morphological properties of the nanocomposites. Mechanical properties (tensile strength, tensile modulus, elongation at break, impact strength) of the nanocomposites have been evaluated by universal testing machine (UTM). Mechanical testing results reveal that there is… More >

JITENDRA. S. TATE^1,2,*, HARISH KALLAGUNTA^1,2, ANDREW ALVAREZ¹

Journal of Polymer Materials, Vol.38, No.1-2, pp. 101-120, 2021, DOI:10.32381/JPM.2021.38.1-2.9

Abstract The exponential growth in composites and their increased use in military, aerospace, energy, and automotive industry is driven by their high performance and light weight. High performance thermosetting polymers such as cyanate ester have received considerable attention due to its ability of volatile-free curing. It also offers advantages such as excellent radiation shielding, high thermal stability, and hydrophobicity with lots of potential for enhanced mechanical strength. This research article discusses the results of effects of multiwalled carbon nanotubes (MWCNT) at predetermined loading levels of 0.5wt%, 1wt% and 1.5wt% on mechanical, thermal and flammability properties of cyanate ester modified carbon fiber… More >

LAVANYA, R¹, NATCHIMUTHU, N^2,*

Journal of Polymer Materials, Vol.38, No.1-2, pp. 89-100, 2021, DOI:10.32381/JPM.2021.38.1-2.8

Abstract Rubber composites of nitrile (NBR) and Ethylene-Propylene-Diene (EPDM) containing unmodified and modified microcrystalline cellulose(MCC) are evaluated for their processing behaviour. The used modified MCC (T-MCC) was treated by N,N-dimethylacetamide/lithium chloride (DMAc/ LiCl).ATR-FTIR spectra of NBR-MCC composites have indicated N-H stretching and bending vibrations and confirmed interactions between nitrile rubber and MCC. AFM studies have indicated that the average roughness of NBR-T-MCC was significantly reduced when compared to that of NBR-untreated MCC. Important processing parameters such as scorch time and cure time are found to decrease significantly for both NBR and EPDM composites withT-MCC. Mechanical properties of these composites are found… More >

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

Journal of Polymer Materials, Vol.38, No.1-2, pp. 71-87, 2021, DOI:10.32381/JPM.2021.38.1-2.7

Abstract Glass/Biofibers/Epoxy methacrylate of bisphenol-C (G/BF/EBCMAS) sandwich composites was prepared by compression molding. G/BF/EBCMAS showed good mechanical and good to excellent electrical properties and excellent chemical resistance. Studied properties are compared with EBCMAS and G/EBCMAS. In comparison with G/EBCMAS, G/BF/EBCMAS showed considerable decline of tensile strength (18-63.4%), flexural strength (18.8-38.7%), flexural modulus (12.8-50.7%), Izod impact strength (17.4-43.5%), Barcol hardness (2.1-16.7%) and dielectric strength (23.8-76.8%) except flexural strength of G/BM/EBCMAS. G/WC/EBCMAS (96.7%), G/B/EBCMAS (79.2%), G/GN/EBCMAS (83.3%) and G/RH/EBCMAS (97.9%) showed decline of volume resistivity, whereas other sandwich composites showed 1150-58233% improvement. The decrease in mechanical properties and dielectric strength of G/BF/EBCMAS sandwich… More >