ÇAĞLA GÜL GÜLDİKEN, LEVENT AKYALÇIN, HASAN FERDİ GERÇEL^*

Journal of Polymer Materials, Vol.36, No.4, pp. 337-349, 2019, DOI:10.32381/JPM.2019.36.04.4

Abstract In the present study, polybenzimidazole (PBI) polymer which has a great importance in polymer electrolyte membrane (PEM) research was synthesized via the solution polycondensation method, under various synthesis conditions to put forward the effect of the synthesis parameters on the properties of the synthesized polymer and consequently to the quality of the prepared polymer electrolyte membrane. The synthesized polymers were characterized in terms of their chemical structure, thermal degradation behaviour, and molecular weight by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (¹ H NMR), thermogravimetric analysis (TGA). The Mechanical properties, acid-doping level capacity, proton conductivity, and fuel cell… More >

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 >

KAZIM SHAMIM RIZVI, P. K. DUTTA

Journal of Polymer Materials, Vol.36, No.3, pp. 217-228, 2019, DOI:10.32381/JPM.2019.36.03.2

Abstract In this investigation we have shown the preparation of carboxylic acid containing new chromophore : 4-(3-(4-nitrophenyl) thioureido) benzoic acid and its use.The chemical modification of chitosan, e.g., chitosan- acid salt complexes is done under mild conditions. The synthesis of chromophore was carried out by conventional methods and the novel polymer complex was soluble in most of the organic solvents. The modified chitosan was analyzed by various techniques like optical properties by UV and SHG spectroscopy which showed red shift. The antibacterial activity showed obvious effect against food pathogenic bacteria. More >

FATMA LOUZRI, SADJIA BENNOUR

Journal of Polymer Materials, Vol.37, No.1-2, pp. 55-76, 2020, DOI:10.32381/JPM.2020.37.1-2.5

Abstract Poly(N,N-dimethymethylacrylamide -co-crotonic acid) (P(DMA-CAx)) hydrogels were prepared by free radical polymerization, using N,N- methylenebisacrylamide (NMBA) as cross-linking agent. The synthesized hydrogels were characterized by Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). The effects of comonomer composition and pH of the medium on the swelling behavior of hydrogels were investigated. The obtained results showed that the swelling capabilities of hydrogels increased as crotonic acid content and pH increased. In order to evaluate the controlled release potential of the polymeric matrix, it was loaded with potassium nitrate and ammonium nitrate as fertilizers and the release kinetics was studied as a… More >

ELIF ANT BURSALI^1,*, DILER ABACI¹, MURAT KIZIL², MURUVVET YURDAKOC¹

Journal of Polymer Materials, Vol.38, No.3-4, pp. 231-245, 2021, DOI:10.32381/JPM.2021.38.3-4.5

Abstract Genipin cross-linked/boron doped starch/polyvinily alcohol (PVA) based hydrogel (SH-GNP-B) was synthesized as a new material having antimicrobial and antioxidant activity. The prepared hydrogel was characterized by X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Thermal Gravimetric Analysis (TGA) and Scanning Electron Microscope (SEM) methods and evaluated for in vitro antimicrobial activities against selected organisms by disc diffusion tests. The antioxidant activity of the prepared hydrogels was evaluated using 2,2-diphenyl-1- picrylhydrazyl radical scavenging assays. Swelling behavior of the hydrogel was also investigated. The synthesized hydrogel was thermally stable and showed pH independent swelling tendency. SH-GNP-B hydrogel was found to have antimicrobial… More >

SOBHA KOTA^*, RATNAKUMARI ANANTHA, VAYUNANDANA RAO GOVADA, PRADEEP DUMPALA

Journal of Polymer Materials, Vol.40, No.3-4, pp. 285-303, 2023, DOI:10.32381/JPM.2023.40.3-4.10

Abstract The exoskeleton of marine shrimp contains a natural, biocompatible polymer chitin, which is dumped as a waste. The study proposes the sustainable single-pot-extraction of chitosan from the waste and its use in the fabrication of wound-dressings, and thus leverage its piezoelectric, antioxidant, hypoglycaemic and medicinal properties in wound-healing. The Fourier transform infrared spectrum revealed that marine chitosan contains functional groups with N-O, O-H, and CO stretching. Scanning electron micrographs demonstrated the spherical and mesoporous structures of the extracted chitosan. X-ray diffraction analysis showed a semi-crystalline phase of chitosan particles with a mean size of 28.9 nm. The film prepared with… More >

Maria Inês Clara^1,2,3,*, Maria Cristina Canavarro^2,3, Ana Severina⁴, Susana Ramos⁴, Carla Rafael⁴, Ana Allen Gomes^1,2,3

Psycho-Oncologie, Vol.18, No.1, pp. 49-57, 2024, DOI:10.32604/po.2023.044320

Abstract Objectif: L’objectif de l’étude fut de comparer la fatigue ressentie par les patients du cancer par rapport à celle de la population en générale, ainsi que d’examiner les facteurs de risque psychobiologiques associés à la fatigue. Matériel et méthodes: Dans cette étude quantitative et transversale, nous avons analysé les indicateurs cliniques et sociodémographiques de 389 participants (68.38% de femmes) : 148 patients du cancer sous traitement actif, 55 patients dans l’après-traitement d’un cancer, 75 patients atteints d’une autre maladie chronique et 111 personnes en bonne santé. Résultats: La fatigue s’exprimait de manière différente chez les patients ayant des antécédents de… More >

Flavia Oliveira Monteiro da Silva Abreu^1,2,*, Taysse Holanda¹, Joice Farias do Nascimento¹, Henety Nascimento Pinheiro¹, Rachel Menezes Castelo¹, Hélcio Silva dos Santos³, Thais Benincá⁴, Patrícia da Silva Malheiros⁴, Júlio César Sousa Prado⁵, Raquel de Oliveira Fontenelle⁵, Maria Madalena de Camargo Forte²

Journal of Renewable Materials, Vol.12, No.2, pp. 285-304, 2024, DOI:10.32604/jrm.2023.043919

Abstract With the increase in antimicrobial resistance, it has become necessary to explore alternative approaches for combating and preventing diseases. DB-cinnamaldehyde (CNM) and Benzyl4-amino (B4AM) are bioactive compounds derived from chalcones but with restricted solubility in aqueous media. Nanoemulsions can enhance the solubility of compounds and can be a promising alternative in the development of novel antimicrobials, with reduced side effects and prolonged release. The objective of this study was to evaluate the stability of oil-in-water nanoemulsions loaded with two distinct types of chalcones at two different dosages, to propose a stable formulation with antimicrobial properties. Results showed that nanoemulsions presented… More > Graphic Abstract

Xiao Feng^1,2,3,*, Zheng Yuan¹

CMC-Computers, Materials & Continua, Vol.78, No.2, pp. 1881-1895, 2024, DOI:10.32604/cmc.2023.047243

Abstract First, we propose a cross-domain authentication architecture based on trust evaluation mechanism, including registration, certificate issuance, and cross-domain authentication processes. A direct trust evaluation mechanism based on the time decay factor is proposed, taking into account the influence of historical interaction records. We weight the time attenuation factor to each historical interaction record for updating and got the new historical record data. We refer to the beta distribution to enhance the flexibility and adaptability of the direct trust assessment model to better capture time trends in the historical record. Then we propose an autoencoder-based trust clustering algorithm. We perform feature… More >

Yue Yang¹, Jiarui Zheng¹, Long Cheng^1,*, Yongnan Zhu², Hao Wu²

Energy Engineering, Vol.121, No.3, pp. 703-728, 2024, DOI:10.32604/ee.2023.044721

Abstract To effectively quantify the impact of distributed photovoltaic (PV) access on the distribution network, this paper proposes a comprehensive evaluation method of distributed PV grid connection combining subjective and objective combination of assignment and technique for order preference by similarity to an ideal solution (TOPSIS)—rank sum ratio (RSR) (TOPSIS-RSR) method. Based on the traditional distribution network evaluation system, a comprehensive evaluation system has been constructed. It fully considers the new development requirements of distributed PV access on the environmental friendliness and absorptive capacity of the distribution grid and comprehensively reflects the impact of distributed PV grid connection. The analytic hierarchy… More >