Nanocomposite structures of polypyrrole derivatives and poly (acrylonitrile‐co‐itaconic acid) produced by in situ polymerization as carbon nanofiber precursor

2019 ◽  
Vol 31 (3) ◽  
pp. 536-543
Author(s):  
Havva Baskan ◽  
Ezgi Ismar ◽  
Hale Karakas ◽  
A. Sezai Sarac
Keyword(s):  
Itaconic Acid ◽  
Carbon Nanofiber ◽  
In Situ Polymerization ◽  
Poly Acrylonitrile ◽  
Nanocomposite Structures

scholarly journals The influence of composition of poly(n-isopropylacrylamide-co-itaconic acid) hydrogel on immobilized Candida rugosa lipase activity

2008 ◽  
Vol 62 (6) ◽  
pp. 339-344
Author(s):  
Nikola Milasinovic ◽  
Melina Kalagasidis-Krusic ◽  
Zorica Knezevic-Jugovic ◽  
Jovanka Filipovic
Keyword(s):  
Mechanical Properties ◽  
Itaconic Acid ◽  
Lipase Activity ◽  
Acid Content ◽  
Immobilized Enzyme ◽  
In Situ Polymerization ◽  
Immobilized Lipase ◽  
Candida Rugosa ◽  
Candida Rugosa Lipase

The application of lipases as catalysts in chemical reactions has been deterred by the high cost of isolation and purification of enzymes, the instability of their structure when they are isolated from their natural environment, contamination of products with residual protein, their sensitivity to process conditions, etc. These problems could be overcome using immobilized lipases. Immobilization is achieved by fixing enzymes to or within solid supports and as a result a heterogeneous system is obtained. The present paper reports on the immobilization of Candida rugosa lipase in hydrogels based on N-isopropylacrylamide and itaconic acid. Immobilization of lipase is carried out by two different methods. In the first method, lipase is added to the reaction mixture before polymerization and crosslinking (in situ polymerization), while in the second method the synthetized hydrogels are immersed in lipase solution and left to rich the equilibrium swelling. The specific activities of the immobilized lipase were determined in both cases and compared. The amount of the immobilized lipase is higher if the immobilization is carried out by immersing hydrogel in lipase solution. It was observed that in both cases lipase activity increases with an increase of the itaconic acid content up to 10 wt% and thereafter decreases. From the measurements of shear storage moduli (G') it was concluded that the increase of the itaconic acid content decreases the mechanical properties of the hydrogels. SEM analysis confirmed the highly porous structure of hydrogels. It was found that greater pores were achieved when the enzyme was immobilized by in situ polymerization. When the enzyme was immobilized by in situ polymerization the itaconic acid content had not great effect on the mass of the immobilized enzyme, except for the 100/0 sample. On the contrary, for the samples where the enzyme was immobilized by swelling, the increase of the itaconic acid content increases the mass of the immobilized enzyme. Concerning the activity of the immobilized lipase, the swelling degree and mechanical properties of the investigated hydrogels, the best results were performed by the 95/5 hydrogel sample.

scholarly journals Hollow IF-MoS2/r-GO Nanocomposite Filled Polyimide Coating with Improved Mechanical, Thermal and Tribological Properties

Coatings ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 25
Author(s):  
Jian Wu ◽  
Xiang Yin ◽  
Liwen Mu ◽  
Xin Feng ◽  
Xiaohua Lu ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Wear Rate ◽  
Carbon Nanofiber ◽  
In Situ Polymerization ◽  
Protective Film ◽  
Inorganic Fullerene ◽  
Reduced Graphene ◽  
Polyimide Coating ◽  
Frictional Interface

Polyimide (PI) is one of the most excellent polymers for coating. However, the high friction coefficient and the high wear rate of pure PI limit its further applications. In this work, the hollow inorganic fullerene-like MoS2/reduced graphene oxide (HIF-MoS2/r-GO) nanocomposite filled PI coating is prepared by in situ polymerization. Reinforcement in mechanical strength and thermal stability is realized on the PI composite coating with incorporation of HIF-MoS2/r-GO, which performs better than carbon nanofiber (CNF). Reduced elastic modulus and hardness of HIF-MoS2/r-GO/PI coating is increased by 8.3% and 4.8%, respectively. The addition of HIF-MoS2/r-GO also results in 24% higher residual mass at 800 °C than CNF. Tribological study indicates that, HIF-MoS2/r-GO/PI achieves a wear rate reduction of 79% compared with pure PI under dry sliding condition, which is much more effective than other nanofillers including CNF, r-GO nanosheets and MoS2 nanoparticles. Under ionic liquid-lubricated condition, the presence of HIF-MoS2/r-GO in PI results in a 30% reduction in wear rate and 10% reduction in friction coefficient as compared to pure PI. It is thought that the HIF-MoS2/r-GO in PI can be slowly released to the frictional interface and form a protective film during sliding, in this way the aggregation problem is successfully solved.

Evaluation of Antimicrobial, Structural, Magnetic, and Thermal Potential of Silver Nanoparticles Anchored Polyaniline-Itaconic Acid-CuO Nanocomposites Synthesized From In-Situ Polymerization Method

2021 ◽  
Author(s):  
Parthiban E ◽  
Sudarsan S
Keyword(s):  
Electron Microscopy ◽  
Silver Nanoparticles ◽  
Itaconic Acid ◽  
In Situ Polymerization ◽  
Polymeric Nanocomposites ◽  
X Ray ◽  
Betel Leaf ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron

Abstract The silver nanoparticles (AgNPs) have been embedded within the itaconic acid (IA), polyaniline (PANi), and copper oxide (CuO) to form Ag@PANi-IA-CuO polymeric nanocomposites. In-situ polymerization of itaconic acid has been carried out in the presence of aniline monomers using anhydrous iron trichloride as an oxidising agent. The piper betel leaf extract was used to a reduction of AgNO3. The anchoring of AgNPs onto nanocomposite has been characterized using different techniques such as Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED) X-ray diffraction (XRD), and energy-dispersive X-ray (EDX). Biological, magnetic, and thermal properties of nanocomposites have also been studied in antimicrobial, vibrating sample magnetometer (VSM), and thermogravimetric analysis (TGA). Hence, these types of silver nanoparticles anchored polyaniline-itaconic acid-CuO nanocomposite has shown an attractive application in the field of biomedical and wastewater treatment.

Electrospun nanofibers of poly (acrylonitrile-co-itaconic acid)/silver and polyacrylonitrile/silver: In situ preparation, characterization, and antimicrobial activity

2019 ◽  
pp. 152808371986817
Author(s):  
Havva Baskan ◽  
Imren Esentürk ◽  
Sibel Dösler ◽  
A Sezai Sarac ◽  
Hale Karakas
Keyword(s):  
Silver Nanoparticles ◽  
Itaconic Acid ◽  
Electrospun Nanofibers ◽  
Antimicrobial Activities ◽  
E Coli ◽  
In Situ Preparation ◽  
Thermal Features ◽  
Nanofiber Membranes ◽  
Poly Acrylonitrile

In this study, it was aimed to prepare silver nanoparticles by reduction of silver salt (AgNO3) in situ by means of only synthesized polyacrylonitrile (PAN) and poly(acrylonitrile-co-itaconic acid) (P(AN-co-IA)) polymers, and N,N dimethylformamide (DMF). Thereafter, PAN/Ag and P(AN-co-IA)/Ag nanofibers were prepared via electrospinning. Spectroscopic and morphologic characterizations, electrical and thermal features, and antimicrobial activities of the prepared nanofibers against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans were carried out in detail. It was observed that P(AN-co-IA) was much more effective than PAN on the reduction of AgNO3 and formation of silver nanoparticles. Silver nanoparticles and also itaconic acid contributed to decrease the cyclization temperature of PAN by generating sharp exothermic peaks. In addition, electrical conductivity of the nanofibers increased dramatically from E−13 to E−4 related to the presence of silver nanoparticles. Furthermore, incorporation of silver nanoparticles to the nanofiber membranes let bactericidal/fungicidal activities, which started at 6–24 h and continued for up to 168 h, against S. aureus, E. coli, P. aeruginosa, and C. albicans. The prepared silver containing nanofibers can be regarded as good candidates for potential use in the biomedical and pharmaceutical applications.

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