scholarly journals Different Approaches to Oxygen Functionalization of Multi-Walled Carbon Nanotubes and Their Effect on Mechanical and Thermal Properties of Polyamide 12 Based Composites

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 308 ◽  
Author(s):  
Magdalena Kwiatkowska ◽  
Robert Pełech ◽  
Anna Jędrzejewska ◽  
Dariusz Moszyński ◽  
Iwona Pełech

In this work the preparation of polyamide 12 (PA12) based composites reinforced with pristine and surface-modified carbon nanotubes is reported. A qualitative and quantitative evaluation of multi-walled carbon nanotube functionalization with oxygen containing reactive groups achieved by different procedures of chemical treatment is presented. Simple strong oxidative acid treatment as well as chlorination with subsequent chloroacetic acid treatment were applied. Carbon nanotubes (CNTs) were also subjected to chlorine and ammonia in gaseous atmosphere with small differences in after-ammonia treatment. Commercial COOH-functionalized carbon nanotubes were compared with nanotubes that were laboratory modified. The effect of CNT functionalization was evaluated basing on the improvement of mechanical and thermal properties of polyamide 12 composites prepared by in situ polymerization. It was found that high concentration of oxygen-containing functional groups on nanotube surface is not sufficient to improve the composite performance if the structure of carbon nanotubes is defective. Indeed, the best effects were achieved for composites containing nanotubes modified under mild conditions, seemingly due to a compromise between morphology and surface chemical structure.

2015 ◽  
Vol 44 (5) ◽  
pp. 300-305 ◽  
Author(s):  
X. Jiang ◽  
L. Lin ◽  
X. Bai ◽  
S. Wang ◽  
C. Wang

Purpose – The purpose of this paper is to investigate the effects of carbon nanotubes (CNTs) on the mechanical, thermal and colour properties of solvent-containing two-component polyurethane (PU) coating. Design/methodology/approach – Fourier transform infrared spectroscopy and observation of dispersion stability were used to assess the effects of acid treatment on CNTs. The CNTs and PU composite coating was synthesised by in situ polymerisation and bending polymerisation, and the mechanical, thermal and colour appearance properties of coating were characterised. Findings – It was found that desirable modifications to CNTs occurred after acid treatment; thus, mainly carboxylic acid groups were introduced onto the surface of CNTs. And the acid-treated CNTs could improve the mechanical and thermal properties of PU coating, and the properties of composite coating was improved more successfully by in situ polymerisation than by blending polymerisation. Practical implications – The investigation established a method to synthesise CNTs and PU composite coating. The mechanical and thermal properties of PU coating could be improved by the inclusion of CNTs. Originality/value – This study established a method to synthesise CNTs and PU composite coating by in situ polymerisation and blending polymerisation; the effects of CNTs on modifying mechanical, thermal and colour properties of PU coating were investigated and compared in detail.


e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Morteza Ghorbanzadeh Ahangari ◽  
Abdolhosein Fereidoon ◽  
Seyfolah Saedodin

AbstractIn the present work, the effect of different acid treatment times of singlewalled carbon nanotubes (SWNTs) on the mechanical and thermal properties of polypropylene (PP)/maleated polypropylene (PP-g-MA) nanocomposites was investigated. The acid treatment process was based on a mixture of concentrated sulphuric and nitric acids. The SWNTs were treated with the acid mixture for 1, 3, and 6 h. FTIR, Raman spectroscopy and TEM revealed the values of carboxylic groups, graphitization and morphology of acid treated SWNTs, respectively. The thermal and mechanical properties and the morphology of nanocomposites were investigated by tensile tests, DMTA, DSC, and SEM.


2012 ◽  
Vol 11 (06) ◽  
pp. 1240030
Author(s):  
LIN CHENG ◽  
RUI WANG

Surface-modified carbon nanotubes (CNTs) and nano- Ce–Zr mixed oxides (CZO) were prepared and employed initially as supports of H3PW12O40 (HPW) for NO x adsorption–decomposition. Both CNTs and nano-CZO are favorable supports for HPW. After loading with HPW, the NO x adsorption efficiency increases, especially for HPW/CZO in which the highest adsorption efficiency can achieve 98% at the HPW loading of 70%, much higher than that of single HPW. NO x adsorption efficiency can be influenced considerably by catalyst preparing conditions, in particularly, ethyl alcohol is superior to water as solvent for HPW loading onto CNTs; the –OH containing CNTs shows better promotion effect on the adsorption of NO x than that containing –COOH when using absolute ethyl alcohol as solvent; mechanical grinding method is superior to incipient impregnation method in loading HPW onto the support of CZO. For both catalysts of HPW/CNTs and HPW/CZO, with the increase of HPW loading, the NO x adsorption efficiency tends to reach a peak value before dropping down. Heated from 150°C to 450°C at a rate of 50°C/min, the adsorbed NO was found to decompose into N2 , O2 and N2O , and yields of N2 being 21.8% and 27.3%, respectively for HPW/CNTs and HPW/CZO were obtained.


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