Investigation of thermal and tensile properties of poly(benzimidazole-imide) composites incorporating salicylic acid–functionalized multiwalled carbon nanotubes

2016 ◽  
Vol 30 (2) ◽  
pp. 139-152
Author(s):  
Mohammad Ali Takassi ◽  
Amin Zadehnazari

This work describes a novel aromatic poly(benzimidazole-imide) (PBII) with amino salicylic acid (ASA) segments in the main chain by melt/solid polymerization method under solvent-free conditions and its composites reinforced with ASA-functionalized multiwalled carbon nanotubes (MWCNTs-ASA). The polymer was obtained in high yield with an amorphous morphology, was soluble in various organic solvents, such as N,N′-dimethylacetamide, N,N′-dimethylformamide, N-methyl-2-pyrrolidone, and dimethyl sulfoxide, and could afford flexible and tough film via solution casting. MWCNT-ASA/PBII composite films were also prepared by casting a solution of precursor polymer containing different fractions of MWCNTs-ASA into a thin film (1, 2, and 5 wt%). The cast films exhibited good mechanical properties with tensile strengths of 90.00–128.3 MPa, elongation at break of 4.6–7.9%, and tensile modulus of 1.6–2.9 GPa. They were reasonably stable up to a temperature above 400°C for the PBII and above 450°C for the composites. Structural and morphological evaluation of the composites was carried out by Fourier transform infrared spectroscopy and X-ray diffraction. Dispersion of MWCNT-ASA in the polymer matrix was investigated by field emission scanning and transmission electron microscopy.

2008 ◽  
Vol 22 (09n11) ◽  
pp. 1807-1812 ◽  
Author(s):  
H.-S. KIM ◽  
W.-I. PARK ◽  
Y. KIM ◽  
H.-J. JIN

Silk films prepared from regenerated silk fibroin are normally stabilized by β-sheet formation through the use of solvents (methanol, water etc.). Herein, we report a new method of preparing water-stable films without a β-sheet conformation from regenerated silk fibroin solutions by incorporating a small amount (0.2 wt%) of multiwalled carbon nanotubes (MWCNTs). To extend the biomaterial utility of silk proteins, forming water-stable silk-based materials with enhanced mechanical properties is essential. Scanning electron microscopy and transmission electron microscopy were used to observe the morphology of the MWCNT-incorporated silk films. The wide-angle X-ray diffraction provided clear evidence of the crystallization of the silk fibroin induced by MWCNT in the composite films without any additional annealing processing. The tensile modulus and strength of the composite films were improved by 108% and 51%, respectively, by the incorporation of 0.2 wt% of MWCNTs, as compared with those of the pure silk films. The method described in this study will provide an alternative means of crystallizing silk fibroin films without using an organic solvent or blending with any other polymers, which may be important in biomedical applications.


2018 ◽  
Vol 32 (1) ◽  
pp. 76-88 ◽  
Author(s):  
Zahra Rafiee ◽  
Milad Kolaee

The chiral poly(amide-imide) (PAI) was synthesized by the direct polycondensation reaction of imide-dicarboxylic acid, N-trimellitylimido-l-phenylalanine with diamine and 1,5-naphthalenediamine. Multiwalled carbon nanotubes (MWCNTs)/polymer composite films were prepared via dispersing of acid-functionalized MWCNTs (MWCNT-COOH) as reinforcement at MWCNT loadings of 5, 10, and 15 wt%. The PAI/MWCNT composite films were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, and transmission electron microscopy (TEM). The TEM results confirmed that the carboxylated MWCNTs were well dispersed in the polymer matrix. The thermogravimetric analysis data showed an improvement of thermal stability of composites containing the MWCNT as compared to the pure polymer. In this research, PAI/MWCNT composite 15 wt% was used as a novel and efficient adsorbent for removal of malachite green dye from aqueous solution.


Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 285
Author(s):  
Lingfei Li ◽  
Qiu Sun ◽  
Xiangqun Chen ◽  
Zhaohua Jiang ◽  
Yongjun Xu

The low dielectric constant of the nonpolar polymer poly(1-butene) (PB-1) limits its application as a diaphragm element in energy storage capacitors. In this work, Ba(Zr0.2Ti0.8)O3-coated multiwalled carbon nanotubes (BZT@MWCNTs) were first prepared by using the sol–gel hydrothermal method and then modified with polydopamine (PDA) via noncovalent polymerization. Finally, PB-1 matrix composite films filled with PDA-modified BZT@MWCNTs nanoparticles were fabricated through a solution-casting method. Results indicated that the PDA-modified BZT@MWCNTs had good dispersion and binding force in the PB-1 matrix. These characteristics improved the dielectric and energy storage performances of the films. Specifically, the PDA-modified 10 vol% BZT@ 0.5 vol% MWCNTs/PB-1 composite film exhibited the best dielectric performance. At 1 kHz, the dielectric constant of this film was 25.43, which was 12.7 times that of pure PB-1 films. Moreover, its dielectric loss was 0.0077. Furthermore, under the weak electric field of 210 MV·m−1, the highest energy density of the PDA-modified 10 vol% BZT@ 0.5 vol% MWCNTs/PB-1 composite film was 4.57 J·cm−3, which was over 3.5 times that of PB-1 film (≈1.3 J·cm−3 at 388 MV·m−1).


2021 ◽  
Vol 21 (11) ◽  
pp. 5673-5680
Author(s):  
Muthukrishnan Francklin Philips ◽  
Jothirathinam Thangarathinam ◽  
Jayakumar Princy ◽  
Cyril Arockiaraj Crispin Tina ◽  
Cyril Arockiaraj Crispin Tina ◽  
...  

The authors report the preparation of the nanocomposite comprising of vanadium pentoxide (V2O5) and selenium (Se) nanoparticles and functionalized multiwalled carbon nanotubes (MWCNTs) (V2O5@Se NPs/MWCNTs). Since Se NPs possesses extraordinary physicochemical properties including larger surface area with higher adsorption capacity, V2O5 NPs were adsorbed onto Se NPs surface through physisorption process (designated as V2O5@Se NPs). The nanocomposite synthesized hydrothermally was evaluated for its antimicrobial activity. The morphology and microstructure of the nanocomposite were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis, respectively. Fourier transform infrared spectroscopy (FTIR) and UV-Visible spectroscopy (UV-Vis) were employed to analyze the spectral properties of nanocomposite. The microbicidal efficacy of nanocomposite was tested against Gram-negative (G-)ZGram-positive (G+) bacteria and fungus. This is the first report on the synthesis of V2O5@Se NPs/MWCNTs nanocomposites by chemical method that showed microbicidal effect on micro-organisms. The thiol (-SH) units facilitates the enrichment of V2O5@Se NPs onto MWCNTs surface. Ultimately, it reflects on the significant antimicrobial activity of V2O5@Se NPs/MWCNTs.


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