Synthesis and biodegradability assessment of poly(amide-imide)s containing N-trimellitylimido-l-amino acid and 5-(2-benzimidazole)-1,3-phenylenediamine

This paper addressed construction and biodegradability assessment of chiral synthetic poly(amide-imide)s (PAI)s. These polymers were prepared by polycondensation reaction of chiral diacids; N-trimellitylimido-S-valine (7a), and N-trimellitylimido-l-leucine (7b) with 5-(2-benzimidazole)-1,3-phenylenediamine (4) in the presence of tetrabutylammonium bromide as a green media under microwave irradiation. The morphology observations of the aforementioned polymers exhibit that these macromolecules are nanostructured particle and so, good candidate as carrier for biomedical application. Furthermore, in vitro toxicity and soil biodegradability test of the different synthetic diacids (7a, 7b) and the obtained PAIs were employed to evaluate the biological activity of these materials. In Petri plate technique, the monomers and obtained polymers exposed on glass lamels were all colonized by fungal saprophytes and due to this invasion, a weight loss up to 35 % was observed in the material. The soil burial test and measuring dehydrogenase activity revealed that the aforementioned monomers and polymers are biologically active and probably biodegradable under the soil. Normal wheat seedling growth took place in the vials containing the aforesaid monomers and polymers. It could be concluded that the synthesized monomers and their polymers are biologically active, and they are nontoxic to ecosystems and natural environments.     

A straightforward preparation and characterization of novel poly(vinyl alcohol)/organoclay/silver tricomponent nanocomposite films

In the present investigation, novel poly(vinyl alcohol)/organoclay/silver (PVA/OMMT/Ag) tricomponent nanocomposite (NC) films with different compositions were prepared by solution intercalation method under ultrasonic irradiation process. The NC films were obtained by mixing a colloidal solution consisting of Ag nanoparticles (NPs) (3, 5, 7 and 9 wt%) with a water solution of PVA and OMMT (10 wt%) via solution casting method. The scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetric analysis (TGA) were utilized to characterize the morphology and properties of the PVA/OMMT/Ag NC films. TGA confirmed that the heat stability of the nanocomposite was improved. The enhancement in the thermal properties of the hybrid materials was due to strong hydrogen bonding between OH groups of PVA, free acid functionalized groups of OMMT, and the Ag NPs. SEM and TEM results also showed that the OMMT and Ag NPs were dispersed homogeneously in the PVA matrix on nanoscale.     

Novel chiral poly(amide-imide)/surface modified SiO2 nanocomposites based on N-trimellitylimido-l-methionine: Synthesis and a morphological study

In the present investigation, novel poly(amide-imide) (PAI)/SiO₂ nanocomposites (NCs) containing l-methionine moiety in the main chain were prepared via a simple and fast ultrasonic irradiation process. PAI was synthesized by direct poly condensation reaction of N-trimellitylimido-l-methionine with 4,4′-diamino diphenylether in molten tetra-n-butyl ammonium bromide/triphenyl phosphite as a green condensing agent. Due to the high surface energy and tendency for agglomeration, the surface of SiO₂ NPs was modified with chiral diacid. The obtained NCs were characterized by Fourier transform-infrared (FT-IR) spectroscopy, thermogravimetry analysis, X-ray powder diffraction, field emission-scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). The FT-IR spectroscopy indicated that the chiral diacid as the coupling agent was attached on the surface of SiO₂ NPs. FE-SEM, and TEM images showed that SiO₂ NPs were dispersed rather homogeneously in the PAI matrix.     

Novel nanocomposites obtained by dispersion of LDH modified with N‐tetrabromophthaloyl‐glutamic in poly(amide‐imide) having N‐trimellitylimido‐l‐leucine and 4,4′‐diaminodiphenylether units

Layered double hydroxides (LDHs) have attracted much attention as nanofillers in polymer nanocomposites (NCs) due to their particular surface structural, positively charged layer and so on. In this study, a chiral diacid was synthesized by the reaction of tetrabromophthalic anhydride and glutamic acid. LDH was modified by co‐precipitation of aluminum nitrate, magnesium nitrate, and glutamic acid containing diacid. Chiral poly(amide‐imide) (PAI) was synthesized by direct polycondensation reaction of N‐trimellitylimido‐l ‐leucine and 4,4′‐diaminodiphenylether. Different NCs of the obtained modified LDHs and the chiral PAI were prepared in a short time using ultrasonic technique. The morphology and the structure of the obtained samples were characterized by Fourier transform infrared, thermogravimetric analysis (TGA), field emission scanning electron microscopy, transmission electron microscopy, and X‐ray diffraction analysis. TGA of the NCs showed a special order in thermal stability in compression with the neat PAI owing to the uniform distribution of the nanofillers. POLYM. COMPOS., 37:1323–1329, 2016. © 2014 Society of Plastics Engineers     

Microwave assisted functionalization of carboxylated‐multiwalled carbon nanotubes with 5‐aminoisophthalic acid and its application for the preparation of chiral poly(ester‐imide)/CNT nanocomposites

This article presents the results of investigation into surface modification of carboxylated‐multiwalled carbon nanotubes (MWCNT)s by 5‐aminoisophthalic acid under microwave irradiation as a fast, safe, and simple method. The different contents of functionalized MWCNTs (5, 10, 15 wt%) were effectively dispersed in an aromatic polymer through ultrasonic irradiation to prepare MWCNT reinforced polymer nanocomposites (NC)s. The chiral poly(ester‐imide) (PEI) was prepared by a direct polycondensation of chiral diacid with 4,4′‐thiobis(2‐tert‐butyl‐5‐methylphenol). The effect of the presence of MWCNTs on morphological and thermal properties of the NCs was investigated by X‐ray diffraction, FT‐IR spectroscopy, thermogravimetric analysis (TGA), transmission electron microscopy, and field emission scanning electron microscopy. According to TGA data, the PEI/MWCNT NCs showed a much better thermal stability than pristine polymer. The microstructure study of the NCs indicated the compatibility of functionalized MWCNTs with PEI and uniform distribution of them in the polymer matrices. POLYM. COMPOS., 37:835–843, 2016. © 2014 Society of Plastics Engineers     

Surface Treatment of ZrO2 Nanoparticles with Biosafe Citric Acid and Its Utilization for the Synthesis of L-leucine Based Poly(Amide–Imide) Nanocomposites

This study aimed at preparing three nanocomposites of optically active poly(amide–imide) and zirconium dioxide (ZrO₂) inorganic nanoparticles through the ultrasonic process. First, the surface of ZrO₂ nanocomposites was chemically modified with bio-active citric acid in the basic media. Then, the poly(amide–imide) was reinforced with modified nanocomposites and three poly(amide–imide)/ZrO₂-citric acid nanocomposites were synthesized by ultrasonic irradiation. The poly(amide–imide) was prepared by polycondensation of N-trimellitylimido-L-leucine with 4,4′-diaminodiphenylsulfone using of triphenyl phosphite and molten tetra-n-butylammonium bromide as green media. The obtained poly(amide–imide)/ZrO₂-citric acid nanocomposites were characterized by different techniques.     

Study on morphology,thermal, mechanical and Cd(II) adsorption properties of PVC/α-MnO<Subscript>2</Subscript>-stearic acid nanocomposites: production and application

Alpha manganese dioxide nanorods (α-MnO₂) were successfully functionalized with stearic acid (SA) by solvothermal method to prevent agglomeration. The α-MnO₂-SA nanorods were employed as a filler for the preparation of poly(vinyl chloride) (PVC) nanocomposite (NC) films with different percentages (1, 3 and 5 wt%). The morphology, mechanical and thermal properties of the obtained NCs were investigated. The results showed that α-MnO₂-SA can effectively improve the properties of PVC. The enhancement in properties of the NCs was attributed to the improved interfacial bonding by modification. Also, these NCs were used as adsorbent for removal of cadmium ions. Our finding suggests that the PVC/α-MnO₂-SA NCs are good candidates for efficient Cd(??) removal from the wastewater.     

Efficient functionalization of multi‐walled carbon nanotubes with p‐aminophenol and their application in the fabrication of poly(amide‐imide)‐matrix composites

The ultrasonically assisted preparation and characterization of poly(amide‐imide) (PAI) composites containing functionalized multi‐walled carbon nanotubes (MWCNTs) are reported. To improve the dispersion in and compatibility with the polymer matrix, the MWCNTs were surface‐modified with p‐aminophenol (p‐AP) under microwave irradiation. The process is fast, one‐pot, easy and results in a high degree of functionalization as well as dispersibility in organic solvents. The p‐AP‐functionalized MWCNTs (MWCNTs‐AP) were analysed by means of field emission and transmission electron microscopy, Fourier transform infrared spectroscopy, X‐ray diffraction and thermogravimetric analysis (TGA). The results consistently confirm the formation of p‐AP functionalities on MWCNTs which are able to undergo additional reactions, while the structure of the MWCNTs remains relatively intact. MWCNTs‐AP/PAI hybrid films were prepared with various MWCNTs‐AP contents (5–15 wt%) using a solution‐casting technique. Microscopic observations show that the dispersion of the MWCNTs‐AP is improved as a result of the organic groups on the MWCNT surface and functional groups in the PAI structure. The properties of the obtained composites were characterized extensively using the aforementioned techniques. TGA results show that the hybrid films exhibit a good thermal stability. Tensile mechanical testing was performed for the prepared composites, the results of which indicate an increase in the elastic modulus and tensile strength with increasing MWCNTs‐AP content. © 2013 Society of Chemical Industry