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Study of the segmental mobility of polymer chains is important when the polymer is used as drag reduction agents of crude oil. Electron spin resonance (ESR) spectroscopy can provide important information about segmental dynamics of polymer chains, which is related to their microenvironment. In this article, we employed an amphiphilic polymer to study the effect of hydrophilic/hydrophobic balance of the polymers on the segmental motion of polymer chains. Poly(styrene-co-maleic acid) (PSMA) was spin labeled with 4-amino TEMPO radicals by increasing the concentration of radical moiety on the polymer chains. The PSMA and spin labeled-PSMAs (SL-PSMAs) were characterized by nuclear magnetic resonance (NMR), Fourier transform infrared (FT-IR) spectroscopy, Cyclic voltammetry (CV) and ESR techniques. Inter-polymer complexes (IPCs) of SL-PSMA-2 were prepared by employing polyethylene glycols (PEGs) of varying molecular weights. The results showed that the increased hydrophobic interactions of nitroxide radicals on the SL-PSMAs’ chains reduced the rotational mobility of spin labels and the random coil-to-globular transition of polymer chains occurred at higher pH value for SL-PSMAs, which showed a slow motion component in the ESR spectra of SL-PSMAs. Further, by increasing the molecular weight of PEGs in IPCs the complexation was increased, which also reduced the rotational motion of spin labels due to interpolymer hydrogen bonding causing a slow motion component in the ESR spectra.

The structure of polyolefin has an important influence on its performance and application. Ethylene/1-hexene copolymerization is one of the important ways to control the structure of the polyolefin. However, research on the ethylene/1-hexene copolymerization catalyzed by nickel complexes with different steric ligands remains to be refined. Here, three α-diimine nickel catalysts are used to study the ligand effect on catalytic performance in the ethylene/1-hexene copolymerization. Reaction activity, molecular weight, phase-transition temperature and branching density of the resultant copolymer are measured to evaluate the catalytic performance. The results indicate that the steric ligands could exert great effect on the copolymerization. As for the chemical valance of Ni species, detailed EPR demonstrate that the presence of excess co-catalyst can reduce Ni(II) to the lower valance and affect the catalytic performance.

Phenol is the toxicant present in cigarette smoke that causes pulmonary diseases, eyes infection, and even various kinds of cancer. So, in this research, an attempt was done to prepare a suitable absorbent to remove phenol from cigarette smoke. A novel bio-based adsorbent succinylated carboxymethyl starch (S-CMS) was prepared by reacting carboxymethyl starch (CMS) with succinic anhydride (SA) in the presenting of N, N-dimethylformamide (DMF) solvent and pyridine. The structure of the S-CMS was confirmed by spectroscopic techniques including proton nuclear magnetic resonance and Fourier transform infrared. The S-CMS crystallinity and thermal properties were checked by x-ray diffraction and thermogravimetric analysis. The results showed a decrease in thermal properties and crystallinity for S-CMS. The S-CMS were tested as adsorbents for the removal of phenol. The adsorption efficiencies of CMS, S-CMS1, S-CMS2, and S-CMS3 towards phenol were shown to be 0.297 g/g, 0.321 g/g, 0.322 g/g, and 0.324 g/g, respectively.

Polypyrrole nanotube/ferrocene-modified graphene oxide composites (PNT/GO-Fc, PNT/GO-Fc-GO, PNT/GO-EDA-Fc and PNT/GO-EDA-Fc-EDA-GO) were fabricated via in situ chemical oxidative polymerization. The prepared composites were characterized by FTIR, XRD, XPS, Raman, TGA, SEM, TEM and EDS. The electromagnetic interference shielding performance of the prepared composites was evaluated by a coaxial method within the frequency range of 1.0–4.5 GHz. The results demonstrated that the composite of PNT/GO-EDA-Fc-EDA-GO-7:1 exhibited the best electromagnetic interference shielding property with 28.73 dB (at the frequency of 1.0175 GHz with the thickness of 3.0 mm) of total shielding effectiveness by adding 50 wt% of the composite in the paraffin matrix. And the composite of PNT/GO-EDA-Fc-EDA-GO-7:1 exhibited good conductivity with a value of 1.320 S/cm. The relationship between the conductivities of prepared samples and the EMI shielding performance was investigated.

Hypothesis Organic radical polymers with tailored pendant functionalities have emerged as exciting and promising materials for their application versatility. Moreover, eco-friendly polymer-based organic nanomaterials with redox-active pendant side groups can replace the harmful heavy metal-based inorganic materials. On the other hand, self-assembled nanomaterials are of great interest and attracted more attention recently for their promising application in different advanced fields, but it is yet challenging to predict suitable hydrophilic-lipophilic balance (HLB) for stimuli-responsive random copolymers assembly due to structural irregularity. Among several experimental techniques, electron paramagnetic resonance (EPR) spectroscopy plays a unique and promising role in revealing structural and dynamic information of nanostructured radical containing materials. Experiments In this study, a series of spin labeled amphiphilic random copolymers poly(methyl methacrylate-co-acrylic acid) have been synthesized and characterized by FT-IR, UV–Vis spectroscopies, TGA, DSC and water contact angle (CA) techniques. Their electrochemical properties have been determined by cyclic voltammetry (CV) in different organic solvents. EPR spectroscopy has been applied with other analytical techniques to elucidate the smart supramolecular nanoparticles (SNPs) formation, stimuli-responsiveness and structural changes through the dynamics of different molecular interactions. Findings The structural and dynamic information of self-assembled nanoparticles have been observed to be dependent on multiple-stimuli-responsiveness in different microenvironments by applying physiological and chemical parameters such as the different concentration of radicals, pH, temperature, nature of the solvent and reducing agent. The obtained results reveal the knowledge to understand insight into the mechanism for the formation of stimuli-responsive colloidal nanoparticles assembled from amphiphilic random copolymers with apt HLB value. The CV results reveal that the charge transfer process of the nanoparticles in solution was diffusion regulated and depended on the accessibility of radicals. The radical (spin labeled) polymers offer a broad way to develop stimuli-responsive materials in various colloidal nanostructures by changing the microenvironment, appreciating their potential advanced applications in electronic devices, catalysis, stimuli-triggered drug/gene delivery and reactive oxygen species (ROS) scavenger.

Succinylated starches (SS) were prepared by the reaction of normal starch (NS) and porous starch (PS) with succinic anhydride (SA) in the presence of DMF solvent and base pyridine, respectively. The proton nuclear magnetic resonance and Fourier transform infrared were used to confirm the successful synthesis of the SS (SS1, SS2, SS3 and SS4, respectively). The X-ray diffractometer XPert PRO (Cu Kα, λ = 1.54 A) was used to study the crystallinity of NS, PS and SS. The XRD analysis showed that the SS exhibited amorphous nature after succinylation. Thermogravimetric analysis and differential thermal analysis of NS, PS and SS showed that succinylation decreased the thermal stability. The morphology of the NS, PS and SS was studied by SEM. These SS were used as adsorbents for phenol removal. The adsorption efficiencies for phenol by NS, SS1, SS2, SS3 and SS4 were found to be 0.084 g/g, 0.165 g/g, 0.173 g/g, 0.183 g/g and 0.189 g/g, respectively.

To overcome the migration problems of burning rate catalysts (BRCs), ferrocene-based amide compounds (AM-Fcs) were synthesized. The successful synthesis of AM-Fcs were confirmed by proton nuclear magnetic resonance, and Fourier transform infrared spectroscopy. The electrochemistry behaviors of AM-Fcs were examined by cyclic voltammetry (CV). The CV experimental results indicated that these AM-Fcs showed good electrochemical performances, which were contributable to their burning rate (BR) catalytic activity in composite solid propellants. The anti-migration test of AM-Fcs verified significantly slower migration than ferrocene and the most commonly used BRCs catocene. Thermal stability and BR catalytic impact of AM-Fcs on the thermal decomposition of ammonium perchlorate (AP) were studied by thermogravimetry and differential thermogravimetry. These AM-Fcs revealed good catalytic behaviors on the thermal degradation of AP.

In this study, poly(cyclotriphosphazene-co-piperazine) p(HCCP-co-PIP) nanospheres were prepared. The successful preparation of the p(HCCP-co-PIP) nanospheres was confirmed by FT-IR, SEM, TEM, XRD, ...

Poly(2-(diethylamino)ethyl methacrylate) (PDEAEMA) is a pH-sensitive polymer, while a few recent studies have shown it to possess temperature responsiveness as well. In this article, poly(2-(diethylamino)ethyl methacrylate-co-2,2,6,6-tetramethyl-4-piperidyl methacrylate)s, DEA-TMPMs, were synthesized. The TMPM moieties in DEA-TMPMs were subsequently oxidized with hydrogen peroxide to obtain poly(2-(diethylamino)ethyl methacrylate-co-2,2,6,6-tetramethylpiperidine-1-oxyl methacrylate), DEA-TMPs, having nitroxide radicals on the polymer chains. DEA-TMPMs were characterized by nuclear magnetic resonance spectroscopy, gel permeation chromatography, differential scanning calorimetry and thermogravimetry techniques, whereas DEA-TMPs were analyzed by Fourier transform infrared spectroscopy, cyclic voltammetry, and electron paramagnetic resonance (EPR) spectroscopy. The results showed that at low pH, the rotational mobility of nitroxide radicals was reduced as EPR spectra mostly consisted of slow-motion component. This slow-motion component in the EPR spectra remained unchanged below neutral pH. These results indicated a sort of interaction among nitroxide radicals and protonated amine groups of DEAEMA monomers.

In this article, starch phosphate-g-poly (methacrylic acids) (SP-g-PMAAs) were synthesized by dual modification. Firstly starch phosphate (SP) was synthesized by phosphorylation of native starch (NS) with mono sodium-phosphate and di sodium-phosphate. Afterwards, methacrylic acid (MAA) was grafted onto SP via free radical polymerization to synthesize SP-g-PMAAs. The structure of the SP and SP-g-PMAAs was investigated by phosphorus nuclear magnetic resonance, proton nuclear magnetic resonance and fourier-transform infrared spectroscopy. The X-ray diffraction studies showed that the modification diminished the crystalline nature of SP and SP-g-PMAAs. The SEM images showed spherical or polyhedral smooth surface for the starch. After modification, SP and SP-g-PMAAs exhibited distorted and rougher surfaces which are assumed to be good for adsorption. The dual modification produced phosphate and carboxylic groups on the starch backbone. The phosphate and carboxylic groups have high tendency to make hydrogen bonding with phenol. The comparative adsorption studies of NS, SP and SP-g-PMAAs were checked for phenol. The experimental results showed adsorption efficiencies of 0.022 g/g, 0.082 g/g, 0.100 g/g, 0.148 g/g and 0.151 g/g for NS, SP, SP-g-PMAA1, SP-g-PMAA2 and SP-g-PMAA3, respectively. The following findings revealed that dual modification enhanced the adsorption ability of NS.

The electrochemical behavior of catechol in the presence of sulfanilic acid has been examined in aqueous solution with numerous pH values, different electrodes and different concentration of sulfanilic acid, using cyclic voltammetry, controlled potential coulometry and differential pulse voltammetry. The reaction of o-benzoquinone with sulfanilic acid in the second scan of potential was observed. It is assumed that the reaction occurred between the sulfonate group of sulfanilic acid and quinone, rather than between the amino group of sulfanilic acid and quinone. The products derived from the reaction are associated with electrons transfer at more negative potentials than those from catechols. The significance of catechol's pH in presence of sulfanilic acid was studied by varying pH from 2 to 9. The concentration influence of sulfanilic acid with the fixed concentration of catechol (2 mM) was determined from 2 mM to 12 mM. The reaction was toughly affected by the pH, as well as by the concentration of sulfanilic acid. The reaction was mostly promising in 2 mM of sulfanilic acid and 2 mM of catechol at pH 7.

Understanding segmental dynamics of polymer chains is important to decipher the microscopic behavior in order to modulate the bulk properties of polymers. Study of electron spin resonance (ESR) spectroscopy of polymer chain segments is useful to understand internal dynamics of polymer chains in solution. In this paper, poly(oligoethylene glycol methacrylate-co-2,2,6,6-tetramethyl piperidin-4-yl methacrylate)s, OEG-TMPMs, were synthesized. The synthesized OEG-TMPMs were characterized by nuclear magnetic resonance (NMR) spectroscopy, gel permeation chromatography (GPC), differential scanning calorimetry (DSC) and thermogravimetric (TG) techniques. The TMPM moiety in OEG-TMPMs was oxidized to 2,2,6,6-tetramethyl-1-piperinidyloxy-4-yl methacrylate (TMP) to generate nitroxide radicals. These nitroxide radical-containing OEG-TMPs were analyzed with Fourier transform-infrared (FT-IR) spectroscopy, cyclic voltammetry (CV) and ESR spectroscopy. The effect of side chain length on the segmental mobility of OEG-TMPs was studied. The results showed that the longer pendent chains as in OEG-TMP-4 imparted higher flexibility to the backbone of the polymer and increased rotational freedom of nitroxide radicals as compared to restricted mobility in the case of shorter polymer side chains.

Cigarette industry plays an important role in the economy of the advanced countries. But the cigarette smoke contains toxic chemicals such as phenol which causes various kind of diseases and affect human life. In this paper, we synthesized carboxymethyl starch grafted poly vinyl imidazole (CMS-g-PVIs) by reacting carboxymehtyl starch (CMS) with vinyl imidazole (VI). The structures of the CMS-g-PVIs were investigated by 1H NMR and FT-IR. The crystalline properties of the CMS and CMS-g-PVIs were checked by XRD. The thermal properties of the original CMS and CMS-g-PVIs were investigated by TGA analysis. It was found that the modified starches had high thermal stability due to aromatic imidazole ring. The modified starches also showed more rough and distorted morphology as compared to native CMS. The CMS-g-PVIs were subjected for phenol adsorption and showed adsorption efficiencies of 0.170 g/g, 0.190 g/g, 0.192 g/g and 0.199 g/g for CMS, CMS-g-PVI 1, CMS-g-PVI 2 and CMS-g-PVI 3, respectively. Due to higher grafting ratio, CMS-g-PVI 3 showed good adsorption efficiency of 0.199 g/g for phenol. The obtained results showed that the grafting of vinyl imidazole on CMS can increase the adsorption efficiency of native CMS towards phenol.

Efficient composite solid propellants possess stable burning rate (BR) and low-pressure exponents. To achieve the ideal performance of propellants, addition of burning rate catalysts (BRC) to the propellants system is one of the best choice. BRC are of tremendous notable significance in composite propellants for their distinctive feature to positively enhance the operational efficiency of solid propellants. In this regard, many valuable kinds of BRC have been synthesized. Due to their better ignitability, ferrocene-based compounds are well-known class of BRC. However, considerable migration and diffusion tendency of this developed class of useful compounds during storage procedures of composite solid propellants limit their practical use as an ideal BRC. This article reviews recent advances in the active field of Fc-based derivatives. In gradual addition, this article also highlights recent progress of Fc-based derivatives as a BRCs and adequately discuss their significant improvements in anti-migration properties.