The poly(glycidyl methacrylate) microsphere (PGMA microsphere) is one of the most useful colloidal particles due to its structural arrangement. It has an easy functionalization, dispersion, adsorption and swelling properties. The PGMA was effectively used as a precursor for the development of many novel and advanced materials with enhanced properties lead to diverse applications. For instance, the incorporation of nanoparticles in PGMA exhibited progressive properties. Nevertheless, homogeneous distribution of nanoparticles in polymers is not that much simple due to their tendency to get aggregate. Whereas, the homogeneous distribution of nanoparticles in the PGMA is quite easy due to its grafting ability. The design, development and characterization of PGMA based novel materials for improved properties and apply those materials for diverse problems has gained a great interest among the researchers from the past one decade. This review highlights the insights on different methods of preparation of PGMA based materials to attain the desired properties and provide useful information about the characteristic features of the PGMA microspheres. This review also useful to evaluate some of the key aspects for the development of PGMA based materials and endow with new possible ways and ideas to take up some innovative research.
Composite films of methyl cellulose and poly(urethane-imide) are obtained. At the poly(urethane-imide) content in the films above 50% phase separation of the polymers is observed. Using the methods of dynamic mechanical analysis and X-ray diffraction the structural organization of the films is studied, the temperatures of relaxation transitions are determined, and the mechanical characteristics of the composite films are investigated.
Reactor polymer compositions (RPCs) based on UHMWPE with M w = 1000 kg mol –1 and low molecular weight HDPE (LMWPE) were studied. Two series of UHMWPE compositions were used to determine the influence of the molecular weight and properties of the LMWPE fraction on the morpho-logy, mechanical and rheological properties of UHMWPE/LMWPE. Сompositions, including from 10 to 80 wt % UHMWPE with M w = 160 kg mol –1 (PE-160) were obtained in a two-stage process of ethylene polymerization with a metallocene catalyst. They differed in the order of introduction of PE-160 into UHMWPE (PE-160/UHMWPE and UHMWPE/PE-160). Compositions of UHMWPE and LMWPE with M w = 48 kg mol –1 (PE-48/UHMWPE) with PE-48 content from 6 to 30 wt % were synthesized in a single-stage polymerization of ethylene in the presence of a tandem catalyst. A comparison of the shape and size of particles of nascent polymer products was made using the SEM method. The morphology, tensile, dynamic mechanical and rheological properties of RPC have been studied depending on the method of their preparation, the content of the low molecular weight fraction, its molecular weight and physical and mechanical properties. An increase in the proportion of PE-160 and PE-48 in PE-160/UHMWPE and PE‑48/UHMWPE leads to an increase in RPC crystallinity, tensile modulus and dynamic mechanical modulus with significant deviations from the additivity rule.
A theoretical model describing the self-assembly in dilute solutions of amphiphilic macromolecules containing the backbone built of the solvophilic units (the P groups) and the solvophobic side chains (the H groups) possessing orientational mobility relative to the backbone units has been elaborated. In the framework of strong segregation limit (The size of the insoluble regions of the formed micelles is on the order of the hydrophobic side chains), state diagrams of the solution have been calculated with and without accounting for the orientational entropy contribution of the side groups to the total free energy of the solution at different thermodynamic qualities of solvent for the macromolecules and the grafting density of the H groups; the regions of stability of spherical and cylindrical micelles as well as planar bilayers (vesicles) have been revealed. It has been found that the contribution of the orientational entropy significantly affects the view of the state diagrams. In the case of considering the orientational mobility, the conditions of the cylindrical micelle stability are very sensitive to the change in the grafting density of the side groups. This sensitivity can be the reason why the formation of long cylindrical (wormlike) micelles is not observed in experiments and computer simulations. As earlier demonstrated at a qualitative level, the orientational mobility of the side groups can lead to the emergence of the orientation-induced attraction between the polymer micelles (A. I. Buglakov, D. E. Larin, and V. V. Vasilevskaya, Polymer 232 , 124160 (2021)). In this study, exact analytical calculations of the energy of orientation-induced attraction for the case of the interaction between two planar bilayer micelles has been performed. At distances being of the order of the size of the side H group, the orientation-induced attraction forces are much stronger than the van der Waals forces and, hence, the orientation-induced attraction can be decisive in the formation of large aggregates observed in experiments.
-The approach to the prediction of permeability of polymer membranes based on polyimides and polyamidoimides towards helium is described. According to the approach, the activation energy of helium penetration is expressed by a relationship involving the van der Waals volume of the repeat unit and a set of atomic parameters characterizing the contribution of each of the atoms and intermolecular interaction types into the value of activation energy. The contributions of the imide cycles, type of the connection (meta-, para-, or ortho-), and of the CF3, CH3, CO, Cl, F, and SO2 polar groups have been accounted for. Repeated solution of the redundant set of equations obtained on the basis of the proposed relationship has afforded the parameters giving the correspondence of the calculated values and the experimental data on the membranes permeability with correlation coefficient 0.965. Hence, the possibility to search for the structures of polyimides and polyamidoimides with the target permeability without laborious and expensive experiments has been demonstrated.
The interest for the preservation of the steel structure of ships and their prevention from corrosion in salted water is becoming more demanding with respect to the release of the toxic substances and their impacts on environment. Therefore, it is urgent to develop an adequate inhibitor to preserve the sea from the pollution. In this context, the study of the corrosion inhibition of a mild steel in seawater (i.e. 5% NaCl) by the polymer polyaniline (PANI) was carried out by using conventional techniques such as weight loss, electrochemical methods and scanning electron microscopy (SEM) coupled with the Energy Dispersive Spectrometry (EDX).The monitoring by cyclic voltammetry (i.e. current vs. voltage) allowed to see the influence of the scanning speed on the surface steel phenomena and showed also a linear evolution of the cathodic current density with the square root of the voltage scanning rate (i.e. I p = f ( V 1/2 ), where the diffusional type of charges transport was made in evidence. Whilst, the polarization curves using the sweep voltammetry in conjunction of the Tafel’s processing, permitted to record the corrosion parameters. The electrochemical tests are thus, promising and have made it possible to highlight the effect of PANI cathodic corrosion inhibitor. The results obtained so far reveal a significant effectiveness against steel corrosion even at lower concentration (i.e. 0.3 g/L) where the inhibition rate was optimized to 93.28%. Besides, the SEM and EDX analyses allowed the clarification of the inhibition mechanism and support the relative inhibition efficiency.
A mathematical model for the volume structure of the polymer fringe on the surface of a prolate spheroidal nanoparticle in the external electric field is developed. Using this model and the molecular dynamics method the conformational changes of uniformly charged polypeptides adsorbed by a charged metal nanospheroid the nature of the polarization of which along the major axis periodically changes with time are studied. An analytical model for the interaction of polyelectrolyte units with the charged nanospheroid is constructed relying on the generalized Gaussian chain model in the superposition electric field taking into account the complex pattern of the surface charge density distribution of the polarized adsorbent. Unidimensional atomic density distributions of polypeptides along the major axis of the nanospheroid, as well as the radial atomic density distributions of polypeptides in the equatorial region of the nanospheroid, are calculated. It is shown that at a low temperature in the central region of the nanospheroid the enveloping polyelectrolyte fringe is formed with its width being dependent on the full charge of the nanospheroid, the amplitude of the external electric field, and the fraction of charged units in the adsorbed macromolecule. At a higher temperature the nature of conformational rearrangements of the adsorbed polyelectrolyte macromolecule changes: either the periodic displacement of polyelectrolyte units on the oppositely charged pole of the nanospheroid or a periodic shift of the formed polyelectrolyte ring relative to the equator along the major axis occurs.
In recent years, stimuli-responsive polymers, a kind of functional material, have drawn increasing attention. In this paper, acrylamide azobenzene was introduced into the molecularly imprinted polymer by copolymerization with acrylic acid in the presence of template molecules methylene blue, crosslinker N,N '‑methylene bisacrylamide, and initiator azobisisobutyronitrile, which makes the imprinting material have the effect of light-operated and further expand the application range of imprinting materials. Detailed studies of the photo-regulated uptake and release process suggested that the binding affinity of imprinted recognition sites in imprinting materials could be changed under the alternating irradiation of ultraviolet and visible light. The adsorption isotherm experiments and adsorption kinetic experiments showed that the adsorption of methylene blue by the imprinted material conforms to the monolayer chemical adsorption and quasi-second-order kinetic model. Additionally, the relevant thermodynamic parameters were calculated. These thermodynamic parameters proved that the adsorption process was spontaneous, endothermic and entropy-increasing.
The carbazole derivatives containing aromatic rings with long alkyl groups such as C-6, C-8, C-10 and 3,4-bis(4-iodophenoxy) thiophene are synthesized. The products of carbazole derivatives and 3,4-bis(4-iodophenoxy) thiophene interaction were polymerized using FeCl3 oxidant. The structural characteristics of the synthesized compounds were obtained by FT-IR and NMR spectroscopy. UV measurements are performed to determine the optical changes of the copolymers in the presence of metal ions such as Ag+, Cd2+, Co2+, Cu2+, Fe2+, Fe3+, Hg2+, Li+, Ni2+, Pb2+, Zn2+. The selectivity of Fe3+ is investigated by recording of the absorbance changes of Fe3+ solutions prepared at different concentrations. The effect of pH is also investigated in optical sensor studies. According to UV measurements, the materials containing thiophene and carbazole units can be considered as candidates for sensor production due to their selectivity towards Fe3+ ions.
Polymer Science: Peer Review Journal Infusion of a Polymer in a Porous Medium: Application of Cement to Concrete Hawachi I* and Sammouda H Laboratory of Energy and Material (LabEM-LR11ES34) University of Sousse-Tunisia, ESSTHS, Rue Lamine Abbassi, Tunisia *Corresponding author: I Hawachi, Laboratory of Energy and Material (LabEMLR11ES34) University of Sousse-Tunisia, ESSTHS, Rue Lamine Abbassi, 4011, Hammam Sousse, Tunisia Submission: December 20, 2021;Published: February 03, 2022 DOI: 10.31031/PSPRJ.2022.03.000552 ISSN: 2770-6613 Volume3 Issue1
As a high-endurance, high-temperature insulating material, the insulating property of polyimide must be improved, and the optimal synthesis of polyimide-based composite needs to be further explored. In this paper, the AC conductivity of multiple series of polyimide filled nanocomposite films are simulated by the Bagging Model. The prediction results show that the multi-series of polyimide-based nanocomposite films, which are filled with different inorganic nanoparticles and different doping contents, are predicted by 5-fold cross validation. The predicted value of the model fits well with the practical measured value. Further analysis of the results shows that the mean absolute error, mean squared error, and root mean squared error of the Bagging Model are less than those of the Linear Regression, Medium Tree, Coarse Tree, support vector regression (SVR), Gaussian process regression of the RQ nucleus, K-nearest neighbor, Random Forest, and AdaBoost models. Thus, for predicting the AC conductivity of polyimide nanocomposite films, the Bagging Model is better than other models to provide theoretical direction for the design of a high insulation polyimide composite. This modeling method may effectively reduce the time required for researchers to design nanocomposite films, greatly improving their efficiency and reducing the cost of research in the future.
The Huggins and Kraemer plots are compared to estimate the intrinsic viscosity of macromolecules belonging to different classes of macromolecular compounds. It is shown that the Kraemer plot is linear in a larger range of concentrations suitable for extrapolation to zero concentration. A change in the sign of the Kraemer parameter makes it possible to detect the prevalence of polymer–polymer interactions over volume effects more clearly than an increase in the Huggins parameter.
In this study, polyethylene terephthalate samples were blended with hybrid fibers such as chinlon, polypropylene and polyurethane and subjected to glycolysis to obtain fiber derived polyester polyol precursor. Consequently, the polyester precursor was reacted with maleic anhydride to prepare a fiber derived unsaturated resin. The effect of reaction conditions, type of hybrid fibers and their contents on the structure of the polyester polyol precursors were investigated by Fourier transform infrared spectra, hydrogen nuclear magnetic spectra, gel permeation chromatography, high performance liquid chromatography, liquid mass spectrometry and thermogravimetric analysis. The polyester polyol precursors were further used to synthesize fiber derived unsaturated resins with proper viscosity and acid value. Finally, cured resins with excellent thermal stability and mechanical performance for potential commercial application were obtained.
The process of Couette flow of a hydrocarbon liquid in the slit pores has been simulated and the dynamics of the liquid molecules ordering depending on the liquid density and the slit size has been investigated by means of molecular dynamics. Statistical analysis of the resulting regions of ordered molecules of the hydrocarbon fluid has indicates that the wall material and the liquid viscosity affect the size of such regions.
Poly(butyleneterephthalate) has the disadvantage of being brittle, so recycled polymer is often used less in real life. In this study, recycled poly(butylene terephthalate) was mixed with low-density polyethylene utilizing the plastic mixer and injection molding machine to improve it elastic modulus. The analyses were carried out by using the mixture of poly(butylene terephthalate) and 10 wt % of low-density polyethylene. The results indicate that tensile strength of the mixture is higher than that of pure polyethylene but less than that of recycled poly(butylene terephthalate). However, the mixture has the higher elastic modulus than pure polymers and its hardness is improved also.
Polymer blends of polyolefins with poly(ethylene oxide) are obtained by the deformation of polypropylene and high-density polyethylene films in aqueous-ethanol PEO solutions by the crazing mechanism. The content of PEO with a molecular weight of 4 × 103 in the blends depends on the porosity of polyolefin matrices and grows with an increase in the degree of stretching of the films to 28% in HDPE–PEO blends and to 32% in PP–PEO blends. According to DSC studies, the crystallization of PEO is accompanied by decrease in the melting temperature by 4–6 K in the HDPE matrix and 6–7 K in the PP matrix and reduction in the degree of crystallinity by 24–49% in the HDPE matrix and 44–76% in the PP matrix compared with PEO crystallized in the “free” state. Using X-ray diffraction data, the sizes of crystallites of PEO with М = 4 × 103 in the pores of polyolefins deformed by the crazing mechanism are first calculated, and it is shown that PEO macromolecules orient perpendicular to the axis of stretching of PP and HDPE matrices.
This paper reports a detailed kinetic investigation on crystallization mechanisms occurring in two familiar industrial polyolefins, high-density polyethylene (HDPE) and isotactic polypropylene (iPP), under isothermal as well as non-isothermal conditions. Kinetic analysis by advanced kinetic approach to polymer crystallization processes suggests that the crystallization of HDPE and iPP goes to completion by following fairly invariable nucleation/diffusion phenomena. Nevertheless, crystallization mechanisms of both HDPE and iPP show dependence on mode of experiment. Under non-isothermal conditions, HDPE follows a crystallization mechanism intermediate between random nucleation followed by isotropic one-dimensional (1D) growth of spherulites and two-dimensional (2D) growth of spherulites. Under isothermal conditions, it predominantly follows 2D growth of spherulites. On the other hand, while iPP follows a crystallization mechanism analogous to HDPE under non-isothermal conditions, it pursues three-(3D) dimensional growth of spherulites under isothermal conditions. In general, pre-exponential factor remains independent of temperature in all the crystallization cases studied. Moreover, polymeric chains of HDPE demonstrate relatively slower transport rate when compared with iPP. The obtained kinetic parameters are interpreted in terms of their probable physical meanings and practical worth of the present study is taken into account and discussed.
The glucose-responsive insulin release system was proved to be an effective way to deliver insulin. Here, dendritic mesoporous silica and phenylboronic acid were used to prepare a simple insulin delivery system, and its glucose-responsive properties were studied. Briefly, dendritic mesoporous silica was prepared by the biphase stratification approach. 3-Fluoro-4-carboxyphenylboronic acid was grafted on the hydroxypropyl chitosan to obtain phenylboronic acid-modified hydroxypropyl chitosan. In a weakly acidic environment, insulin was loaded on the dendritic mesoporous silica. The loading capacity and encapsulation efficiency could reach 32.1 and 94.6%, respectively. After that, modified hydroxypropyl chitosan was coated on the insulin-loaded dendritic mesoporous silica to obtain an insulin release system. Then sodium alginate was coated on insulin release system followed by calcium ion crosslinking to obtain another insulin release system. The results demonstrated that both systems had excellent performance in sustained insulin release. Glucose-responsive behavior was observed in the case of the former insulin release system.
A different series of oligomeric ester was synthesized by combining different acid chlorides with a novel azine monomer and their structure was confirmed using a variety of spectroscopy techniques. The sensing ability of the synthesized azine fluorophore with various metal ions was evaluated in DMF/H2O solution and it was exposed those fluorophores have selective “turn off” fluorescence reaction to Mn2+ ion. The correlation coefficient was determined using Stern-Volmer linear plot and found to be R2 = 0.99223 for PBHMM and R2 = 0.9517, 0.9526, and 0.9295 for PBHMP, PBHOP, and PBHAP, respectively. The Benesi–Hildebrand plots were used to determine the binding constant of fluorophores Ka and the values are 1.00393, 1.00192, 1.00436, and 1.00132 M–1 for PBHMM, PBHMP, PBHOP, and PBHAP respectively. UV and theoretical (DFT) studies were used to confirm the mechanism of interaction between fluorophore and quencher in the ground and excited states. The monomer and dimer of oligomers were theoretically investigated using DFT at the B3LYP/6-311G level of the fundamental set and is helping to explain the mechanism of the fluorophore interaction with metal ion and electrical studies of the oligomer. In comparison with non-doped oligomers, doped oligomers exhibit increased conductivity upon increasing the iodine doping duration on oligomers. The electrical conductivity of oligomers was compared with charge density on imine nitrogen obtained from Huckel’s equations and band gap values. Dielectric analysis was carried out at different temperatures and frequencies using the four-point probe technique. The PBHAP oligomer shows a high dielectric constant at the low applied frequency at 373 K due to polarized high loosely attached π bonds.
