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.
