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Chemical modification of the surface of halloysite nanotubes (HNT) by alkalization (with sodium hydroxide (NaOH)) and grafting with silanes (bis(trimethylsilyl)amine (HMDS)) was carried out. The efficiency of the alkalization and grafting process was evaluated by X–ray diffraction (XRD), Fourier–transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and the nitrogen adsorption method were used. XRD and FTIR analysis confirmed the formation of bonds of trimethylsilyl groups to the HNT surface which changed the nature of the surface from hydrophilic to hydrophobic. In addition, it was noted that grafting with silanes decreases by 7.2% the specific surface area of the halloysite compared to the alkalized material. High–density polyethylene (HDPE) composites with halloysite (HNT), alkalized halloysite (alk–HNT), and HMDS–modified halloysite (m–HNT) were processed in the molten state in a Brabender mixer chamber. On SEM/EDS micrographs of HDPE composites with silanized HNT, a change in surface characteristics from smooth to ductile was observed. Higher melting point values based on differential scanning calorimetry (DSC) analysis of HDPE composites with 5%wt silanized halloysite in comparison with HNT and alk–HNT of, respectively, 2.2% and 1.4% were found, which indicates a slight beneficial influence of the filler on the quality of ordering of the crystalline phase of the matrix. [ABSTRACT FROM AUTHOR]

The article presents research on the thermal decomposition of individual ingredients and compositions that are physical mixtures of emulsion poly(vinyl chloride) (PVC), cadmium yellow, and stearic acid. The results of the tests were TG, DTA, and DTG graphs. From their course, the initial decomposition temperatures, maximum decomposition rate, and final temperatures were determined, and changes in the mass of samples and the values of thermal effects were calculated. The influence of pigment and stearic acid on the thermal decomposition of PVC was investigated. Cadmium yellow, modified in an alkaline medium and containing hydroxyl groups, was also used for the tests. It was found that the presence of both pigment and stearic acid had a retarding effect on the initiation of thermal decomposition of PVC. The addition of CdS modified in an alkaline environment had a more or less similar effect on the initial decomposition temperature of PVC. Depending on the composition of the polymer and the value of the final temperature, different values of thermal effects and the amount of products formed were indicated. [ABSTRACT FROM AUTHOR]

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The results of a study on latexes obtained by emulsion copolymerization of acrylic, methacrylic and vinyl monomers without surfactants are presented. The monomers included ethyl acrylate and butyl acrylate, methyl and butyl methacrylate and methacrylic acid. The yield of the copolymerization reaction, the polymer concentration in the latex, the pH, surface tension, intrinsic viscosity number, Huggins constant, the molecular weight of the polymer and the particle size in the latex were determined. The stability of the latexes was tested by determining the values of non‐overt and overt coagulation thresholds. The values of the limiting equivalent conductivity and the anode zeta potential were determined. The relative hardness of latex membranes and their mass change after hot water extraction were investigated. The relationships between the properties of individual latexes were established. The main aim of the research was to determine the influence of copolymer composition on the electrokinetic properties of polymer particles in latex. They determine the possibility of developing a new type of paint for electrophoretic painting with the use of latexes. © 2022 Society of Industrial Chemistry. [ABSTRACT FROM AUTHOR]