Polymer Science, Series B最新文献

To extend the service life of concrete in harsh environments, this paper introduces a silicone-modified polyurethane with self-repairing capabilities. The integration of silicone and disulfide bonding into the polyurethane molecular chain endows the material with a self-repairing ability and hydrophobicity. The incorporation of silicone significantly enhances the polyurethane’s hydrophobicity, while the introduction of disulfide bonds enables damage repair under mild conditions, and the repair efficiency can reach 90%. This combination of hydrophobicity and self-repairing properties holds paramount importance in protecting concrete and ensuring its prolonged use.

In the description of multicenter ion-coordination polymerization of isoprene on the catalytic system GdCl₃· n(i-C₃Н₇OH)‒Al(i-C₄H₉)₃ the inverse kinetic task for the scheme of a process with slow initiation has been solved. The task of determining the number of active centers of polymerization was solved by deconvolution of experimental MWDs through superposition of Flory distributions. It has been shown that four types of active centers participate in polymerization, the kinetic difference of which in the process of formation of polymer fractions with their characteristic average molecular weights and the most probable MWD, is associated with their difference in the concentrations of pre-reaction catalytic centers and the rate constants of reactions occurring on them. For each type of active centers, partial conversions of monomer consumption and rate constants of initiation, chain propagation, and chain transfer to the monomer are determined.

In light of the persistent challenges in herbicide release control, this study aims to investigate the factors influencing the release rate of herbicides from polymer–montmorillonite clay composites. Understanding these factors can provide valuable insights for the development of improved controlled release systems, offering enhanced precision and efficiency in herbicide delivery. Polymer-montmorillonite clay composites carrying 2,4-dichlorophenoxy acetic acid as controlled release systems were prepared by in-situ polycondensation. The intercalated polymeric 2,4-dichlorophenoxy acetic acid composites were characterized using various analytical techniques. Release studies were conducted in aqueous media at different pH levels over an extended period of approximately 80 days. The results revealed the significant influence of various factors on the release rate of the herbicide, including polymer structure, medium composition, percentage of polymer grafting onto clay, clay-to-polymer ratio, and swelling behavior. These findings have important implications for the development of controlled release systems for herbicides. Understanding the factors influencing release rates enables the optimization of composite design and formulation for efficient herbicide delivery. Moreover, this research provides a foundation for future investigations aimed at enhancing the release performance and overall effectiveness of polymer-montmorillonite clay composites. Potential avenues for further research include exploring tailored polymer structures, modifying the clay matrix, and optimizing the clay-to-polymer ratio.

Silicone-modified polyurethane has low silicon content and instability of the synthesis process limits its application expansion. In this study, the waterborne organosilicon acrylic polyurethane prepolymer emulsion with high silicon content (WSi_hAPU) were prepared by using hydroxy-terminated polydimethyl siloxane as soft segments. Waterborne organosilicon acrylic polyurethane (WSiAPU) can be controlled by simple mixing the ratio of WSi_hAPU and waterborne acrylic polyurethane (WAPU) in different proportions, and the WSiAPU films were freely regulate their silicon content range at 0–11.6%. Series WSiAPU emulsions had excellent storage stability, which can be diluted mechanically to a concentration of 0.1% and stored for up to 6 months. The structure and properties of the WSiAPU samples, their films by UV cured and the fabric subtract coating WSiAPU composites were characterized by the X-ray Photoelectron spectroscopy (XPS), the water contact angle (WCA) and water absorption rate (WAR), etc. This resulted in an increase in the hydrophobicity of WSi_hAPU and WSiAPU. The WCA and the WAR of the WSiAPU films increased to 108.79° and decreased to 6.44%, and the WAR of the WSiAPU treated fabric substrates Cotton was reduced from 705.12 to 4.12%. This resulted in an increase in the hydrophobicity of WSi_hAPU and WSiAPU.

Electrically conductive composite textile and textile combining electrically conductive and magnetic properties have been obtained on the basis of biocompatible non-toxic materials: commercial non-woven textiles, electrically conductive polypyrrole and magnetite (Fe₃O₄). The composite textile has been formed from two-layer fibers, where the fibers of the original textile are coated with a polypyrrole shell, and the textile combining electrically conductive and magnetic properties have had a three-layer structure, where magnetite particles are deposited on top of the polypyrrole shell. The composite textiles have retained the structure of the original fabric with free interfiber space: the specific surface area of the materials and their mechanical properties have been similar in value. The composition of materials, their electrically conductive, magnetic, and redox properties have been investigated. The interaction of the composite textile and the textile combining electrically conductive and magnetic properties with electromagnetic radiation in the frequency range of 4–8 GHz have been investigated in comparison with a commercial radio-absorbing material based on carbonyl iron.

β-ocimene (3,7-dimethyl-1,3,6-octatriene), a dimer of isoprene, which can be found in various essential oils such as ocimium plant genus, holds the potential to serve as a source material for creating elastomers entirely derived from bio-based sources. Due to its structural similarity to myrcene (C₁₀H₁₆), this conjugated diene, offers the possibility of undergoing polymerization using the same method employed for myrcene. This involves the utilization of neodymium trisborohydride as a pre-catalyst activated by boron derivatives in the presence of triisobutyl aluminum. This innovative approach has led to the successful production of 1,4-cis polyocimene, a significant achievement in the field of polymer chemistry. Detailed analysis through the application of ¹³C NMR and DEPT 135 spectroscopy has shed light on the microstructure of the resulting polyocimene. It has been revealed that the polymer exhibits a predominant microstructure of 1,4‑cis (comprising up to 83.38% of the structure) along with the presence of 1,2-trans isomer (constituting 16.62%). The findings also highlight that the molecular weight distributions of the polymer are relatively broader (PDI > 2). This catalytic system enables the production of polymers that can be used as promising starting materials for bio-based thermoplastic elastomers.

Mesoporous silica nanoparticles (MSNs) were synthesized by alkaline catalysis, hydrolysis condensation reactions, and template removal of tetraethoxysilane (TEOS). MSNs were used as fillers and carriers to immobilize polymer components and form three-dimensional grids within the material, thus imparting the absorbent resin with the required mechanical strength. Carboxymethyl chitosan (CTS) was used as the substrate for synthesizing composite water absorbent resin. A composite superabsorbent resin was prepared by grafting copolymerization with acrylamide (AM) and acrylic acid (AA) and it was referred to as MSNs@CTS-g-P(AA-co-AM). The liquid absorption and adsorption performances of heavy metal ions were examined in different environments. The results showed that the water absorption rate of MSNs@CTS-g-P(AA-co-AM) reached 740 g/g at water absorption equilibrium. Compared with known organic/inorganic composite water absorbing resins, the composite resin involving MSNs had good water retention performance, which was evident from the water retention rate reaching a maximum of 91.8% when the resin was dried at 80°C for 6 h. This was attributed to the composite resin forming a stable three-dimensional network structure due to the MSNs, strong salt resistance, and better adsorption performance.

In this paper, amino terminated polydimethylsiloxane (APT-PDMS) was synthesized by ring opening reaction of octamethylcyclotetrasiloxane (D4). Then, the slippery liquid infused porous surfaces (SLIPS) of polyimide were prepared from APT-PDMS, 1,2,4,5-cyclohexane tetracarboxylic dianhydride (HPMDA) and 2,2'-bis[4-(4-aminophenoxyphenyl)] propane (BAPP) by two-step method. The composition and structures of products were characterized by Fourier transform infrared spectroscopy (FTIR), the thermal stability of the substrate was studied by thermogravimetric analyzer, the surface morphology and properties of the substrate was observed by scanning electron microscope and Contact angle test. The results show that Slide angle (SA) and stability were the best when the polymer concentration was 30 mg/mL, and the slip angle after oil filling was 3°. Compared with the superhydrophobic surface, the SLIPS own excellent anti-icing and anti-freezing performance, thermal stability, and antibacterial adhesion performance.

With the use of quantum-chemical and kinetic methods, the influence of free amino groups in amine monomers on the rate of their reaction with ethylene carbonate is studied. It was stated that the catalytic effect in diamine appears at the length of the chain of 3–7 atoms. A decrease in activation barriers is associated with the formation of less strained proton transfer and stabilization cycles in transition states. The theoretically found dependence of the rates of aminolysis of ethylenecarbonate on the structure of amines is confirmed experimentally by kinetic measurements.

1,3-Dioxolane polymer (PDXL) was synthesized using Halloysite, a natural clay material, as solid acid catalyst for cationic ring-opening polymerization. This catalyst was activated with 0.5 M sulfuric acid solution to increase its Brønsted-type acidity. Polymerization of DXL was carried out in bulk under magnetic stirring at low temperature, leading to the formation of polydioxolane. The Halloysite and synthesized polymer were characterized by several techniques including X-ray fluorescence (XRF), X-ray diffraction (XRD), Infrared spectroscopy (FTIR), and nuclear magnetic resonance (NMR). To assess the dispersing power of the synthesized PDXL and its hydration activity, the setting time, consistence and compressive strength of cement paste and mortar containing poly(1,3-dioxolane) was studied, compared to the commercial polyethylene glycol (PEG) used as reference in this study. The results showed the retarding effect of PDXL on the setting times of cement paste, accompanied by a decrease in normal consistency, which allows its use as superplasticizer or dispersant agent. Thus, PDXL improved the compressive strength of cement mortar compared to PEG polymer effect.