Polymer Science, Series B最新文献

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.

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.

This study focused on thermosetting high-ortho phenolic epoxy fibers prepared by blending thermosetting high-ortho phenolic resins (HOT-PRs) with F-704 epoxy resins and using dry spinning, thermal curing, and microwave curing methods. The structure was characterized by infrared spectroscopy, microinfrared spectroscopy, nuclear magnetic resonance spectroscopy, and scanning electron microscopy. The heat resistance of different fibers was studied by thermogravimetric analysis, and the mechanical properties of the fibers were determined using a fiber tensile strength tester. Results showed that the HOT-PRs successfully used the phenolic hydroxyl groups and the hydroxyl groups in the methylol groups to promote the ring-opening reaction of the epoxy groups to form ether bonds. The breaking strength of the thermally cured fibers was 206 MPa, and the elongation at break was 14.5%. The microwave-cured fibers had good heat resistance with an initial weight loss temperature of 315°C and a char yield of 59.7% at 800°C.

Glycidyl azide polymer (GAP) with tetra hydroxyl functional groups often known as tetra functional GAP or t-GAP is a potential energetic polymeric binder for high-energy composite solid rocket propellant and plastic bonded high explosive formulations. t-GAP is synthesized via azidation of the tetrafunctional precursor of poly-epichlorohydrine (t-PECH) by sodium azide in DMSO. In this article, synthesis of t-GAP is studied using IR-spectroscopy, and an attempt is made to monitor the reaction progress through characteristic IR absorption bands corresponding to C–N₃ in t-GAP and C–Cl in t-PECH vibrations aiming to optimize reaction parameters.

In order to evaluate the bio-degradation performance of different kinds of poly(lactic acid) (PLA) rapidly, a new method, called hydro-thermal degradation was developed. Four kinds of commercial grade PLA were analyzed by both bio-degradation and hydro-thermal degradation with their degradation performance investigated via weight loss (%), infrared spectra (IR), size-exclusion chromatography (SEC), and X‑ray diffraction measurements (XRD). The experimental results showed that the bio-degradation performance, which would take several years to degrade totally, could degrade in a short time (2 h) at 170°C by the hydro-thermal degradation. The order of the degradation rate is Revode101 > Revode210 > Revode190 > Revode290, corresponding with the structure characteristics of them. Thus, this new method provides a simple and effective way to degrade the PLA rapidly and to evaluate its bio-degradation performance.

The features of radical polymerization of methyl methacrylate involving phenazine as photocatalyst, under UV irradiation, have been investigated. It has been found that the phenazine-based compositions allow initiation of the methyl methacrylate polymerization and, in certain cases, performing it in a controlled regime. It has been shown that it is possible to prepare poly(methyl methacrylate) over sufficiently wide range of molecular mass by adjusting the composition of the phenazine + organobromine compound + tertiary amine catalytic system, the obtained polymer being prone to further modification via block copolymerization. A specific feature of the suggested catalytic compositions is the possibility of the polymer synthesis to high conversion using a low concentration of the catalyst and without prior degassing of the reaction mixture.

A cooligomer has been synthesized with a yield of 93% by triple condensation of 2-allylphenol, formaldehyde, and ethylenediamine (0.5 : 4.0 : 1.0). The molecular weight and molecular weight distribution of the product were determined (M_w = 860 and M_n = 470), and it was revealed that cooligomer has sufficiently high thermal stability (a significant loss of cooligomer mass was observed at ~400°C). Thermal self-crosslinking (up to 280°C) of the cooligomer and its crosslinking with acrylonitrile in the presence of the initiator benzoyl peroxide (1%) followed by hydrolysis of the resulting polymer in the presence of KOH were carried out. Their structure was studied by IR spectroscopy. The sorption properties of the crosslinked hydrolyzed polymer were examined for the extraction of uranyl ions from model aqueous systems under batch conditions at various pH values, concentrations, and sorption times. It has been found that the maximum recovery of uranyl ions by the hydrolysis product of the crosslinked polymer at pH 7 is 90.8% and the sorption capacity is 203.5 mg/g. The dependence of the batch (“static”) sorption capacity of the crosslinked polymer on the equilibrium and initial concentration of uranyl ions was considered. It has been shown that the sorption capacity stabilizes at ~300 mg/g. The sorption properties of the crosslinked polymer were confirmed by both IR spectroscopy data and by the results of energy dispersive X-ray spectroscopy and scanning electron microscopy.

In this study, VO_x was prepared by oxalic acid and vanadium pentoxide under nitrogen atmosphere and SiO₂ was grown on the surface of VO_x. Block copolymer (PCL-b-PDMS-b-PCL) was synthesized by hydroxy terminated poly(dimethylsiloxane) and caprolactone, and the composite material containing inorganic particles was obtained by blending VO_x/SiO₂ with PCL-b-PDMS-b-PCL. The porous film was constructed by breathing pattern method, and the supersmooth surface was obtained by injecting lubricating oil into the porous film. The composite was tested by Fourier transform infrared spectroscopy, hydrogen NMR spectroscopy, scanning electron microscopy, contact angle and anti-bacterial adhesion. The results showed that PCL-b-PDMS-b-PCL was successfully synthesized, and the prepared composite material containing inorganic particles had excellent superslippery properties after oil injection, and the sliding angle was 2°.