Modeling of Mechanical Properties of Polymeric Systems with Branching/Crosslinking,Particularly Their Mechanical Resistence and Stability

A theoretical method for the estimation of mechanical characteristics of polymeric structures is proposed. This method uses the statistical polymer method for modeling branched/crosslinked structures. The proposed method is utilized for the estimation of mechanical resistance and stability of microporous polymeric materials. An engineering method for the evaluation of mechanical stability and resistance of polymeric materials is derived.     

Theoretical Modeling of Mechanical Resistance and Stability and Related Characteristics of Polymeric Systems with Branching/Cross-Linking

A theoretical (thermodynamic) method for the estimation of mechanical characteristics of polymeric systems is proposed. This method uses the statistical polymer method for modeling of branched/cross-linked structures. The weak interaction between macromolecules is modeled in the approach of their mutual interpenetration. The proposed method is used for the estimation of mechanical resistance and stability of microporous polymeric materials. An engineer method for the evaluation of mechanical stability and resistance of polymeric materials is derived.     

Investigation of ultrasound velocity measurements of polymeric parts with different surface roughness

Ultrasound velocity is a crucial parameter for polymeric parts because it characterizes the mechanical properties and micro structure. In our previous study, we proposed a frequency-domain method for measuring ultrasound velocity via full spectrum analysis (UFSA). In this study, we conducted a series of experiments to compare the accuracy and feasibility of three measurement methods: time of flight method (TOF), ultrasonic water immersion method (UWI) and UFSA. The methods were applied to measure polymeric parts with different surface roughnesses; in addition, experiments were conducted to evaluate the effect of an external disturbance and to characterize the micro structure. Error analyses were performed for the methods. The experimental results showed that the TOF method was only suitable for measuring polymeric parts with flat surfaces, whereas the UWI and UFSA methods performed well for the measurement and characterization of polymeric parts with rough surfaces. The UFSA method had higher anti-interference ability than the other two methods. X-ray diffraction experiments indicated a negative correlation between the ultrasound velocity measured by the UWI and UFSA methods and the degree of orientation of the polymeric parts. The results obtained in this study provide guidance for the application of these methods.     

Detection of defects in components made of dispersion-filled polymeric materials by the method of infrared thermography

A method allowing one to determine the presence of hidden defects in dispersion-filled polymeric materials by means of a thermal imager is studied. The results of studies of the determination of hidden defects in samples of dispersion-filled polymeric materials are reported. The dependence of the determination of hidden defects in samples of dispersion-filled polymeric materials on the method of the transfer of excess temperatures to the tested object is established.     

Impact testing of polymeric foam using Hopkinson bars and digital image analysis

The present investigation aims at testing polymeric foam under impact loading using large diameter nylon Hopkinson bars and optical field measurements. Accurate average stress-strain relations can be obtained when soft large diameter polymeric pressure bars and the appropriate data processing are used. However, as there are generally no homogeneous strain and stress fields for polymeric foams, an optical field observation is needed. In contrast to quasi-static tests where the digital image correlation (DIC) measurement is commonly used, technical difficulties still remain for the reliable use of DIC under impact conditions. In this paper, an accurate synchronization method based on the displacement measurement of the end of pressure bars (calculated by a robust DIC algorithm) is preferred to conventional MCDL box time synchronization. Also, the bar end displacement measurement offers a complementary calibration method for the tension/strain conversion coefficient. Strain fields are obtained for tests on foam sample at impact velocities up to 20 m/s. The localized strain fields permit better understanding of the observed stress plateau from SHPB results. The relevance of the present method for establishing mechanical response of polymeric foam is then demonstrated.     

Metal-polymer “superglue” for dirty polymer surfaces

Current methods of bonding metals to polymeric surfaces involve chemical reactions between atomically clean surfaces (S. Paul, Surface Coatings, Wiley, New York 1985). We propose a novel method of attaching metals to polymeric surfaces which does not require chemical bonding and is designed to be effective for polymeric surfaces which are not clean.     

Facile Preparation of Polymeric Dimers from Amphiphilic Patchy Particles

A straightforward strategy for assembling polymeric dimers from amphiphilic nanoparticles is reported. Amphiphilic polymeric nanoparticles with a mixed‐shell of PEO/P2VN blocks and a flexible core of PAA blocks are fabricated by a non‐covalent crosslinking method. Uniform polymeric dimers are efficiently and simply obtained via hydrophobic interactions under optimized conditions in selective solvent. The steric hindrance generated by reorganization of hydrophilic polymer brushes during the interparticle association is critical for morphological selectivity in the assembly. General applicability offers the possibility to organize functional NPs into superstructures with well‐defined geometry and association numbers.     

An improved test method for characterising touch properties of porous polymeric materials

A new test method and instrument was developed to provide overall evaluation and characterisation of touch properties of porous polymeric materials. The test method and instrument can simulate the dynamic contact process between human skin and porous polymeric materials and obtain the mechanical and physical performance during contact. In the improved test method, a new measurement principle was proposed, and the mechanical device was redesigned, including surface friction measurement components. Most indices were redefined and the grading and classification methods were studied to give a direct overall evaluation of the touch properties for industrial applications. The objective test results and analysis, subjective evaluation method and prediction model of touch properties are also presented. The improved test method provides an objective measurement of thermal-mechanical properties using a single measuring instrument for new product development and quality control of porous polymeric materials.     

SYNTHESIS OF POLYESTER-POLYETHER MULTIBLOCK COPOLYMERS FROM POLYESTERS

A polymeric method was explored for the preparation of polyester-polyether multiblock copoly-mers using polyesters and polpethers as starting materials. The mechanism of the reaction and theeffect of the segment structure on it, the segment sequence of the block copolymers prepared havebeen studied. It has been shown that to the polymeric method the degree of compatibility betweenstarting polyester and polyether is of paramount importance, which determines not only the com-positional homogeneity of the block copolymers formed but also the success of the polymeric methodto get the block copolymers of the expected structure.     

Synthesis of nanosized carbonated apatite by a modified Pechini method: hydroxyapatite nucleation from a polymeric matrix

Pechini method is a materials synthesis method based on the preparation of a polymeric matrix. The advantage of this method is the ability to obtain materials with different particle sizes depending on the synthesis condition with a homogeneous distribution. In this work, carbonated hydroxyapatite (c-OHAp) nanoparticles were obtained by a modified Pechini method. To obtain the polymeric precursor of the c-OHAp, the polymeric matrix was prepared through a polyesterification reaction between citric acid and ethylene-glycol. Adding calcium hydroxide and ortophosphoric acid in aqueous solutions, raising the temperature up to 140 °C/2 h and keeping constant the pH at 8. The polymeric matrix was calcinated at different ranges of temperature from 200 to 600 °C in order to obtain the c-OHAp powder. The results show the presence of c-OHAp a as unique phase. The thermal analysis indicates that the c-OHAp phase was obtained at 600 °C. The particle size of the obtained material was <50 nm.     

Doping of polyaniline with polymeric dopants in solid state,gel state and solutions

Polystyrene with different degrees of sulfonation was empolyed as a polymeric dopant for polyaniline. The purpose of using a polymeric dopant is to avoid the migration of a small molecule dopant to increase stability of the doped complex. We applied the polymeric dopant to polyaniline in three different ways: in solid state, in solution and in gel state. In solid state, the conducting form was achieved only through a novel thermal doping method with the increase in temperature and pressure. In solution, the doping process was shown to be dependent on the nature of the solution and also on the molecular weight of the polymer. In the gel form of polyaniline, a polymeric dopant with a surprising low degree of sulfonation was found to be successful in the doping process.     

从聚酯合成聚酯-聚醚多嵌段共聚物

研究直接以聚酯为原料,合成聚酯-聚醚多嵌段共聚物。研究了反应机理、链段结构对反应的影响以及由此法制备的多嵌段共聚物的链段序列结构。实验结果表明,链段相容性对聚合物法的影响至为重要,链段相容性不仅决定了所得嵌段共聚物的组成均一性,而且还决定了某一链段结构的多嵌段共聚物能否用聚合物法制备。     

Potentiometric Method for Evaluation of Protective Properties of Polymeric Coatings

A new method is proposed for evaluation of protective properties of polymeric coatings. The method allows evaluation of the corrosion rate of a coated metal by means of potentiometric indication.     

Polymeric micelles in diagnostic imaging

The results are presented describing the use of polymeric micelles for gamma, magnetic resonance (MR), and computed tomography (CT) imaging. Micelle-forming diacyllipid-PEG conjugates were loaded with monomeric and polymeric amphiphilic chelates, containing entrapped metals, such as 111-In or Gd, and used for the experimental gamma and MR imaging of lymphatics in rabbits. The method is described to prepare polymeric iodine-containing PEG-based micelles which may act as a long-circulating blood pool imaging agent for CT. Experimental CT-imaging performed in mice and rabbits demonstrated high potential of a micellar contrast agent.     

Conventional synthesis of amphiphilic block copolymer utilized for polymeric micelle by mechanochemical solid-state polymerization

The first example is presented here of an amiphiphilic block copolymer synthesized by mechanochemical solid-state polymerization and used to form polymeric micelles. A model amphiphilic block copolymer was synthesized first, possessing galactose as a hydrophilic side chain and theophylline as a hydrophobic side chain, by mechanochemical solid-state polymerization. The resulting copolymer had a narrow molecular weight distribution. Polymeric micelle formation was subsequently carried out with the copolymer by a dialysis method. To gain insight into the physicochemical properties of the polymeric micelle, dynamic light scattering (DLS) measurements were performed. A narrow distribution of diameters was observed in the polymeric micelle solution, and these micelles were disrupted by the addition of sodium dodecyl sulfate (SDS). It was also confirmed by DLS measurements that the polymeric micelles were spherical. These results suggested that the block copolymer synthesized by mechanochemical solid-state polymerization was as suitable for the preparation of polymeric micelles as materials obtained by living polymerization.     

Combining carbon and polymeric particles in an inert fluid as a promising approach to synthesis of nanocomposites

Russian Journal of Applied Chemistry - Effective method for introduction of dispersed filler particles into a polymeric matrix was developed. The method is based on disaggregation and uniform...     

Determination of Halogenated Hydrocarbons in Insulating Polymeric Foams

A simultaneous thermal analysis/mass spectroscopy system was used for the determination of halogenated hydrocarbons in polymeric foam insulation materials. The investigation of ten different polymeric foams show that this equipment is a sensitive and reliable tool for the identification and determination of the bubbling agent. The results are compared with the Purge and Trap method. This revised version was published online in July 2006 with corrections to the Cover Date.     

Measurement of residual stresses in polymeric parts by indentation method

An indentation method was studied as a means of measuring the residual stress in an injection molded polymeric specimen because destructive methods restrict the reuse of measured parts and it is not possible to apply them to small and complicated parts. The load-displacement curve was measured for indentation at stressed and non-stressed positions. Residual stress distribution of the injection molded part was calculated by comparing the load-displacement curve results with respect to the indentation depth. The residual stresses measured by the indentation method were reliable because they were in good agreement with numerical results and those measured by the hole drilling method. The indentation method can be utilized to measure the residual stresses in polymeric parts for practical applications, particularly for small or complicated parts.     

Facile electrochemical fabrication of polymeric templates for spatially selective deposition of metals

Here, we report on a simple and general approach to fabricate polymeric (poly(2-methoxyaniline)) templates for deposition of silver in the form of micro islands on the electrode surface. The method is based on the application of electrochemically generated hydrogen microbubbles to locally block polymerization of monomers on the surface. This yields micrometer-sized holes within the forming polymeric film, which act as gate sites enabling further selective deposition of the metal on the surface.     

微盘电极应用-聚在乙二醇离子导体中的伏安分析

在聚乙二醇离子导体中, 研究了二茂铁在其中的伏安性质, 结果表明如果电活性物质与聚合物溶剂不发生相互反应, 那么电活性物质在聚合物溶剂中的扩散仍然遵循Fick扩散方程, 其伏安结果可以定量描述。提出了在聚合物离子导体中不需要知道电活性物质的摩尔浓度就可估算扩散系数的伏安方法, 探索了在聚合物离子导体中电活性物质的扩散规律。