最新刊期
卷 26 ， 期 6 ， 2013
- 摘要：According to the modern condensed polymers physics the polymer solutions can be divided in 5 classes according to concentration: extremely dilute solution; dilute solution; semi-dilute solution; concentrated solution and highly concentrated solution. There are 4 dividing concentrations between these solutions: dynamic overlap concentration; overlap concentration; entanglement concentration and full Gaussian concentration. The last one was nominated by author. The definitions and physical meanings of these dividing concentrations were introduced in this work, and the reason for naming of full Gaussian concentration was explained in particular. Also the essences and microscopic images of macromolecular chains conformations,of the correlative effects between segments in these solutions with different concentrations were discussed in detail. By the way the influences of the concentrations on the solution properties were discussed simply.关键词：Polymer solution;Dividing concentrations;Full Gaussian concentration;Lytropic condensation
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发布时间：2022-09-18 - 摘要：Keratin is the main component of wool, feathers, nail, and other epithelial coverings. This review focuses on the keratin extraction and promising applications on the biomedical field. The typical chemical methods based on acid-based hydrolysis, reduction and oxidation are summarized. As a natural biomacromolecule, keratin has good bioactivity, biocompatibility,biodegradation, mechanical property, and natural abundance. Keratin-based biomaterials have emerged as potential candidates for many biomedical applications.关键词：Keratin;Extraction;Biomedical application
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发布时间：2022-09-18 - 摘要：Polypropylene is one of the most important general plastics and widely used for automobile,household appliances, electronic products, package, building material, furniture and so on. For the production of polypropylene industrially, external donor is expected to add and change the process of polymerization, and thus to control the physical properties of PP products finally. The progress of external donor and dual external donor mixed based silane technology for Z-N catalyst in propylene polymerization were reviewed, and the application of the said external donor and dual external donor mixed for new production were also reviewed.关键词：Propylene polymerization;External donor based silane;Dual donor technology;Progress
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发布时间：2022-09-18 - 摘要：This article briefly described the development of amine-end-functionalized polymers at home and abroad. Three types of end-functionalized polymers prepared by primary amines,secondary amines and tertiary amines were introduced respectively. Meanwhile, the functionalization reaction mechanism, conditions and characteristics of using different amine end-capping agents to synthesize end-functionalized polymers were analyzed and compared in depth. This article described that the reaction conditions developed from low temperature to room temperature or higher and from needing to add polar modifier to using non-polar hydrocarbon solvents, and the functionalization reaction developed from single special end-capping reactions to general functionalization reactions. In the end,the prospect of future development of amine end-functionalized polymers was indicated.关键词：End-functionalized polymers;Amine end-capping agent;Research progress
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发布时间：2022-09-18 - 摘要：PVA/n-HA composites suiting for microinjection molding were prepared based on Solid State Shear Milling (S3 M) and molecular complexation technologies, And the microinjection molding of PVA/n-HA composites with n-HA content of 30% were realized. The thermal properties, rheological properties of PVA/n-HA composites were characterized by differential scanning calorimetry (DSC),thermogravimetric analysis (TGA) and high pressure capillary rheometer. The results showed that the melt point of modified PVA/n-HA composites decreased and the thermal decomposition temperature increased, obtaining the thermal processing window of more than 120℃. PVA/n-HA composites showed shear-thinning behavior and the low melt viscosity at high shear rate was suitable for microinjection molding. So PVA/n-HA composites had good mold filling performance. The structure and properties of PVA/n-HA microinjection molded samples were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results showed that n-HA was well dispersed in PVA matrix and increased the dimension stability of the injection samples. Due to the effect of high shear force inducing crystallization of PVA in microinjection molding, the crystallinity of PVA/n-HA microinjection molded sample was higher than that of conventional injection molded sample.关键词：Poly(vinyl alcohol);Nano-hydroxyapatite;Microinjection molding;Rheological property
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发布时间：2022-09-18 - 摘要：A new diamine monomercontaining a built-in, stabilized ortho ester group was synthesized by diglycerol with two steps of transesterification. Two new highly hydrophobic copolymer poly (ortho ester amide) (POEAd-1 and POEAd-2) were obtained by polycondensation ofthe monomer with suberic acid bis (N-hydroxysuccinimide ester) and dodecanedioic acid bis( N-hydroxysuccinimide ester). The number average molecular weight of POEAd-1 and POEAd-2 were determined by gel permeation chromatography (GPC) ,and calculated to be 1.24 × 104 and. 1.81 × 104 with polydispersity index(PDI) of 1. 59 and 1.93,respectively. Thermal stabilityof POEAd-1 and POEAd-2 via thermogravimetric analysis ( TGA) were investigated),the temperature of the onset 5 % weight loss is up to 198. 5℃ and 202. 5℃,respectively. Hemolysis test and MTT cytotoxicity test indicate that POEAd-1 and POEAd-2 has good biocompatibility as a potential biomedical materials, can bewidely used in the field of controlled drug deliever.关键词：Poly(ortho ester);Biomaterial;Biocompatibility
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发布时间：2022-09-18 - 摘要：Polyvinyl alcohol (PVA) hydrogel was prepared by means of chemical crosslinking with boric acid as the crosslinker. The optimum ratio of crosslinker to PVA was sought based on the studies of elasticity and swelling behavior of PVA hydrogel. The influence of temperature on the elasticity and the influence of swelling time, salt concentration, and temperature on the swelling ratio were tested. The results show that with the increase of crosslinker, the swelling ratio and elastic modulus value of PVA hydrogel gradually increased, and when reached maximum, then decreased with the increase of crosslinker. When the ratio of crosslinker to PVA equals 10 %,the elasticity and swelling property of PVA hydrogel are the best. The swelling ratio of PVA hydrogel gradually increases with the swelling time increase, and reaches swelling equilibrium in aqueous solution within 40h. The swelling ratio of PVA hydrogel reduces with the increase of salinity in aqueous solution; however, its resistance to salinity is quite strong. It can swell twice its size in water of 10% salinity, so it is applicable to high salinity reservoirs. The swelling ratio and elasticity of PVA hydrogel are not sensitive to temperature; there is hardly any change with the increase of temperature. Consequently, PVA hydrogel is applicable in reservoir temperature.关键词：PVA hydrogel;Boric acid;Swelling behavior;Elasticity
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发布时间：2022-09-18 - 摘要：The inclusion complex of 2-phenoxylethyl acrylate (POEA) with methylated-β-cyclodextrin(Me-β-CD) was synthesized in water and characterized by UV-vis and 1 H NMR spectra. A series of hydrophobically modified cationic polyacrylamide P(AM-DAC-POEA) were synthesized by the copolymerization of AM, DAC and la. The flocculation and absorptive experiments of P (AM-DAC-POEA) in sullage of kaolin demonstrated that the flocculation and absorptive properties can be increased effectively by the hydrophobic interaction. The results indicate that the copolymerization of Me-β-CD encapsulated hydrophobic monomer and hydrophilic monomer in a homogeneously system provides a green method to obtain amphiphilic and functional polymers.关键词：Hydrophobically modified cationic polyacrylamide;Flocculant;Cyclodextrin;Inclusion complex
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发布时间：2022-09-18 - 摘要：Amphiphilic block copolymer Polystyrene-b-Poly(ethyleneoxide)monomethyl ethermethacrylate-b-Polystyrene (PSt-b-POEOMA-b-PSt) was synthesized by reversible addition fragmentation chain-transfer (RAFT) polymerization. The structure of the copolymer was characterized by FT-IR,1HNMR, and GPC measurements. Three different ratio copolymers can readily be self-assembled into micelles in aqueous solution. It evidently observed the structure of micelles by transmission electron microscopy (TEM),with the decrease in the proportion of hydrophilic segments, the micelle size decreased slightly. The drug loaded PSt-b-POEOMA-b-PSt micelles prepared by the dialysis method were then used carrier of liposoluble drug vitamin E, whose morphology was observed by TEM, and was still core-shell structure. The thermal properties of the drug-loaded micelles were observed by different scanning calorimetry (DSC). The results showed that the glass transition temperature (T_g) of polystyrene was reduced slightly in the process of loading VE to the kernel. The drug loading content (DLC) of the copolymers was 70 %-80 % by ultraviolet (UV) analysis.关键词：RAFT polymerization;Amphiphilic block copolymer;Self-assembly;Micelles
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发布时间：2022-09-18 - 摘要：The efficiency of hydrophobic associating polyacrylamide ( HAP) used for polymer flooding is determined by its microstructure. The study on analysis means of the microstructure can contribute to screening good functional polymer systems for EOR. The atomic force microscopy (AFM) and scanning electron microscope (SEM) are used to observe the microstructures of HAP solutions at different concentrations, while dynamic light scatter (DLS) and AFM are used to analyze particle size distribution. The DLS results show that as the concentration increases particle size is larger and double peaks appear; the relatively loose network with weak salt resistant ability is replaced by dense network structure that is less susceptible to salt. Both the particle size by DLS and the microstructures can be measured by the AFM at the same time. The comparisons of three means at various solution conditions provide comprehensive characterization revealing the relation of structure and properties of HAP.关键词：Hydrophobic associating polyacrylamide;Microstructure;EM;AFM;DLS
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发布时间：2022-09-18 - 摘要：Recently, the coaxial electrospinning are widely utilized to fabricate various multifunctional composite materials. Meanwhile, the confined crystallization of polymers takes much attention and many techniques are applied to prepare confinements for semi-crystalline polymers. Based on the two study backgrounds, in this paper, two kinds of polyacrylonitrile(PAN)/polyethylene oxide (PEO) and cellulose acetate (CA)/PEO composite fibers were fabricated by coaxial electrospinning. With the helps of scanning electron microscopy (SEM) and transmission electron microscopy (TEM),the morphologies of the composite fibers were analyzed. It was found that the composite fibers were core-sheath structure, where the PEO as the core was embedded in the sheath PAN or CA. Tuning the concentration of PEO during electrospinning process, the diameter of the composite fibers and PEO core was changed, and therefore, different confinements were prepared for the semicrystalline PEO. Moreover, the mechanical properties of the composite fiber membranes were also tested. As a result, the tensile properties of CA/PEO composite fiber membranes were better than those of PAN/PEO composite fiber membranes.关键词：Coaxial Electrospinning;Composite fibers;Sheath-core Structure;Polyethylene oxide;Tensile properties
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发布时间：2022-09-18 - 摘要：Based on linear intersect, the graphic user program of reactivity ratio of two-component copolymerization calculation was designed according to least squares principle by using Matlab GUI in the paper. Compared with traditional approaches of reactivity ratio' solution,this graphical user program has the characteristics of simple design principle and fast computation. In addition, the terse interface,friendly interaction and practical input platform was provided by Program. The results of actual application indicated that the data by using graphic user program are closed to the value which calculated by microcomputer dynamic search method and Tidwell-Mortimer method, and much more smaller minimum sum of squares of deviations than using slope-intercept method. Avoiding the inconsistency of calculation result which caused by equation asymmetry of slope-intercept method.关键词：Reactivity ratio;Copolymerization;Matlab;Graphical user program
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发布时间：2022-09-18 - 摘要：The high functionalities of naturally occurring macromolecules such as DNA,proteins and collagen arise from their supernatural helical structures. The precisely ordered secondary structure plays important roles in realizing biological activities and is the ubiquitous object in nature. Helical structure is chiral and optically active, and the unique structure provides sophisticated properties and functions for helical polymers, which allows the potential applications of helical polymers in chiral recognition and asymmetric catalysis together with chirality response and data storage. In this paper, the overview of helical polymers is provided, and the research progress of static and dynamic helical polymers, as well as functions and applications of helical polymers, is reviewed in detail.关键词：Helical polymers;Helical structures;Static helical;Dynamic helical;Function and application
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发布时间：2022-09-18 - 摘要：In the teaching of specialty experiment, we improved the students' manipulative ability, ability of anglicizing as well as solving problems, by using the ways such as reforming traditional experiment content. First, the comprehensive experiment and designing experiment were introduced, the students were encouraged to reading, analysising and rearranging the literatures and then preparing academic experimental scheme,which helped themselves to design one useful item based on the design. Second,in order to improve the students' comprehensive quality and independent innovative ability, we designed new kinds of performance evaluation.关键词：Experiment teaching;Comprehensive experiment;Design experiment;Performance evaluation
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发布时间：2022-09-18 - 摘要：The curriculum of Polymeric Materials contains the major traditional polymeric materials such as plastics, rubbers,fibers, adhesives, coatings and polymer blends, which are used very broadly in industry and daily life. Therefore, it is one of the major curriculums for the undergraduate students majoring on Polymeric Materials and Engineering. Compared with other appealing curriculums such as polymer chemistry and functional polymers, however,the contents are less attractive. Measures are thus taken, especially by using the discussible and interactive teaching method. One of the important features is that some selected polymeric materials are assigned to a team of students, who should prepare slides and present to all other students. Discussion is followed with questions, answers and comments from all audiences including the teachers. The unresolved questions shall be brought back and answered after further reading and thinking. By this way, the knowledge is well delivered, while the class is not boring anymore.关键词：Polymeric materials;Discursive;Interactive;Teaching
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发布时间：2022-09-18 - 摘要：Open experimental teaching is an important means to train and improve students' comprehensive ability. In order to meet the social demand for polymer materials and engineering, improve the students' ability to analyze and solve problems, set up multi-level open experimental system as basic verification type, comprehensive and design type. This paper discussed the open experimental models and innovative talent training of polymer materials and engineering, found the problem to be solved in the course of practice and proposed the improved methods. After teaching practice open experimental teaching is beneficial to improve the students' knowledge structure and effectively enhance their practical and innovative ability.关键词：Open experimental teaching;Innovation and personnel training;Improved methods
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发布时间：2022-09-18
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