最新刊期
卷 25 ， 期 8 ， 2012
- 摘要：In this work the macromolecular chain’s conformations in dilute, semidilute,concentrated and extra concentrated polymer solutions were discussed respectively, at the same time the interactions between macromolecules, the complex correlative effects and the changes of macromolecular sizes were explained in detail, and the definition of excluded volume and several concepts: thermic correlation, long-range correlation and full Gaussian concentration were introduced. It is indicated that the conformations at different chain’s size ranges are different in the solutions of different concentrations, and that the single chain’s size happened contraction in lytrooic condensation process of macromolecules, from Flory size RF to unperturbed chain dimension R0. This is a specialty of lytrooic condensation of macromolecules.关键词：Macromolecular chain;Conformation;Polymer solution;Lytropic condensation
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发布时间：2022-09-18 - 摘要：Biodegradable polymers are regarded as one of the solution of the "white pollution" problem, which is caused by the traditional polymers such as PP, PE and PS etc. Poly (butylenes succinate) (PBS), one of the most important biodegradable aliphatic polyesters, has drawn much attention from both scientific and industrial community due to its comparable mechanical performance to PP and PE. However, as most biodegradable polymer, PBS also has some limitations including poor processing, lacking of variety and narrow application fields. Therefore, reports on its modification have increased. This paper reviews the recent development on PBS chemical and physical modification.关键词：Poly(butylenes succinate);Modification;Chemical modification;Physical modifications
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发布时间：2022-09-18 - 摘要：The non-metallocene late transition metal catalysts have shown potential application on the coordination copolymerization of olefin with polar monomer due to their good ability of resistance to hetero-atoms. This paper mainly reviewed the advances in studies on catalysts for the coordination copolymerization of ethylene and propylene with Methyl Acrylate or Methyl Methacrylate by Fe、Co、Ni、Pd、Cu non-metallocene late transition metal catalysts. We focuse on the effect of the structure of non-metallocene late transition metal catalysts in which Fe, Co, Ni, Pd as the center metal on the coordination copolymerization activity of ethylene and propylene with Methyl Acrylate or Methyl Methacrylate and the molecular weight of the copolymer, and emphasize that the design of new ligands was an important way to exploit new non-metallocene late transition metal catalysts.关键词：Ethylene;Propylene;(M)MA;Late transition metal catalysts;Coordination polymerization
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发布时间：2022-09-18 - 摘要：Electrospinning has been recognized as the most simple and effective technique for the fabrication of polymer nanofibers. The electrospun nanofibrious membranes have many advantages, such as very thin diameter, light weight, high specific surface, high porosity, etc. Compared with the traditional fibrious membranes, the electrospun nanofibrious membranes possess some unique morphology and structure characteristics, which can be divided into three levels. The third-level morphology describes the apperance morphology of the electrospun nanofibrious membranes including many fibers. The second-level morphology covers macromorphology of single nanofiber.The first-level morphology is the single nanofibers’ microstructure. This paper describes the morphology and structure of the three-level nanofibers, and then indicates these fibers’ applications in the future.关键词：Electrospinning;Nanofibers;Morphology;Structure
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发布时间：2022-09-18 - 摘要：Breath figures (BF) method is a dynamic templating method for surface patterning of polymers. The BF method represents a single-step technique for fabricating films with ordered microscale holes utilizing condensed water droplets as templates, which evaporate after they leave ordered imprints on the film surfaces. After the establishment of the BF methodology system, new research trends have been developed in recent years. Researches concerning the preparation of chemically heterogeneous patterns based on the BF method and structural/chemical secondary processing towards the original honeycomb-patterned structures have become two of the most representative research directions of the BF method. Gradually the focus of research shifted from BF methodology to how to utilize the BF method in developing new functionalities and structures. This review comprehensively summarizes the two most representative research directions of the BF method in order to give the insight of the future development of this technique.关键词：Surface patterning;Breath figures method;Self-assembly;Functional structure
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发布时间：2022-09-18 - 摘要：Lignin is an abundant renewable resource and shows a great potential for application. In recent years, research on the application of lignin has received much attention. In this work, the recent research status on the comprehensive application of lignin is reviewed. Two kinds of application are introduced:used directly and used after liquefaction. The research situation of lignin liquefaction for bio-oil and phenolic compounds is discussed in detail. In addition, the liquefaction mechanism is also summarized. Finally, the problems and difficulties involved are discussed, the research direction on the application of lignin is proposed.关键词：Lignin;Liquefaction;Phenolic compounds;Application
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发布时间：2022-09-18 - 摘要：Due to the need of conserving petroleum resources, protection of the environment and developing concerns of economy, using renewable bio-based raw materials to replace petroleum derived polymeric materials have attracted great interest from scientists and the industry. Elastomer is a kind of material which is widely used in many fields. However, elastomers are mainly obtained from petroleum. Research on the development of bio-based elastomers is vital to cut down the use of petroleum and protect our environment. This article briefly introduces three kinds of bio-based elastomers—bio-based polyurethane elastomer, bio-based polyamide elastomer, bio-based polyester elastomer—which have received much more attention recently. It mainly focuses on the raw materials of the bio-based elastomer, synthetic routes and comparison between bio-based elastomers and the petroleum-based ones.关键词：Bio-based;Elastomer;Vegetable oil;Polyurethane;Polyamide;Polyester
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发布时间：2022-09-18 - 摘要：Polypropylene (PP) is a general polymer material with excellent performance and low price. However, the use of PP has been restricted by its poor dyeability, hydrophilicity, cohesiveness, and poor compatibility with other materials because of the nonpolarity of PP. Introduction of polar functional group to molecular chain of polypropylene (PP) by the method of solid phase grafting copolymerization would not only keep the original excellent properties of PP, but also have the advantages of low temperature, low pressure, low cost, high grafting degree and no need of solvent recovery, etc. In this paper, the reaction mechanism of solid-phase grafting was briefly introduced, and the latest advances in solid phase grafting copolymerization of polypropylene from the aspect of grafting monomers were reviewed. The effect of the reaction technology on grafting degree, grafting efficiency and properties of grafting copolymer was then discussed.关键词：Polypropylene;Solid-phase grafting;Grafting mechanism;Grafting monomer
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发布时间：2022-09-18 - 摘要：Atom transfer radical polymerization (ATRP) is an effective controlled/living polymerization method. It can be used to design polymer structure and control molecular weight. Thus it is of great potential research value. This paper reviews the research progress of ATRP, especially for catalysis/initiation mechanism of traditional ATRP catalysis/initiation system, RATRP catalysis/initiation system, AGET ATRP catalysis/initiation system, SR&NI ATRP catalysis/initiation system, ICAR ATRP catalysis/initiation system, ARGET ATRP catalysis/initiation system, hybrid and bimetallic catalyst system. Moreover, the current situation of ATRP application methods, such as bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization etc., was summarized.关键词：Atom transfer radical polymerization;Catalysis;Initiation;Polymerization method
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发布时间：2022-09-18 - 摘要：Poly (phenylene sulfide) is a kind of semicrystalline thermoplastic polymers with typical cross-linking character, thermal cross-linking, chain growth, oxidative cross-linking and oxidative reactions occur at different levels during the heat-treatment in different atmospheres. The molecular weight and thermal stability of thermal treated PPS are improved, the crystallization properties is also changed. The mechanism of thermal treatment and its application in engineering are mentioned in this work, it is meanly focus on the influence on properties of PPS with different thermal treatment and the combination with engineering application. Finally, summarizes the problems in post-processing and provides a new idea to combine the heat-treatment and improvement of toughness in the same process.关键词：Poly (phenylene sulfide);Thermal Cross-linking;Mechanism;Application
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发布时间：2022-09-18 - 摘要：The BOPP film specialty resin of grade L5D98 were produced industrially by PetroChina Guangxi Petrochemical Company according to controlling impurity content of material, bed level of reactor, dew-point temperature difference of reactor, optimizing ratio of catalyst systems and so on. The properties of different batches L5D98 resin, such as melting flow rate (MFR),MFR ratio, isotacticity, xylene solubility and crystallinity were analyzed. The results indicated that on one hand, the process were stable in control, on the other hand, the properties were no great differences between different batches L5D98 samples thus productions were able to meet the processing requirement of downstream customers.关键词：BOPP;Grade L5D98;Preparation and Properties
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发布时间：2022-09-18 - 摘要：The poly (styrene-co-glycidyl methacrylate) (PSG) latex microspheres were prepared by soap-free emulsion polymerization. The resulted PSG microspheres were further modified with 1,6-hexanediamine as a space arm to get the amino-modified PSGN microsphere. Captopril was coupled onto the surface of PSGN microspheres by the activation with N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC) and N-Hydroxysuccinimide (NHS), so that the affinity polymer microspheres immobilized captopril was finally obtained. The effects of the ratio and concentration of catalysts, pH, temperature and time on the coupling reaction between the PSGN microspheres and captopril were examined. It was shown that the effect of immobilization was much better under the condition of 25℃, pH=4.0, m(NHS)∶m(EDC)=1∶2, m(EDC)=4mg/mL.关键词：Soap-free emulsion polymerization;Affinity polymer microsphere;Captopril;Styrene;Glycidyl methacrylate
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发布时间：2022-09-18 - 摘要：Organic and polymer photovoltaic cells are becoming an extremely active research area to meet the urgent need for clean and renewable energy managements due to their potential applications as flexible, low cost and solution processable energy sources. In this article, the influence of introducing a small amount of NPB into the mixed P3HT:PCBM solution on the performance of the polymer solar cells was investigated. It was found that adding NPB improved bulk heterojunction grown which enhanced the photovoltaic performance. When NPB content is 0.4mg/mL, PCE increased from 1.05% to 1.64%. The UV-Vis absorption spectra showed that the intensities of the absorption peaks at 560 and 610 nm increased because of the increased absorption π→π* transition of P3HT after adding NPB. SEM results also showed that the P3HT:PCBM phase separation increased markedly after adding NPB which is valuable for exciton dissociation. It was found that the hole mobility could be pronouncedly influenced by adding NPB.关键词：Polymer solar cell;Bulk heterojunction;NPB;Ternary blend films
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发布时间：2022-09-18 - 摘要：Based on the molecular determination methods of DMSO recrystallization and rapid cooling, two poly(glycolic acid) samples had been prepared. By the tests of DSC and XRD, the change of the crystal sizes and the degree of crystallinity of the samples were discussed, and the intrinsic viscosities of the different samples were measured and compared. The stability of the samples in hexafluoroisopropanol was also investigated. A series of results showed that the rapid cooling was effective to avoid the PGA’s thermal degradation in DMSO; because the PGA degraded rapidly in HFIP solvent, the measurement of molecular weight should be carried out quickly after the PGA sample solvent was prepared. According to the Mark-Houwink equation, the relationship between the weight average molecular weight and intrinsic viscosity was built as: Ln(η)=-10.90*Ln(Mw) +0.96, r=0.995. The weight average molecular weight could be calculated by the determination of intrinsic viscosity due to this equation.关键词：Poly(glycolic acid);Recrystallization of DMSO;Rapid cooling;Molecular weight
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发布时间：2022-09-18 - 摘要：Polyacrylamide(PAM) has been widely applied in many fields. The Cationic polyacrylamide(CPAM), as one kind of very important polyacrylamide, is playing a significant role in our daily life and industrial production, especially in the field of sewage treatment. This paper summarizes the main applications of CPAM and its mechanisms of action, and also highlights the traits and latest progresses on several pop synthetic techniques of CPAM. This paper also demonstrates the latest research status of CPAM home and abroad, and sets a developmental prospect of CPAM, which is expected to provide a reference and basis for the further study of CPAM in the future.关键词：Polyacrylamide;Cationic polyacrylamide;Methods of polymerization
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发布时间：2022-09-18 - 摘要：Supercritical carbon dioxide (scCO2) as a green solvent has attracted much attention in the academic community and industrial sector. In the last decade, new polymerization techniques related to scCO2, such as carbon dioxide hybrid mediums and continuous stirred reactor tank, have been developed. Moreover, various functional polymer materials including fluoroplastics, fluoroelastomers, core-shell composites, porous materials, and perfluorosulfonic acid membranes, have been prepared using the technology of supercritical carbon dioxide. The above mentioned recent developments in the area are introduced briefly in this article.关键词：Supercritical carbon dioxide;scCO2 hybrid medium;Continuous stirred tank reactor;Fluoropolymers;Functional polymer materials
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发布时间：2022-09-18 - 摘要：Polylactide (PLA) is an aliphatic polyester composed of lactide (LA) repeat units. It is the biodegradable and biocompatible material and has attracted much attention recently for the biomedical, pharmaceutical and environmental applications. The review summarizes recent developments in the catalytic polymerization of lactide. Emphasis is placed on the new initiators/catalysts for the ring opening polymerization (ROP) of lactide. Single-site that has high rates or stereocontrol catalysts is provided. Because the stereochemistry of monomeric units in the polymer chains plays a decisive role in the mechanical, physical and degradation proterties of PLA materials, Different polylactide architectures, namely stereoregular PLLA and PDLA, atactic, heterotactic, syndiotactic and stereoblock PLAs are produced depending on the catalysts and the LA monomers used. In this review, we mainly focus on single site catalysts, including aluminum, rare earth metal and the environmentally friendly iron, zinc, magnesium and nonmetallic catalysts for the stereoselective polymerization of lactide. Catalysts displaying low toxicity and biocompatibility are emphasized. It can be reasonably anticipated that the synthesis and practical applications of environmentally friendly PLA will keep increasing at the industrial scale. In this respect, further development in the stereocontrolled ROP of lactide using well-defined single site complexes and nonmetallic catalytic systems will be an attract topic.关键词：Lactide;Polylactide;Catalyst;Ring opening polymerization;Stereoselectivity
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发布时间：2022-09-18 - 摘要：The comprehensive teaching experiment was designed by using pre-treatment method of ultrasonic extraction, chemical leaching and gas chromatography-mass spectrometry. The value of PAEs in six kinds of representative food packaging materials was detected. According to analyzing the total ion chromatogram in abundance and the target compounds, types and contents of PAEs in the packaging materials are found. This experiment was applied in the experimental teaching successfully, and its effect was good.关键词：Comprehensive teaching experiment;GC-MS;Food packaging materials;PAEs
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发布时间：2022-09-18 - 摘要：The problem-based instruction aims at strenghening problem consciousness and enhanceing abilities in discovering, analyzing and solving problems. The problem-based instruction is of great significance in modifying traditional teaching, developing students' abilities in discovering, analyzing and solving problems and forming creativeness. In Guilford' Intellectual Theory, the intellegence is decomposed into 120 intelligence factors which will help to understand the basic characters of thought. Combining the problem-based instruction with the intelligence structure theory in polymer composite course, setting problems according to the intelligence factors can cultivate students' scientific thinking pattern, train the thinking skills of induction, analysis, association and so on, and improve the learning and research level.关键词：Problem-based instruction;Intelligence structure;Polymer composite
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发布时间：2022-09-18
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