最新刊期
卷 31 ， 期 2 ， 2018
- 摘要：A better understanding of the diffusional behavior of molecules in gels is required for fundamental research work on polymer gels as well as for practical work such as developments of drug delivery systems and separation membranes based on gels. The diffusion coefficient (D) obtained by pulse field gradient nuclear magnetic resonance (PFG NMR) is an effective means to elucidate the dynamics in gel systems. The measurements of D for probe molecules in gels reveal the mobility of the molecules and provide information about the gel network size. In the first section of this article,the self- diffusion phenomenon and the self-diffusion coefficient measurement techniques are briefly introduced. In the second section,we introduced the principle of self-diffusion coefficient measurement by PFG NMR. In the third section,the applications of PFG NMR technology in polysaccharide gel research are introduced.关键词：Pulse field gradient nuclear magnetic resonance (PFG NMR);Self-diffusion coefficient ( D);Molecular dynamics;Polysaccharide;Gel;Probe molecule;Network size
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发布时间：2022-09-05 - 摘要：As a kind of nonsteroidal anti-inflammatory drug, ibuprofen is widely applied in clinic due to its good antipyretic,analgesic and anti-inflammatory effects. However,there are still some adverse effects in its practical applications. This promotes scientists to improve the performance of ibuprofen by chemical modification ( e. g. esterification,amidation) or polymeric loading. Their research progress is summarized. It is pointed that the bio-based polymer conjugates have good prospect in the future due to the combination of chemical modification and slow release function into one improvement method.关键词：Ibuprofen;Chemical modification;Drug delivery;Polymer conjugates;Biodegradable materials
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发布时间：2022-09-05 - 摘要：Slow crack growth is the main reason of fracture failure for polyethylene (PE) pipes. Currently,the test for slow crack growth which commonly used in the industry is lack of efficiency and reproducibility,which restrict the accurate evaluation for performance of slow crack growth resistance and development of PE pipes. In order to solve these problems, foreign scholars put forward two new test methods of fast evaluation-Strain Hardening Test Method (SH) and Cyclic Cracked Round Bar Test Method(CRB). Test procedures of these two methods are separately introduced,and research progresses of these two methods are reviewed from rationale and experimental study. It is suggested that future research should be in four aspects:investigating the test condition of strain hardening response at room temperature,combining the linear elastic fracture theory with CRB method,improving the life prediction method based on CRB method and indicating how these two methods can be applied to other plastic pipes.关键词：Polyethylene pipes;Slow crack growth;Strain hardening test method(SH);Cyclic cracked round bar test method(CRB)
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发布时间：2022-09-05 - 摘要：Cellulose nanocrystal (CNC) has attracted extensive attention in many fields of scientific research due to its unique chiral nematic liquid crystal structure,especially the application in bio-liquid crystal materials has become the current research hotspot. This paper reviews the research of CNC and its chiral nematic derivative materials during these years. In this paper,the formation and regulation of CNC chiral nematic liquid crystal phase are introduced. Secondly,the preparation methods of CNC chiral nematic derivative materials are summarized,such as sulfuric acid hydrolysis combined with evaporation induced self-assembly method (EISA), chiral template combined with sol-gel method and solution. The application of CNC chiral nematic liquid crystal structure assembly materials in optical materials,functional polymer resin materials and medical materials are expounded, and the prospect of future development is also discussed.关键词：Cellulose nanocrystal;Chiral nematic;Liquid crystal phase;Nanocomposites
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发布时间：2022-09-05 - 摘要：A block copolymer, poly(ethylene oxide)-b-poly(N-acryloyl-L-proline methyl ester) short as D12-EA,was prepared via RAFT polymerization using macromolecular chain transfer agent containing dodecyl endgroup,whose structure was characterized by GPC and 1 H NMR. The self-assembly of D12-EA in water and the reassembly behavior upon variation of temperature was explored via a combination of UV-Vis, dynamic light scatter (DLS),static light scatter (SLS),TEM, and temperature-variable 1H NMR. The D12-EA formed spherical micelle in water with radius about 20 nm when solution temperature was below the cloud point (CP) of thermo-sensitive poly (N-acryloyl-L-proline methyl ester) (A block). However,it reversibly transformed into vesicle with radius around 90 nm when solution temperature was above CP of A block. As revealed by 1H NMR spectra,the transition from sphere to vesicle was driven by the switch of A block form hydrophilic corona to hydrophobic core of micelle above CP to form aggregate with lower free energy.关键词：Amino acid;N-Acryloyl-L-proline methyl ester;Thermo-sensitive;Dodecyl;Reassembly
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发布时间：2022-09-05 - 摘要：Polyvinylamine is applied in this paper to prepare the perovskite film as organic ammonium source. In this case,the perovskite crystal grains are linked together by the polymeric carbochain backbone through the A-site occupation on the surface of perovskite crystal grains via polymeric primary amines. The results of 1 H-NMR, SEM and XRD indicated that this kind of microscopic structure is able precisely to regulate the perovskite morphology due to the direct polymeric participation in the growing process of perovskite crystals,which will effectively improve the long-term stability of perovskite solar cells.关键词：Polyvinylamine;Perovskite;Morphological regulation;Covalent connection
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发布时间：2022-09-05 - 摘要：Preparing ABS-based Wood-Plastic Composites by calendaring-molding technology, the effects of the amount of compatibilizer ABS-g-MAH on the properties of wood flour/ABS composites were investigated. The results show that, using compatibilizer ABS-g-MAH can effectively improve the interface compatibility between the wood flour and ABS matrix,the mechanical properties,thermal decomposition temperature and processing flowability of composite materials can all be improved. The mechanical properties of composite materials can be reached the maximum values at 8 % (wt) ABS-g- MAH, while the compatibilizer ABS-g-MAH can not improve the creep resistance of the composite materials.关键词：Wood flour;ABS;ABS-g-MAH;Composite materials
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发布时间：2022-09-05 - 摘要：The methanolysis of nylon 66 (PA66) was investigated using concentrated sulfuric acid (H2SO4) as a catalyst. The structures of the products were characterized by FT-IR and 1 H NMR, and the results showed that the obtained products are dimethyl adipate (DMA) and hexamethylene diamine (HMD),respectively. Using L9(34) orthogonal experiment,the effects of temperature,time,H2SO4 dosage and methanol dosage on the methanolysis reaction were studied. And the optimum reaction conditions were obtained: the molar ratio of PA66 to H2SO4 is 1:2,the molar ratio of PA66 to methanol is 1:20,reaction temperature is 120℃,reaction time is 5h. Under these conditions, the conversion of PA66 was 100%,the yields of DMA and HMD were reached to 86. 04% and 88. 62%, respectively.关键词：Nylon 66;Alcoholysis;Dimethyl adipate;Hexamethylene diamine
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发布时间：2022-09-05 - 摘要：The cases' teaching is very important for the improvement of the teaching effectiveness of the subject of the " Polymer Physics",the enhancement of the abilities of the thinking of,analyzing and solving the problem, and the excavation of the innovative and creative abilities of the students. The general principles to choose the cases for the library were introduced,The princilples include the unity of the aim,the typicalness of the content,strictness,accuracy,reality, practicity, comprehensiveness and variety. The management and operation of the library were also presented from the construction of each case and the method to choose the case. The establishment of the cases' library provided a solid ensurance for the effective polymer physics teaching.关键词：Polymer physics;Case library;Teaching reform
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发布时间：2022-09-05 - 摘要：The enterprise practice is an important teaching part of polymer materials and engineering major,and is also key mode to cultivate engineering capacity and innovation ability for students. Aimed at resolving the problems occurred during the practical teaching in school-enterprise cooperation mode,the two-dimensional code technology derived from internet was innovatively utilized in the practical teaching. The specific performing method was provided,aiming to transform the practice mode from enterprise technicians' teaching to students' self-learning and exploration, and thus help students give an active role in practice. Meanwhile,the implementation effect,the problems encountered,and the prospect of application in practical teaching in school-enterprise cooperation mode were expatiated as well. It is a new attempt to improve the quality of practical teaching in school-enterprise cooperation mode.关键词：School-enterprise cooperation;Practical teaching;Enterprise practice;Two-dimensional code
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发布时间：2022-09-05 - 摘要：In this paper, based on the our university personnel training mode in the polymer engineering field as samples to study,was studied the innovation entrepreneurship education and the constructing of training center for the engineering undergraduate and graduate cultivate. Through the analysis of domestic innovation entrepreneurship training center,found out the problems existing in the constructing of training center in China,and determined the ways to solve these problems, so that the engineering students in accumulation of theoretical knowledge and practical ability and innovative thinking to get improved. The employment channels cultivated undergraduate and graduate were broaden, the "to retain and use" senior technical applied talents of polymer materials engineering practice and innovation ability were cultivated.关键词：Innovation and entrepreneurship education;Practice;Constructing of training center
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发布时间：2022-09-05 - 摘要：Abstrct: In order to meet the needs of the teaching reform of coating and coating technology,the author applied PBL teaching model to this course. The PBL teaching model carries out problem-based and student-centered teaching method. Compared to the traditional teaching model,this model not only could cultivate students' ability of independent study and thinking,but also could improve the students' comprehensive quality,including the ability of organizing, cooperating, expressing, analyzing and solving problems. In addition, after the implementation of PBL teaching model in this course,the author analyzed the necessity and advantage of the PBL teaching mode,and pointed out the problems existing in the implementing of the PBL teaching mode,then gave the relevant countermeasures.关键词：PBL teaching model;Coating and coating technology;Application
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发布时间：2022-09-05
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