专业英语--材料部分ppt课件.ppt

Scientific EnglishforPostgraduates for Professional Master Degree1Introduction to the course About the course Polymer Materials (郑学晶郑学晶) Metal Materials (胡俊华胡俊华) Inorganic Materials (范冰冰范冰冰) Material Engineering, Nano Materials, Scientific Literature Reading & Writing (陈德良陈德良) About meSichuan University Bachelor & MasterInstitute of Chemistry Chinese Academy of Sciences PhDTechnology University of Eindhoven The Netherlands PostdocZhengzhou University Associate Professor in Polymer Science & EngineeringAbout MaterialsLife in the 21st century is ever dependent on an unlimited variety of advanced materials. In our consumptive world, it is easy to take for granted the macro-, micro-, and nanoscopic building blocks that comprise any item produced. We are spoiled by the technology that adds convenience to our lives, such as microwave ovens, laptop computers, digital cell phones, and improved modes of transportation. However, we rarely take time to think about and appreciate the materials that constitute these modern engineering feats.The term material may be broadly defined as any solid-state component or device that may be used to address a current or future societal need. For instance, simple building materials such as nails, wood, etc. address our need of shelter. Other more intangible materials such as nanodevices may not yet be widely proven for particular applications, but will be essential for the further needs of our civilization. Although the above definition includes solid nanostructural building blocks that assemble to form larger materials, it excludes complex liquid compounds such as crude oil, which may be more properly considered a precursor for materials. Materials science is an interdisciplinary field applying the properties of matter to various areas of science and engineering. This scientific field investigates the relationship between the structure of materials at atomic or molecular scales and their macroscopic properties. It incorporates elements of applied physics and chemistry. Materials science also deals with fundamental properties and characteristics of materials.Example sentences: Various:Chemical properties, at the nano-scale, describe how the chains interact through various physical forces.A polymers architecture affects many of its physical properties including, but not limited to, solution viscosity, melt viscosity, solubility in various solvents. Investigate:Title: A novel spectroscopic approach to investigate transport processes in polymers: in the case of water-epoxy system Incorporate:Halogens like chlorine and fluorine are very rare in natural polymers, but many synthetic polymers incorporate these elements.A thermo-responsive polymer is incorporated into a fuel cell in order to maintain optimum hydration of the polymer electrolyte membraneExample sentences:Classes of MaterialsMaterials science encompasses various classes of materials, each of which may constitute a separate field. There are several ways to classify materials. For instance by the type of bonding between the atoms. The traditional groups are ceramics, metals and polymers based on atomic structure and chemical composition. New materials has resulted in more classes. One way of classifying materials is: Biomaterials Carbon Ceramics Composite materials Glass MetalsNanomaterialsPolymersRefractorySemiconductorsThin FilmsFunctionally Graded Materials Result in, resulting:The addition of a higher ratio of crosslinking agent will result in a very viscous polymer.It serves as a solvent, which is incorporated into the polymer structure, resulting in low VOC emissions.The resulting mixture was subject to sonication for 1 min in an ice bath. 1. Introduction to Polymers and Polymerizations (Polymer Composition and Structure, Polymerization Mechanism) 2. Polymer Physics (Chain structure, aggregate structure, polymer multicomponent systems, molecular weight and molecular weight distribution) 3. Polymer Chemistry (Addition and condensation polymerization, free radical polymerization, polymerization processing)4. Polymer Structural Analysis (SEM, TEM, FTIR, DSC, Mechanical tests)5. Polymer Processing (Extrusion, Injection molding) Contents of Polymer MaterialsA Polymer is a macromolecule composed of repeating structural units. The small molecules that combine with each other to form polymer molecules are termed monomers, and the reactions by which they combine are termed polymerizations. poly means many and mer = parts. For example: Polyethylene is made by joining many ethylene molecules together. The process of joining is called polymerization. In a polymer, the subunits are typically connected by covalent chemical bonds.1What are polymers?13monomerpolymerLike most other technological development, polymers were first used on an imperial basis, with only very incomplete understanding of the relationships between structure and properties. The first used polymers used were natural products that date back to antiquity. The first truly synthetic polymer was a densely cross-linked material based on the reaction of phenol and formaldehyde called Bakelite. Bakelite was a thermoset; that is, it did not flow after the synthesis was complete. The first synthetic thermoplastics, that is, materials that could flow on heating, were poly(vinyl chloride), polystyrene and nylon 66. 2Historical Development of Polymers thermo- “热热” thermocouple thermodynamics thermoforming thermogram thermometer热电偶热电偶热力学热力学热压成形热压成形温谱图，温度记录图温谱图，温度记录图温度计温度计About Polymer PhysicsChain structure of polymers leads on to physical and mechanical behavior. Polymer chains have three basic properties:1. The molecular weight and molecular weight distribution of the molecules.2. The conformation (构象构象) of the chains in space.3. The configuration (构型构型) of the chain.3Chain Structure of PolymersConfiguration and conformationThe term configuration refers to the organization of the atoms along the chain. Some authors prefer the term “microstructure” rather than configuration. Configurational isomerism (异构异构) involves the different arrangements of the atoms and substituents in a chain, which can be interconverted only by the breakage and reformation of primary chemical bonds, including its composition, sequence distribution, steric configuration, geometric and substitutional isomerism, and so on. iso- isomer 异构体异构体 isobutane 异丁烷异丁烷 isooctane 异辛烷异辛烷 isochronous 同步的，等时的同步的，等时的 isoelectric 等电位的等电位的The term conformation refers to the different arrangements of atoms and substituents of the polymer chain brought about by rotations about single bonds, which has taken on two separate meanings: (a) the long-range shape of the entire chain, and (b) the several possibilities of rotating atoms or short segments of chain relative to one another. Examples of different polymer conformations includes the fully extended planar zigzag, helical, folded chain, and random coils.include: Other important natural polymers include the proteins, which are polymers of amino acids, and the nucleic acids. The subjects include polymer products and applications, polymer manufacturing, processing and machinery. Head-to-Head and Head-to-Tail ConfigurationThis involves the difference between head-to-head and head-to-tail placement of the monomeric units, or mers, during polymerization. The head-to-tail structure of polystyrene may be writtenand its head-to-head structure may be written The thermodynamically and spatially preferred structure is usually the head-to-tail configuration, although most addition polymers contain a small percentage of head-to-head placements. If the synthesis is deliberately arranged to that the head-to-head configuration is obtained, the properties of the polymer are far different. Using polyisobutylene as an example, the melting temperature of the head-to-head configuration was 187 oC, whereas the head-to-tail configuration could only be crystallized under stress, and then with a melting temperature of 5 oC. The head-to-head and head-to-tail configurations cannot be interchanged without breaking primary chemical bonds.化学名词中常用词头、词尾与中介符号化学名词中常用词头、词尾与中介符号词头与词尾词头与词尾中文与结构中文与结构举举 例例mono-uni-metha-一，甲一，甲单体单体monomer单轴晶体单轴晶体uniaxial crystal甲烷甲烷methanebi-di-etha-二，乙二，乙联二苯联二苯biphenyl二氧化碳二氧化碳carbon dioxide乙烷乙烷ethanestri-ter-propa-三，丙三，丙三乙酰胺三乙酰胺triacetamide三氯化合物三氯化合物terchloride丙烷丙烷propanetetra-quadric-buta-四，丁四，丁四氯化物四氯化物tetrachloride四价四价quadrivalence丁烷丁烷butane(to be continued)hepta-septi-七，庚七，庚庚烷庚烷heptane七价的七价的septivalentocta-八，辛八，辛辛烷辛烷octanenona-九，壬九，壬壬烷壬烷nonanedeca-十，癸十，癸癸烷癸烷decanepenta-quique-五，戊五，戊戊烷戊烷pentane五价五价quiquevalencehex-sexi-六，己六，己己烷己烷hexane六价的六价的sexivalentCopolymers Many kinds of polymers contain two kinds of mers. These can be combined in various ways to obtain interesting and often highly useful materials. Some of the basic copolymer nomenclature is presented in Table 1, including some of the trinary copolymers. The connectives in copolymer nomenclature will be defined below. Table 1. Some copolymer terminology (术语术语)TypeConnectiveExampleShort sequencesUnspecifiedStatisticalRandomAlternatingPeriodic -co-stat-ran-alt-per-Poly(A-co-B)Poly(A-stat-B)Poly(A-ran-B)Poly(A-alt-B)Poly(A-per-B-per-C)Long sequencesBlockGraftStar-block-graft-star-Poly A-block-poly BPoly A-graft-poly Bstar-poly ANetworks Cross linkedInterpenetrating-cross-inter-cross-poly Across-poly A-inter-cross-poly BAggregate Structure of Polymers The bulk state, sometimes called the condensed or solid state, includes both amorphous and crystalline polymers. While amorphous polymers do not contain any crystalline regions, “crystalline” polymers generally are only semicrystalline, containing appreciable amounts of amorphous material. When a crystalline polymer is melted, the melt is amorphous. semi- “半半”semi-finalsemi-finishedsemi-opaque semilethal半决赛半决赛半制成的半制成的半透明的半透明的半致死的半致死的Depending on temperature and structure, amorphous polymers exhibit widely different physical and mechanical behavior patterns. At low temperatures, amorphous polymer are glassy, hard, and brittle. As the temperature is raised, they go through the glass-rubber transition. The glass transition temperature (Tg) is defined as the temperature at which the polymer softens because of the onset of long-range coordinated (长程协同长程协同) molecular motion. Linear amorphous polymers flow above Tg, while cross-linked amorphous polymers exhibit rubber elasticity above Tg.The Crystalline State Polymers crystallized in the bulk state are never totally crystalline, a consequence of their long-chain nature and subsequent entanglements. The melting temperature of the polymer, Tm, is always higher than the glass transition temperature, Tg. The development of crystallinity in polymers depends on the regularity of structure in the polymer. Thus isotactic (全同全同) and syndiotactic (间同间同) polymers usually crystallize, whereas atactic (无规无规) polymers, with a few exceptions (where the side groups are small or highly polar), do not. Regular structures also appear in the polyamides (nylons), polyesters, and so on, and these polymers make excellent fibers.Structure of Crystalline Polymers The Fringed Micelle Model (缨状微束模型缨状微束模型) The Folded Chain Model (折叠链模型折叠链模型) The Switchboard Model (插线板模型插线板模型) Extended Chain Crystals (伸直链晶伸直链晶) Spherulites (球晶球晶)The Fringed Micelle ModelAccording to the fringed micelle model, the crystallites are about 10 nm long. The disordered regions separating the crystallites are amorphous. The chains wander from the amorphous region through a crystallite, and back out into the amorphous region. The chains are long enough to pass through several crystallites, binding them together. The Folded Chain Model Ideally, the molecules fold back and forth with hairpin turns. While adjacent reentry has been generally confirmed by small-angle neutron scattering and infrared studies for single crystals, the present understanding of bulk crystallized polymers indicates a much more complex situation. The Switchboard Model In the switchboard model, the chains do not have a reentry into the lamellae (晶片晶片) by regular folding, but rather reenter more or less randomly. The model more or less resembles an old-time telephone switchboard. Extended Chain Crystals Wunderlich pointed out that in thermodynamic equilibrium the crystalline state has an extended chain macroconformation. This extended chain conformation can be brought about by annealing for long periods of time, particularly under pressure. During this time, the fold period of the lamellae gradually increases. SpherulitesWhen polymer samples are crystallized from the bulk, the most obvious of the observed structures are the spherulites. As the name implies, spherulites are sphere-shaped crystalline structures that form in the bulk. One of the most important problems to be addressed concerns the form of the lamellae within the spherulite. Spherulites are remarkably easy to grow and observe in the laboratory. Simple cooling of a thin section between crossed polarizers is sufficient, although controlled experiments are obviously more demanding. It is observed that each spherulite exhibits an extinction cross, sometimes called a Matrese cross. This extinction is centered at the origin of the spherulite, and the arms of the cross are oriented parallel to the vibration directions of the microscope polarizer and analyzer. The Amorphous State The amorphous state is defined as a condensed, noncrystalline state of matter. Many polymers are amorphous under ordinary use conditions, including polystyrene and poly(methyl methacrylate). Above the glass transition temperature, if the polymer is amorphous and linear, it will flow, albeit the viscosity may be very high. If the polymer is crystalline, it is clearly a solid. Above the melting temperature, it becomes amorphous. If the polymer is cross-linked, then it never flows, and never really becomes a liquid, but remains a soft amorphous solid.Morphology of Multicomponent Polymers There are few miscible polymer blends which exhibit homogeneous structure. Most polymer blends, grafts, blocks, and IPNs exhibit phase separation, forming quite complex morphologies. It must be emphasized that their wide application in commerce arises largely because of the synergistic properties, included by such a phase separated structure. Applications have included impact-resistant plastics, thermoplastics, elastomers, coating, and adhesives. Polymer blend The Figure below shows a typical morphology of binary immiscible blends, where the major component forms the continuous phase, or matrix. And the minor component forms dispersed phase, or domain. During the processing of polymer blends, several factors are especially important in determining the final size and shapes of the minor phase: composition, viscosity ratio, interfacial tension, shear rate/shear stress, and processing conditions. The general problem of the size and shape of polymer molecules stands at the very heart of polymer science and engineering. I