1、1. All molecules, whether the small type or the large type that result when particular small molecules join together, are made up of atoms (such as carbon, hydrogen, oxygen, or nitrogen). When any small molecule is formed, the atoms join together into a specific arrangement that is characteristic of

2、 the particular molecule. The types of atoms and their arrangement determine the properties of the molecule. 所有的分子，無論是小分子還是由特定小分子連在一起而產生的大分子，都是由原子組成（如碳，氫，氧，氮）。當任何一個小分子形成時，原子以特定排布連接在一起，這種排布為某一分子所特有。原子的類型及排布決定了分子的性質。2. The bulk properties are determined by both the molecular properties (properties tha

3、t depend upon the molecular nature of the material, such as chemical reactivity) and the collective properties (properties that depend upon the interaction of the molecules, such as crystal formation). Subsequent chapters examine both the molecular and bulk properties of plastics because understandi

4、ng many properties of plastics, such as mechanical strength, melting point, and solvent reactivity, depends upon understanding both the molecular and the bulk nature of plastic materials. （高分子的）整體性質由分子性質（由組成物質分子的特性所決定的性質，如化學反應活性）和聚集性質（由分子間相互作用所決定的性質，如晶型）所共同決定。隨后的章節會分別考察分子性質和聚集性質，因為要理解塑料的諸多特性，如機械強度，熔

5、點和溶解性，須建立在理解塑料分子性質和整體特性的基礎之上。3. Typical molding processes are extrusion, injection molding, compression molding, and casting. Molding companies that have plastic parts as their principal products usually have many plastic processing machines and make parts in large quantities. Typical examples of th

6、ese companies are plastic-pipe extruders, injection molders of automotive parts, or plastic-toy manufacturers.典型的模制工序有擠出成型，注入成型，擠壓成型，鑄造成型。擁有塑料零件并將其作為主要產品的成型公司一般有很多塑料成型加工設備，并大規模地制造零件。這些公司的典型例子有塑料管擠出商，機動零件的注射成型商，或者塑料玩具制造商。4. The solid state of polymeric materials is, in some ways, more complex that th

7、e solid state of most ionic, metallic, and small covalent molecules. The complexity in polymers arises because solid polymeric materials can exist, in two very distinct types of structures. In one type, the polymer molecules are randomly coiled about each other with entanglement, called amorphous. I

8、n the second type of configuration, the polymer molecules can pack together into regular, repeating structural patterns. These regularly packed regions are called crystals or crystalline regions. 高分子材料的固態在某些方面要比大部分離子型，金屬型，以及小型共價的分子的固態更復雜。高分子這種復雜性的產生是因為高分子材料可以兩種截然不同的結構類型存在。第一種構造類型中，高分子鏈無規地互相盤繞而纏結在一起，

9、稱為非晶態。第二種構造類型中，高分子鏈可以聚集在一起并形成一種規整，重復的結構模式。這些規整的聚集區域稱為晶區。5. The most important (but not the only) feature of a polymer that determines whether it will be amorphous or crystalline is the shape of the polymer repeat unit. If the repeat unit is complex, especially with large pendant groups, the polymer

10、cannot pack tightly together and will be amorphous. Some of the most common amorphous polymers are polystyrene, acrylic, polycarbonate, and most copolymers. Approximately half of the most common commercial plastics are amorphous.決定高分子是晶態還是非晶態的最重要特征之一是高分子重復單元的形態。若重復單元很復雜，特別是帶有大型側基時，高分子不能緊密堆積在一起并形成非晶態

11、。一些最常見的非晶態高分子有聚苯乙烯，丙烯酸塑料，聚碳酸酯以及大部分共聚物。約有一半最常見的商業化塑料是非晶態的。6. The amount of crystallinity in the polymer depends upon several factors.The most important is the size and regularity of the pendant groups (the groups attached to the main polymer backbone). If these pendant groups are relatively small and

12、 are regularly spaced along the polymer chain, they will not interfere with each other and the polymer chains can pack closer together. Forces of attraction and other similar interactions between polymers, such as hydrogen bonding, also increase crystallinity. 高分子中結晶度的數量由幾個因素決定。最重要的因素是側基（連接在高分子主鏈上的基

13、團）的尺寸和規整性。如果這些側基相對較小并沿高分子主鏈有規律地分隔排布，t它們不會互相干預，進而高分子鏈可以更緊密的堆積在一起。高分子之間的吸引力及其他類似的相互作用，如氫鍵，也會提高結晶度。7. The effect of crystallinity on impact toughness is somewhat more involved. The crystalline sections of a polymer are not as effective in absorbing and dissipating impact energy as are the amorphous reg

14、ions because the atoms in the crystalline regions are not as free to rotate, vibrate, and translate. This restriction on atomic movement causes highly crystalline materials to be stiffer and more brittle. Therefore, even though the strength increases, the impact toughness often decreases for highly

15、crystalline materials. 結晶度對沖擊韌性的影響在某種程度上更為復雜。高分子結晶部分對沖擊能量的吸收和耗散不如非晶區有效，因為和非晶區相比，晶區中原子的轉動，振動和轉化不是那么自由。這種在原子運動上的約束導致高結晶度的材料表現的更硬更脆。故而，盡管強度增加，高結晶度材料的沖擊韌性通常會降低。8. Viscosity is the resistance to flow that is present in all fluids. Some fluids, like liquid polymers have very high viscosities, which arise

16、from the entanglement of the polymer chains. A key thermal effect on viscosity is that as the temperature increases, viscosity drops. This is a critical property in many plastic processes because the viscosity affects mold filling and other shaping processes in which it can most easily be controlled

17、 by the use of temperature.粘度是所有流體所表現出的對流動的抵抗能力。一些流體，如液態高分子，具有很高的粘度，這種高粘度產生于高分子鏈的纏結。粘度的一個關鍵熱效應是其隨溫度的升高而下降。這是許多塑料加工工藝中的一個關鍵特性，因為粘度會影響模具填充及其他成型工序，在這些工序中通過調整溫度可以很容易地控制粘度。9. To become a gas, a molecular chain would have to completely disengage from its neighbors and much energy would be needed. However,

18、 as the amount of energy in the polymer system is increased to try and boil the liquid, the internal vibrations increase and become so great that the energy flowing along the polymer chain exceeds the energy of the covalent bonds. When this occurs, the bonds break and decomposition occurs. Hence, be

19、fore a polymer will boil to form a gas, it will decompose by breaking primary bonds.欲成為氣體，一條分子鏈將必須從他旁邊的鏈中脫離出來并需要大量能量。然而，由于嘗試使液體沸騰所需能量在高分子體系中增加，高分子的內振動增加并變得非常顯著，以至于沿著高分子鏈的能流超過了共價鍵的能量。當上述情況發生時，價鍵斷裂，高分子發生分解反應。故而，高分子將要沸騰并變為氣體之前，它將通過主價鍵的斷裂而分解。10. Creep becomes greater as the temperature of the polymer in

20、creases and as the amount of secondary bonding and entanglement decreases. Therefore, polymers that have high secondary bonding, such as crystalline polymers, have inherently less creep than do amorphous polymers, assuming other factors are equal. Creep is also reduced by high entanglement, by the p

21、resence of large pendant groups that inhibit movement, by crosslinking, and by the inherent stiffness of the backbone of the polymer. 當高分子的溫度升高，以及次價鍵和纏結效應減弱時，蠕動變得更顯著。因此，有強次價鍵的高分子，如結晶高分子，在假設其他因素相同時本身就比非晶高分子有更少的蠕變。通過抑制分子運動的大型側基的出現、交聯以及高分子主鏈固有的硬性，分子鏈的高度纏結也會減少蠕變。11. For some applications, the maximum us

22、e temperature may be lower than the HDT because of excessive creep of the plastic material. Plastics with high creep may, given enough time, eventually distort, even under only moderately elevated temperatures or even at room temperatures. The maximum structural use temperature is, in these cases, d

23、etermined from the lowest temperature at which change in the plastic material occurs that would be detrimental to the particular application.對于一些應用，由于塑料過度的蠕變，最高使用溫度可能比熱變形溫度（heat distortion temperature）低。高度蠕變的塑料，即使只在適度的高溫或甚至在室溫下，如果給定充足時間最終將扭曲變形。在上述情況下，結構上的最大使用溫度就由塑料中產生的變化不利于特定應用時所處的最低溫度來決定。12. The de

24、composition temperature can be determined using DSC or TMA but is probably easier to obtain using a test called thermogravimetric analysis (TGA). In some polymers, degradation can occur at temperatures below the decomposition temperature because of the presence of certain contaminating materials wit

25、hin the polymer mass. The most common of these contaminants are residual catalyst particles, often metals. 用差示掃描量熱法（differential scanning calorimetry）或TMA可以測定分解溫度，但用一種叫做熱重分析的測試方法貌似更容易獲得這一溫度。在一些高分子中，分解反應可以在低于分解溫度的溫度下發生，因為高分子中存在某些污染物質。這些污染物最常見的有殘余催化劑粒子，多數情況下是金屬。13. Both the average molecular weight an

26、d the shape of the molecular weight distribution can significantly affect some key physical and mechanical properties of the polymer, such as tensile strength, impact toughness and creep resistance. In general, a higher average molecular weight increases all of these properties. The reason is primar

27、ily explained by intermolecular interactions. Two of the most common of these interactions are entanglement and secondary bonding.平均分子量和分子量分布情況都會對高分子的一些關鍵的物理機械性能產生深遠影響，如抗拉強度，沖擊韌性和蠕變強度。一般地，一個更高的平均分子量會使所有這些特性增長。原因主要可用分子間相互作用來解釋。這些相互作用中最常見的兩種是纏結和次價鍵。14. In solids, as energy is added through mechanical

28、forces, the chains will gradually disentangle and the secondary bonds will eventually dissolve, thus allowing the molecules to translate relative to each other to relieve the stress. However, this untangling and sliding takes time to accomplish. Therefore, at higher shear rates, the polymer molecule

29、s do not have as much time to move and the disentanglement is forced, resulting in a greater resistance to movement. The result is an apparently stiffer material when sheared very quickly.在固體中，當通過機械力施加能量時，分子鏈將逐漸解纏，次價鍵最終將打開，這樣就允許分子相對于彼此發生轉化以緩解壓力。然而，這種解纏和滑移需要時間來完成。因此，在高的剪切速率下，高分子沒有足夠的時間來運動而被迫解纏，從而具有更大

30、的對運動的抵抗力。結果是當高速剪切時，材料明顯更堅硬。15. The molecular interpretation (in polymers) of elastic and plastic behavior is that in the elastic region the strain results from recoverable movement-stretching out of the twisted molecules in the amorphous regions and minor deformations in the crystalline regions. At

31、the yield point, nonrecoverable movements begin that result in permanent deformation. Some of the most common are disentanglement of the molecules, slip of one molecule past another in a way that the slip could not be recovered, slip along a crystal plane, and formation of a crack. 對高聚物彈性和塑性行為的分子狀態的

32、解釋是：在彈性區，應變產生于可恢復的運動非晶區中從纏繞的分子中伸展以及晶區中的較小變形。在屈服點，不可恢復的運動開始發生并導致永久性變形。最常見的形式有分子鏈的解纏，一個分子相對于另一分子滑移并且在某種程度上滑移不能恢復，沿晶面滑移，及破裂的形成。16. In summary, the true stress-strain curve reflects what is actually happening at the molecular level, a continuous increase in the stress, while the engineering stress-strai

33、n curve reflects the necking of the sample and better indicates what a plastic part might do in actual use. Therefore, when the engineering strain-to-failure is reported, the value is often given as a ratio of the amount of deformation compared to the original length. 概括的說，實際應力應變曲線反映了隨著應力的逐漸增加分子水平的真

34、實變化，而工程應力應變曲線卻反映了試樣的細頸部分并更好的顯示了一個塑料制品在實際使用中起什么作用。因此，當知道了失效工程應變后，就能評估相對于原始長度的形變比例17. Most viscoelastic materials will also show significant deformations with static (unchanging) loads but over long periods of time. This property is called creep, defined as the gradual deformation of a material under

35、a static load. If a viscoelastic material is loaded for a long period of time, at a high temperature, with a substantial load, the sample will eventually break. This is called creep rupture.大多數粘彈性材料在長時間的靜載荷作用下也能表現出明顯的形變。這種特性叫做蠕變，是在靜載荷作用下材料逐漸變形的定義。在高溫下如果長時間給粘彈性材料施加一個很大的力，那么試樣最終會斷裂。這就叫做蠕變斷裂。18. The ab

36、ility of a material to absorb energy without breaking (rupture) is called toughness. Two types of toughness can be considered, equilibrium toughness and impact toughness. Equilibrium toughness is related to the area under the stress-strain curve because energy absorption is the summation of all of t

37、he force resistance effects within the system. The impact toughness (sometimes called impact strength) is defined as the energy absorbed by a material upon sudden impact. 材料吸收能量而不斷裂的能力叫做韌性。韌性分兩種：平衡韌性和沖擊韌性。平衡韌性與應力應變曲線下的面積有關，因為吸收的能量是系統內抵抗力的效果的總和。沖擊韌性（有時也叫沖擊強度）是材料受到突然沖擊時吸收的能量。19. The strength and modul

38、us of many plastic materials can be substantially increased by the addition of strong, high-modulus materials, called reinforcements. These reinforcements are often in the shape of fibers (such as fiberglass) because fibers can be made very stiff, primarily in their long direction. These materials,

39、which combine plastics with reinforcements, are called composites.當添加了高強度高模量的材料（增強劑）后很多材料的強度和模量大大提高了。這些增強劑通常是纖維狀的（像玻璃纖維），因為在縱向上纖維強度很好。這些把塑料和增強劑結合在一起的材料叫做復合材料。20. Commodity resins are those that are sold in very large volumes and can be obtained, with only minor variations in properties, from several

40、, competing resin manufacturers. The resins most commonly referred to as commodity resins are polyethylene, polypropylene, polyvinyl chloride, polystyrene, and various modifications of these basic resins. All of the commodity resins are polymerized by the addition mechanism from monomers containing

41、a carbon-carbon double bond, three hydrogens, and one pendant atom. 通用樹脂的銷售量非常大，并能從一些競爭的樹脂生產廠商那兒獲得，只是性能有少許差異。通常被稱作通用樹脂的樹脂有：聚乙烯、聚丙烯、聚氯乙烯、聚苯乙烯和以這些樹脂為基礎的各種改性樹脂。所有這些通用樹脂都是從含有碳碳雙鍵、三個氫原子和一個側基原子的單體通過加成機理聚合得到的。21. Most of the resins identified as engineering thermoplastics possess the following key property

42、 characteristics. (1) High strength and stiffness, comparable to most metals and other natural, structural materials when adjusted for the difference in weights. (2)Retention of mechanical properties over a wide range of temperatures, especially high temperatures. (3) Sufficient toughness to withsta

43、nd incidental impacts (4) Dimensional stability throughout the temperature range of normal use. (5) The ability of the material to withstand environmental factors, (6) As easy to shape and finish as metals because they are often substituted directly for a metal. 被當做熱塑性工程塑料的大多數樹脂具有如下一些主要性能參數：1.高的強度和剛

44、度，當調整質量上的差異后同大多數金屬材料和天然結構材料類似。2.在較寬的溫度變化范圍之內，特別是在高溫時，仍保持機械性能。3.足夠的抗沖擊強度。4.在常溫變化下使用擁有尺寸穩定性。5.材料的承受環境因素能力。6.由于經常被用來替代金屬，還應像金屬一樣很容易造型和完成。22. Engineering thermoplastics are generally strong and have, a high use temperature, good impact strength, good dimensional stability over a wide range of temperatur

45、es, generally good resistance to environmental conditions, and are much more moldable than the metal, ceramic, or wood parts that they often replace. 熱塑性工程塑料通常很牢固并具備很高的使用溫度，好的抗沖擊強度，在寬的溫度變化范圍內擁有好的穩定性，好的環境抵抗力，并且比金屬、陶瓷或常被取代的木制品更容易成模.23. Even though the ram injector machine was developed before the reci

46、procating screw machine and is generally less expensive to build, some important advantages of the reciprocating screw machine have given it a preeminent position in the marketplace. These advantages include (1) more uniform melting, (2) improved mixing of additives and dispersion throughout the res

47、in, (3) lower injection pressures, (4) larger permissible part area, (5) fewer stresses in parts, and (6) faster total cycle. 即使柱塞式注射機比往復式螺桿機先發展并且花費也比較低，往復式螺桿機的一些重大優勢也使它在市場上擁有了卓越的地位。這些優勢包括：1.更均一的融合性能。2.在樹脂中添加劑的混合和擴散性能更好。3.較低的注射壓力。4.更大的部件允許面積。5.部件中更低的殘余應力。6.更短的循環周期。24. Several hoppers can feed one ma

48、chine so that fillers, colorants, or other additives can be introduced simultaneously. However, because of the limited size (barrel length) of most injection molding machines, mixing capability is poor and so most fillers and other resins are preferably blended in a separate extrusion operation. Col

49、orants are commonly added as preextruded concentrates rather than directly to the injection molding machine. 幾個加料斗可以同時向一個機器加料，這樣的話填料、顏料或其他一些添加劑可以同時加入。然而由于大多數注射成型設備的尺寸（料筒長度）受到限制，使得混合能力低下，所以大多數的填料以及其他樹脂應該用單獨的擠出工序混合。著色劑通常是在預擠出物成型時加入，而不是直接加到注射成型設備中。25. The keys to success in injection molding are (1) th

50、e proper machine for good melting and rejecting of the resin, (2) the proper resin for appropriate part performance, (3) a good mold for part definition and removal, and (4) proper operation for efficient molding cycles. The major factors that determine costs are material type, mold cost, parts per

51、cycle, and mold cycle time. Here, the material type is usually determined by the part design and performance requirements. 注射成型工藝成功的關鍵有：1.把樹脂良好融化并注射的機器。2.擁有恰當的制件性能的樹脂。3.讓制件能很好成模脫模的模具。4.高效成型周期的正確操作。決定成本的主要因素有：不同種類原材料的成本、模具成本、每個生產周期生產的制件、成型周期的時間。其中原材料類型通常是由制件的設計以及其性能需要所決定的。26. Sheet extrusion introduc

52、ed the concept of a wide die (clothes hanger die) that allows even or plug flow through the die so that internal stresses will not be created. This type of die is also used in coating wide materials such as paper and fabric. A wide die can also be used to feed material to a calendering operation in

53、which rolls are used to change the shape of the molten plastic material. 片材擠壓引進了寬口模（衣架式口模）的概念，即使是塞式流動也被允許通過這種口模，故不會形成內應力。這種口模也被用在涂覆像紙張和布料等寬材料上。在混煉橡膠操作中寬口模被用來加料，輥碎機的這種操作是用來改變熔融塑料材料的形狀的。27. Of all the equipment and key operating parameters, both from the viewpoint of required function and operational effect, one important operational concept should be reemphasized. Extruder