研究天然橡膠的性能-畢業(yè)論文外文翻譯

1、study on properties of natural rubber(partly )1 tree of rubbernatural rubber collected from plant fluids, although the world has 2000 duozhong plants can produce natural rubber, but a large-scale promotion planting is the main rubber brazil the natural rubber in the main component is the type gather

2、 isoprene, has the flexibility, and set out high strength, the anti-peel resistance and wear resistance, easy to be good with other material and other characteristics, widely used in adhesive tape, rubber tires, products of the production. brazil or rubber high temperature, high humidity, wind, fert

3、ile soil, mainly grow in southeast asia, and other low-latitude region. natural conditions in china, by restricting only hainan, guangdong, yunnan, climate conditions can grow, usable area is about 15 million mu, at present has planted 14 million acres around, the annual output is 600000 tons.2 the

4、characteristics and distribution of natural rubberrubber is originated in the brazilian amazon river basin in the western region, is now horse-drawn yue cloth and asia, africa, oceania, latin america duoge 40 countries and regions. planting area is larger nations have: indonesia, thailand, malaysia,

5、 china, india, vietnam, nigeria, brazil, sri lanka, liberia, etc. zhijiao area is mainly distributed in hainan, guangdong, guangxi, yunnan, fujian, taiwan also can be planted in hainan, among them as the main zhijiao area.natural rubber tree planting, tropical rain forests of regional basic distribu

6、tion within 15 °c in the equator, mainly in southeast asia, at about of the world natural rubber planting area of 90%. the main producers have thailand, indonesia, malaysia, china, india, vietnam and burma, sri lanka, especially the total output is given priority to, before more than 60% of wor

7、ld output, and will produce that most of the natural rubber for export, among them, thailand and indonesia have exports than as high as 90% above. thailand, indonesia and malaysia period in the april general tapping rubber trees to the following february.3 varietiesnatural rubber, also called china

8、rubber or caoutchouc, is an elastomer (an elastic hydrocarbon polymer) that was originally derived from latex, a milky colloid produced by some plants. the plants would be 6tapped that is, an incision made into the bark of the tree and the sticky, milk colored latex sap collected and refined into a

9、usable rubber. the purified form of natural rubber is the chemical polyisoprene, which can also be produced synthetically. natural rubber is used extensively in many applications and products, as is synthetic rubber. it is normally very stretchy and flexible and extremely waterproof.the commercial s

10、ource of natural rubber latex is the para rubber tree (hevea brasiliensis), a member of the spurge family, euphorbiaceae. this is largely because it responds to wounding by producing more latex, also this means that the tree is able to photosynthesise more.other plants containing latex include gumap

11、ercha (palaquium gutta),111 rubber fig (ficus elastica), panama rubber tree (castilla elastica). spurges (euphorbia spp.), lettuce, common dandelion (taraxacum officinale). russian dandelion (taraxacum koksaghyz). scorzonera (tau-saghyz), and guayule (parthenium argentatum). although these have not

12、been major sources of rubber, germany attempted to use some of these during world war ii when it was cut off from rubber suppliesoitation needed】 these attempts were later supplanted by the development of synthetic rubbers. to distinguish the tree-obtained version of natural rubber from the syntheti

13、c version, the term gum rubber is sometimes used.4 discovery of commercial potentialthe para rubber tree initially grew in south america. charles marie de la condamine is credited with introducing samples of rubber to the acadgmie royale des sciences of france in 1736.121 in 1751, he presented a pap

14、er by francois fresneau to the academie (eventually published in 1755) which described many of the properties of rubber. this has been referred to as the first scientific paper on rubber.121when samples of rubber first arrived in england, it was observed by joseph priestley, in 1770, that a piece of

15、 the material was extremely good for rubbing off pencil marks on paper, hence the name rubber. later it slowly made its way around englansouth america remained the main source of the limited amounts of latex rubber that were used during much of the 19th century. in 1876, henry wickham gathered thous

16、ands of para rubber tree seeds from brazil, and these were germinated in kew gardens。england. the seedlings were then sent to ceylon (sri lanka). indonesia，singapore and british malaya. malaya (now malaysia) was later to become the biggest producer of rubber. about 100 years ago, the congo free stat

17、e in africa was also a significant source of natural rubber latex, mostly gathered by forced laboir liberia and nigeria also started production of rubberin india, commercial cultivation of natural rubber was introduced by the british planters, although the experimental efforts to grow rubber on a co

18、mmercial scale in india were initiated as early as 1873 at the botanical gardens, calcutta. the first commercial hevea plantations in india were established at thattekadu in kerala in 1902. in the 19th and early 20th century, it was often called nindia rubber.n in 2010, india's natural rubber co

19、nsumption stood at 0.978 million tons per year, with production at 0.893 million tons; the rest was imported with an import duty of 20%.5 propertiesrubber exhibits unique physical and chemical properties. rubber's stress-strain behavior exhibits the mullins effect the payne effect and is often m

20、odeled as hyperelastic. rubber strain crystallizes.owing to the presence of a double bond in each repeat unix natural rubber is sensitive to ozone cracking.6 elasticityin most elastic materials, such as metals used in springs, the elastic behavior is caused by bond distortions. when force is applied

21、, bond lengths deviate from the (minimum energy) equilibrium and strain energy is stored electrostatically. rubber is often assumed to behave in the same way, but it turns out this is a poor description. rubber is a curious material because, unlike metals, strain energy is stored theimally.in its re

22、laxed state, rubber consists of long, coiled-up polymer chains that are interlinked at a few points. between a pair of links, each monomer can rotate freely about its neighbour, thus giving each section of chain leeway to assume a large number of geometries, like a very loose rope attached to a pair

23、 of fixed points. at room temperatue rubber stores enough kinetic energy so that each section of chain oscillates chaotically, like the above piece of rope being shaken violently. the entropy model of rubber was developed in 1934 by werner kuhn.when rubber is stretched, the "loose pieces of rop

24、eh are taut and thus no longer able to oscillate. their kinetic energy is given off as excess heat. therefore, the entropy decreases when going from the relaxed to the stretched state, and it increases during relaxation. this change in entropy can also be explained by the fact that a tight section o

25、f chain can fold in fewer ways (w) than a loose section of chain, at a given temperature (nb. entropy is defined as s二k*ln(w). relaxation of a stretched rubber band is thus driven by an increase in entropy, and the force experienced is not electrostatic, rather it is a result of the thermal energy o

26、f the material being converted to kinetic energy. rubber relaxation is endothermic, and for this reason the force exerted by a stretched piece of rubber increases with temperature. (metals, for example, become softer as temperature increases). the material undergoes adiabatic cooling during contract

27、ion. this property of rubber can easily be verified by holding a stretched rubber band to your lips and relaxing it. stretching of a rubber band is in some ways equivalent to the compression of an ideal gas, and relaxation is equivalent to its expansion. note that a compressed gas also exhibits &quo

28、t;elastic” properties, for instance inside an inflated car tire. the fact that stretching is equivalent to compression may seem somewhat counterintuitive, but it makes sense if rubber is viewed as a one-dimensional gas. stretching reduces the "space" available to each section of chain.vulc

29、anization of rubber creates more disulfide bonds between chains, so it shortens each free section of chain. the result is that the chains tighten more quickly for a given length of strain, thereby increasing the elastic force constant and making rubber harder and less extensible.when cooled below th

30、e glass transition temperatu© the quasi-fluid chain segments hfreezem into fixed geometries and the rubber abruptly loses its elastic properties, although the process is reversible. this is a property it shares with most elastomers. at very low temperatures, rubber is rather brittle; it will br

31、eak into shards when struck or stretched. this critical temperature is the reason winter tires use a softer version of rubber than normal tires. the failing rubber oring seals that contributed to the cause of the challenger disaster were thought to have cooled below their critical temperature; the d

32、isaster happened on an unusually cold day.7quality standardsour futures trading market shanghai futures exchange natural rubber contracts for domestic level standard delivery level scr5 glue and import of smoke rss3, including domestic level glue standard glue scr5 is also known as the number 5, exe

33、cute the national standard glue issued by the technical supervision bureau of natural rubber gb/t8081 1999 version of the quality indexes. the import of smoke to the international rss3 gum rubber quality and packaging meeting certain nnatural rubber levels of quality and packaging international stan

34、dardn (green) (1979)-wang jh, chen dj, min hl, et al .study on properties of nature rubber/attapulgite nanocomposites;proceedings of 2009 international conference on advanced fibers and polymer materials, vols 1 and 2;2009:57-63附錄:研究天然橡膠的性能（部分）1橡膠樹天然橡膠采自植物的汁液，雖然世界上有2000多種植物可生產(chǎn)天然橡 膠，但大規(guī)模推廣種槓的主要是巴西橡膠樹

35、。采獲的天然橡膠主要成分是 順式聚異戊二烯，具有彈性大、定伸強(qiáng)度高、抗撕裂性和耐磨性良好、易 于與其它材料粘合等特點，廣泛用于輪胎、膠帶等橡膠制品的生產(chǎn)。巴西 橡膠樹喜高溫、高濕、靜風(fēng)、沃土，主要種植在東南亞等低緯度地區(qū)。受 自然條件制約，我國僅海南、廣東、云南等地氣候條件可以種植，可用面 積約1500萬畝，目前已種植1400萬畝左右，年產(chǎn)量在60萬噸左右。2天然橡膠的特性和分布橡膠樹原產(chǎn)于巴西亞馬遜河流域馬拉岳西部地區(qū),現(xiàn)已布及亞洲、韭 遡、大洋洲、拉丁美洲40多個國家和地區(qū)。種植面積較大的國家有：印度 尼西亞、泰國、馬來西亞、中國、印度、越南、尼日利亞、巴西、斯里蘭 卡、利比里亞等。我國植

36、膠區(qū)主要分布于海南、4、廣西、掘建、云南， 此外臺灣也可種植,其中海南為主要植膠區(qū)。天然橡膠樹屬熱帶雨林喬木，種植地域基本分布于南北緯15°c以內(nèi)， 主要集中在東南亞地區(qū)，約占世界天然橡膠種植面積的90%。生產(chǎn)國主要有 泰國、印度尼西亞、馬來西亞、中國、印度、越南、緬甸、斯里蘭卡等， 尤以前三國為主，產(chǎn)量占世界產(chǎn)量的60%以上，且將所產(chǎn)天然橡膠的絕大部 分用于出口，其中，泰國和印度尼西亞的出口占產(chǎn)量比高達(dá)90%以上。泰國、 印度尼西亞和馬來西亞的割膠期一般在4月到次年2月。3種類天然橡膠，也被稱為中國橡膠或者生橡膠，是一種植物產(chǎn)生的彈性體。 天然橡膠是一種以聚異戊二烯為主要成分的天然

37、高分子化合物,分子式是 （c5i18）n,其成分中91%94%是橡膠坯（聚異戊二烯）,其余為蛋白質(zhì)、 脂肪酸、灰分、糖類等非橡膠物質(zhì)。天然橡膠是應(yīng)用最廣的通用橡膠。天然橡膠樹上的切口變成了這棵樹的樹皮彩色乳膠液，牛奶裝狀的乳 液收集和提煉成一個可用的橡膠。天然橡膠的精煉的形式，是化學(xué)生產(chǎn)述 可以綜合。天然橡膠是廣泛使用在許多應(yīng)用和產(chǎn)甜，合成橡膠，通常都是 很有彈性的和靈活的，并且非常防水。商業(yè)來源的天然橡膠膠乳是（段樹的橡膠樹割面干涸?。┑某蓡T，這在 很大程度上是因為它有牛產(chǎn)更多的乳液，這也意味著類似于樹也能受傷。還有其他含有乳業(yè)的植物。盡管這些沒有橡膠的國家，例如徳國的主 要來源是使用其中的

38、一些。在二次世界大戰(zhàn)期間，當(dāng)它被切斷了從橡膠供 應(yīng)需要。天然橡膠按形態(tài)可以分為兩大類：固體天然橡膠（膠片與顆粒膠）和 濃縮膠乳。在日常使用中，固體天然橡膠占了絕大部分的比例。膠片按制造工藝和外形的不同，可分為煙片膠、風(fēng)干膠片、白皺片、 褐皺片等。煙片膠是天然橡膠中最具代表性的品種，一直是用量大、應(yīng)用 廣的一個膠種，煙片膠一般按外形來分級，分為特級、一級、二級、三級、 四級、五級等共六級，達(dá)不到五級的則列為等外膠。顆粒膠（即標(biāo)準(zhǔn)膠）是按國際上統(tǒng)一的理化效能、指標(biāo)來分級的，這 些理化性能包括雜質(zhì)含量、塑性初值、塑性保持率、氮含量、揮發(fā)物含量、 灰分含量及色澤指數(shù)等七項，其中以雜質(zhì)含量為主導(dǎo)性指標(biāo)，

39、依雜質(zhì)之多 少分為5l、5、10、20及50等共五個級別。4潛在商機(jī)發(fā)現(xiàn)橡膠樹生長段最初在南美洲o法國的科學(xué)家查爾斯瑪 麗德拉 condaminc引入樣品的橡膠塊。在1751年，他發(fā)表了一篇由弗 朗索瓦的academie fresneau（最終于1755年出版）形容許多性質(zhì)的橡膠。這 已經(jīng)被稱為第一次橡膠的科學(xué)論文。當(dāng)樣品的橡膠初到英國，這是觀察到約瑟夫普里斯特利，在1770年, 那一塊材料是菲常好，在紙上擦去鉛筆記號，因此名字橡膠。后來它慢慢 路英格蘭。南美仍然是最主要的來源數(shù)量有限的膠乳橡膠用的19th世紀(jì)期間的大 部分。1876年，亨利韋翰聚集成千上萬的降落傘橡膠樹的種子發(fā)芽巴西，這 是

40、在丘花園，英格蘭。于是派出的苗錫蘭（斯里蘭卡），印度尼西亞,新加坡 和英屬馬來亞。馬來亞（現(xiàn)在）后來馬來西亞成為中國最大的生產(chǎn)國的橡膠。 大約100年前，自由的國家在非洲剛果也是一個重要的源泉。在印度，商業(yè)化種植天然橡膠引入英國種植園主，雖然實驗努力種植 橡膠在商業(yè)規(guī)模開始在印度，早在1873年就在美國，加爾各答植物園。第 一代的商業(yè)hevea種植園在印度西南部喀拉拉邦thattekadu成立于1902年。 在19th和早期20th世紀(jì)，這是通常被稱為“印度橡膠” o在2010年，印度 的天然橡膠消費量在978萬噸/年，而產(chǎn)量在893萬噸。剩下的依賴于進(jìn)口， 進(jìn)口依賴度為20%。由于天然橡膠具有上述一系列物理化學(xué)特性，尤其是其優(yōu)良的回彈性、 絕緣性、隔水性及可塑性等特性，并且，經(jīng)過適當(dāng)處理后還具有耐油、耐 酸、耐堿、耐熱、耐寒、耐壓、耐磨等寶貴