




版權(quán)說(shuō)明:本文檔由用戶提供并上傳,收益歸屬內(nèi)容提供方,若內(nèi)容存在侵權(quán),請(qǐng)進(jìn)行舉報(bào)或認(rèn)領(lǐng)
文檔簡(jiǎn)介
1、精品文檔unitl1 .Notallpolymersarebuiltupfrombondingtogetherasinglekindofrepeatingunit.Attheotherextreme,proteinmoleculesarepolyamidesinwhichnaminoaciderepeatunitsarebondedtogether.Althoughwemightstillcallnthedegreeofpolymerizationinthiscase,itislessusefull,sinceanaminoacidunitmightbeanyoneofsome20-oddmo
2、leculesthatarefoundinproteins.Inthiscasethemolecularweightitself,ratherthanthedegreeofthepolymerization,isgenerallyusedtodescribethemolecule.WhentheactualcontentofindividualaminoacidsisknownJtistheirsequeneethatisofspecialinteresttobiochemistsandmolecularbiologists.并不是所有的聚合物都是由一個(gè)重復(fù)單元鏈接在一起而形成的。在另一個(gè)極端
3、的情形中,蛋白質(zhì)分子是由n個(gè)氨基酸重復(fù)單元鏈接在一起形成的聚酰胺。盡管在這個(gè)例子中,我們也許仍然把n稱為聚合度,但是沒有意義,因?yàn)橐粋€(gè)氨基酸單元也許是在蛋白質(zhì)中找到的20多個(gè)分子中的任意一個(gè)。在這種情況下,一般是分子量本身而不是聚合度被用來(lái)描述這個(gè)分子。當(dāng)知道了特定的氨基酸分子的實(shí)際含量,它們的序列正是生物化學(xué)家和分子生物學(xué)家特別感興趣的地方。1,題目:Anotherstriking.答案:.thatquantitylowsaturationbottommuchabsorb2 .乙烯分子帶有一個(gè)雙鍵,為一種烯燒,它可以通過連鎖聚合大量地制造聚乙烯,目前,聚乙烯已經(jīng)廣泛應(yīng)用于許多技術(shù)領(lǐng)域和人們的
4、日常生活中,成為一種不可缺少的材料。Ethylenemoleculewithadoublebond,asakindofolefins,itcanmakechainpolymerizationpolyethylene,atpresent,polyethylenehasbeenwidelyusedinmanyfieldsoftechnologyandPeople'sDailylife,becomeakindofindispensablematerials.Unit31Thepolymerizationratemaybeexperimentallyfollowedbymeasuringthe
5、changesinanyofseveralpropertiesofthesystemsuchasdensity,refractiveindex,viscosity,orlightabsorption.Densitymeasurementsareamongthemostaccurateandsensitiveofthetechniques.Thedensityincreasesby20-25percentonpolymerizationformanymonomers.Inactualpracticethevolumeofthepolymerizingsystemismeasuredbycarry
6、ingoutthereactioninadilatometer.Thisisspeciallyconstructedvesselwithacapillarytubewhichallowsahighlyaccuratemeasurementofsmallvolumechanges.Itisnotuncommontobeabletodetectafewhundredthsofapercentpolymerizationbythedilatometertechnique.聚合速率在實(shí)驗(yàn)上可以通過測(cè)定體系的任一性質(zhì)的變化而確定,如密度、折射率、黏度、或者吸光性能。密度的測(cè)量是這些技術(shù)中最準(zhǔn)確最敏感的。
7、對(duì)許多單體的聚合來(lái)說(shuō),密度增加了20%-25%。在實(shí)際操作中,聚合體系的體積是通過在膨脹計(jì)中進(jìn)行反應(yīng)測(cè)定的。它被專門設(shè)計(jì)構(gòu)造了毛細(xì)導(dǎo)管,在里面可以對(duì)微小體積變化進(jìn)行高精確度測(cè)量。通過膨脹計(jì)技術(shù)探測(cè)聚合過程中萬(wàn)分之幾的變化是很常見的。Unti42合成聚合物在各個(gè)領(lǐng)域中起著與日俱增的重要作用,聚合物通常是由單體通過加成聚合與縮合聚合制成的。就世界上的消耗量而論,聚烯燒和乙烯基聚合物居領(lǐng)先地位,聚乙烯、聚丙烯等屬聚烯燒,而聚氯乙烯、聚苯乙烯等則為乙烯基聚合物。聚合物可廣泛地用作塑料、橡膠、纖維、涂料、粘合齊U等Thesyntheticpolymersplayanincreasinglyimporta
8、ntroleonarangeofdomains,whicharesynthesizedbymonomersthroughadditionpolymerizationorcondensationpolymerization.Polyolefinandvinylpolymerhavetakentheleadintermsoftheworldconsumption.PE,PP,etc.belongtothepolyolefin,whilePS,PVCetc.belongtothevinylpolymer.Polymerscanbewidelyappliedinplastics,rubbers,fib
9、ers,coatings,gluesandsoon.Unit7Ring-openingpolymerizationsproceedonlybyionicmechanisms,thepolymerizationofcyclicethersmainlybycationicmechanisms,andthepolymerizationoflactonesandlactonesbyeitheracationicoranionicmechanism.Importantinitiatorsforcyclicethersandlactonepolymerizationarethosederivedfroma
10、luminumalkylandzincalkyl/watersystems.Itshouldbepointedoutthatsubstitutionnearthereactivegroupofthemonomerisessentialfortheindividualmechanismthatoperateseffectivelyinspecificcases;forexample,epoxidespolymerizereadilywithcationicandanionicinitiators,whilefluorocarbonepoxidespolymerizeexclusivelybyan
11、ionicmechanisms.開環(huán)聚合反應(yīng)只能通過離子機(jī)理進(jìn)行,環(huán)醍(的開環(huán))聚合主要通過陽(yáng)離子機(jī)理,而內(nèi)酯和內(nèi)酰胺的聚合物是通過陽(yáng)離子或陰離子機(jī)理。對(duì)于環(huán)微和內(nèi)酯型聚合物很重要的引發(fā)劑是那些來(lái)自于烷基鋁和烷基鋅/水的體系。應(yīng)該指出的是(對(duì)于)在活性基團(tuán)附近有取代的單體,只能由單一機(jī)理,(這一機(jī)理)是在特定條件下的有效操作,例如環(huán)氧聚合能用陽(yáng)離子和陰離子引發(fā)劑,然而碳氟環(huán)氧化物的聚合只能是陰離子機(jī)理。ChineseEnglishMolecularStructure聚丁二烯polybutadiene_CHCCHCHn聚苯乙烯Polystyrene_CH2_CH6三氯化鈦titaniumtric
12、hlorideCl-TiClCl四氫吠喃TetrahydrofuranT2Cu0、CH2T2c-Ch丁基鋰butyllithiumCH3CH2CH2CH2-Li異丁烯isobutyleneH3C-C=CF21CH3酚鈉Phenolsodium(1:_0N3氯化鈉sodiumchlorideNaCI烯丙基AllylCH2=CHCH2一光氣,碳酰氯phosgeneo:IcClcUnti81 Polymerscanbeclassifiedintotwomaingroups,additionpolymersandcondensation_polymers.Thisclassificationisbas
13、edonwhetherornottherepeatingunitofthepolymercontainsthesameatomsasthemonomer.Therepeat!ngunitofanadditionpolymerisidentical_with/to_themonomer,whilecondensationpolymerscontain_different/lessbecauseofformationof_compound/byproduct_duringthepolymerizationprocess.Thecorrespondingpolymerizationprocessed
14、wouldthenbecalledadditionpolymerizationandcondensationpolymerization.Aswasmentionedearlier,thisclassificationcanresultin_confusion,sinceithasbeenshowninlateryearsthatmanyimportanttypesofpolymerscanbe_preparedbybothadditionandcondensationprocesses.Forexample,polyesters,polyamidesandpolyurethanesareus
15、uallyconsideredtobe-Condensationpolymers,buttheycanbepreparedbyadditionaswellasbycondensationreaction.Similarly,polyethylenenormallyconsideredan_addition_polymer,canalsobepreparedby_condensation_reaction.2. AnswerthefollowingquestionsinEnglish(1) Whatischainpolymerization?Manyolefinicandvinylunsatur
16、atedcompoundsareabletoformchain-likemacromoleculesthrougheliminationofdoublebond.(2) Whichkindsofmonomerscancarryoutstep-growthpolymerizationprocess?Therearetwokindsofmonomerscouldcarryoutstep-growthpolymerizationprocess.Oneispolyfunctionalmonomersandtheotherisasinglemonomercontainingbothtypesoffunc
17、tionalgroups.(3) Whatpropertiesofpolymerscanbebasedonformeasuringthemolecularweight?Themolecularweightofpolymercouldbemeasuredbasedoncolligativeproperties,lightscattering,viscosity,ultracentrifugationsedimentation.3. Pleasewriteoutatleast10kindsofpolymersbothinEnglishandinChinese乙烯1- buteneacrylonit
18、rileethylene vinylchloridepropylenePolyester聚酯polystyrene,聚苯乙烯polyamide聚酰胺polypropylene聚丙稀polyethylene聚乙烯polyurethane聚氨酉旨polyvinylalcohol聚乙烯醇Polyvinylchloride聚氯乙烯polybutene聚丁烯polyether聚醍1,4-丁二烯四領(lǐng)乙烯苯乙烯異丁烯丙烯酸4.Pleasewriteoutatleast10kindsofmonomersbothinEnglishandinChineseandthecorrespongingchemicalst
19、ructure1,4-butadiene tetrafluoroethylenestyrene isobutene acrylic acid5Ingeneral,head-to-tailadditionisconsideredtobethepredominantmodeofpropagationinallpolymerizations。However,whenthesubstitutesonthemonomeraresmall(anddonotofferappreciablesterichindrancetotheapproachingradical)ordonothavealargereso
20、nancestabilizingeffect,asinthecaseoffluorineatoms,sizableamountsofhead-to-headpropagationmayoccur.Theeffectofincreasingpolymerizationtemperatureistoincreasetheamountofhead-to-headplacement。Increasedtemperatureleadstolessselective(morerandom)propagationbuttheeffectisnotlarge.Thus,thehead-to-headconte
21、ntinpoly(vinylacetate)onlyincreasesfrom1.30to1.98percentwhenthepolymerizationtemperatureinincreasedfrom30to90.通常在所有聚合物的鏈增長(zhǎng)中,頭尾加成是主要方式。然而,當(dāng)單體中的取代基很小(對(duì)接近的自由基沒有空間阻礙)或沒有較大的共振穩(wěn)定作用,如氟原子,則有相當(dāng)量的頭頭增長(zhǎng)發(fā)生。提高聚合溫度的影響是提高頭一頭排列的量。溫度的提高導(dǎo)致較少的選擇(更多的無(wú)規(guī))增長(zhǎng),但影響不大。因而,在聚乙酸乙烯酯中,當(dāng)聚合溫度由30C提高到90C,頭頭含量?jī)H由1.3%提高到1.98%。2. Writeouta
22、nabstractinEnglishforthetextinthisunitPolymerswithdifferentstructurespresentvariousproperties.Usually,polymersaredividedintothreecategories,i.e.plastic,elastomer,fiberwithdifferentinitialmodulusrangerespectively.Polymersshowquitedifferentbehaviorsduetothedifferentinterchainforcesinelastomerandfiber.
23、However,withtheadventofnewtechniquesandmechanismstoimprovethestructureofpolymers,polymersmaybeclassifiedandnamedaccordingtothemechanism,andtheirpropertieswilllargelydependonthestructure.3. PutthefollowingwordsintoChineseentanglement2糾纏irregularity無(wú)規(guī)sodiumisopropylate異丙醇鈉permeability滲透T生crystallite微晶stoichiomertricbalanee當(dāng)量平衡fractionation分播法lightscattering光散射matrix基體diffraction彳衍射4. PutthefollowingwordsintoEnglish形態(tài)morphology酉旨化esterification異氨酸酉旨isocyanate雜質(zhì)impurity二元胺diamine轉(zhuǎn)化率changerat
溫馨提示
- 1. 本站所有資源如無(wú)特殊說(shuō)明,都需要本地電腦安裝OFFICE2007和PDF閱讀器。圖紙軟件為CAD,CAXA,PROE,UG,SolidWorks等.壓縮文件請(qǐng)下載最新的WinRAR軟件解壓。
- 2. 本站的文檔不包含任何第三方提供的附件圖紙等,如果需要附件,請(qǐng)聯(lián)系上傳者。文件的所有權(quán)益歸上傳用戶所有。
- 3. 本站RAR壓縮包中若帶圖紙,網(wǎng)頁(yè)內(nèi)容里面會(huì)有圖紙預(yù)覽,若沒有圖紙預(yù)覽就沒有圖紙。
- 4. 未經(jīng)權(quán)益所有人同意不得將文件中的內(nèi)容挪作商業(yè)或盈利用途。
- 5. 人人文庫(kù)網(wǎng)僅提供信息存儲(chǔ)空間,僅對(duì)用戶上傳內(nèi)容的表現(xiàn)方式做保護(hù)處理,對(duì)用戶上傳分享的文檔內(nèi)容本身不做任何修改或編輯,并不能對(duì)任何下載內(nèi)容負(fù)責(zé)。
- 6. 下載文件中如有侵權(quán)或不適當(dāng)內(nèi)容,請(qǐng)與我們聯(lián)系,我們立即糾正。
- 7. 本站不保證下載資源的準(zhǔn)確性、安全性和完整性, 同時(shí)也不承擔(dān)用戶因使用這些下載資源對(duì)自己和他人造成任何形式的傷害或損失。
最新文檔
- 供水合同范本
- pvc地板購(gòu)銷合同范例
- 代辦購(gòu)房合同范例
- 分居合同范例
- 目視化施工方案
- 分銷電纜合同范例
- M公司員工培訓(xùn)管理優(yōu)化研究
- 零信任框架下的電動(dòng)汽車智能充電的訪問控制研究
- 保管采購(gòu)合同范例
- 眾籌開店合同范例
- 成都市2024屆高中畢業(yè)班第二次診斷性監(jiān)測(cè)-2024年全國(guó)各地高考語(yǔ)文模擬卷作文導(dǎo)寫講練
- 醫(yī)保統(tǒng)計(jì)信息管理制度
- 達(dá)格列凈治療心衰機(jī)制
- 2024年保育員(初級(jí))證考試題庫(kù)及答案
- 40篇英語(yǔ)短文搞定3500個(gè)單詞 正文
- 2024年度《冠心病》全套課件(完整版)
- 正面吊安全操作規(guī)程培訓(xùn)
- 2023年臺(tái)州市中考科學(xué)(正卷)和答案
- 經(jīng)典美味的宮保雞丁
- 孤獨(dú)癥兒童心智解讀能力
- 2023-2024學(xué)年人教版(2019)必修 第三冊(cè)Unit 2 Morals and Virtues Reading and Thinking 課件(22張)
評(píng)論
0/150
提交評(píng)論