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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

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