纺织比较教程教案1.docx
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纺织比较教程教案1.docx
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纺织比较教程教案1
《纺织比较教程》
教案
(2010~2011学年第2学期)
适用现代纺织技术专业
院系(部)纺织学院
班级_09现纺一、二、三班
教师刘纪营
教案首页
本次课标题:
LearningScene1CottonSpinning
Sub-scene1Thematerialforcottonspinning
授课日期
2011.2.21
授课班级
09现纺1、2、3班
课时
2小时
上课地点
1ja307
教
学
目
标
能力(技能)目标
知识目标
1.CanidentifyCottonMorphology
2.CanmusterCottonPropertiesandItsUse
3.Cottonplantingandpicking
4.Cottonginningandgrading
1.CottonMorphologyandItsProperties&Use
2.CottonPropertiesandItsUse
3.Cottonplantingandpicking;
4.Cottonginning;
5.Cottongrading;
教
学
任
务
及
案
例
(1)CottonMorphology
(2)CottonPropertiesandItsUse
(3)Cottonginning;
(4)Cottongrading;
重
点
难
点
重点:
CottonPropertiesandItsUse
难点:
CottonginningandCottongrading
单
元
考
核
工作过程考核50%,阶段作业考核50%
参
考
资
料
山东科技职业学院教学平台,专业英语,相关音频
教学设计
步骤
教学内容
教师活动
(方法与手段)
学生活动
时间分配
告知
(教学内容、
目的)
教学内容:
(1)CottonMorphology
(2)CottonPropertiesandItsUse
(3)Cottonginning;
(4)Cottongrading;
教学目的:
(1)KnowCottonMorphologyandCottonPropertiesandItsUse
(2)KnowCottonginningandCottongrading;
讲授
听
2分钟
引入
(任务项目)
1.What’stheUseofCotton?
2.HowtoginCottonandgradeCotton?
启发
提问
小组讨论
3分钟
操练
(掌握初步或基本能力)
Unit1CottonMorphologyandItsProperties&Use
1.1CottonMorphology
1.2CottonPropertiesandItsUse
Unit2CottonPlanting,PreliminaryWorking
2.1CottonPlantingandPreliminaryWorking
2.2CottonTestingandCottonClassification
教师讲解
演示
学生听
并与学生互动
48分钟
深化
(加深对基本能力的体会)
提问:
1.HowaboutCottonPropertiesandItsUse?
2.HowtoginCottonandgradeCotton?
启发诱导
重点讲解
小组操作
3分钟
归纳
(知识和能力)
知识点:
(1)WaysofCottonginningandCottongrading;
(2)CottonMorphologyandItsProperties&Use
能力点:
(1)UnderstandsomeknowledgeaboutCottonginningandCottongrading.
(2)KnowhowtoginCottonandgradeCotton.
在教师引导下,先由学生总结,
教师再归纳
小组讨论
代表发言
2分钟
训练
巩固
拓展
检验
训练项目
1.学生能英汉互译对话
2.学生能英汉互译课文书信
辅导
个人操作
0
总结
(1)CottonPropertiesandItsUse
(2)WaysofCottonginningandCottongrading
教师讲授或提问
2分钟
作业
工作页下次上课前完成,并自学下次课的内容
0分钟
后记
教学内容
Unit1CottonMorphologyandItsProperties&Use
1.1CottonMorphology
Cotton,whichcomesfromseedhairs,isthemostwidelyusedofthenaturalcellulosicfibersandiswellknowntomostconsumers.Itspopularitystemsfrombothitsrelativeeaseofproductionanditsapplicabilitytoawidevarietyoftextileproducts.
Fig.2-1Burstbollsinafield Fig.2-2Cottonbolls
Thecottonfibermaybefrom0.3to5.5cmlong.Underthemicroscopeitappearsasaribbonlikestructurethatistwistedatirregularintervalsalongitslength.Thetwists,calledconvolutions,increasethefiber-to-fiberfrictionnecessarytosecureastrongspunyam.Thefiberrangesincolorfromayellowishtopurewhite,andmaybeverylustrous.However,mostcottonisdull.
Fig.2-3Cottonflower Fig.2-4Cottonpod
Fig.2-5 Cottonfiber
Fig.2-6Photomicrographofacottonfiber
Fig.2-7thetwistsandwrinklesofcottonFig.2-8somewhatbean-shapedcrosssections
Across-sectionalviewrevealsthatthefiberiskidney-shapedwithcentralhollowcoreknownasthelumen.Thelumenprovidesachannelfornutrientswhiletheplantisgrowing.Thefiberconsistsofanoutershell,orcuticle,whichsurroundstheprimarywall.Theprimarywall,inturn,coversthesecondarywallsurroundingthelumen.Thecuticleisathin,hardshellwhichprotectsthefiberfrombruisinganddamageduringgrowth.Inuseasatextilefiber,thecuticleprovidesabrasionresistancetocotton.
1.2CottonPropertiesandItsUse
Arelativelyhighlevelofmoistureabsorptionandgoodwickingpropertieshelpmakecottononeofthemorecomfortablefibers.Becauseofthehydroxylgroupsinthecellulose,cottonhasahighattractionforwater.Aswaterentersthefiber,cottonswellsanditscrosssectionbecomesmorerounded.Thehighaffinityformoistureandtheabilitytoswellwhenwetallowcottontoabsorbaboutone-fourthofitsweightinwater.Thismeansthatinhotweatherperspirationfromthebodywillbeabsorbedincottonfabrics,transportedalongtheyarnstotheoutersurfaceoftheclothandevaporatedintotheair.Thus,thebodywillbeaidedinmaintainingitstemperature.
Unfortunately,thehydrophilicnatureofcottonmakesitsusceptibletowater-bornestains.Water-solublecolorantssuchasthoseincoffeeorgrapejuicewillpenetratethefiberalongwiththewater;whenthewaterevaporates,thecolorantistrappedinthefiber.Perhapsthemajordisadvantagetocottongoodsistheirtendencytowrinkleandthedifficultyofremovingwrinkles.Therigidityofcottonfiberreducestheabilityofyarnstoresistwrinkling.Whenthefibersarebenttoanewconfiguration,thehydrogenbondswhichholdthecellulosechainstogetherarerupturedandthemoleculesslideinordertominimizethestresswithinthefiber.Thehydrogenbondsreforminthenewpositions,sothatwhenthecrushingforceisremovedthefibersstayinthenewpositions.Itistheruptureandreformationofthehydrogenbondsthathelpstomaintainwrinkles,sothatcottongoodsmustbeironed.
Cottonisamoderatelystrongfiberwithgoodabrasionresistanceandgooddimensionalstability.Itisresistanttotheacids,alkalies,andorganicsolventsnormallyavailabletoconsumers.Butsinceitisanaturalmaterial,itissubjecttoattackbyinsects,moldsandfungus.Mostprominentisthetendencyforcottontomildewifallowedtoremaindamp.
Cottonresistssunlightandheatwell,althoughdirectexposuretoconstantstrongsunlightwillcauseyellowingandeventualdegradationofthefiber.Yellowingmayalsooccurwhencottongoodsaredriedingasdryers.Thecolorchangeistheresultofachemicalreactionbetweencelluloseandoxygenornitrogenoxidesinthehotairinthedryer.Cottonswillretaintheirwhitenesslongerwhenline—driedordriedintheelectricdryer.
Ofmajorinterestisthefactthatcottonyarnisstrongerwhenwetthanwhendry.Thispropertyisaconsequenceofthemacro-andmicro-tructuralfeaturesofthefiber.Aswaterisabsorbed,thefiberswellsanditscrosssectionbecomesmorerounded.Usuallytheabsorptionofsuchalargeamountofforeignmaterialwouldcauseahighdegreeofinternalstressandleadtoweakeningofthefiber.Incotton,however,theabsorptionofwatercausesadecreaseintheinternalstresses.Thus,withlessinternalstressestoovercome,theswollenfiberbecomesstronger.Atthesametime,theswollenfiberswithintheyarnspressuponeachothermorestrongly.Theinternalfrictionstrengthenstheyarns.Inaddition,theabsorbedwateractsasaninternallubricantwhichimpartsahigherlevelofflexibilitytothefibers.Thisaccountsforthefactthatcottongarmentsaremoreeasilyironedwhendamp.Cottonfabricsaresusceptibletoshrinkageuponlaundering.
Perhapsmorethananyotherfiber,cottonsatisfiestherequirementsofapparel,homefurnishings,recreational,andindustrialuses.Itprovidesfabricsthatarestrong,lightweight,pliable,easilydried,andreadilylaundered.Inapparel,cottonprovidesgarmentsthatarecomfortable,readilydriedinbright,long-lastingcolors,andeasytocarefor.Themajordrawbacksareapropensityforcottonyarnstoshrinkandforcottonclothtowrinkle.Shrinkagemaybecontrolledbytheapplicationofshrink-resistantfinishes.Durable-presspropertiesmaybeimpartedbychemicaltreatmentorbyblendingcottonwithmorewrinkle-resistantfiber,suchaspolyester.
Inhomefurnishings,cottonservesindurable,general-servicefabrics.Althoughtheymaylacktheformalappearanceofmaterialsmadefromotherfibers,cottongoodsprovideacomfortable,homeyenvironment.Cottonfabricshavebeenthemainstayofbedlinensandtowelsfordecades,becausetheyarecomfortable,durable,andmoisture-absorbent.Polyester/cottonblendsprovidethemodernconsumerwithno-ironsheetsandpillowcasesthatretainacrisp,freshfeel.
Forrecreationaluse,cottonhastraditionallybeenusedfortentingandcampinggear,boatsails.tennisshoesandsportswear.Cottonisparticularlywell-suitedfortent.Atentfabricmustbeableto“breath”,sothattheoccupantsarenotsmotheredintheirowncarbondioxide.Furthermore,exchangeofairwiththeoutsideatmospherereducesthehumiditywithinthetentandkeepsitfrombecomingstuffy.Fabricswovenfromcottoncanbeopenenoughtoprovidegoodairpermeabilityforcomfort.Tentsshouldalsoshedwater,whenwetbyrain,cottonyarnsswell,reducingtheintersticesbetweentheyarnsandresistingthepenetrationofwater.Today,however,heavycanvasgearisbeingsupplantedbyrightweightnylonintentingequipment.
Cottoncord,twineandropesareusedinindustrytobind,hold,andlashallkindsofthings,frombalestoboats.Cottonyarnsareusedtoreinforcebeltsondrivemotorsandinworkclothing.
Table2-1Fibersproperties
Property
Evaluation
Shape
Fairlyuniforminwidth,12-20micrometers;lengthvariesfrom1 cmto6 cm(½to2½inches);typicallengthis2.2 cmto3.3 cm(⅞to1¼inches).
Luster
high
Tenacity(strength)
Dry
Wet
3.0-5.0g/d
3.3-6.0g/d
Resiliency
low
Density
1.54-1.56g/cm³
Moistureabsorption
raw:
conditioned
saturation
mercerized:
conditioned
saturation
8.5%
15-25%
8.5-10.3%
15-27%+
Dimensionalstability
good
Resistanceto
acids
alkali
organicsolvents
sunlight
microorganisms
insects
damage,weakenfibers
resistant;noharmfuleffects
highresistancetomost
Prolongedexposureweakensfibers.
Mildewandrot-producingbac
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