尼龍12及其彈性體拉伸過程中的結(jié)構(gòu)與力學(xué)性能關(guān)系研究.pdf

1、中國科學(xué)技術(shù)大學(xué)碩士學(xué)位論文尼龍12及其彈性體拉伸過程中的結(jié)構(gòu)與力學(xué)性能關(guān)系研究姓名：柏蓮桂申請(qǐng)學(xué)位級(jí)別：碩士專業(yè)：同步輻射及應(yīng)用指導(dǎo)教師：李良彬20100501AbstractABSTRACTInthiswork，therelationshipbetweenthestructureandmechanicalpropertiesofpolyamide12(PA12)anditselastomers(polytetrahydrofuran

2、—PA12segmentedcopolymers)weresystematicallystudiedIntheyieldstage，atransientphasenamed0c’’phasewasinducedItdisappearedwhenthestressincreasedDeformationinduced僅”phasealsooccurredwhendrawingpolyamide12fPA12)initssegmentedc

3、opolymersformwithpolytetrahydrofuran(PTHF)Inthesesegmentedcopolymers，whichcontainedahighco／tentofPTHFthemetastable0【’’phasecouldexistatrobmtemperatureWhenthetemperatureandcontentofPA12increasedthe0c’’phasewasatransientph

4、ase，onlysurvivedinawidowofstressandtemperatureThestructuralevolutionofPA12duringtensiletestwasstudiedusingin—situwideXrayscattering(WAXS)belowandaboveglasstransitiontemperature(Tg)Duringtheyieldstage，theYphasewastransfor

5、medtoatransient僅”phase，whoselifetimedecreasedwiththeincreaseoftemperamreWhenthestressincreasedattemperaturebelowTg，thetransienta”phasewastransformedtomesomorphicstateHoweveraboveTg，thefinalstateWas丫’phaseThedifferentfina

6、lstateisduetothecompetitionandcouplingbetweenextemalworkandthermalactivationAttemperaturebelowTg，theextemalworkisthemainreasonwhythetransientphaseappearsandfurthertransformstomesomorphicstate，whilethermalactivationdrives

7、thetransitionfromthetransient0t’’phaseto丫’phaseattemperatureaboveTgThephasetransitionsoccurintheplasticdeformationregion，whichshowsaclosecorrelationbetweenthemechanicalresponseandthestructuralevolutionduringtensiledeform

8、ationDeformation—inducedphasetransitionbehaviorofpolyamide12(PA12)initssegmentedcopolymersformwithpolytetrahydrofuran(PTHF)wasstudiedwithinsituWAXSatdifferenttemperaturesInthesesegmentedcopolymers，whichcontainahighconten

9、tofPTHFatransformationfromthestable^rphasetoametastable0c”phasewasobservedduringtensiledeformationatroomtemperatureThedeformationinduceda’’phaseisnotathermodynamicstablephasebutarisesfromkineticoriginsAfterthereleaseofte

10、nsileforcefollowingdeformation，themetastable0【”phaseCanpartiallytransformbacktotheinitialphaseThereversiblephasenaturemaycontributesomewhattotheelasticityofPTHFPA12systemsaSaresultofthisenthalpiccontributionUponincreasin