Cov Yam Cuam Tshuam Rau Qhov Kub Hloov Iav, Qhov Kub Yaj thiab Qhov Kub Ntsws Viscous ntawm Polymers

Qhov kub hloov iav (Tg), qhov kub yaj (Tm) (rau cov polymers crystalline) thiab qhov kub ntws viscous (Tf) (rau cov polymers uas tsis yog crystalline) ntawm cov polymers yog cov ntsuas kub tseem ceeb. Tg txiav txim siab qhov kub ua haujlwm ntawm cov polymer, thaum Tm thiab Tf txiav txim siab qhov kub ua tiav ntawm cov polymer. Muaj ntau yam uas cuam tshuam rau Tg, Tm thiab Tf tus nqi ntawm cov polymer.

Kev cuam tshuam ntawm cov qauv polymer thiab cov khoom

I. Cov qauv saw hlau

(1) Cov saw hlau tseem ceeb. Kev qhia txog cov pab pawg nruj xws li phenyl, biphenyl pawg thiab cov ntawv cog lus ob chav sib txuas ntawm cov saw hlau tseem ceeb ua rau cov saw hlau ruaj khov dua, thaum Tg, Tm thiab Tf txhua yam nce ntxiv; kev qhia txog ether daim ntawv cog lus thiab cov ntawv cog lus ob chav sib cais ntawm cov saw hlau tseem ceeb ua rau cov saw hlau yoog tau, thiab Tg, Tm thiab Tf txhua yam txo qis.

(2) Cov pab pawg sab. Thaum cov pab pawg sab yog ib pab pawg nruj, qhov yooj ywm ntawm cov saw hlau txo qis thaum qhov ntim ntawm cov pab pawg sab nce ntxiv, thiab Tg, Tm thiab Tf txhua tus nce ntxiv; thaum cov pab pawg sab (lossis cov saw hlau sab) yog ib pab pawg yooj ywm (lossis cov saw hlau yooj ywm), qhov loj dua ntawm cov pab pawg sab (saw hlau), qhov yooj ywm zoo dua, ces qhov yooj ywm ntawm tag nrho cov saw hlau molecular zoo dua, thiab Tg, Tm thiab Tf txhua tus txo qis.

Qhov kev sib xyaw ua ke ntawm (1) thiab (2) qhia tau hais tias txhua yam tseem ceeb ntawm cov qauv saw hlau uas ua rau cov saw hlau tawv tuaj yeem ua rau cov nqi Tg, Tm thiab Tf nce ntxiv, thiab txhua yam tseem ceeb ntawm cov qauv saw hlau uas ua rau cov saw hlau yooj ywm tuaj yeem txo cov nqi Tg, Tm thiab Tf.

II. Cov zog sib txuas ntawm cov molecule
Cov polymers polar, nrog rau kev sib cuam tshuam muaj zog ntawm cov pab pawg polar ntawm cov saw molecular thiab cov zog intermolecular muaj zog, muaj cov nqi Tg, Tm thiab Tf loj dua li cov nqi sib xws rau cov polymers uas tsis yog polar; thiab cov nqi Tg, Tm thiab Tf txhua tus nce nrog rau kev nce ntawm cov zog intermolecular.

III. Qhov hnyav ntawm cov molecule
Vim tias Tm muaj feem cuam tshuam nrog kev siv lead ua, feem ntau, qhov hnyav ntawm cov molecular tsis muaj feem cuam tshuam rau Tm thiab ob qho tib si Tg thiab Tf nce nrog rau qhov hnyav ntawm cov molecular nce. Rau Tg, qhov sib txawv no pom tseeb dua ntawm qhov hnyav ntawm cov molecular qis, thaum Tg hloov qeeb heev thaum qhov hnyav ntawm cov molecular nce mus rau qee qib.

Qhov cuam tshuam ntawm qhov hnyav molecular rau Tf tseem ceeb dua li ntawm Tg. Qhov no yog vim qhov cuam tshuam ntawm qhov hnyav molecular rau Tg yog vim qhov cuam tshuam ntawm qhov kawg ntawm cov saw hlau, uas tsuas yog pom tau thaum cov ntsiab lus ntawm qhov kawg ntawm cov saw hlau ntawm lub kaw lus siab dua, piv txwv li qhov hnyav molecular qis dua; tom qab qhov hnyav molecular siab txog qee qhov thiab qhov hnyav ntawm qhov kawg ntawm cov saw hlau me me txog li qhov tsis tseem ceeb, nws cov nyhuv rau Tg tsis tseem ceeb.

Tf yog qhov kub tseem ceeb uas qhov chaw nruab nrab ntawm tag nrho cov saw polymer raug tshem tawm, thiab kev txav mus los ntawm tag nrho cov saw yog ua tiav los ntawm kev txav mus los ntawm txhua ntu saw. Qhov hnyav molecular siab dua, qhov ntau dua ntawm cov ntu saw uas xav tau txav mus los ua ke, thiab qhov ntau dua ntawm cov zog sib txhuam uas yuav tsum tau kov yeej thaum lub sijhawm txav mus los, thiab qhov siab dua Tf. Yog li ntawd, tus nqi Tf yog nyob ntawm qhov hnyav molecular.

Kev cuam tshuam ntawm lwm yam

I. Cov khoom siv me me uas yaj tau

Cov tshuaj yas lossis lwm yam khoom siv uas yaj tau qee zaum ntxiv rau cov khoom xyaw kom txhim kho cov khoom ua haujlwm lossis muab qee yam rau cov khoom thaum lub sijhawmkev tsim thiab kev ua cov polymerHauv cov ntaub ntawv ntawm cov polymers, cov molecule me me no sib npaug rau cov tshuaj diluents thiab lawv txo cov Tg, Tm thiab Tf ntawm cov polymer.

II. Cov zog sab nraud

Cov zog sab nraud uas ib sab muaj ib qho kev thawb rau ntawm cov saw hlau, yog li ntawd, kev nce cov zog sab nraud tuaj yeem txo qis Tg thiab Tf. Kev nce lub sijhawm ntawm lub zog sab nraud kuj ua rau cov molecule txav mus rau hauv qhov kev taw qhia ntawm lub zog sab nraud, uas kuj txo qis Tf. Kev nce siab ntawm qhov siab txo qhov ntim dawb thiab ua rau Tg thiab Tf nce.

Qhov cuam tshuam ntawm cov zog sab nraud rau Tm yog raws li nram no: thaum ib lub polymer crystallizes nyob rau hauv lub zog tensile, lub peev xwm los crystallize nce, tsa qib ntawm crystallinity thiab tseem melting point ntawm cov crystals, piv txwv li Tm nce; crystallizing nyob rau hauv siab ua rau kom tuab ntawm lub wafer, uas ua rau kom zoo meej ntawm cov crystal, kuj ua rau Tm siab dua.

III. Tus nqi xeem

Qhov no yog hais txog qhov loj ntawm tus nqi xeem tau txais los ntawm qhov kev xeem kub. Txij li thaum kev txav ntawm cov saw polymer yog ib qho txheej txheem so thiab yog nyob ntawm lub sijhawm, muaj kev sib raug zoo ntawm tus nqi xeem Tg thiab qhov ntsuas lub sijhawm sim: kev nce tus nqi ntawm kev sov lossis qhov zaus ntawm kev sim dynamic yuav ua rau Tg nce. Tib yam yog qhov tseeb rau Tf, thiab qhov sib txawv yog qhov tseeb rau Tm. Thaum kuaj Tm tus nqi, yog tias qhov kub nce qeeb qeeb, cov noob tsis zoo tuaj yeem yaj ua ntej thiab tom qab ntawd rov ua dua rau hauv cov siv lead ua kom zoo dua thiab ruaj khov ntawm qhov kub siab dua me ntsis. Qhov kawg hu ua "melting point" yog qhov kub uas txhua qhov siv lead ua kom zoo dua yaj thiab yuav siab dua tus nqi ntsuas ntawm qhov kub nce sai.