LCD Kev Loj Hlob Thiab Cov Yam Ntxim Saib Ntxim Ua Hauv Cov Ntxaij Ntxhais Luam Ntawv

Cov kua nplaum ua kua yog ib lub sij hawm siv rau cov kua tau tsim los ntawm qee cov tshuaj nyob rau hauv lub xeev los yog hauv lub xeev. Kev tshawb nrhiav cov kua nplaum yuav ua rau taug kev mus txog 1888. Lub Austrian botanist FReinitzer pom tias cov cua kub cua ntawm Chol2esteryl Benzoate (C6H5CO2C27H45, xa mus rau CB) mus rau 145.5e melts mus ua kua dej, thiab 145.5e yog lub ntsiab lus ntawm cov khoom . Ua kom cua sov mus txog 178.5e, cov kua paug dej yuav maj mam tig mus rau hauv cov kua ntshiab ntshiab, thiab qhov txheej txheem ntawm turbid kom pom tseeb yog reversible [2]. OLehmann systematically cov kev tshawb fawb tias cov khoom siv dag zog ntawm cov khoom muaj ntsis zoo ib yam li cov isotropic kua hauv ib qho chaw ntsuas kub [1]; Txawm li cas los, lawv cov khoom siv kho qhov muag zoo ib yam li cov neeg muaj laib thiab yog anisotropic. Yog li no, cov theem ntawm cov kua thiab cov siv lead ua tau raug xa mus ua kua qaub (crystal) theem.
Hauv lub sijhawm xyoo 1930, tib neeg tau kawm LCD ntev, tiam sis vim cov khoom tsim tawm tsawg, lawv tsis tau thov. Mus txog rau xyoo 1960s, vim muaj kev loj hlob sai ntawm cov technologies tshiab xws li microelectronics, aerospace, laser, microwave, ultrasonic, holographic, nuclear magnetic resonance thiab roj-kua chromatography, nws yuav tsum tau siv ib co xov xwm uas ua raws li cov lus qis rau qis- zog excitation ua kua muaju. Muaj chaw rau koj siv. Tom qab R. Williams tau luam tawm lub tshuab hluav taws xob ua kua ntawm cov kua siv lead ua kua dej hauv xyoo 1967, cov kua pleev ua kua dej tau txais txiaj ntsig zoo thiab kev tshawb fawb tau nthuav tawm thoob plaws ntau yam hauj lwm. Cov kev tshawb fawb ntawm cov kua siv lead ua kua thaum xyoo 1960 kuj nthuav dav rau hauv cov kab polymers. Txoj kev loj hlob ntawm cov kua qaug tshuaj molecular qis tau ze li ntawm ib puas xyoo thiab tau txais kev tshawb fawb txog qhov tob thiab nws daim ntawv thov uas nws kim heev. Txoj kev loj hlob ntawm cov kua tshuaj kua polymer tau nyob ib ntus ntev ntev. Cov kua nplaum uas ua kua polymer uas cov kws tshawb fawb tau pom thawj zaug yog lub hauv paus ntawm cov nqaij ntshiv, uas muaj phospholipids thiab alcohols. Xyoo 1937, Bawden thiab Pirie tau tshawb pom cov kua qia ntxig hauv kev tshem tawm ntawm kev haus luam yeeb mosaic. Nyob rau hauv xyoo 1950, Elliott thiab Robinson thiab lwm tus neeg tau pom tias cov khoom cua peptide kuj muaj kua siv ua kua. Nyob rau xyoo 1970, lub tshuab hluav taws xob muaj zog thiab high-modulus polyamide fibers tau qhia, thiab daim ntawv thov kua siv tshuab ua kua tshuab cim pib ntawm ib theem tshiab hauv txoj kev tshawb ntawm cov kua tshuaj kua tshuaj polymer [3]. Qhov tshwm sim ntawm cov tshav kub kub uas tsim los ntawm polystyrene kua crystal nyob rau hauv nruab nrab-1970s qhib tau ib daim teb tshiab ntawm polymer kua Crystal. Muaj ntau txoj hlua khi thiab semi-rigid saw polymers tau pom, thiab ib co zawg saw hlau polymers thiab ntau cov biopolymers muaj cov kua qaub cawv ua kua. Nws tau raug pom tias macromolecules polymerized los ntawm cov kab ntawm cov pas nrig-xws li cov qauv ncaj nraim zoo li anisotropy rau cov kua ntxhuav uas tsis muaj molecular kua. Qhov no macromolecule tuaj yeem ua tiav qib siab ntawm qhov kev txiav txim siab, thiab nws cov yaj lossis kev daws teeb meem tuaj yeem ua raws nraim.
Xyoo 1968, DuPont Tuam Tsev hauv Teb Chaws Asmeskas tau pib kawm cov kua siv lead ua kua polymer poly (p-phenylene terephthalate) thiab siv los saws hauv cov kua qoob loo ntawm qhov ntsuas kub. Txoj kev tshawb fawb tau ua tiav xyoo 1971, uas yog lub npe hu ua B. Fibre, uas tau muab tso rau hauv industrial ntau xyoo thaum Lub Ob Hlis 1972, thiab luam tawm PRD-49 tshiab fiber (polyparaxylamine). Xyoo 1973, cov B-fiber ntau thiab PRD-9 fiber ntau cov npe Kevlar thiab Kevlar-49 (hu ua aramid 1414 thiab aramid 14 nyob rau hauv Suav teb) feem ntau Kevlar kua fiber qhib cov ntaub ntawv keeb kwm ntawm polymer kua Crystal khoom, thiab tom qab, Hauv teb ntawm polymer science, txoj kev loj hlob thiab kev loj hlob ntawm ntau cov kua siv lead ua kua polymers pib vam. Tam sim no, ntau cov kua siv lead ua kua polymers tau zoo tsim hauv txoj kev kuaj sim, thiab lawv tau ua tiav industrial ntau lawm, xws li industrialization ntawm cov thermoplastic txhaj molded kua siv ua kua polymers, uas yog tsim los ntawm Dartco Manufacturing Co., Ltd. luam lub npe Xydar. Ib qho thermoplastic uas tiv taus kub thiab muaj lwm yam khoom zoo heev [4].
1.1 Nta
(1) Lub zog muaj zog thiab siab heev hauv kev taw qhia
Feem ntau cov khoom siv ua kua siv lead ua polymer cov khoom no muaj. Piv nrog rau cov zis saw polymer, cov kua siv lead ua kua polymer nrog lub caij mesogenic hauv lub ntsiab muag los yog cov saw hlau ntawm lub molecule muaj feem ntau cov feature ntawm molecular saw orientation nyob rau sab nraud quab yuam. Yog li, txawm tias tsis tas li ntawm cov khoom siv reinforcing, nws tuaj yeem ncav cuag lossis tshaj li qhov kev ua haujlwm dag zog ntawm cov khoom siv hluav taws xob zoo tshaj plaws los ntawm ntau tshaj kaum feem ntawm cov iav fiber ntau, qhia txog cov yam ntxwv ntawm lub siab thiab kev ua haujlwm siab. Piv txwv li, Kevlar lub zog muaj qee lub zog thiab ib qho kev qhia tshwj xeeb yog kaum zaug uas muaj hlau [5].
(2) koj cov hluav taws kub ua haujlwm
Txij thaum lub hauv paus ntawm cov kua siv lead ua kua polymer hauv cov mesogenic kua mas feem ntau yog ntawm cov nplhaib uas muaj suab nrov, nws cov hluav taws kub kuj tsis zoo. Piv txwv li, Xydar muaj ib qho chaw nruab nrab ntawm 421 ° C, thiab muaj kev kub ntxhov ntawm 560 ° C hauv huab cua, thiab kub kub ntawm 350 ° C, uas yog siab dua cov khoom uas ploj feem ntau.
(3) Heev coefficient ntawm thermal expansion
Vim tias qhov kev qhia tau siab, cov kua siv lead ua kua polymer muaj cov coefficient ntawm kev nthuav dav hauv qhov kev khiav tawm uas yog ib qho kev txiav txim siab ntawm qhov sib txawv tsawg tshaj li ntawm cov khoom ua haujlwm xws li niaj hnub, kev nkag mus rau theem ntawm cov hlau thiab txawm tias qhov tsis zoo.
(4) Cov nplaim nplaum zoo heev
Cov kua siv ua kua polymer molecular saw yog muaj ntau ntau ntawm cov ntxhuav rwj, thiab nws yog ib qho nyuaj rau hlawv tsuas yog cov fiber muaj cov xim roj carbon monoxide, thiab carbonization tom qab combustion qhia tias cov kev txwv ntawm cov pa oxygen (LOI) ntawm cov polymer tus loj.