Polyethylene (PE)
1. Kev ua haujlwm ntawm PE
PE yog cov yas tsim ntau tshaj plaws ntawm cov yas, nrog rau qhov ceev ntawm 0.94g / cm3. Nws yog tus cwj pwm los ntawm kev ua translucent, mos, tsis muaj tshuaj lom, pheej yig, thiab ua haujlwm yooj yim. PE yog ib qho crystalline polymer thiab muaj qhov tshwm sim tom qab shrinkage. Nws muaj ntau hom, feem ntau siv yog LDPE uas yog softer (feem ntau hu ua mos roj hmab los yog paj ntaub), HDPE uas yog feem ntau hu ua tawv mos roj hmab, uas yog nyuaj tshaj li LDPE, muaj tsis zoo lub teeb transmittance thiab siab crystallinity. ; LLDPE muaj kev ua tau zoo heev, zoo ib yam li engineering plastics. PE muaj cov tshuaj tiv thaiv zoo, tsis yooj yim rau corrode, thiab nyuaj rau luam tawm. Qhov saum npoo yuav tsum tau oxidized ua ntej luam ntawv.
2. Kev thov ntawm PER
HDPE: ntim hnab yas, khoom siv txhua hnub, thoob, xov hlau, khoom ua si, khoom siv hauv tsev, ntim
LDPE: ntim cov hnab yas, paj yas, cov khoom ua si, cov xov hlau loj, cov ntawv sau, thiab lwm yam.
3. PE txheej txheem cov yam ntxwv
Qhov tseem ceeb tshaj plaws ntawm PE qhov chaw yog tias lawv muaj qhov loj molding shrinkage tus nqi thiab nws muaj peev xwm shrinkage thiab deformation. PE cov ntaub ntawv muaj qhov nqus dej tsawg thiab tsis tas yuav qhuav. PE muaj qhov kub thiab txias ntau yam thiab tsis yooj yim rau decompose (qhov decomposition kub yog li 300 ° C). Kev ua haujlwm kub yog 180 txog 220 ° C. Yog tias qhov kev txhaj tshuaj siab siab, qhov khoom ntom ntom yuav siab thiab tus nqi shrinkage yuav tsawg. PE muaj qhov nruab nrab fluidity, yog li lub sij hawm tuav yuav tsum tau ntev dua thiab pwm kub yuav tsum nyob twj ywm (40-70 ° C).
Lub degree ntawm crystallization ntawm PE muaj feem xyuam rau cov txheej txheem molding. Nws muaj qhov kub thiab txias dua. Qhov qis pwm kub, qhov qis dua qhov crystallinity. . Thaum lub sij hawm crystallization txheej txheem, vim lub anisotropy ntawm shrinkage, sab hauv kev nyuaj siab concentration yog tshwm sim, thiab PE qhov chaw yog yooj yim deform thiab tawg. Muab cov khoom tso rau hauv chav dej da dej hauv 80 ℃ dej kub tuaj yeem so cov kev ntxhov siab sab hauv rau qee yam. Thaum lub sij hawm molding txheej txheem, cov khoom kub yuav tsum siab tshaj qhov pwm kub. Kev txhaj tshuaj siab yuav tsum tsawg li tsawg tau thaum ua kom ntseeg tau qhov zoo ntawm qhov. Qhov txias ntawm pwm yog tshwj xeeb yog yuav tsum tau ceev thiab txawm, thiab cov khoom yuav tsum tau kub thaum demolded.
Polypropylene (PP)
1. Kev ua tau zoo ntawm PP
PP yog crystalline polymer nrog qhov ntom ntawm tsuas yog 0.91g / cm3 (tsawg dua dej). PP yog qhov sib sib zog nqus ntawm cov yas siv ntau. Ntawm cov khoom siv dav dav, PP muaj qhov zoo tshaj plaws tshav kub tsis kam, nrog kub deformation kub ntawm 80 mus rau 100 ° C thiab tuaj yeem boiled hauv dej kub. PP muaj qhov zoo ntawm kev ntxhov siab tawg tsis kam thiab lub siab khoov qaug zog lub neej, thiab feem ntau hu ua "100% yas". ".
Kev ua tau zoo ntawm PP yog zoo dua li ntawm cov ntaub ntawv PE. PP cov khoom yog lub teeb yuag, tawv thiab tshuaj tiv thaiv. Qhov tsis zoo ntawm PP: tsis tshua muaj qhov tseeb, tsis txaus rigidity, huab cua tsis zoo, yooj yim los tsim "tooj liab kev puas tsuaj", nws muaj qhov tshwm sim tom qab shrinkage, thiab cov khoom muaj kev laus, ua nkig thiab deformed.
2. Kev siv PP
Ntau yam khoom siv hauv tsev, pob tshab lub hau, cov kav dej tshuaj, cov thawv ntim tshuaj, cov khoom siv kho mob, ntawv sau, cov khoom ua si, filaments, khob dej, turnover boxes, kav, hinges, thiab lwm yam.
3. Txheej txheem yam ntxwv ntawm PP:
PP muaj qhov zoo fluidity ntawm lub melting kub thiab zoo molding kev ua tau zoo. PP muaj ob yam ntxwv:
Ua ntej: qhov viscosity ntawm PP yaj txo qis nrog qhov nce ntawm shear npaum li cas (tsawg cuam tshuam los ntawm qhov kub thiab txias);
Thib ob: Lub degree ntawm molecular orientation yog siab thiab tus nqi shrinkage yog loj.
Kev ua haujlwm kub ntawm PP yog zoo dua nyob ib ncig ntawm 200 ~ 250 ℃. Nws muaj qhov zoo thermal stability (decomposition kub yog 310 ℃), tab sis nyob rau hauv high kub (280 ~ 300 ℃), nws yuav degrade yog hais tias nws nyob twj ywm nyob rau hauv lub chim ntev. Vim tias qhov viscosity ntawm PP txo qis nrog qhov nce ntawm qhov shear npaum li cas, nce qhov kev txhaj tshuaj thiab kev txhaj tshuaj nrawm yuav txhim kho nws cov fluidity; Txhawm rau txhim kho shrinkage deformation thiab dents, pwm kub yuav tsum tau tswj nyob rau hauv thaj tsam ntawm 35 txog 65 ° C. Lub crystallization kub yog 120 ~ 125 ℃. PP yaj tuaj yeem dhau los ntawm qhov sib txawv ntawm cov pwm nqaim heev thiab tsim kom muaj ntug. Thaum lub sij hawm melting txheej txheem, PP yuav tsum tau nqus ib tug loj npaum li cas ntawm melting tshav kub (loj tshwj xeeb tshav kub), thiab cov khoom yuav kub heev tom qab tawm ntawm lub pwm. PP cov ntaub ntawv tsis tas yuav qhuav thaum lub sij hawm ua, thiab lub shrinkage thiab crystallinity ntawm PP yog qis dua cov PE.
Post lub sij hawm: Dec-28-2023