PVA txheej txheem ntau lawm thiab kev siv dav

Polyvinyl Alcohol (PVA) yog cov khoom siv hluavtaws uas tsim los ntawm polymerization ntawm vinyl acetate tom qab hydrolysis. Nov yog cov ntsiab lus ntawm PVA cov txheej txheem tsim khoom thiab nws cov kev siv dav:

Txheej txheem ntau lawm:

1. Polymerization ntawm Vinyl Acetate:
   • Vinyl acetate monomers yog polymerized siv cov dawb radical pib nyob rau hauv lub xub ntiag ntawm ib tug hnyav los yog raws li ib tug emulsion. Cov kauj ruam no ua rau tsim cov polyvinyl acetate (PVAc), ib qho dawb, dej-soluble polymer.
2. Hydrolysis ntawm Polyvinyl Acetate:
   • PVAc polymer yog hydrolyzed los ntawm kev kho nws nrog cov tshuaj alkaline (xws li sodium hydroxide) nyob rau hauv kev tswj xyuas. Cov tshuaj tiv thaiv hydrolysis no cleaves acetate pawg los ntawm cov pob txha polymer, uas ua rau tsim cov polyvinyl cawv (PVA).
3. Purification thiab ziab:
   • Cov tshuaj PVA tau dhau los ua cov kauj ruam ua kom huv kom tshem tawm cov impurities thiab cov monomers tsis muaj kev cuam tshuam. Cov kua dej huv PVA yog tom qab ntawd qhuav kom tau cov khoom PVA flakes lossis hmoov.
4. Kev ua haujlwm ntxiv:
   • PVA flakes lossis hmoov tuaj yeem ua tiav rau hauv ntau hom ntawv xws li granules, pellets, lossis kev daws teeb meem, nyob ntawm daim ntawv thov.

Kev siv dav dav:

1. Adhesives thiab Binders:
   • PVA feem ntau yog siv los ua cov ntawv nplaum hauv cov nplaum, nrog rau cov kua nplaum ntoo, cov ntawv nplaum, thiab cov nplaum nplaum. Nws muaj zog adhesion rau ntau yam substrates thiab muab cov yeeb yaj kiab zoo heev.
2. Textiles thiab Fibers:
   • PVA fibers yog siv nyob rau hauv textile daim ntaub ntawv xws li weaving, knitting, thiab nonwoven fabrics. Lawv nthuav tawm cov khoom xws li lub zog tensile siab, ua haujlwm tsis zoo, thiab tshuaj lom neeg ruaj khov.
3. Paper Coatings thiab Sizing:
   • PVA yog siv rau hauv cov ntawv txheej thiab sizing formulations los txhim kho nto smoothness, printability, thiab number case adhesion. Nws txhim khu lub zog thiab durability ntawm cov khoom ntawv.
4. Khoom siv:
   • PVA-raws li formulations yog siv nyob rau hauv kev tsim kho cov ntaub ntawv xws li mortar additives, pobzeb adhesives, thiab cementitious coatings. Lawv txhim kho kev ua haujlwm, adhesion, thiab durability ntawm cov khoom siv.
5. Ntim Films:
   • PVA zaj duab xis yog siv rau kev ntim cov ntawv thov vim lawv cov khoom thaiv zoo heev, dej tsis kam, thiab biodegradability. Lawv yog siv nyob rau hauv ntim khoom noj, ua liaj ua teb zaj duab xis, thiab tshwj xeeb ntim daim ntawv thov.
6. Cov khoom siv tshuaj pleev ib ce thiab kho tus kheej:
   • PVA yog siv rau hauv cov tshuaj pleev ib ce thiab cov khoom tu tus kheej xws li cov plaub hau styling gels, cream, thiab tshuaj pleev ib ce. Nws muab cov yeeb yaj kiab-forming zog, thickening, thiab stabilizing teebmeem.
7. Kev siv tshuaj kho mob thiab tshuaj:
   • PVA yog siv rau hauv kev kho mob thiab kev siv tshuaj xws li kev xa tshuaj, kev hnav khaub ncaws, thiab kev tiv thaiv lo ntsiab muag. Nws yog biocompatible, non-toxic, thiab nthuav tawm cov dej solubility zoo heev.
8. Kev lag luam zaub mov:
   • PVA yog siv los ua zaub mov ntxiv hauv ntau daim ntawv thov xws li cov yeeb yaj kiab uas siv tau, ntim cov khoom qab zib lossis cov as-ham, thiab ua tus neeg sawv cev thickening hauv cov khoom noj. Nws suav tias yog kev nyab xeeb rau tib neeg noj.

Hauv cov ntsiab lus, Polyvinyl Cawv (PVA) yog ntau yam polymer nrog ntau yam kev siv thoob plaws hauv kev lag luam xws li nplaum, textiles, ntawv, kev tsim kho, ntim, tshuaj pleev ib ce, kho mob, tshuaj, thiab khoom noj. Nws cov khoom tshwj xeeb ua rau nws tsim nyog rau ntau daim ntawv thov uas yuav tsum tau ua zaj duab xis, nplaum, khi, thaiv, thiab dej-soluble zog.