Phenol-formaldehyde cob. Cov kev npaj thiab kev siv. zog

Phenol formaldehyde cob - ib tug hluavtaws cob muaj thaj chaw ntawm thermosets los yog thermosets. Tej resins yog oligomeric los yog kua tshuaj, tau los ntawm polycondensation ntawm formaldehyde nrog phenol nyob rau hauv ib tug acidic los yog alkaline nruab nrab (resol, novolac cob los yog bakelite). Qhov no ntxiv muaj feem xyuam rau qhov kawg khoom zog.

Cov khoom ntawm phenol-formaldehyde resins

Phenol formaldehyde cob (formula [-C6H3 (OH) -CH2-] n) muaj ib tug high hluav taws xob rwb thaiv tsev, zoo corrosion thiab cov neeg kho tshuab stability. Zoo kawg nkaus soluble nyob rau hauv uas muaj ntxhiab thiab aliphatic hydrocarbons, ketones thiab chlorinated kuab tshuaj. Nws tseem yog soluble nyob rau hauv ncov qaumteb qabteb ntsiab thiab aqueous alkali daws teeb meem. Tom qab tua phenol-formaldehyde resins yog hloov dua siab tshiab rau hauv gustosshitye microheterogeneous polymers ntawm amorphous qauv.

Nyob qhov twg lub phenol formaldehyde cob yog thov?

- nyob rau hauv zus tau tej cov yas: tawv cob hu ua resite, solidified roj nyob rau hauv lub xub ntiag ntawm sulphonic acids - karbolit, nyob rau hauv lub xub ntiag ntawm lactic acid - neoleykoritami;

- nyob rau hauv zus tau tej cov varnishes, adhesives, hluavtaws, bearings, nres tas, khoom rau billiards;

- los ntawm karbolit (kho phenol-formaldehyde cob) manufactured tsev nyob multimers ib co Soviet qauv;

- tseem yog cov tshuaj yeeb dej caw siv raws li ib tug phau ntawv rau zus tau tej cov sau molding compositions nrog txawv fillers (ntoo hmoov, iav fiber, cellulose), chipboard thiab fibreboard, pouring thiab Impregnating compositions (rau sau fiber thiab woven cov ntaub ntawv rau plywood) adhesives.

Phenol formaldehyde cob: txais thiab ecology

Thiab formaldehyde thiab phenol siv nyob rau hauv qhov siv thiab ua phenol-formaldehyde resins, yog tshuaj lom thiab cov tshuaj. Formaldehyde cob muaj ib tug tsis zoo feem nyob rau tib neeg lub cev: ua eczema thiab dermatitis. Ntxiv mus, formaldehyde kuj muaj carcinogenic zog.  

Bakelite - hardened cov khoom ntawm phenol-formaldehyde cob nyob rau hauv lub xub ntiag ntawm ib lub hauv paus. Qhov no teeb meem yog ib yam uas tseem ceeb heev nyob rau hauv ntau yam spheres ntawm tib neeg lub neej. Bakelite yog ib tug neeg txom nyem neeg xyuas pib ntawm tshav kub, tab sis exhibits zoo kuj mus txhua yam kev puas tsuaj: kev poob siab, poob siab, kev sib txhuam los yog siab. Ib qho yooj yim mus ua hauj lwm nyob rau hauv ib tug tshwj xeeb tshuab dhos. Nws yog ib tug zoo insulator. Lub diluted alkali, acid thiab dej nws tsis ua ntawv thov, tsuas yog concentrated sulfuric los yog nitric acids. Resistant mus +300 degrees, tshwm sim nyob rau ntau dua combustion kub.

Nws yog Ameslikas tsim kom muaj ib tug kev hloov rau shellac - ib tug tshwj xeeb cob ua nyob rau hauv cov xwm teb chaws sov lacquer scale kab.

Phenolics. daim ntawv thov

Phenoplast - ib lub hnab yas uas yog tau ua los ntawm solidification formaldehyde resins ntawm tsa kub nyob rau hauv ua ke nrog rau tej uas muab tub lim. Tam sim no, qhov no cov ntaub ntawv uas yog unsurpassed nyob rau hauv nws cov khoom. Siv phenoplasts no yog ua los:

- substance npaj rau luam Circuit Court laug cam - getinaks;

- ib yam khoom uas tsim ib tug yam ntxwv cov ntaub ntawv uas - PCB;

- pheej yig ntsiab rau board ua si - checkers, dominoes, chess;

- ib co ntsiab ntawm chav ua noj accessories: tuam haujlwm txais rau roj qhovcub, kettles thiab riam, huam thiab cov lauj kaub;

- bakelite phenolic lo;

- hluav taws xob khoom - nyob, plugs, hluav taws xob meters, keyboards, relays, electric tsav housings, hlws ris thawv, magnetic actuators, thiab lwm yam.;

- yam rau engineering, e.g., cov kauj ruam rau Escalators, ntau yam terminals thiab nqhuag;

- costume jewellery, souvenirs, ntawv sau, tej lus sij hawm.