Tsab ntawv xov xwm no hais txog yuav ua li cas kom phim txheej tshuab kab nrawm thiab qhov cub ntev kom ntseeg tau tias organosilicone nplaum ncav cuag lub hom phiaj kho kom sov rau PTFE daim kab xev. Lub hauv paus ntsiab lus tseem ceeb: tag nrho lub sijhawm nyob hauv t_total = qhov cub ntev L ÷ kab ceev v yuav tsum tsis pub tsawg tshaj li qhov yuav tsum tau kho lub sijhawm kho. Tau txais cov yam ntxwv kho mob los ntawm DSC lossis cov tshuaj nplaum kho mob uas tsim kom muaj 'kub - yam tsawg kawg nkaus kho lub sij hawm' kev sib raug zoo. Cov qauv sib npaug sib npaug: faib qhov cub rau hauv ib cheeb tsam, xam ti = Li / v thiab tcure(Ti), xyuas kom ∑(ti/tcure(Ti)) ≥1. Cov txheej txheem suav: teeb tsa qhov kub thiab txias nrog qhov ntev Li thiab kub Ti; teem kab ceev v, xam txhua cheeb tsam lub sij hawm nyob thiab qhov sib piv; iterate kom txog thaum tag nrho ≥1 (safety margin 1.1-1.2 pom zoo).

Kab lus no suav nrog txoj hauv kev los tswj cov crystallinity ntawm PTFE txheej ntawm Teflon high-temperature ntaub. Kev tswj hwm tus nqi cua txias yog qhov ncaj qha thiab ua haujlwm tau zoo: Kev ua kom txias sai (quenching) los ntawm cov ntaub thaiv cua txias, cov tub yees txias lossis cov dej tso tsheb hlau luam - cov saw hlau molecular khov ua ntej kev txiav txim, tsim cov pob zeb me me tsis zoo; txheej yog mos, tawv nrog optimized non-stick kev ua tau zoo, me ntsis txo hardness / hnav tsis kam. Kev ua kom txias qeeb (annealing) los ntawm kev txuag hluav taws xob ntawm 10-50 ° C / h los yog lub tshuab cua txias - molecular chains tag nrho npaj rau hauv loj ua tiav spherulites; txheej muaj siab hardness, zoo heev hnav tsis kam, ruaj khov qhov ntev, txo yooj thiab nce brittleness.

Kab lus no hais txog daim ntawv thov ntawm Teflon high-temperature daim ntaub nyob rau hauv kub-cua ncig sintering furnaces. Kev ua tau zoo: siv tau raws li tsis yog-stick cushion ntawm mesh siv los yog cov tais thaum lub qhov cub kub ≤260 ° C (kub kom qhuav, binder tshem tawm, slurry curing) - txhim kho demolding thiab khaws efficiency. Kev txwv nruj me ntsis ntawm qhov nruab nrab / siab kub (300-950 ° C) - PTFE decomposes tso cov tshuaj lom HF thiab perfluoroisobutylene, corroding cov cuab yeej thiab ua rau tuag taus. Lub hauv paus ntsiab lus ntawm kev nyab xeeb: yog lub qhov cub kub tsis meej lossis tsis tuaj yeem lav qis dua 260 ° C, tsis txhob siv. Cov khoom tseem ceeb: kev pabcuam txuas ntxiv -70 ° C txog 260 ° C, luv luv 300 ° C; heev tsis-stick thiab tshuaj inertness; zoo heev hluav taws xob rwb thaiv tsev; tsis tshua muaj kev sib txhuam (~ 0.04); fiberglass puag muab lub zog tensile siab.

Kab lus no sib piv qhov sib txawv ntawm cov hluav taws xob hluav taws xob hluav taws xob thiab cov cua kub cua kub kho cov txheej txheem ntawm crosslinked qauv uniformity ntawm silicone nplaum txheej. Thaum tshav kub kub hloov tshuab: kub-cua cia siab rau convection-conduction nrog maj mam kub nce, me me sab hauv / sab nraud kub sib txawv; IR tau txwv qhov tob tob nrog qhov nqus ntawm qhov chaw muaj zog (ntau txog kaum rau pua pua micrometers) tsim kom muaj qhov tob tob-rau-sab hauv gradient. Cov teebmeem ntawm crosslink uniformity: kub-cua ua rau synchronous curing sab hauv thiab tawm nrog uniform crosslink ntom; IR ua rau cov txheej txheem saum npoo kom nrawm nrawm 'skin film' uas cuam tshuam cov cua sov thiab cov saw hlau sab hauv, tsim kom muaj qhov sib txawv ntawm qhov sib txawv ntawm qhov chaw mus rau sab hauv.

Kab lus no suav nrog qhov sib txawv ntawm PTFE emulsions tsim los ntawm kev ncua polymerization vs dispersion polymerization. Qhia meej: ncua kev kawm ntawv polymerization tsis tuaj yeem tsim PTFE emulsion ncaj qha; PTFE tiag emulsion tsuas yog los ntawm dispersion polymerization. 'Kev ncua-txoj kev emulsion' yog tiag tiag aqueous ncua kev kawm ntawv ntawm av suspension-polymerized resin micropowders. Dispersion polymerization (thawj emulsion): spherical hais (0.1-0.3μm, nqaim faib), stabilized los ntawm perfluorinated surfactants, siab molecular hnyav (> 94% crystallinity), muaj zog fibrillation, yuav tsum tau 380 ° C sintering rau daim ntawv nruam tawv zaj duab xis.

Tsab ntawv xov xwm no hais txog yuav ua li cas kom phim qhov kub thiab txias ib nrab ntawm peroxide crosslinking agents (BPO thiab DCP) nrog cov txheej txheem kho qhov rais rau Teflon daim kab xev. Cov ntaub ntawv tseem ceeb: BPO — 1-min ib nrab-lub neej ntawm ~ 131 ° C, 1-hr ntawm ~ 92 ° C, 10-hr ntawm ~ 72 ° C; DCP - 1-min ntawm ~ 171 ° C, 1-hr ntawm ~ 135 ° C, 10-hr ntawm ~ 115 ° C. Kev sib txuam logic: nplaum xav tau 97-99% crosslinking = 5-7 ib nrab-lub neej; curing lub sij hawm = 5-7 × ib nrab-lub neej ntawm lub hom phiaj kub. Rov qab-xws li kub los ntawm cov kab ntau lawm nyob rau lub sij hawm los yog rov qab xam lub sij hawm los ntawm qhov siab tshaj plaws tso cai kub.

Kab lus no suav nrog cov kab nrawm nrawm rau PTFE high-temperature fabric impregnation ntau lawm kab. Ceev ceev: 2-15 m / min, ruaj khov kev khiav hauj lwm ntau 3-8 m / min, nyias fabrics / high-ceev kab mus txog 10-15 m / min. Kev txwv los ntawm impregnation nkag mus rau: ntaub yuav tsum tau tag nrho saturated nrog PTFE emulsion rau hauv fiber ntau nras interiors - kev kub ceev ua rau impregnation tsis txaus, resin tshaib plab thiab qhuav fibers; emulsion viscosity, solids concentration, fabric weave density tag nrho txo ​​qhov nkag mus, yuav tsum tau qeeb qeeb rau cov ntaub tuab / ntom. Txheej txheej: ntau dhau (2-6+) yuav tsum tau ua kom tuab tsis muaj txheej txheem; thawj dhau qeeb qeeb rau kev thauj mus los, cov ntawv hla tom ntej tuaj yeem nce nruab nrab.

Kab lus no sib piv qhov sib txawv ntawm cov hluav taws xob hluav taws xob hluav taws xob thiab cov cua kub cua kub cua sov ntawm cov qauv sib txuas sib txuas ntawm cov txheej txheem silicone nplaum. Thaum tshav kub kub hloov mechanisms: kub-cua yog convection-conduction, maj mam thiab zuj zus, tsim nruab nrab kub gradient; IR yog hluav taws xob-absorption nrog khaus deg nqus (micrometers mus rau millimeters) tsim qhov tob-rau-sab hauv gradient. Effects on crosslink density distribution: hot-air allows inner and outer portions to enter vulcanization temperature range nearly simultaneously, yielding uniform crosslink density along thickness; IR ua rau cov txheej txheem saum npoo los kho tam sim ua cov tawv nqaij tawv uas cuam tshuam kev hloov pauv cua sov, ua rau muaj kev sib tw ntse ntawm crosslink ntom ntom ntawm qhov chaw sab hauv.

Kab lus no suav nrog cov ntsiab lus silica thiab daim ntawv thov scenarios ntawm high-silica iav fiber ntau ntaub. Cov ntsiab lus ntawm Silica: Cov ntsiab lus tseem ceeb yog SiO₂ ≥96% (tus qauv 96-98%, qib hwm> 99% ntawm cov kua qaub leaching thiab sintering, mus txog cov ntshiab quartz fiber ntau). Kev tsim khoom: E-iav ntaub tau dhau los ua cov kua qaub kub kom yaj cov khoom tsis-silica (boron oxide, sodium oxide), tsim cov pob txha pob txha silica, ces sintered rau densification. Cov txiaj ntsig tseem ceeb: kev pabcuam txuas ntxiv ntawm 900 ° C hauv oxidizing atmospheres, lub sijhawm luv tshaj 1200 ° C, softening point ze 1700 ° C; tshuaj stability tiv thaiv feem ntau cov kua qaub/alkalis tshwj tsis yog HF thiab kub phosphoric acid; tsawg dielectric tsis tu ncua thiab ruaj khov rwb thaiv tsev ntawm qhov kub thiab txias.

Kab lus no piav qhia txog cov yam ntxwv ntawm microstructural ntawm Teflon high-temperature ntaub. Substrate skeleton: iav fiber ntau weaving kev ntxhib los mos nyob rau hauv dawb / twill weaves nrog siab porosity (micron-scale pores nyob rau hauv fiber bundles thiab ntawm warp-weft nodes) muab qhov chaw rau PTFE impregnation. Txheej morphology: tag nrho impregnation encapsulation txoj kev 'reinforced qhob' qauv qhov twg iav fibers yog reinforcing theem, PTFE yog nruam matrix; nto nodular microstructure ntawm nodules (particles) interconnected los ntawm nplua fibrils tsim thaum sintering; nruam daim tawv nqaij txheej (ob peb mus rau kaum ntawm microns tuab) ntawm ntshiab PTFE raws li qhov tseem ceeb barrier rau tshuaj inertness, tsis-stick zog, thiab hluav taws xob rwb thaiv tsev.