Slide Hóa Lý Polyme TS. Nguyễn Huy Tùng- PLM Center - Hanoi University of Technology

8/7/2019 Slide Ha L Polyme TS. Nguyn Huy Tng- PLM Center - Hanoi University of Technology

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HA L POLYME

TRUNG TM NGHIN CU VT LIU POLYME

Ging vin: Nguyn Huy Tng


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Polyme l g?

1820 Thomas Hancock pht hin ra rng khi nghin cao su chy tt hn, dtrn hp vi cht n v d to hnh.

1839 Charles Goodyear nhn thy tnh cht n hi ca cao su t nhin cth tng ln, v dnh b loi b khi c un nng vi lu hunh - ccp bng sng ch v lu ho cao su t nhin

1851 Nelson Goodyear (anh trai ca Charles) ng k sng ch khi lu hocao su t nhin vi mt lng ln lu hunh to thnh vt liu rt cng(thng gi l cao su cng) ebonithay vulcanit

Xenlulo nitrat (nitroxenlulo) Christian Schonbein pht hin nm 1846, c dng ph bin lm thuc n. ng dng quan trng hn ca Xenlulonitrat l lm cht do do c tnh cht n

hi, d tan trong dung mi thch hp v to hnh di tc dng ca nhit v psut. V d: hn hp ca Xenlulonitrat v long no lm phim chp nh

1892 t nhn to viscoza, mng xellofan 1910 nha Bakelit phenol-formadehyt (tc gi l Leo Baekeland) l polyme

tng hp hon ton c sn xut cng nghip v thng mi ho. Cao su nhn to u tin c tng hp t 2,3 dimetyl butadien c trong

chin tranh th gii I.


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Polyme l g? S pht trin ca ngnh cng ngip polyme b hn ch v s hn ch hiu bit v bn cht ca

polyme. Cc nh khoa hc ch nhn bit c mt s tnh cht bt bnh thng ca polyme v nhnchung h coi tnh cht ca polyme l tp hp ca nhng phn t nh hn.

Hermann Staudinger (1920) a ra mt s gi thuyt v nhng khi nim quan trng trong ngnh

khoa hc polyme: Polyme c to bi nhng phn t rt ln l nhng chui nhng n v ho hc n gin lin

kt vi nhau bng lin kt cng ho tr a ra khi nim i phn t m t polyme. Cc thc nghim nghin cu v phng php tng hp, tnh cht, cu trc ca polyoxymetylen

v polystyren cho mt cn c vng chc v quan im i phn t. Cc gi thuyt ca Staudinger c chng minh xa hn na bng nhng nghin cu tinh

th hc ca cc polyme t nhin Herman Mark, Kurt Meyer v cc cng trnh ca Wallace

Carothers v ch to polyamit v polysyren. u thp k 1930 hu ht cc nh khoa hc u b thuyt phc v cu trc i phn t ca polyme. Trong vng 20 nm sau, nhng cng trnh v polyme tng nhanh chng, S ra i tp ch Polymer

Science ng nhng cng trnh nghin cu khoa hc ca polyme v nhng khi nim c bn cangnh khoa hc polyme.Nhng l thuyt v thc nghim ca Paul Flory ni bt trong giai on ny,v ng nhn gii Nolben Ho hc 1974 v nhng ng gp lu di v quan trng ca ng tronglnh vc khoa hc polyme. Nm 1953 Staudinger nhn gii Nobel v nhng cng trnh nghin cutin phong trong lnh vc ny.

Mt lng ln nhng polyme tng hp c thng mi ho nh: polystyren, poly(metyl

metacrylat), nylon 6,6, PE, PVC, . Mt s lnh vc ng dng tin tin ca polyme:

Polyme chu nhit, chu oxy ha tt ng dng trong tu v tr Nha k thut thay th cho kim loi Polyme khng chy, gim ti thiu lng khi hoc hi c Polyme phn hu sinh hc Polyme ng dng trong sinh hc v d: ch t tiu, c quan ni tng nhn to Polyme dn in


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Polyme l g?

nh nghaCH

H

H

H

CH

H

C

H

H

H

H

CH

H

C

H

H

C

H

H

H

H

CH2H Hn

metan etan propan polyetylen

Polyme l hp cht cao phn t c cu to t rt nhiu nhm c cuto ho hc ging nhau lp i lp li v chng ni vi nhau bng lin kt ng

ho tr. Oligome polyme khi lng phn t thp (hp cht trung gian), chamang nhng c trng tnh cht nh polyme. S phn bit gia oligome vpolyme khng r rng, tuy nhin oligome khng c s thay i r rng vinhng tnh cht quan trng.

Monome l nhng phn t hu c n gin c cha lin kt kp (i hocba) hoc c t nht hai nhm chc hot ng c kh nng phn ng vi nhauto thnh polyme tham giaphn ng trng hp.


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Polyme l g?

Mt xch c bn (repeating unit or monomeric unit):

l nhng phn lp i lp li trong mch polyme.

C CH2 C

O

N

H

CH2

O

N

H4

6C CH2 C

O

N

H

CH2

O

N

H4

6

n

polystyren

Polyamit 6,6

C HH2C C HH2C C HH2C C HH2C

n


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Polyme l g?

Nhm cui (end groups) l nhm nguyn t c trng nm cui mch

polyme. Nhng oligome hot ng c cha nhm cui c kh nng tham giaphn ng trng hp thng c dng tng hp copolyme v polymekhng gian (v d: nha epoxy).

trng hp (P) (degree of polymerizaion) l s mt xch c bn trongphn t polyme

M = Mo.PTrong : Mo khi lng phn t ca mt xch c bnM khi lng phn t ca polyme

Nhng phn t polyme ca mt polyme khng c cng chiu di hay khi lngphn t khi nim: trng hp trung bnh


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Polyme l g?

Homopolyme l nhng polyme c to thnh t mt loi monome

Copolyme l polyme c to thnh t hai hay nhiu monome khcnhau. Rt nhiu polyme tng hp c gi tr thng mi, v du: ABS, cao suBuna-S,

S sp xp ca cc monome trn mch copolyme ph thuc vo

phng php v c ch tng hp. C th chia thnh cc loi sau (cc vd sau trong trng hp copolyme c cha 2 loi mt xch c bn khcnhau)


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Polyme l g?

Copolyme u n

Copolyme khi

Copolyme ngu nhin

Copolyme ghp


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Polyme l g?


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Polyme l g?


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Polyme l g?


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Polyme l g?


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Polyme l g?

Hnh dng phn t polyme

(a) mch thng

(b) mch nhnh

(c) mng li

(c) hnh sao

(d) hnh rng lc

(e) hnh thang

(e) hnh cy(dendrimers and hyperbranched polymer)


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Polyme l g?

Lin quan n s sp xp ca nguyn t v nhm th trong mch chnh

H2CCH

R

H2C CH HC

R

CH2

R

CH2 CH

R

HC CH2

R

n

H2CCH

R

H2C CH

R

CH2 CH

R

H2C CHn

R

u ni u

u ni ui

Nu xt v mt nhit ng hc v cu trc khng gian th cu trc uni ui chim a s, mc d a s polyme cha mt lng nh cu trcu ni u. Nu tng hp c hai dng cu trc u ni u v u ni uiring bit thi tnh cht ca 2 polyme khc nhau rt ln

V d: polyisobutylen (Malanga v Vogl 1983)cu trc u ni u c Tm = 1870Ccu trc u ni ui ch kt tinh di p sut v Tm = 50 oC


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Polyme l g?

ng phn quang hc: khi c nguyn t cacbon bt i trong mch polyme

H2C C

R

n

H

H2C C

R

CH2 C

R

H2C C

R

H H H

H2C C

R

H

H2C C

R

CH2 C

H

H2C CH

R

H R H

CH2 C

H

R

n

H2C C

R

H

H2C C

R

CH2 C

H

H2C CH

H

H R R

CH2 C

R

H

n

izotactic

syndiotatic

atatic


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Polyme l g?

Phn loi polymea) Phn loi theo phng php tng hp

+ Polyme t nhin+ Polyme trng hp+ Polyme trng ngng

b) Phn loi theo cu to ho hc+ Polyme mch cacbon+ Polyme d mch: trong mch chnh ngoi nguyn tcacbon cn c cc nguyn t khc nh O, N, S

H2C On

O CH 2 O C

O

CH 2 C

O

x y

n

C NH

O

CH2 NH C O

O

CH 2 Ox y

n

Si O

R

R

n

polyoxymetylen

polyeste

polyuretan

polysiloxan


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Polyme l g?

c) Phn loi theo tnh cht

polyme

elastomePolyme nhit do Polyme nhitrn

Tinh th V nh hnh

d) Phn loi theo lnh vc ng dng: cht do, lp ph bo v,sn, si, cao su, keo dn, polyme compozit,


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Polyme l g?

Cch gi tn polyme

Cch gi n gin nht tn polyme = poly + tn camonome

V d: etylen polyetylenVinylclorua polyvinyl clorua

Polyme i t dn xut th 1 ln ca etylen c cha gc

vinyl CH2 = CH - gi l polyme vinylic

CH 2 CH

OH

n

CH 2 CH

F

n

polyvinylalcol

polyvinyl florua


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Polyme l g?

Polyme i t dn xut nhm th 2 ln ca etylen c cha gc vinyliden

c tn gi: poly + vinyliden + tn nhm th

CH2 C

n

CH2 C

CN

n

polyvinyliden clorua

polyvinyliden xianua

CN

Cl

Cl

Polyme d mch: tip u ng poly ri n tn gi hp chtV d: polyeste, polyamit, polyuretan


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Polyme l g?


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Polyme l g?


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Polyme l g?


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Polyme l g?

2003Brooks/Cole,ad i

visionofThomsonLearning,Inc.ThomsonL

earning

isatradem

arkusedher e

inunderlicense.


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Polyme l g?


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Polyme l g?


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Polyme l g?


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Polyme l g?


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Polyme l g?


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Polyme l g?


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Polyme l g?


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Polyme l g?


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mm do ca polyme

i + 1i

S thay i hnh dng i phnt polyme mch cacbon khiquay quanh trc lin kt 2nguyn t i v i+1. ( - gcho tr, = 1800 - , - gcquay quanh trc lin kt)


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mm do ca polyme

Cis

Trans


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mm do ca polyme

E0

360

G0 G0

180

T T

Th

n

ng

S thay i nng lng ca 1,2-

dicloetan khi mt phn phn tquay so vi phn kia. Pha di lcc hnh chiu phn t ng vicc gc quay

Nng lng cn thit phn t

chuyn t mt v tr c th nngnh nht sang v tr c th nng lnnht gi l thm th nng quay ni

ti (E0).

V tr tng i ca cc nguyn t vnhm nguyn t trong phn t c th thayi c m khng c s ph v cc linkt ho hc, gi l hnh thi sp xp ca

phn t.


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mm do ca polymePhn t phi

ph v tm thilin kt

quay ri mikhi phc li khi

quay xong.

V tr tng i ca cc nguynt v nhm nguyn t trongphn t khng th thay ic nu khng ph v cclin kt ho hc, gi l hnh

thi cu to ca phn t.


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Cc yu t xc nh mm do ca i phn t:

- Khi lng phn t: v l thuyt th khi lng phn t (hay diphn t) khng nh hng n mm do ca mch v gi tr thmth nng khng ph thuc vo di mch m do cu trc quytnh. Nhng khi mch di hn th s lng hnh thi sp xp tng lndo cch mch phn t cng vn cun li c m khng dngthng.

- Mt mng khng gian: s tng tc mnh gia cc phn t s

lm gim linh ng ca cc on nh ta thy trng hp cclin kt hydro trong polyamit. Cc lin kt ha hc bn vng gia cci phn t cn nh hng mnh hn n linh ng ca ccon.

- Kch thc nhm th: cc nhm th c kch thc v trng lng

ln mch nhnh ca phn t polyme lm cn tr s quay ca mtxch

- Nhit : c tc dng lm tng linh ng ng hc ca cc ontrong mch polyme


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Hin tng hi phc ca polyme

2

1

Thi gian

ng

sut,

0

Hi phc ng sut

=constant

0

=constant

ng cong hi phc ng sut

1. Polyme mch thng

2. Polyme mch khng gian

Nu ko nhanh mt mu polyme v nh hnh mch thng n mt di no th ng sut c hc cn thit gi cho di ny khng i s gim dntheo thi gian.


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Hin tng ng sut trong mu gim l do nguyn nhn sau: khi mu b konhanh, cu trc ca n khng kp thay i v cc i phn t khng th ngay

lp tc dui thng ra, cng khng th chuyn ng tng i vi nhau.V vy s ko dn xy ra khng nhng do cc i phn t hoc cc b duira, m cn do bin dng cc gc ho tr hoc thay i khong cch gia ccnguyn t trong phn t, ngha l theo kiu bin dng ca cc vt rn thpphn t. S thay i ny i hi lc tc dng rt ln, ln hn nhiu so vilc cn thit ko dui i phn t ra.

Polyme b ko cng nhanh th cc on i phn t cng khng kp duithng hoc sp xp li, v ng sut trong mu cng mt dn di scng cao. Ta bit rng moun n hi , do tc bin dng cngln th mun n hi cng ln. Ni cch khc, khi tc ko mu tng lnth mu c v nh cng hn.

d

dM =

Hi t hi h l


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trng thi ko cng, di tc dng ca chuyn ng nhit, trong mu dndn xy ra s sp xp li cc on. y l qu trnh t pht trin a mu

n mt trng thi cn bng mi ph hp vi iu kin bn ngoi. S spxp li cc on trc ht dn dn khi phc li cc khong cch nguyn tv cc i lng gc ho tr ban u. iu ny xy ra c l do s chuynt t qua v s hnh thi sp xp, t cun cht n dui dn ra, ca cc iphn t v cc b phn t. S bin dng cc lin kt (yu t nng lng)c thay th dn bi s sp xp li ca cc n v ng hc, mt hnh

dng mi ca i phn t (yu t entropi). Qu trnh ny lm gim mnh lcgi mu dn di cho trc. Khi thi gian tc dng ca ng sut ln,do s cn tr ca lc ko ngy cng gim, chuyn ng nhit (yu tentropi) bt u dn dn cun cc phn t dui thng li. Qu trnh cunphn t li km theo s trt ca chng vi nhau, ngha l cc phn t btu dch chuyn khng thun nghch. y chnh l bin dng chy. Kt qu

l ng sut cn thit duy tr dn di ban u tip tc gim xung. Huqu ca tt c s sp xp li cu trc polyme k trn l hnh dng mu thayi (khng thun nghch) ph hp vi dn di cho.


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Hi t hi h l


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Trng thi mm cao


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Trng thi mm cao

ng thc quan trng ny cho thy nguyn nhn chng li lc gy bindng n hi l s thay i ni nng v entropi ca vt th bin dng. T

rt ra kh nng c hai loi n hi - mt loi ch lin quan n s thay i ninng khi bin dng, loi khc ch lin quan vi s thay i entropi.

V d ca loi th nht l s n hi ca tinh th l tng, khi

Trong trng hp ny ton b cng ca lc ngoi c tiu th thayi ni nng ca vt bin dng bng cch thay i nng lng tng tc giacc phn t v nguyn t (thay i gc ho tr v khong cch gia ccnguyn t).

V d ca loi th hai l n hi ca cc kh l tng. Ta bit rng ninng ca cht kh l tng khng ph thuc vo th tch ca n, tc l

0=

Tl

S

Tl

UF

=

0=

Tl

U

Tl

STF

=


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Trng thi mm cao


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Trng thi mm cao

S = klnW(k- hng s Bolzmann)

Khi ngng ko, mu s t ng co li, ngha l tr v hnh thi sp xp vixc sut cao nht. Khi entropi s tng ln.

Bin dng mm cao ca cao su thc t:

Bin dng mm cao ca cao su thc t phc tp hn so vi cao su l tng

do cc nguyn nhn sau.

Bin dng ca cao su thc t lun lun c s thay i th tch (V const).iu ny c ngha l khong cch gia cc phn t trong h thng (mch,segment v.v) cng thay i dn n ni nng thay i. c bit khi gi trbin dng kh ln, cao su t nhin v mt s cao su tng hp c th kttinh, do thay i ni nng cn bao gm c nhit to ra khi kt tinh.


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Trng thi thy tinh


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Trng thi thy tinh

Khi nhit thp s sp xp li cc phn t cht lng s khng xy ra,trt t gn ca cc ht cht lng cng khng thay i. Khi s xy ra s ngkt cht lng - s ho thu tinh (tt nhin nu nh khi lm lnh khng xy ra skt tinh do xut hin cc trt t sp xp xa). Nu tip tc lm lnh, cc cu trcca cht lng ho thu tinh cng khng th thay i theo nhit c, dtc lm lnh rt nh. S ho thu tinh s d hnh dung hn nu gi thit ltrong qu trnh ny xut hin cc lin kt phn t c nh no loi trchuyn ng nhit ca cc phn t (v d s to thnh lin kt hydro trong chtlng).

Cc c im chuyn ng nhit ca i phn t c nh hng r rt nquy lut thu tinh ho polyme. i vi cht thp phn t, ch cn c nh mtim bt k ca phn t l n mt kh nng chuyn ng nhit v

chuyn sang trng thi thu tinh. Nhng i vi cht cao phn t, c nh 1im khng lm mt linh ng ca phn t. Mun lm mt linh ngca i phn t cn phi c nh tt c cc on ca n.

Trng thi thy tinh


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Trng thi thy tinh

Nh vy mun polyme chuyn sang trng thi thu tinh cn c mc khu mch bi cc lin kt phn t ln v khong cch gia cc nt trongmng khng gian bng hoc nh hn di ca on. di ca on cngln th s lng lin kt cn ho thu tinh cng nh. Ngc li, ho thutinh mt h thng c i phn t rt mm do cn c s lng lin kt rt ln,iu ny ch thc hin c nhit thp. S xut hin mng lin kt giacc phn t rt c trng cho cc polyme c cc nhm chc phn cc (OH,Cl, CN v.v...) trong mch phn t hoc mch nhnh. Cc polyme ny ngay

nhit thng cng nm trong trng thi thy tinh.c im ca polyme trng thi thu tinh

Khi mt h thng i phn t ng c li thnh th thu tinh th trong khng ch c ton cc phn t polyme kt b cht ch. l v s ho thu

tinh chnh l s c nh cc v tr sp xp tng h ngu nhin ca i phn tc trng cho trng thi mm cao. Mc d th tch ring ca polyme thu tinhnh hn ca polyme mm cao, n vn ln hn nhiu so vi gi tr tnh toncho cc mch phn t kt b cht ch hoc cho cc thu tinh thp phn t.Nh vy thu tinh polyme c c trng bi mt " xp" no .


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Trng thi thy tinh


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Trng thi thy tinh

Nguyn nhn s gim ng sut thi im hnh thnh "c eo" v bt u bin dngmm cao bt buc nh sau: polyme thu tinh khng phi h thng cn bng. Trong hthng ny bt c nhit T no cng tn ti nhng ng sut ni. Cc ng sut ny

khng hi phc c do nht ca h qu ln v linh ng nh ca cc phn tb "ng bng". Nhng ch cn s dch chuyn di tc dng ca ngoi lc bt u(khi bin dng mm cao bt buc xut hin), cc ng sut ni s thc y s dchchuyn ca cc on nhanh hn, gp phn vo vic sp xp li cu trc.Gi tr ng sut cc i ti xut hin bin dng mm cao bt buc c gi l gii

hn mm cao bt buc, k hiu b.

b

Tb T

Khong nhit Tg - Tb ca polyme thu tinh c nghathc t to ln v trong khong ny polyme khng th hintnh gin. Trn thc t, khong nhit ny dao ng t 0n 1000C hoc hn na. Cc i phn t mm do khiho thu tinh nhit thp s to ra thu tinh cht chvi s lng ln cc lin kt gia phn t kh bn vng.Cc thu tinh nh vy c khong nhit Tg - Tb nh.

Chng hn cc loi cao su b ph hu gin lin sau khinhit h xung di Tg. Cc thu tinh kt b xp vicc i phn t cng v c kh nng bin dng mm caobt buc ln to ra mt nhm ring vi khong Tg - Tbln, v d PVC (Tg - Tb =170K), PMMA (Tg - Tb =100K).

Trng thi chy nht


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g t c y t

S chy, l s pht trin cc bin dng do khng thun nghch, cn khoahc nghin cu s chy v cc bin dng trong gi l lu bin hc(rheology). Mt trong nhng nh lut u tin ca s chy l nh lut Niutn

(Newton, th k 17). Theo nh lut ny, nu tc ng ln cht lng mt ngsut khng i th cht lng s chy vi mt vn tc khng i, ilng vn tc chy c xc nh bi hng s gi l nht

t

dt

d

dz

dvt

==

dz

dvgradient vn tc, tng ng vi tc bindng dtd

Trng thi chy nht


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g y

ng cong chy trong to bnh thng(a) v to logarit (b)1. Cht lng Niutn; 2. Cht lng nht d thng (vt do biukin)

3. H thng dilactan; 4. Vt th do (vt th Bingham).


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Trng thi chy nht


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g y

c im u tin ca polyme nng chy l chng c nht cao. V dpolyizobutylen (khi lng phn t khong 106) 150C c nht

~3.1011 Pa.s (3.1012 p); nhit ln hn Tm nht c th gim 1-2 bc,nhng vn ln n mc polyme vn bo ton hnh dng ca n lu v thihn nu khng c lc ngoi tc dng. so snh, ta c nht ca thu tinhthp phn t l ~1012 Pa.s. Gi tr nht cao nh vy ca polyme nng chyl kt qu ca cu trc mch di ca chng; ngc li, cng l mt bng

chng v cu trc nh vy.

c im th hai ca polyme nng chy l s chy thc lun lun b chekhut bi cc qu trnh bin dng mm cao km theo n. Khi xt cc c tnhbin dng ca polyme v nh hnh mch thng, nh bit vo bt k thi

im no bin dng ca chng cng c to thnh bi 3 thnh phn:n hi, mm cao v chy nht. (xem cc hin tng hi phc).

Trng thi chy nht


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g y

c im th ba l s tng nht ca polyme nng chy trong qu trnhchy ca n. c im ny gn lin vi c im th hai. S pht trin bin

dng mm cao trong qu trnh chy polyme c nh hng r rt n khnng chy ca n. V bin dng mm cao lin quan vi s dui thng mchphn t nn trong qu trnh chy cc phn t s dui di theo hng chycho n khi xc lp c cc gi tr cn bng ca hnh thi sp xp duithng. S dui thng ca cc i phn t v s dch chuyn ca chng trong

trng thi ny dng nh tng ng vi s tng nht ca h thng viu lm s thay i hnh thi sp xp kh khn hn (h thng cc phnt dui thng lun lun c nht cao hn cc phn t cun li). S tng nht ca polyme nng chy trong cc iu kin ng nhit l c trng ringch polyme mi c (nu nh trong qu trnh chy khng xy ra qu trnh to

cu trc no). c im ny l c s ca kh nng to mng v to si capolyme nng chy trong cc iu kin ng nhit.

Trng thi chy nht


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g y

c im th t - l c ch chy c bit ca polyme, khc vi cc cht lngthp phn t. Khi tc ng lc ln mt cht lng thng thng, cc phn t cht lngvn ang chuyn ng nhit hn lon, bt u chuyn ng ch yu theo hng tc

dng lc. S chuyn ng ny b cn tr bi lc tng tc gia cc phn t, lc mast ni, tc l nht ca cht lng. Khi phn t "nhy" t m ny sang m khc, nbuc phi tiu th mt nng lng vt qua s tng tc vi cc phn t ln cnc. S chuyn ng nh vy ca phn t c th xt nh mt qu trnh bay hi: phnt chuyn t trng thi ngng t thnh hi v sau li ngng t li. Nu vic xem xtnh vy l hp l th phi c mi lin h gia nhit ho hi v nng lng hot ho

chy nht.c im th nm ca s chy polyme l n lun lun km theo cc qu trnh c

ho. di ln hn ca i phn t v nht ca polyme nng chy ( nht c thcn tng hn na trong qu trnh chy) i hi phi c nhit cao v ng sut ln gy nn s chy. V vy, ti mt nhit chy cho trc lun lun c th c mt thiim m nng lng c hc t vo h thng cao ph v lin kt ha hctrong polyme. Qu trnh ph hu phn t nh vy (cn gi l cracking c - ho) s gynn s gim khi lng phn t, d tm thi v cc mnh gy c th li phn ng vinhau theo c ch ti hp hoc ghp nu chng l cc gc. Do cc qu trnh c ho, nht s gim i v s chy c thc y nhanh hn.

Ha do polyme


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Ha do polyme


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Polyme ha do l mt dng dung dch polyme m c. Vic a vopolyme mt lng khng ln (ti 30%) cc cht lng thp phn t c sicao (gi l cht ho do) l mt trong nhng phng php quan trng nht bin tnh cu trc vt liu polyme. Trn thc t vic ho do lm tng nhi ca vt liu, tng chu lnh v lm qu trnh gia cng n d dng hn.V mt l thuyt, bn cht ca ho do l thay i nht ca h thng, tng mm do ca i phn t v tng linh ng ca cc cu trc ngoi viphn t.

Khi xy ra qu trnh do ho, cc phn t tng i nh ca cht ho dothm nhp vo polyme, tch cc i phn t polyme ra, ph v cc cu trcngoi vi phn t, bao bc cc i phn t bng mt lp n phn t, che chncc nhm c cc. Nu cht ho do khng tch cc i phn t ra khinhau th cc cu trc ngoi vi phn t c th khng b ph v nhng linhng ca chng s tng ln v nh hng n tnh cht polyme. Loi do ho

ny c th xy ra c khi i lc gia polyme v cht ho do rt thp: cc phnt cht ho do khng th ph v cc cu trc ngoi vi phn t m ch chenvo gia chng trn mt phng phn cch, dng nh ch thm t v bitrn chng, tng linh ng ca cc cu trc ny ln. Loi do ho ny cgi l do ho gia cc cu trc (gia cc b).


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Ha do polyme


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Cn lu rng cn nhiu iu cha r trong c ch ho do. V d khi nghincu cc h thng gm polyme v cht ho do u phn cc, ngi ta xc

nh c rng s gim nhit thu tinh ca polyme t l thun vi phn molcht ho do c s dng (quy tc phn mol)

Trong : k - hng s; n - phn mol ca cht ho do

Vai tr ca cht ho do l ch khi tng tc vi cc nhm c cc ca polymev dng nh che chn chng, cht ho do lm yu tng tc gia cc phnt v gim Tg. Do mi nhm phn cc trong i phn t ch kt hp c vimt phn t cht ho do, s lng cc nhm b che chn trong i phn t s

trng vi s lng phn t cht ho do. Chnh v vy, s gim Tg c xcnh ch bi s lng cc phn t cht ho do, v - mt cch gn ng - khngph thuc vo hnh dng v kch thc ca chng.

nkTg .=


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Tnh cht c hc ca polyme


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ng sutF: Lc tc dng, N

S: Tit din ngangSFk =

bh

FL

u 2

3

=

F: Lc tc dng, N

L: Khong cch gia hai gi , mm

b: Chiu rng ca mu, mm

h: Chiu dy ca mu, mm

S

Fn =

F: Lc tc dng, N

S: Tit din ngang

ng sut l ti trng tvo mt n v thitdin mu. Ty vo dngtc ng m xc nhng sut l ko, nn

hoc un c o bngPa hay MPa

Tnh cht c hc ca polyme


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Bin dng tng i

lt: di thi im t

l0: di thi im ban u00,

0

0

lllt =

Modun n hi

d

dE =

Ty vo dng ng sut (ko, trt,..) m c modun n hi ko hocmodun n hi trt. Thng thng phi ch r E c xc nh gi trbin dng no. Nu khng ta hiu l E c xc nh trong vng bin

dng n hi Hook

Cu hi n tp


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1. Polyme l g? Polyme khc hp cht thp phn t nh th no? Th nol monome, oligome.

2. Th no l trng hp, nhm cui v mt xch c bn?

3. C my loi copolime? Cho v d minh ha.

4. Hnh thi sp xp khc hnh thi cu to nh th no?

5. C my cch phn loi polyme? Cho v d minh ha.

6. Phn ng trng hp khc g vi phn ng trng ngng? Cho v d minhha.

7. c im c trng ca polyme m cc hp cht thp phn t khng c?

8. mm do ca polyme l gi? Cc yu t nh hng n mm doca polyme?

9. Hy gii thch ti sao giai on u ca hin tng hi phc ng sut thcc gc ha tr v di lin kt li b thay i?

Cu hi n tp


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10.Trong hin tng hi phc ng sut, hy gii thch ti sao cc phn tpolyme trong qu trnh trt ln nhau th chng li cun trn li?

11.Trong trng thi mm cao, ti sao khi tc dng lc ln cc phn t polymelm chng dui thng ra th li lm cho entropi gim xung?

12.Hin tng chy ngui trong polyme thy tinh l g?

13.Ti sao khi hiu s Tg Tb gim xung th polyme cng mm do?

14.Ch s chy l g? Lm th no xc nh c ch s chy?

15.c im ca polyme chy nht l gi?

16.Trnh by c ch ha do polyme?

17.Ti sao khi cho cht ha do vo th nhit ha thy tinh ca polymegim xung?

18.Modun n hi c trng cho tnh cht g ca vt liu?

19.Polyme blend l gi?

20. bn mi tnh (creep) khc vi bn mi ng (fatigue) nh th no?

Slide Hóa Lý Polyme TS. Nguyễn Huy Tùng- PLM Center - Hanoi University of Technology

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Transcript of Slide Hóa Lý Polyme TS. Nguyễn Huy Tùng- PLM Center - Hanoi University of Technology