bg polyme ch3 chain conformation

Tran Hai Ninh - Polymer Center- HUTS *Chng 3: Tnh mm do ca mch polyme (Polymer Chain Flexibility)Nguyn nhn chnh lm cho mch polyme mm do: kch thc khng cn i ca mch polyme kh nng quay quanh trc cc lin kt to thnh mch chnh ca polyme

Tran Hai Ninh - Polymer Center- HUTS

Tran Hai Ninh - Polymer Center- HUTS *Chiu di ca mch polyme Polyethylene (PE)Nu n = 10,000 th chiu di mch phn t PE khi dui thng l bao nhiu?(zigzag planar)


*3.1. S quay ni ti trong phn t3.1.1. Hin tng quay ca phn t thpetan CH3 CH3 HC

Tran Hai Ninh - Polymer Center- HUTS *S ph thuc th nng phn t etan vo gc quay nhm metyl


Tran Hai Ninh - Polymer Center- HUTS *n-butan CH3 CH2 CH2 CH3


Tran Hai Ninh - Polymer Center- HUTS *Trng thi nng lng caoTrng thi nng lng thp(quan st dc theo trc C2-C3)


Tran Hai Ninh - Polymer Center- HUTS *EoEEo - Thm th nng quay (thm th nng hot ha)Eoetan = 15 kJ.mol-1Eetan = 2,1 kJ.mol-1


Tran Hai Ninh - Polymer Center- HUTS *3.1.2. Hin tng quay ni ti trong phn t polymeXt mt mch polyme c lp (isolated polyme chain), cc nguyn t C ch lin kt vi nhau bng lin kt n (lin kt )Alkan CnH2n+2 n 1 lin kt (lin kt n)C bao nhiu hnh thi sp xp ca mch phn t alkan?3n-3


Tran Hai Ninh - Polymer Center- HUTS *Trong thc t, s quay ni ti ca phn t polyme b cn tr do: Lc tc dng gia cc phn t (intramolecular interation): lc lin kt hydro, lc Vandevan, lc phn tc, lc nh hng Lc tc dng gia cc nguyn t (intermolecular interation) trong cng mt mch (lc ni phn t): Tc dng tng h khong cch gn gia cc nguyn t ca cc mt xch ln cn cn tr quay t do. Tc dng tng h khong cch xa l lc tc dng tng h gia cc nguyn t hoc nhm nguyn t ca cc mt xch cch xa nhau.


Tran Hai Ninh - Polymer Center- HUTS *


Tran Hai Ninh - Polymer Center- HUTS *3.1.3. mm nhit ng v mm ng hc E c trng cho mm nhit ng (thermodynamic flexibility) ca polyme khi c cn bng nhit ng. mm nhit ng cho bit kh nng bin i hnh thi sp xp ca mch v kh nng xy ra s thay i . gc quay (angle of rotation)


Tran Hai Ninh - Polymer Center- HUTS * mm ca mch c xc nh bng i lng Eo gi l mm ng hc (kinetic flexibility). Eo: (thm th nng quay potential rotation barrier or hindrance potential) nh hng n vn tc bin i hnh thi sp xp. Eo cng ln th cc mt xch quay cng chm v tnh mm do ca mch cng b.E: Nng lng tc ng t bn ngoi (chuyn ng nhit, lc c hc hoc cc lc khc)


Tran Hai Ninh - Polymer Center- HUTS * mm do ng hc v mm do nhit ng c th khng trng nhau.Khi mm nhit ng ln (E nh) nhng vn tc quay ca cc mt xch c th b (Eo ln) th mch vn c th cng S quay quanh cc lin kt v thay i hnh thi sp xp (t v tr c nng lng cc tiu ny n mt v tr c nng lng cc tiu khc) ch c th xy ra khi c nng lng d tr cn thit.


Tran Hai Ninh - Polymer Center- HUTS * Nu khng c nng lng d tr cn thit (ln hn Eo) th cc mt xch ch c th chuyn ng nhit c trng ring (v d: dao ng xung quanh cc v tr c nng lng cc tiu). Dao ng ny cng nh th mch phn t cng cng.


Tran Hai Ninh - Polymer Center- HUTS * phn cc ca phn t Phn t khng phn cc Phn t phn cc


Tran Hai Ninh - Polymer Center- HUTS *3.1.4. Cc yu t nh hng n tnh mm do ca mch Thm th nng quay Khi lng phn t Kch thc mch nhnh Mt mng li khng gian Nhit


Tran Hai Ninh - Polymer Center- HUTS * Thm th nng quay Eo Thm th nng quay ph thuc vo lc tc dng tng h bn trong phn t v gia cc phn t v do ph thuc vo phn cc ca cc nhm th.(cc gi tr c tnh khi hp cht trng thi kh l tng)

Eo (kcal/mol)H3C CH32,80H3C C2H53,40H3C CH(CH3)23,90H3C C(CH3)34,40H3C CH=CH21,95

Eo (kcal/mol)H3C CF33,700,45H3C OH1,07H3C SH1,06H3C NH21,90H3C SiH31,70F3C CF34,35


Tran Hai Ninh - Polymer Center- HUTS * Mch polyme c thm th nng quay thp th c mm do cao Polyme mch hydrocacbon: PE, PP, Polyisobutylen, Polybutadien, Polyisopren Polyme d mch c cha cc nhm C O C, - CO O , - NH COO v c phn tch bi s lng lng ln nhm CH2 Mch polyme c cha nhm th phn cc vi hm lng thp (v d cao su polyclopren v cao su nitril) Mch polyme c cha nhm th kch thc nh ( - CH3) hoc thm ch ln hn nhng sp xp tha tht trn mch chnh. (v d polyisobutylen, poly(butadien co- styren)


Tran Hai Ninh - Polymer Center- HUTS *b. Khi lng phn t Khi lng phn t ca mch tng khng lm thay i Eo , nhng kh nng bin i hnh thi sp xp tng ln.c. Mt mng li khng gian Khi s lng lin kt ngang tng ln th di mch trn th hin s mm do s gim xung. Khi mt lin kt ngang rt ln th mm do s bin mt hon ton.V d cao su thin nhin lu ho vi 30% lu hunh


Tran Hai Ninh - Polymer Center- HUTS *d. Kch thc nhm th Kch thc ln ca nhm th lm cn tr s quay ca mt xchPolystyren


Tran Hai Ninh - Polymer Center- HUTS *d. Nhit Khi nhit tng th mm do ca mch polyme tng ln nh tng mm ng hc.


Tran Hai Ninh - Polymer Center- HUTS *Monte Carlo Simulation


Tran Hai Ninh - Polymer Center- HUTS *


bg polyme ch3 chain conformation

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