Nghiên cứu tương tác PANi/EGCG trong quá trình Polyme hóa điện hóa. Phần 3: Tương tác EGCG/PANi

TAP CHI HOA HQC T. 52(1) 1-7 THANG 2 NAM 2014

NGHIEN CU'U TU'aNG TAG PANi/EGCG

TRONG QUA TRJNH POLYME HOA DIEN HOA

3 - TLraNG TAC EGCG/PANI

Mai Thanh Nga'*, Mai Tuyen^ Le Xuan Qul^

Truong Dai hoc Supham Thdi Nguyen

Vien Hoa hoc Cong nghiep Viet Nam

^Vien Ky thuat nhiet dai, Vien Han lam Khoa hoc va Cong nghe Viet Nam

Din Toa soan 20-9-2012

Abstract

This paper presents the third part - the interaction EGCG/PANi which was studied using CV technique durmg

PANi electrochemical synthesis at different EGCG concentration m the electrolyte. The correlations between the

couples Jpa-c, Epa-c, Qg-c were observed modified. The kinetics in the propagation of the electrochemical

polymerization was studied through different reaction rates, such as Vjpa = AJpa/Ac, VQa = AQo/Ac, especially V(E,C|

=A(AJ/AE)/Ac. The reaction rates depend simultaneously on two parameters such as E-CV polanzation potential and c

- number of CV polarization cycles, and has been mostly slowed due to the EGCG adding. EGCG decreased the

porosity of the synthesized PANi, which is formed m small plates or thm disks, evidently different from well known

form of about 300 nm fibers in the case without EGCG. The study also contributed to confirm the signification of the

derivation for the investigation of PANi electrochemical synthesis which was presented previously in the first part.

Keywords: PANi, EGCG, electrochemical polymerization, propagation, CV, synthesis kinetics.

1. GIOI THIEU

Ket qua nghien cuu tuang tac EGCG va PANi

da dupc gio-i thieu mot phin [1, 2]. Cac thong s6 hoa

ly ciia qua ttinh polyme hoa dien hoa ANi dugc xac

djnh chinh xac tir vi phan duo-ng cong phan cue CV

D=AJ/AE, trong do gia trj D^ia, la van toe oxi hoa

cue dai PANi da dugc tong hpp tren dien circ [I].

Day la lin dau tien thong s6 Dnmi dupc sir dung

trong nghien ciiu qua trinh polyme hoa dien hoa ANi

va nghien cuu tac dpng ciia EGCG den khoi mao

polyme hoa dien hoa ANi trong dung dich axit

sunfuric.

Trong giai doan khai mao polyme hoa dien hoa

ANi, sir CO mat ciia EGCG ban diu (khoang 10 chu

ki CV diu) lam giam tic do polyme hoa ANi a

ning dg 5 g/l va gia tang polyme hoa a nong dp 1-3

g/l nhung a ! 0 chu ki CV tiip theo thi chii yeu iam

giam toe dp polyme hoa do tnet tieu kha nang ty xuc

tac ciia qua trinh ting hap dien hoa PANi. Ca chl

tac dgng chii yeu ciia EGCG la hap phu len cac trung

tSm ho^t hoa ciia di?n circ va ciia san pham PANi

trfin be m$t di?n c\rc, lam rao chin ngan can polyme

hoa ANi. Tuy nhien, su hip phu nay cua EGCG hau

nhu khong c6 tac dgng manh din qua trinh oxi hoa

PANi, chuyen tir trang thai khong din dien sang dan

di?n [2]. Bang phirong phap phan eye va do tong tro

di?n h6a da xac djnh dugc sir hip phy EGCG vai

cac nhom OH hoat hoa, tren dien eye thep tao nen

mang xop do phan tOr lan va cong kenh [3-5]. Trong

viing phan cue anot sy hap phu co yeu to tTnh dien

vai tuang tac ciia nhom OH phan ciic, co the dan

den oxi hoa va polyme hoa [3, 6, 7]. Qua trinh oxi

hoa phenol rat phirc tap, c6 the tao thanh quinol, a

muc cao co the ma vong benzen tao thanh cac hgp

chat aliphatic [6, 7].

Tren dien eye bien tinh co PANi, eac trung tam

hoat hoa axit ciia polyme dan tham gia true tiep vao

qua trinh ehuyen dien tich vai nhom OH hoat tinh

[14], truac het la hap phii vai lien ket hoa hgc va

tmh dien [2] roi ehuyen dien tieh tao goe (radical)

hay ion moi, theo sa do phan ung (hinh 1) vai nhom

OH ciia hydroquinon [14].

=N- + HO-C6H4-OH = -N^H'+'O-C6H4-OH (1)

0 Hinh 1: Sa do hap phy va chuyen di?n tich a

trung tam hogt hoa axit (N) tren mach PANi cua

nhom OH hoat tinh