Journal of the Korean Chemical Society 6, Vol. 5, No. 6 Printed in the Republic of Korea w Polyacrylamide y ½ û * w yw (6. 9. 1 Thixotropic Properties of Polyacrylamide Hydrogels with Various Synthetic Conditions Nam Jeong Kim* Department of Chemistry, Sahmyook University, Seoul 139-74, Korea (Received September 1, 6. Polyacrylamide y w y w. cone-plate k w polyacrylamide y m š. š w m w qk w. polyacrylamide y ƒ ƒw ƒ w x ùkü. p y w ùkù. :, m,, Polyacrylamide y ABSTRACT. Influences of synthetic conditions and water content on rheological properties of polyacrylamide hydrogels were studied. The non-newtonian flow curves of polyacrylamide hydrogels were obtained by using a cone-plate rheometer. The rheological parameters were obtained by applying non-newtonian equation to the flow curves for polyacrylamide hydrogels. The polyacrylamide hydrogels are shear thinning under increasing shear rate modes which result in thixotropic behavior. These flow properties are controlled by the characteristics of flow units and the interaction among the flow segments. Keywords: Rheological Properties, Non-newtonian Flow Equation, Thixotropy, Polyacrylamide Hydrogels š y w q 3 w š w xk w. š y,, ph y y q vƒ j ƒw p yw ƒ w. Omari 1 polyacrylamide y j j» p Ÿw, w w j w Ÿ w dwš šl w. Li acrylamide œw ƒ y ƒw y w d šw. Grattoni 3 polyacrylamide y w p n w. t j w w w t y w. 4-6 Tanaka7-9 polyacrylamide y y y y x w. š y w 447
448 ½ û w w w. 1-1 Komarskii 13 polyacrylamide y w p š 3 w w w. š w w wš š w p. š m p dilatancyù thixotropy w dilatancyù thixotropy w p š. 14 Ree-Eyring w Bang 15 dilatant w wš, - r w shear dilatancyl thixotropy y ù, w x w šw. m x shear rateƒ ƒw ƒ x ƒ ƒ dilatancy x ƒ Á ƒ w thixotropyx ù, g x w ùkü. x shear rate ƒ thixotropy w x ³w. thixotropyx16-17 rp, yt, j, v p ùkù shear thinningx. thixotropyx w k w š k k š x ƒ ƒš. yy ³ w k y l thixotropy w e w thixotropy wš ww y x w w. ƒ w ww polyacrylamide y w p m w w. ƒ ƒw thixotropyx ùkü thixotropy w w parameter wš w w parameterl w š k 3 ³w. thixotropy š w parameter thixotropy w. m Eyring S = ---- λ λ 1.», k i' flow unit i group w w unit flow process w š, α i =(λ λ 3 i/ kt. w, λ 1,λ,λ 3 λ w parameter, parameter i i group flow unit w w. i group w flow unit w X i f i, f (1 ( ùkü,» X i i group mole fraction., ( w (1 l w f N w,. (3», β i=1/{(λ/λ 1 ik i', N group y w. m (3. N i k i sinh( α i f i N f = X f i i X i i = 1 f ----- sinh = 1 ( β i S i = 1 α 1 N X i β i S f ----------- sinh 1 ( β i S = ------------------------- α i β i S i = 1 (4 (4 w(sinh 1 X/X. lim βi ( β i S sinh 1 β i S ------------------------- = 1 (5 p w β i S «1 w flow unit 1 Newtonian flow unit w w. Newtonian flow unit f 1 Journal of the Korean Chemical Society
w Polyacrylamide y 449. X 1 β 1 f = ---------- S (6 m ƒ ƒw ü yƒ w ƒ. w yƒ ù, shear w (work ww. y w vw strain energy W ùkü, strain energy.», G spring constantš, S y ƒ ù molecular displacement, S= γs /k f' tx, γ. S w w ww molecular granular displacementƒ w ƒl. Strain energy activation free energy w disentanglement( D e entanglement ( E e y. D E y w flow process e flow unit w, flow activation free energy x»w strain energy(c S j ƒw. flow unit w k ' ùkü», k constraintƒ x flow unit w. w free energy diagram jumping process w ƒ activation energyƒ constraint x w C S j ƒ. y β α 1 S S ( γs W = fds = GSdS = G----------- = CS k f kt k -----exp + C S G ------------------------- k exp C S = = ------------- h RT RT β ( β exp C S = ---------- RT (7 (8 (9 ƒ š», 1 ( β -- λ 1 ---- 1 1 --- -- λ 1 ---- h G = = ----- --------- λ λ kt exp RT k (1. flow unit w (3, D E y w f ùkü. thixotropy š w. X f ----- sinh 1 ( β S exp C S = ---------- RT α (11 x polyacrylamide w x w acrylamide(yacuri, CH :CHCONH, 98%, N,N'-methylenebis-acrylamide (ACROS ORGANICS, C 7H 16N O, 96% benzoyl peroxide(fluka, C 14H 1O 4, mp 13~15 o C, 97% w. ƒƒ fourneck flask(5 ml wì. k» w š paraflim 'M' w. four neck wù, wù PROMIX PR-6(SIBATA, wù f wš ù w z p ƒw ww. w x w polyacrylamide y v y viscometer(bohlin VISCO 88BV w k dw vp BOHLIN Reology AB(version 3. w. spindle speed switch 8, measuring system 1 w w. w w BROOKFIELD TC-5 w. š x x j w, k d, ql w, š ql w ù. w heating mantle w 5 four neck flask 1 ml acrylamide 1 g, N,N'-methylenebisacrylamide.6% (acrylamide w wt%, benzoyl peroxide.1~1% (acrylamide w wt% ygƒ š heating mantle 1 o C ƒw PROMIX 6, Vol. 5, No. 6
45 ½ û PR-6 35 rpm w ww polyacrylamide y w. polyacrylamide ƒ w w, y.,, benzoyl peroxide, š N,N'-methylenebisacrylamide ww. p polyacrylamide w z methanol w z g š.1 g w w. benzoyl peroxide N,N'-methylenebisacrylamide w w polyacrylamide y w,, š. w k dw» w BOHLIN Rheology AB(version 3.v BOHLIN VISCO 88BV viscometer f 1 ml w š g w š. Fig. 1. The second flow curves of polyacrylamide hydrogel for the various concentration of benzoyl peroxide initiators and.5% bisacrylamide at 5 o C. š Thixotropy š BOHLIN VISCO 88BV rheometerl š w x ƒ ƒw w up-curve ƒ w w down-curve ùkú ù w up-curve ùkü. ƒ w š, ƒ j ù š ùkþ. Fig. 1 benzoyl peroxide initiators.5% bisacrylamide ww polyacrylamide y š thixotropyx š x ùkû. bpo ƒ.3% ƒ j w x ù xš networkš w ƒ j w. w w w š. Fig. benzoyl peroxide initiators.6% bisacrylamide ww polyacrylamide y š Fig.. The second flow curves of polyacrylamide hydrogel for the various concentration of benzoyl peroxide initiators and.6% bisacrylamide at 5 o C. 1% bpo ƒ j.3% bpo û š. Fig. 3 benzoyl peroxide initiators.7% bisacrylamide ww polyacrylamide y š thixotropyx.3% bpo ƒ j thixotropy ùküš dilatancy pw x. polyacrylamide w bpo bisacrylamide w ƒ ƒ, xw d ƒ ƒw š w ƒ x f š ƒ Journal of the Korean Chemical Society
w Polyacrylamide y 451 Fig. 3. The second flow curves of polyacrylamide hydrogel for the various concentration of benzoyl peroxide initiators and.7% bisacrylamide at 5 o C. Fig. 5. The flow curves for the various concentration of polyacrylamide hydrogel for the.3% benzoyl peroxide initiators and.5% bisacrylamide at 5 o C. Fig. 4. The flow curves of polyacrylamide hydrogel for the.3% benzoyl peroxide initiators and.5% bisacrylamide at various temperatures. k y ww bisacrylamide bpo w w. Fig. 4.3% benzoyl peroxide initiators.5% bisacrylamide ww polyacrylamide y š ùkü, ƒ f û x f. Fig. 5.3% benzoyl peroxide initiators.5% bisacrylamide ww polyacrylamide y š ùkü ƒ f k f x ùküš. ƒ x w Table 1- ùk ü, qkl ƒ w x šw. up-curve w w šw x w w ql w z, Ree-Eyring w š w. x ƒ Table 1. The rheological parameters of relaxation time (β, structure factor C and shear modulus X /α for the first flow curves of the various polyacrylamide hydrogels at 5 o C Variation of benzoyl peroxide(% bis (% Parameters.1%.5%.1%.3%.5% 1% (β 1 3.65.388 1.75.5.75.7.5% C 1 3.117.883.755.35.75.375 X /α 51.84 35.75 45.3 18.4 13.5 145.46 (β 1 4.6.45 1.94 1.4 5.46 5.45.6% C 1 3.14.44.646.34-1.375-4.17 X /α 58.8 47.6 48.3 5.3 3.6 47.5 (β 1.44.46.4 9.6 3.54.783.7% C 1 3 3.45 4.58 5.44 -.68.436 1.64 X /α 48.46 9.46 35.4 18.4 14. 88.4 (β : sec, C : cal sec /mol, X /α : N/m 6, Vol. 5, No. 6
45 ½ û Table. The rheological parameters of relaxation time (β, structure factor C and shear modulus X /α for the second flow curves of the various polyacrylamide hydrogels at 5 o C Variation of benzoyl peroxide(% bis (% Parameters.1%.5%.1%.3%.5% 1% (β 1.436.47 1.64 1.79 3.75 3.38.5% C 1 3.18 1.46.543.433.5.341 X /α 74.44 56.93 65.81 159.48 115. 96.89 (β 1 3.684.36.45 1.13.365 7.8.6% C 1 3.5.34.488.46.484 3.4 X /α 78.36 5.44 74.8 55.49 174.6 186.4 (β 1.3 3.4.86.984.486 5.54.7% C 1 3 3.4 4.85 3.44-1.46 5.54.48 X /α 4.4 4.5 38.4 1.3 47.54 1.35 (β : sec, C : cal sec /mol, X /α : N/m j zƒ ƒw hysteresis loop w ƒ w y y w šw j ùkü. qk Table 1- thixotropic š thixotropy g qk (β, C š X /α e ùkþ. C structure factor ùküš, α β j w e qk. α š ü w š w l factor hole volume V h. αƒ j hole j» f molecular segment ú. ƒ j modulus qk. y β x j x š w. š y β Table Table 3. The rheological parameters of relaxation time (β, structure factor C and shear modulus X /α for the flow curves of the various temperatures of polyacrylamide hydrogels for the.3% benzoyl peroxide initiators and.5% bisacrylamide Variation of temperatures Parameters 15 o C 5 o C 35 o C 45 o C (β 1.84.5.7 1.45 C 1 3.54.35.4. X /α 198.4 18.4 16.84 143.65 (β : sec, C : cal sec /mol, X /α : N/m w..5% bisacrylamide.5% bpo ww polyacrylamide y y β ƒ ƒ j ùk û..6% bisacrylamide.5% 1% bpo ww polyacrylamide y.7% bisacrylamide.3%bpo ww polyacrylamide y structure factor C x ù dilatancy x š qk l. w qk Table 4. The rheological parameters of relaxation time (β, structure factor C and shear modulus X /α for the flow curves of the various concentrations of polyacrylamide hydrogels for the.3% benzoyl peroxide initiators and.5% bisacrylamide Variation of concentration Parameters.1 g/1 ml.1 g/ ml.1 g/3 ml.1 g/4 ml.1 g/5 ml.1 g/6 ml (β 1.5 1.8.8.68.6.45 C 1 3.35.4.1.16.1.1 X /α 18.4 15.4 14.5 133.43 18.4 11.38 (β : sec, C : cal sec /mol, X /α : N/m Journal of the Korean Chemical Society
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