1802
Ind. Eng. Chem. Res. 1988,27, 1802-1806
Emerson, D. W.; Emerson, R. R.; Joshi, S. C.; Sorensen, E. M.; Turek, J. E. “Polymer-Bound Sulfonylhydrazine Functionality. Preparation, Characterization, and Reactions of Copoly(styrenedivinylbenzensulfonylhydrazine)”. J . Org. Chem. 1979,44,4634. Emerson, D. W.; Gaj, D.; Grigorian, C.; Turek, J. E. “Intraresin reactions of a,w-Alkanediamines with Sulfochlorinated Copoly(styrene-divinylbenzene)”. Polym. Prepr., Am. Chem. SOC.,Div. Polym. Chem. 1982,23, 289. Kunin, R. Ion Exchange Resins, 2nd ed.; Wiley: New York, 1958, p 341ff. Kyba, E. B.; Koga, K.; Sousa, L. R.; Siegel, M. G.; Cram, D. J. “Chiral, Hinged, and Functionalized Multiheterocycles”. J. Am. Chem. SOC.1972, 95, 2691. Min, K.-e.; Lee, H.-k.; Klee, D.-h. “Synthesis of Amphoteric Ion Exchange Resins and Their Physicochemical Properties”. Polymer (Korea) 1985, 9, 68. Nakamura, Y. “High Polymers Containing Free Functional Groups. VII. Resins Containing Sulfoamide, Sulfochloramide, or Sulfodichloramide Group”. J. Chem. SOC.Jpn, Znd. Chem. Sect. 1954, 57, 818. Nicolson, N. J. “An Evaluation of the Methods for Determining the Residual Chlorine in Water”. Analyst 1965, 90, 187.
Palin, A. T. “Methods for the Determination, in Water, of Free and Combined Available Chlorine, Chlorine Dioxide and Chlorite, Bromine, Iodine and Ozone using Diethyl-p-phenylenediamine (DPD)”. J . Inst. Water Works Eng. Sci. 1967, 21, 537. Palin, A. T. “Current DPD Methods for Residual Halogen Compounds and Ozone in Water”. J . Am. Water. Works Assoc. 1975, 67, 32. Shaw, M. P.; Snodgrass, W. J. “Natural Chlorination Kinetics of Secondary Municipal Effluents”. In Water Chlorination Environmental Impact and Health Effects; Ann Arbor Science: Ann Arbor, MI, 1983; Vol. 4, Book 1, pp 113-123. Tschang, C.-J.; Klefenz, H.; Sauner, A. “Macroporous Polymers as Support Material for Covalent Bonding of Protein”. Ger. Patent 2834539, 1980; Chem. Abstr. 1980,93,3076. White, G. C. Handbook of Chlorination for Potable Water, Wastewater, Cooling Water, Industrial Processes and Swimming Pools; Van Nostrand Reinhold: New York, 1972. White, G . C. Disinfection of Wastewater and Water for Reuse; Van Nostrand Reinhold: New York, 1978.
Received for review January 12, 1988 Accepted May 23, 1988
Rheological Properties of Polysaccharide Solutions and Derived Printing Pastes in Continuous and Oscillatory Flow Conditions Romano Lapasin* and Sabrina Pricl Istituto d i Chimica Applicata ed Industriale, Uniuersitd d i Trieste, 34127 Trieste, Italy
Marco Graziosi and Giuseppe Molteni Fratelli Lamberti S.p.A., 23100 Albizzate ( V A ) ,Italy
The rheological properties of printing pastes and the corresponding polysaccharide solutions were examined under continuous and oscillatory shear conditions. A two-parameter Cross model was used for the fitting of the data obtained with a stepwise procedure for all systems. Data from measurements in oscillatory conditions were expanded in a Fourier series; accordingly, the analysis of the viscoelastic behavior was carried out taking into account the fundamental harmonic alone. The temperature effect was described by an Arrhenius model law and consequently discussed in terms of activation energy. Color pastes employed in the machine printing of textiles are rheologically complex fluids. In general, they are aqueous systems with high viscosity, prepared by mixing a thickening agent solution and a dye solution or dispersion. The role of thickening agents in the formulation of printing pastes is of paramount importance since they must impart adequate rheological properties to the pastes in the different flow conditions encountered in the printing process (Schurz et al., 1975; Abdel-Thalouth et al., 1986; Wielinga, 1986). During this process, the materials are moved by the sequence across the mask and, through the screen openings, to the substrate. Thus, the pastes are subjected to flows with shear or extensional components, or both, at different strain rates. High shear rate conditions are present during the first steps of the application process, while after being forced through the screen openings and deposited on the fabric the paste will continue to flow at very low shear rates. Hence, the thickening agents must ensure at the same time both a homogeneous distribution of the printing paste on the screen and its uniform flow through the screen openings. In other words, the paste must be characterized by a good screenability and a complete and uniform penetrability into the cloth; moreover, the best sharpness of definition must be achieved, and the flushing out must be prevented. I t follows that favorable properties for an easy application and a good performance of a printing paste are generally low viscosity values at high shear rates and high viscosities
at low shear rates (or the presence of a yield stress), respectively. As the elastic properties are concerned, they affect both the flow behavior of the paste through the screen openings to the fabric and the following step (flow through the fibers) by governing the elastic recovery of the applied flow. The selection of a thickening agent, which in most cases is confined to natural or semisynthetic polysaccharides with high molecular weights, is determined by the fabric to be printed, the printing conditions, and, above all, the type of dye used. Depending on their chemical nature, the dyes may interact with the thickening agents (i.e., to form complexes or to give a chemical reaction), causing a variation of the rheological properties of the printing pastes and, as a consequence, of their application characteristics. The present work was undertaken with the view of studying the rheological properties of printing pastes having different polysaccharidic solutions as bases and the effects that may derive from the addition of different dyes, temperature variations, and periods of storage.
Experimental Section Materials. The polysaccharides used as thickening agents in the formulation of the printing pastes analyzed in this work were the following: hydroxyethyl guar gum (HEG), (carboxymethy1)cellulose (CMC), and sodium alginates (ALG). Guar gum is a natural plant polysaccharide, with a chemical structure corresponding to a linear backbone of
0888-5S85/S8/2627-~802$01.50/0 0 1988 American Chemical Society
Ind. Eng. Chem. Res., Vol. 27, No. 10, 1988 1803 (1+4)-/3-~-mannosewith side units of (l+)-a-D-galactose. The hydroxyethyl derivatives used in this work were obtained by reaction of guar gum and ethylene oxide in the presence of an alkaline catalyst, and were characterized by a molar degree of substitution (MS) of 0.28 and two different molecular weights (HEG1 and HEG2). The (carboxymethy1)celluloseused was obtained by an etherification reaction between monochloroacetic acid and cellulose in an alkaline medium. The degree of substitution (DS, defined as the number of substituents present on the polysaccharidic chain per monomeric unit) experimentally determined was about 2. Sodium alginate is a polysaccharide extracted from seaweeds; its chemical nature is constituted of sequences of (1+4)-a-L-guluronic acid and (1-+@-D-mannuronic acid. The alginates used in this work were commercial samples having different molecular weights (ALG1 and ALGB). The dyes employed in the formulation of the printing pastes were of three different types: acid (Blue Telon 5g), disperse (Blue Palanil BGF), and reactive (Procion Brown P4/RD). The formulation of the printing pastes was, in any case, adjusted in order to obtain a Brookfield viscosity of about 9000 CPat 20 rpm and 293 K, according to conventional industrial practice. Apparatus and Procedures. Continuous shear and dynamic measurements were carried out with a rheometer (Rotovisko Haake RV 100, measuring system CV loo), mounted with a coaxial sensor system ZB 15 (Couette type). The outer cylinder is driven; the inner cylinder is mechanically positioned and centered by an air bearing. Top and bottom surfaces of the inner cylinder are recessed to minimize end effects. For continuous shear tests, a stepwise procedure was carried out, each shear rate being applied until steady stress values were obtained. In each dynamic test, the outer cylinder was forced to oscillate sinusoidally at a frequency w , and the corresponding oscillation of the inner cylinder, proportional to the resultant torque, was recorded. After steady state was reached, the resultant torque was expanded in a Fourier series to evaluate the amplitude and the phase angle of the fundamental harmonic as well as of the higher harmonics. The Fourier analysis generally revealed that the higher order (odd) harmonics are present but negligibly small as compared with the fundamental harmonics. Therefore, the later analysis was restricted to the fundamental component alone. Experimental Results and Discussion Continuous Shear Tests. From the tests carried out in continuous shear conditions on the polysaccharide solutions, it is shown that the shear-dependent behavior of all the polysaccharide solutions having the same concentration of the printing pastes is shear-thinning, with values of viscosity close to the upper Newtonian plateau, in the explored range of shear rates. In figure 1are reported the plots of r] versus 4 for the two systems HEG. Different models containing two and three adjustable parameters were taken into consideration for the fitting of data relative to all the systems examined (power law: Eyring et al. (1958), Williams and Bird (1962), Cross (1965), Carreau (1968), Morris (1984)). The two-parameter Cross model, described by 70 r]=
1
+ (X4)2/3
=
90
1
+ (4/43/3
(1)
j ';I:
I
; :
I
10
10Shear
10 rate
y
10'
10"
Cl/sl
Figure 1. Flow curves of solutions containing HEG at 298 K: (-1 high molecular weight, (- - -) low molecular weight. Table I. Values for the Cross Model Parameters vo and X Obtained for the Different Polysaccharide Systems nn. Paes A. s polysaccharide HEGl 12.57 0.1605 HEG2 7.68 0.0440 CMC 12.79 0.1218 ALGl 10.64 0.0921 ALG2 8.97 0.0481
allowed the best results to be obtained both in terms of variance and uncertainty in the parameters evaluation. Equation 1derives from the original model proposed by Cross: 70 - 9 m
9=qlm+
1
+
(Xi,)2/3
with the assumption that the qmvalue, corresponding to the lower Newtonian plateau, is negligible with respect to the experimentally determined values of viscosity. In eq 1, X represents the Characteristic time of the material, while qcis the shear rate at which the viscosity is equal to q0/2. The values for the parameters vo and X obtained for the different polysaccharide systems are reported in Table I. An analysis of the values for the parameters shows that the higher the molecular weight of the polysaccharide the higher the values for the zero-shear viscosity (r],,) and the characteristic time (A) for the corresponding solution. From a previous analysis carried out on a series of solutions having different polymer concentrations, it resulted that the rheological properties of the different solutions employed as bases for the preparation of the printing pastes are those expected for the concentrated solutions beyond the entanglement condition. Figure 2a reports the behavior of the values for v0 as a function of concentration for the HEG solutions. Values for t owere obtained by using a superposition procedure for the definition of the master flow curve and using the Cross model to evaluate the upper Newtonian viscosity. In Figure 2b are the plots of the characteristic times (A) as a function of concentration for the same systems. From Figure 2a it is evident that the depencence of qo on concentration is that which is typical of concentrated solutions in the range of concentration explored and that the solutions employed as base for the printing paste are in this range. A shear-dependent behavior similar to that described above for the polysaccharide solutions has been observed for the corresponding printing pastes. In Figure 3 are reported, as an example, the behaviors of r] versus 4 relative
1804 Ind. Eng. Chem. Res., Vol. 27, No. 10, 1988 2
1 o2
I
,
C
I X
I
0
X
l 0 q t
t r r
X ~
'-1
2
0
c
10
10
0
I
1 c
C%W/iLII
Figure 2. Dependence of (a, top) zero shear viscosity (so) and (b, bottom) of characteristic time (A) on concentration (C) for the HEG high molecular weight, ( X ) low molecular solutions a t 298 K: (0) weight.
'
I
t 0
I0
I0 Shear
I
10 rate
2
I0 f
'
I0
'
""'"I
'
I0 rate
f
'
"""'2
10 Cl/s:
'
''.% 10
Table 111. Values for the Cross Model Parameters qo and X Obtained as a Function of Temperature for the Printing Paste Containing HEGl and Acid Dye (AD) and the Corresponding Polysaccharide Solution svstems T. K no. Paas A. s HEGl 293.15 9.10 0.1423 HEGl 298.15 7.79 0.1235 HEGl 303.15 6.32 0.0954 HEGl/AD 293.15 14.13 0.1945 HEGl/AD 298.15 11.40 0.1430 HEGl /AD 303.15 9.68 0.1251
X
X
"""'E
Figure 4. Relative viscosity (sr)versus shear rate (4) for printing pastes containing HEG and acid dye at 298 K: (-) high molecular weight, (- - -) low molecular weight.
I 0
'
Shear
C%uJ/Wl
:
'
From a comparison between the calculated parameters for the polymeric solutions (see Table I) and the printing pastes (see Table 11), it is evident that the addition of a dye produces, as a main effect, an increase in the values of po and A. As a consequence, it follows that the relative viscosity, defined as the ratio between the viscosities of the pastes and those of the corresponding polymeric solutions, does not vary substantially with the shear rate (see Figure 4). Temperature Effects. The effect of temperature on the two parameters, po and A, has been evaluated by carrying out additional continuous shear tests at 293 and 303 K on the printing pastes having HEG as the thickening agent and Blue Telon as a dye and on the corresponding polymeric solution having the same concentration. In both cases, an increase in temperature produces a decrease in the values of the parameters (see Table 111); this effect can be described by an Arrhenius model law:
3
I0
Ci/sl
Figure 3. Flow curves of printing pastes containing HEG and acid dye at 298 K: (-) high molecular weight, (- - -) low molecular weight. Table 11. Values for the Cross Model Parameters so and X Obtained for the Different Printing Pastes printing pastes 70, Pa.s A, s 18.45 0.2436 HEGl/acid dye 11.36 0.0629 HEGZ/acid dye HEGl/disperse dye 14.98 0.1782 10.61 0.0569 HEGZ/disperse dye CMC/reactive dye 15.56 0.1320 15.34 0.1130 ALGl/reactive dye ALG2/reactive dye 8.68 0.0297
to the printing pastes having HEG as the thickening agent and Blue Telon as the dye. Even in this case, the best fit of the data was obtained with the two-parameter Cross model, and the values for the calculated parameters are shown in Table 11.
qo
= A'exp(
$)
A=A"exp ( ; T )-
(3)
The calculated values for the activation energy (E:) are all close to 26.6 kJ. As a consequence, it follows that this parameter is nearly independent of the molecular weight of the polymer and the addition of a dye, while it appears to depend mainly on the nature of the polymer itself. A t the same time, the values of the viscosity obtained at different shear rates and measured as a function of temperature can be plotted by using an Arrhenius-type law: = A exp(
2)
(4)
Ind. Eng. Chem. Res., Vol. 27, No. 10, 1988 1805 20
n y1
*
10-
‘
0
*
a,
#
$
e
t
+
*
* +
L g t
+ +
2
1310 - 1
I0
Shear
I0
rate
9
%+ I
2 ‘ 0. I
10 2
Op##
w
Cl/sl
1
10 Crad/sl
Figure 5. Dependence of activation energy (E,) on shear rate (i.) for printing pastes containing HEG and acid dye: (0) high molecular weight, (*) low molecular weight.
From the plots reported in Figure 5, it is shown that temperature variations cause higher viscosity variations at lower shear rates. Oscillatory Flow Tests. Tests under oscillatory flow conditions were carried out to analyze the viscoelastic components of the systems. Even operating in large strain conditions, a Fourier analysis of the data obtained both for the polymeric solutions and the printing pastes has demonstrated that the dynamic response may be reduced to the component of the fundamental harmonic. Under the experimental conditions employed, the phase lag (6) is substantially independent of the frequency, with values ranging between 1.53 and 1.25 rad. The values of 6 are lower for the systems with the higher molecular weights. The behaviors of the viscous and the elastic components are similar for all systems. As an example, parts a and b of Figure 6 show the behaviors of the real components of the viscosity and of the complex modulus as a function of frequency for the HEG solutions and the pastes obtained from the corresponding bases by the addition of the disperse dye, respectively. The behaviors of q’ and q* with the frequency approximate that of q with T if 9 and w tend to zero, according to the Cox-Merz rule (see Figure 7). The addition of a dye does not modify, in an appreciable way, the values of the phase lag, 6. As it has been observed for the rheological properties in continuous shear conditions, the increments of the real componenb q’ and G’, due to addition of a dye, do not vary substantially with the frequency.
I # a
I
i
d
0. I
1
w
I0 Crad/sl
Figure 6. (a, top) Dynamic viscosity (9”) versus oscillation frequency ( w ) and for storage modulus (G’) versus oscillation frequency ( w ) solutions of HEG and the corresponding printing pastes containing acid dye at 298 K (*) high molecular weight paste and (0) corresponding solution, (#) low molecular weight paste and (+) corresponding solution.
1.0.
rp
t
F
’ 5.;:
*
*
*%* F
*
*
P
Conclusions The continuous shear tests indicate that both the printing pastes and the corresponding polysaccharide solutions show similar shear-dependent behavior, described by a two-parameter Cross model and discussed in terms of the two parameters qo and A. The dye addition mainly produces an increase in the values of qo and &; consequently, the relative viscosity does not vary substantially with the shear rate. The effect of temperature on parameters qo and X can be described by an Arrhenius model law and shows that the activation energy is mainly dependent on the nature of the polysaccharide. As for the continuous shear properties, the dynamic viscosity and the storage modulus of the pastes and the corresponding polysaccharide solutions do not differ appreciably. A1I the systems exhibit a low elastic component when compared with the viscous one.
Figure 7. Comparison of the normalized viscosity (v), dynamic viscosity (q’), and the magnitude of the complex viscosity (q*) for the printing pastes containing low molecular weight HEG and acid dye at 298 K: (0) viscosity (v), (+) dynamic viscosity ( T ’ ) , and (*) complex viscosity (?*).
Nomenclature A’ = proportionality factor in eq 2, Pa-s A“ = proportionality factor in eq 3, Pa-s A = proportionality factor in eq 4, Pa.s C = concentration, % w/w E,‘ = activation energy in eq 2, kJ E,” = activation energy in eq 3, kJ E, = activation energy in eq 4, kJ G’ = storage modulus, Pa R = gas constant, J/(mol.K) T = temperature, K
I n d . Eng. Chem. Res. 1988,27, 1806-1810
1806
t = time, s
Literature Cited
Greek Symbols T = shear rate, l / s
Abdel-Thalouth, I.; Elzairy, M. E.; Hebeish, A. Am. Dyest. Rep. 1986, 75, 32. Carreau, P. J. Ph.D. Thesis, University of Wisconsin, Madison, WI, 1968. Cross, M. M. J. Colloid Sci. 1965, 20, 417. Eyring, H.; Ree, F. H.; Ree, T. Znd. Eng. Chem. 1958, 50, 1036. Morris, E. A. In Gums and Stabilizers for the Food Industry 2; Phillips,G . O., Wedlock, D. T., Williams, P. A., Eds.; Pergamon: Oxford, 1984, pp 57-78. Schurz, J.; Friesen, W.; Schempp, W. Das Papier 1975, 29, V7. Wielinga, W. C. Melliand Textilber. 1986, 1, 45. Williams, M. C.; Bird, A. B. Phys. Fluids 1962,5, 1126.
qc = characteristic shear rate, l / s 6 = phase lag, rad 11 = viscosity, Pa.s qo = zero-shear viscosity, PaBs 1.. = infinite-shear viscosity, P e s q* = complex viscosity, Pa.s 7' = dynamic viscosity, P e s X = characteristic time, s w = frequency, rad/s Registry No. HEG, 39465-11-7; CMC, 9004-32-4; ALG, 3005-38-3; Blue Telon 5G, 12219-38-4; Blue Palanil BGF, 12222-85-4;Procion Brown P4/RD, 12225-72-8.
Received for review January 26, 1988 Revised manuscript received May 23, 1988 Accepted June 6, 1988
Development of Novel Polymeric Soil Stabilizers? Shawqui M. Lahalih* and George Hovakeemian Kuwait Institute f o r Scientific Research, P.O. Box 24885, 13109 Safat, Kuwait
A composition of sulfonated urea-melamine-formaldehyde with poly(viny1 alcohol) was developed and tested on sandy soil for its stabilization. The use of this kind of composition as a soil stabilizer is novel and has not been revealed before. The compressive strength of sandy soil and its resistance to water erosion are significantly improved after it has been treated with this composition. It was found that, at an application rate of 1 % by weight of this composition to the weight of sand, the compressive strength of sand improved by a factor of 3. Erosion of sand by water was also reduced to zero after exposure to three cycles of 6 h, each interrupted by 24 h of curing at a water runoff rate of 6 L/min. The developed composition outperformed commercial soil stabilizers in the stabilization of sand. The results obtained are explained by a proposed mechanism for the mode of action of this composition with sandy soil. Soil erosion is a phenomenon occurring in a wide variety of situations. For example, it is a serious problem in countries with arid climates and in areas with little rainfall. Soil erosion problems are frequently caused by the existence of fine particles on the surface of the soil. These fine particles are poorly bonded and susceptible to erosion by wind and rain. In addition, the structure of the soil determines its properties such as permeability to water, porosity, crust formation, and load carrying capacity. Weak soil and sand structure cause problems in road and highway construction, steep slopes, water channels, construction, excavation banks, and landing sites for aircraft and the like. Extensive research has been carried out to improve soil structure, to reduce soil erosion, to reduce water evaporation, and to increase bonding strength so that it can withstand greater loads. The research has generally had one or two objectives, Le., to prevent or minimize soil erosion and to improve soil load-carrying capacity. For example, acrylamide polymer cross-linked with N,Nmethylenebis(acry1amide) was used by some researchers (Cooke, 1984a-c; Clark, 1984) with other additives such as palm nuts and seaweed as a water-absorbing material for agricultural application. Similarly, plant-growing media based on acrylamide polymers were reported by Clarke (1984), Bosley et al. (1983), and Helbing (1981). Other polymer-based materials were also used to stabilize the soil, such as cellulosic polymers with A1(OH)3 (Bryhn and Loken, 1984) or with latex (Janowisk, 1978), 'Publication No. KISR 2542. 088S-5885/88/2627-1806$01.50/0
lignosulfonates reacted with acrylic acid (Zaslavasky and Rozenberg, 1983), poly(acry1amide) reacted with polyaldehyde and hopohalites (Pilny, 1980,1982), and mixtures of dimer diisocyanate and dimer diamide (Reed and Morre, 1981) and polyelectrolytes (Eikhof and King, 1981). Others (Meknight, 1972) have used cationic polymer latexes prepared from acrylates and anionic lignin from cellulosic material to stabilize soil and prevent soil erosion by wind or water. Others used natural or synthetic rubber latexes with nonionic surfactants to stabilize soil (Bennet, 1977). In addition, Sakata et al. (1970) disclosed a process for forming a gellike material in a soil by injecting an aqueous solution containing three components into the soil. The aqueous solution includes urea, formaldehyde, and poly(vinyl alcohol) and is cured within the soil by the addition of an acidic substance. This process is useful for rendering a water-permeable soil water impermeable and thereby stabilizing it. A composition of poly(viny1 acetate) and cement improved the adhesion of sandy soil (Kazda et al., 1974). Poly(viny1 acetate) together with chlorinated poly(is0butane) was used to improve the resistance of sandy soil to erosion and to protect plants from damage by shifting sand (Regeaud and Trebillon, 1974). Poly(viny1acetate) was also used to consolidate soil by Sakata and Nakabayashi (1969). Poly(viny1 alcohol) stabilized fine sandy loam soil without any effect on plant growth or nitrogen uptake (Sefanson, 1974). Hydrophilic urethane prepolymer consolidated sand particles and produced a water-permeable sand that could 0 1988 American Chemical Society
