The purpose of this thesis is to compare the conductivities of several solutions now in use in producing electroconductive paper. The testing procedure involved the use of a Kiethyl 610 B electrometer with two aluminum discs for conductance through the sheet and two brass strips for conductance across the sheet. Attempts were made to improve the conductance of the solution by the addition of surface agents in the belief that this would lead to better dispersion and thus to better film continuity. No effective method was found to improve the conductivity of a solution of given concentration. Increasing the concentration from 10% to 30% however did give substantial improvements in conductivity

Renner, Howard W.

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Western Michigan University ScholarWorks at WMU Paper Engineering Senior Theses Chemical and Paper Engineering 4-1967 A Study of the Conductivity of Several Conductive Polymers Howard W. Renner Western Michigan University Follow this and additional works at: https://scholarworks.wmich.edu/engineer-senior-theses  Part of the Wood Science and Pulp, Paper Technology Commons Recommended Citation Renner, Howard W., "A Study of the Conductivity of Several Conductive Polymers" (1967). Paper Engineering Senior Theses. 419. https://scholarworks.wmich.edu/engineer-senior-theses/419 This Dissertation/Thesis is brought to you for free and open access by the Chemical and Paper Engineering at ScholarWorks at WMU. It has been accepted for inclusion in Paper Engineering Senior Theses by an authorized administrator of ScholarWorks at WMU. For more information, please contact maira.bundza@wmich.edu. A STUDY OF THE CONDUCTIVITY OF SEVERAL CONDUCTIVE POLYMERS1 by Howard W. Renner A thesis submitted to the Faculty of the Department of Paper Technology of the Degree of Bachelor of Science t Western Michig&n University Kalamazoo, Michigan April, 1967 TABLE OF CONTENTS PAGE HISTORICAL BACKGROUND •••••••••••.••••••••••••••••••• 1 EXPhRIMENTAL DESIGN ••••••••••••••••••••••••••••••••• 5 Rh�ULTS AND CONSLOSIONS ••••••••••••••••••••••••••••• 7 LITERATlJRh CITATIONS •••••••••••••••••••••••••••••••• 13 ABSTRACT: The purpose of this thesis is to compare the conductivities of several solutions now in use in producing electroconductive paper. The testing proce­dure involved the use of a Kiethly 610 B electrometer with two aluminum discs for conductance through the sheet anct two brass strips for conductance across the sheet. Attempts were made to improve the conductance of the solution by the addition of surface agents in the belief that this would lead to better dispersion and thus to better film continuity. No effective method was found to improve the conductivity of a solution of given concentration. Increasing the con­centration from 10% to 30% however did,,give substantial improvements in conductivity. . -1-HISTORICAL BACKGROUND: The copying processes for office use begem to make their appearance in the early J.95O's. The early processes were gener&lly photographicin nature, relying on a positive and e negative paper. Later processes were developed and named "dry" processes because there wr:,s no need to use chemical solutions in the copying machine. Included in the dry processes are Thermofax, Xerography, and Electrofax. The Electrofex process involves the use of a ZnO coating on one side of the sheet. This coating is charged with static electricity and exposed to the orig­inal by use of a lens system. When de.rk areas occur on the origimal, e.g. type or letters,cno light will strike the charged sheet. Areas of the sheet that are exposed to light will dissipnte their charge while unexposed areas will retain their charge. These charged areas will attract the toner pEirticles which a.re fused or dried end the copy is completed. The removBl of the charge from the light exposed areas is e fundbment&l step of the process. The mechanism involved is the light releasing the charge from the ZnO particles that it strikes and the charge being removed by traveling through the resin layer which serves ss a binder for the ZnO. The composition 1 ' ' -2-of this resin layer plays e very important role in the quality and speed of the copying process. Most (1) has pointed out that e resin binder used with CdS or ZnO should not react chemically with it snd also the resin should properly wet and disperse the oxide particles. He notes that too much work put into the system to wet the particles will result in loss of photoconductive properties of the ZnO. Also, sometimes a mixture of resins will work much better than B single resin. Useful resins include polystyrenes, silicons, acrylic and methocrylic esters, chlorine.ted rubber, vinyl polymers and copolymers, cellulose esters and ethers and alkyds. Resins with strong polar groups, e.g. cerbcxyl, chloride, etc. are preferred.Levene (2) stetes that five desira�le characteris­tics of electrophotographic peper �re: 1. Better e.lectrofax sensitivity 2. Whiter sheet 3. Smoothness and wrinkle resistance improvements 4. Immunity to humidity effects 5. Consistent performance. These five areas are necessary for the paper to match the future speed of the electrophotographic processes. Some work h&s been done in the srea of humidity effects by Fird and Veurio (3). They reached· the con­clusion that h�midity effects ere dependent on the type -3-of binder used with the ZnO. The best type of b�nder of those which they tested was a vinyl benzene quaternary ammonium polymer compound. It exhibited the best con­ductivity with the least chHnge due to humidity. KCl was tested but showed poor results ·below 60% R.H. Carbon or metallic particles introduced during or as a subsequent costing were effective in reducing the resistance of the sheet, even at low humidity. Also suggested was trying to improve the conductivity by the addition of a more hygroscopic material than cellulose in the paper. But at high humidities, these showed a tendency to soften the sheet so much &.s to make it unusablbe. Hayek (4) has pointed out thst antistatics are used in the textile industry and may be usable on paper. He claims that the bCtion of an antistatic agent is tbe same as that of a conductive agent. They both probably work on the same principle of adsorption of water by the antistatic agent on the surface of the fiber. This is born out by the dependence of the effectiveness of antistatic agents on R.H. The work of my thesis will be in the area of the resin binder. It will concentrate on the addition of both surface agents and conductive agents in hTI effort .. -4-to accomplish two objectives. First to increase the conductance of the resin layer and second to keep varia­tion in conductance due to humidity effects as minimal as possible. -5-EXPRRIMENTAL DESIGN: The paper stock used as a coating bose was cut into 8 inch by 10 inch grain long sheets. All coatings were applied to the felt side. The coatings were measured in graduates and the necessary dilutions and additions carefully measured out. Any bubbles formed from entrapped air while mixing were allowed to rise out. Mixing was accomplished by inverting the graduate five or six times. A small amount, about 10 ml., of the coating mixture was poured on the top of the sheet and a draw down was made using either a number 3 or a number 11 rod. The samples w0re conditioned by allowing them to stand overnight in a constant tempereture and humidity room. The condition here provided for 50% relative humidity. These samples were then tested for the amount of resistance offered to electric current both through the sheet and across the sheet. The resistonce through the sheet wts measured using two aluminum discs each 4.90 square inches in area. A five kilogram mass was used to provide for constant force on the discs. The measurements were teken with a Kiethly 610 B electrorneter. The across the sheet resistance was measured using two brass strips one inch long end parallel to ebch -6..;other one inch apart. This provided for the meesure­ment of resistance of one square inch of the coated 8Urface. Values were egain me&sured with a Kiethly 610 B. The s&mples were then left overnight in a chamber which was 20% relative humidity. The humidity was controlled by a s&turated solution of potessium acete.te and circulation was provided with a luw speed fan. Measurements of both across and through resistance were tliken using the same apparatus. -7-RESULTS AND CONCLUSIONS: The first agent to be tested was Tamol 850 at both 30% and 10% solids. Also tested was Calgon 261 at 40% and 10% solids. The data is pre­sented in T&ble I. Sever�l important points can be ex­pressed from the above date. The r"irst of these is the dependence of resistsnce on humidity. Much less resist­ance wes encountered et 50% than at 20%. This is due to the extra wE-ter edsorbed in the sheet at the higher humidity aiding in carrying the current through t.he paper. Another observation is in the very large dependence of resistance on the concentration of the conductive agent. For both Calgon 251 and Tamol 850, the resist­ances were much higher at 10% solids than in the more concentrated form. This is probebly due to the dilution of the agent interfering with the conductive mechanism of t.he agent. Another effect exhibited is the dependence of the low solids mixture on the drew down rod number. This effect was not observed for the higher solids. This serves es further evidence for the concentration playing an imr;ortant role as the number 11 rod applies a thick&r coating on the sheet than does the number 3 rod, end the resistances were lower for the number 11 rod samples. -8-There is not enough evidence to say whether or not the resistance hid any special correlation to rod number and ·humidity . The next step of the procedure wes trying to add egents to a 10% solution of Celgon 261. The data collected from these trials is presented in Table II. All samples used in compiling Table II were prepared using 6 number 11 rod. The most interesting observation to make here is that ell of the agents used increased the resistance instead of lowering it. This is further evidence that dilution of the conductive solution only hampers the conductive mechanism of it. Table III shows the resistances obtained from a coating composed of 5% Calgon 2Rl and _5% Tamol 850. The resistance values are higher than the resistances obtained from mixtures of only Calgon 261 and water or Tamol 850 and water. Again, this is evidence that dilu.tion of the agents only hinders their operation. Also suggested by the data of Table III is that the mechanism of the Calgon and Temol may be different. This is further born out when it is considered that when the two solu­tions of 10% each were added together, a pasty pre­cipitate was formed. It is quite surprising th�t the resultant resistances came out roughly in the , -9-same area as other solutions. From my work, I heve .concluded several points. First of these is that humidity hes an effect on the conductance of t:te re sin layer. Second is the strong dependence of conductance on the concentr&tion and amount of the conductive agent present in the sheet. This is shown by the dependence on rod number and concentration. -10-TABLE I50% R.H. 20% R.H.Calgon 261 Surface Through Surfece Through 40% Solids 3 rod .043 5.7 .085 13 11 rod .042 6.5 .080 7.3 10% Solids 3 rod 2.9 5.9 4.3 17 11 rod .85 2.0 1�7 1.3 Te.mol 8;:;,0 30% Sclids 3 rod .44 5.6 3.0 21 11 rod .5 6.8 5.0 28 10% Solids 3 rod 31.5 7.0 74 s.o11 rod 15.0 2.8 16 7.3 All values X 108 ohms ' -11-TABLE II 50% R.H. 20% R.H. Surface Through Surface Through Calgon 10% .85 2.0 1.7 1.3 + Sodium Glycolate 1.7 .92 4.7 4,4 +- Isopropanol 2.0 : 3:·3 3.5 7.0 + Plurs.f ac B-26 1.2 2.9 2.5 3.6 + Plurionic P-123 1.9 1.8 4.6 3.8 All values X 108 ohms -12-r ABLE III Surface Through Surface Through Calgon (5%) +- Tamol (5%) 3 rod 95 .x 108 6.0 X 108 35 X 108 17 X 10811 rod 10.5 .x 108 3.8 X 108 4.9 X 108 6.3 X 108Base Sheet 1.75 X 1011 4.4 X 109 1 2 X 1011 3.0 X 109 -13-LITERATURE CITATIONS: 1. D. s. Most, D. D. Taft, ands. C. Hiedecker;"Some Observations on Resin Functionalityand Electrofax Layer Perform&nce," Re�roducedReport2. Martin Levene; "Electrostatic Printing Papers -Features for Performance Effectiveness," TAPPI46,12) :170-5A(l963)3. Donald P. Fird, Frans V. E. Vaurio; "Electric­ally Conductive Paper for Non•impact Printing,"TAPPI 47(12) :163'165A(l964)4. M. Hayek; "Electrically Conductive and Static­Free Papers," TAPPI 43(2):105-11(1960),. 

A Study of the Conductivity of Several Conductive Polymers

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A Study of the Conductivity of Several Conductive Polymers

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