Akhare, V P

Burghatc, D K

Deogaonkar, V S

IACS Institutional Repository

Indian J. Phys. 68A (6), 553 -  557 (1994)U P  A- an international journalInvestigations on copolymer formation through ultrasonic and viscosity measurementsV P Akbare, D K Burghatc and V S DcogaonkarD e p a i i m e n l  o f  P h y s i c s ,  S h r i  S h i v a j i  w S cicnce C o l l e g e ,  A m r a v a i i - 4 4 4  0>O3, I n d i aR eceived  24 M ay 1994, ai cepted  7 July 1994A b s t r a c t  : U l t r a s o n i c  a n d  v i s c o s i t y  m e a s u r e m e n t s  h a v e  b e e n  e m p l o y e d  l o  s t u d y  t h e  c o i x i l y m e r  f o r m a t i o n  b e t w e e n  p r o t o n  d o n o i  a n d  p r o t o n  a c c e p t o r  m o l e c u l e s  o f  P o l y v i n y l  C h l o r i d e  ( P V C )  a n d  P o l y s t y r e n e  ( P S )  m o l e c u l e s  r e s p e c t i v e l y  T e t r a h y d r o f u r a n  ( T H F )  h a s  b e e n  u s e d  a s  a  c o m m o n  s o l v e n t  M e a s u r e m e n t s  h a v e  h e a p  m a d e  a t  t h r e e  d i f f e r e n t  t e m p e r a t u r e s  3 5 °  a n d  4 0 ° C  M a x i m a  o r  m i n i m a  in  t h e  p r o p e r t i e s  s t u d i e d  h a v e  b e e n  u s e d  t o  p r e d i c t  c o p o l y m e r  f o r m a t i o n .K e y w o r d s  : U l t r a s o n i c  v c h x ' i t y ,  v i s c o s i t y ,  P V C - l ’S ,  d o n o i - a c c e p i o i ,  c o p o l y m e r sP A C S  N o s .  : 6 1 . 4 1  + e .  4 3 . 3 5  C g1. Introductionbxtensive use of polymeric materials in technology has led in recent years to the increased interest to the various problems of the Physics and Chemistry of polymers. Few attempts seem to have been made to use acoustics as a tool in studying physical properties of polymers. Degradation of polymers subjected to ultrasonic waves has been reported to occur by Gowarikar et al [1]. Velocity of ultrasonic waves has been measured by Swarup and Chandra [21 in xylene solutions of phenolic and silicon resins, and a few physical parameters have been calculated. Malikarjuna Reddy etal [3] have measured thermo-acoustic properties of polymers at low temperature using theoretical model proposed by Sharma and Reddy [4-7]. Donor-acceptor interaction in binary system of trichloromethane with ethylacelalc has been interpreted to lead lo the formation of 1 : 1 intennolecular complex by Oswal |81, using dielectric and refractive index measurements. The functional groups participate in the formation of coordinate covalent bond, namely the proton donor and proton acceptor groups. Polyvinyl chloride (PVC) belongs to compounds of proton donor groups called class-A [9], while polystyrene (PS) belongs to a proton acceptor group called clas.s-B |9]. As such, in order to study the interaction between donor-acceptor molecules, samples of PVC and PS have been used with tetrahydrofuran as an inert solvent.€) 19941ACS554 2V P Akhare, D K Burghate and V 5 DeogaonkarSample preparationTwo polymeric solids namely PVC and PS were dissolved in THF so that weight fraction of total solute in THF is of the order of 0.015. The relative concentration of the two solutes were changed in definite proportions. Eight samples were prepared and measurements were taken at three different temperatures,3. Experimental detailsUltrasonic interferometer has been employed to measure ultrasonic velocity in sample solutions at fixed frequency 2 MHz. Viscosity measurements have been made by using an Ostwald viscometer. Temperatures have been kept constant using constant temperature water bath. Density measurements have been made using a density bottle and monopan balance. Accuracy in the mcasuremenLs of ultrasonic velocity is ± 0.5%. Temperature can be kept constant to an accuracy of 0.1‘^ C. Accuracy in the measurement of viscosity and density fiavc been ascertained by measuring viscosity and density of known liquids and comparing ^cm with literature values. Values of ultrasonic velocity, density and viscosity of the .samples have been measured at three different temperatures, 30^C, 35°C and 40'^C. Values of adiabatic compressibility P, .specific acoustic irnpedence Z and viscosity 7] have been calculated using relations.Pa =^expi “  '^'^expt Pexpt^  =  { p s h  I p j y . )  n,.( 1)(2)(3)where IJ — Ultrasonic velocity, rj  ^ = viscosity of water, and = densities of .solutions and water respectively and and = time of fall between specific marks on viscometer for solution and water respectively.Values of Z and rj at different temperatures have been entered in Tables 1,2 and 3. Table 1. Values of U, Zand r; at different weight fractions of PVC/PS at 30®CS N Velocity(cni/s)I0'2emVdynec^xpidyne-S/cm^TJX 10^PoiseWt fraction of PVCWi. fraction of PS1 125050 72.22 110720 1 0448 0.0149 0.00002 124680 72.57 110512 1 2282 0.0131 0.00203 124440 72.87 110274 1.1049 0.0113 0.00374 124000 73..39 J09872 1.1028 0.0094 0.00575 125840 71 33 111404 1.0758 0.0074 0.00766 1255.52 71 66 111137 1.1115 0.0055 0.00937 125120 72.19 110706 0.9439 0.0037 0.01138. 125680 71.87 110706 0.8749 0.0000 0.0150Investigations on copolymer formation through ultrasonic etc. 555Tabic 2. Values of U, ft. Zand nai different weight fractions of PVC/PS atS N Velocity(cm/s)/3„x I0'2 cm^ /dyneZdync-S/cni^T] X 10^PoiseWl Iraciion of PVCWt. fraction of PS1. 124120 75 95 108940 1 1005 0 0150 O.(XXX)2 . 123580 74 73 108278 0 6284 00131 0 00183 123600 74 56 107975 1 0741 0 0114 0 00374 123520 74.71 108359 1 9974 0 (M)94 0.00575 123680 74.50 108524 1 0718 0 (X)75 0.1K)756- 1240(X) 74 12 108708 1 8595 0 0056 0 (X)937 123280 75 28 107750 0 9383 0 CK)37 0 01138, 123640 74 84 108065 0 9371 0 (XXX) 0 0150Table 3. Values of U, Zand T] al differenl weight fractions of TVC/PS at 4()‘C.S N. Veltx;ity x l()‘" r] X 10“ Wr fraction Wl fraction(enVs) cni^ /dync dyne-S/bni' POLSC of PVC of PS1 121520 77 18 1(X)615 0 7240 0.01514 0 (KXX)2 . 121280 77 34 106688 0 8793 0 01325 0(X)173 120640 78 17 106034 0 8882 00113 0 (X)374 120600 80 88 10.3972 0 8541 0 0094 0 00575. 12191X) 76.50 107099 0 9255 0 007.5 0 00766. 1206CXJ 78 16 105666 0.7621 0 0056 0 00947- 1888(X) 81 19 103595 0 69(X> 0 mm) 00151and discussionfrom the Tables 1-3 lhat ultrasonic velocity U, specific acoustic irnpedencc Zand viscosity tj of the sample mixtures show a maximum, at or very near the cqui-weight fractions of the constituent and the adiabatic compressibility shows a minimum there. Further, the maximum velocity i/max' maximum specific acoustic impcdcnce and maximum viscosity decrease with increase of temperature; pa shows an opposite type of behaviour.These experimental observations can be explained on the basis of complex formation through coordinate covalent-bonding between the constituents of the mixture.The presence of the electro-negative chlorine atom in PVC is responsible for activating the hydrogen atom in the molecule. Chlorine being highly electronegative, attracts the shared electron towards itself creating a partial charge on C-atom. The charge S* on C-atom will556 V PAkhare, D K Burghate and VS DeogaonkaratlracL the electron pair shared between the two C-aioms, thereby developing a charge on second carbon atom as shown in Figure 1.i-H -  C ^ 1IHFigure 1.IH HFigure 2.The second carbon atom being attached to two hydrogen atoms, it will pull the shared electron pair to itself. This makes the H-atom to develope an effective charge 5^  which is the proton available as a donor proton. This is shown in Figure 2.Polystyrene contains a proton acceptor group (such as ketones, aldehyde, ethers, esters, tertiary amines, olefines, benzene and other aromatic compounds). The presence of the' aromatic ring imparts this characteristic. By accepting the incoming proton, the styrene ^pts more stabilised by forming a carbonium ion which is more stable than styrene due to the delocalisation of the +ve charge over the benzene ring by resonance mechanism.Thus, with the availability of the proton group in PVC and proton acceptor group in PS, there is every likelihood of the formation of coordinate covalent bond between PVC and PS, giving rise to the copolymer fonnation.wt fraction of pvcFigure 3. Variation ot viscosity rj of sample solunons with weight fractions of PVC ai different constant temps:7570Figure 4. Varmiion of ultrasonic velocity U and adiabatic compressibility of sample solutions with weight fractions of PVC at different constant temperatures.It is such copolymer species which will be statistically expected to be formed in large numbers at or very near the equal concentrations of the donor-acceptor species. These copolymeric formations might be responsible for sudden change in the behaviour of the sample mixtures at or very near the equal concentration.Strepikheyers etai [10] have reported the formation of graft copolymers in polyvinyl acetate with polyethylene in the sidechain, polymethyi acrylate with poly-n-chlorostyrcne in the sidechain, polystyrene with polyvinyl chloride in the sidechain.The bulkier copolymer molecules will naturally exhibit greater viscosity and geater specific acoustic impedence than the individual molecules, giving rise to maximum in tj and z-Similarly, the adiabatic compressibility will decrease with bulkier molecules resulting in a minimum in P„.Increase in energy of vibration accompanied with rise of temperature should be reflected in a decremenl in the maximum values of rj, z and U and increment in the maximum value of compressibility H  of the sample mixtures.5. ConclusionIt therefore follows that the experimental findings can thus be satisfactorily explained on the basis of copolymer formation through coordinate covalent bonding between donor and acceptor molecules employing ultrasonic and viscosity measurements.Further work in isolating the copolymeric species and studying its characteristic physical and chemical properties is of interest and is being shortly undertaken in this laboratory.AcknowledgmentThe authors are thankful to Principal Dr. V R Ghurde and Prof. P B Wani, Head of the Department of Physics, Shri Shivaji Science College, Amravati, loi constant encouragement during Progress of the work.Investigations on copolym er form ation through ultrasonic etc, 551Referencc.s| 1 |  V  R  G o w a n k a r ,  N  V  V i s w a n a l h a n  a n d  J  S r e c d h a i  Pofym er Scierue  ( N e w  D e l h i  W i l c y  K s i o m )  p  2 3 1  ( 1 9 8 6 )• [21 S  S w a r u p  a n d  S  C l i a n d i a  y  Polvm  M ater 5 1 4 7 ( 1 9 8 8 )[3 ]  P  M a l i k a r j u i i a  R e d d y ,  K  R a m k n s h n a  R e d d y ,  C h e w d o p  R a o  a n d  B  K  .S h a r m a  Indian J  Pure A pp l Phyx  2 7  2 7 .5  ( 1 9 8 9 )[4 ]  B  K  S h a m m y  AcousL Soc Am. 7 3  1 ( 3 6 ( 1 9 8 3 )[-5J B  K  S h a n n a  A c u j a a  5 3  1 0 0 ,  1 5 2  ( 1 9 8 3 ) ,  4 3  2 2 1  ( 1 9 7 9 )[ 6 ]  B  K  S h a r m a  a n d  R  R  R e d d y  Indian J  Pure and Appl. Ph\.\ 2 3  3 9 6  ( 1 9 8 5 )[7 J  B  K  S h a n n a  a n d  R  R  R e d d y  Polym  M ater  1 18 0  ( 1 9 8 4 )[8 J  S  L  O s w a l / / i r f w r t  y  Tech tw l  2 7  101  ( 1 9 8 9 )[ 9 ]  A  T a g o r  Phy.sical C hem istry o f  Polym ers  ( M o .s c o w  M i l  P u b l i s h e r s )  E n g l i s h  T r a n s l a t i o n  p  3 4 4  ( 1 9 7 8 )[ 1 0 ]  A  S l r c p i k h e y e r s ,  V  D e r a v i i a k a y a  a n d  G  S l o n i m s k y  A First Course m  Polym er C hem istry  ( M o s c o w  M i r  P u b l i s h e r s )  p  1 8 9 ( 1 9 7 1 )68A(6)-7

Investigations on Co polymer Formation Through Ultrasonic and Viscosity Measurements

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Investigations on Co polymer Formation Through Ultrasonic and Viscosity Measurements

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