I.Rheology:
“Rheology” is by definition ,the science of deformation and flow of the matter.
The Rheological behavior of polymers involves several widely different phenomena ,like Viscose , flow, elasticity , etc.
Which can be related to some extent to different molecular mechanisms.Vico elasticity where the deformation of the polymer specimen is reversible but time dependent and associated with the distortion of polymer chains from their equilibrium conformations through activate segment motion involving rotation about chemical bonds.
Hooken elasticity ,where the motion of chain segments is drastically restricted and probably involves only bond stretching and bond angel deformation .The material behaves like a glass.[1]
Polymer blending is an economical and alternative route to new materials with superior properties [2, 3]. Polymer blends have wide range of applications for production of new material. It is an easy and cheaper method to get material with desired properties [4].
II.Viscometry:
The usefulness of solution viscosity as a measure of polymer molecular weight has been recognized ever since the early work of Staudinger (1930).Solution viscosity is basically a measure of the size or extent ion in space of polymer molecules .
It is empirically related to molecular weight for linear polymers ,the simplicity of the measurement and the usefulness of the viscosity-molecular weight correlation are so great that viscosity measurement constitutes an extremely value able tool for the molecular characterization of polymers.[1]
III.Brief History Of Blends (Polystyrene & Poly Vinyl Acetate)
a.Synthetic Polymers :
The first commercial use of styrene was in synthetic rubbers made by copolymerization with denies in the early 1900`s.poly styrene was produced commercially in Germany about 1930 and successfully in U.S.A in 1937.In 1936 Poly Vinyl Acetate produced.[1]
b.Classification:
Based on consideration method of preparation of polymers , P.S & PVAC are in group of addition polymers starts with a radical initiator ,the same as follows: [5]
IV.Properties Of P.S & PVAC
a .(P.S) : Poly Styrene is a thermo plastic with many desirable properties .it is clear ,transparent ,easily colored and easily fabricated.It has reasonably good mechanical and thermal properties ,but it is slightly brittle and softens below 100oC.
Poly styrene is a a linear polymer ,the commercial product being a tactic and therefore amorphous.
b. (PVAC): The most widely used Polymer of Vinyl Ester is PVAC.
It I utilized not only as a plastic primarily in the form of emulsions but also as the precursor for two polymers which cannot be prepared by direct polymerization.
This polymer is a tactic and hence amorphous .stereo regular polymers have not been offered commercially .the glass transition temperature of PVAC is only slightly above room temperature .(29oC)PVAC is water sensitive in certain physical properties as strength and adhesion ,but does not hydrolyze in neutral systems .Poly Vinyl Acetate is also widely used in adhesives ,both of the emulsion type and of the hot-melt type.[1]
V.Structure
1.Poly Styrene referred as PS in compunction classification is a homo polymer .
Poly Styrene derived from 1-Phenyle Ethylene monomer commonly calls Styrene:
2.Poly Vinyl Acetate referred as PVAC is prepared by the vapor-phase addition of Acetic Acid to Acetylene.[6]
Source based :Poly(Vinyl Acetate)
Structure based :Poly(1-Acetoxy Ethylene)
EXPEREMENTAL
Material: Samples of Poly(Styrene) and Poly(Vinyl Acetate) were obtained from B.D.H limited Pool England without further purification . Samples of Poly Vinyl Acetate will use by M.W average 190000& M.W approximately of Poly Styrene 100000.
The solvent is Toluene Analar grade from ACS, made in European Union Barcelona, Spain.
AIM & OBJECTIVE
Physical properties of polymers in solution play a key role in the fabrication technology of polymers.
Poly styrene as the thermoplastic additive is an illustration of another principle of the importance of thermoplastic properties.
The specific volume of polystyrene at any temperature is greater than either that of P.V.AC .yet it is not near ly as effective as either of these materials for controlling shrinkage.[7]
The present investigation was aimed to carry out a systematic studies of the dilute and concentrated solution properties of P.S and P.V.AC in Toluene at different temperatures and concentrations .the dilute solution properties usually studied by viscosity measurement.
METHODOLOGY
1. DSV: Dilute Solution Viscometery
2. FTIR: Fourier Transform Infra-Red ,Spectroscopy to get information about curing process of P.S & P.V.AC in Toluene.
3. SEM: Scanning Electron Microscopy , will use to observe size and distribution of P.S & P.V.AC in Toluene.
4. TS: Tensile Strength
5. TGA: Thermo Gravimetric Analysis
REFERENCES
1. Fred W.Bill Meyer ,JR Text Book Of Polymer Science ,Page 301,3d Edition ,.New York,(1984).
2. M.S.Han, H.C.Jung, J.H.Park, J.C.Hyun and W.N.Kim, Korean J. Chem.Eng., 19,337(2002).
3.S.Steinmann, W.Gronski, C.Friedrich, Polymer, 42, 6619(2001).
4. V.Suthar, A.Pratap and H.Raval, Bull.Mater.Sci. 23, 215(2000).
5. Seyed Ahmad Mirshokraei.Organic Chemistry.Vol .3.(1991)
6..P.Bahadur, N.V.Sastry.Principles of Polymer Science;India(2003)
۷.D.R.Paul.Seymour New man.Polymer Blends.V.2.P(406)