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TMI Blog1985 (9) TMI 229X X X X Extracts X X X X X X X X Extracts X X X X ..... correct item for assessment is Sub-item 2 as Articles of Plastic because polyvinyl alcohol is a modification of polyvinyl acetate and has been turned into an article i.e. a powder, which is used in textile industries, in sizing yarns, fabrics, and so on. The appellants have contested the assessment of PVA as a polyvinyl derivative. The learned counsel very vehemently declared that it is not a derivative because it is obtained by alcoholysis or hydrolysis. These processes are not polymerisation or co-polymerisation processes and therefore, it is not possible to fit PVA as a polyvinyl derivative with other polyvinyl derivatives. Derivatives that fit under item 15A(l)(ii) must be products of polymerisation or co-polymerisation. 3. The learned counsel quoted the CONDENSED CHEMICAL DICTIONARY By G. HAWLEY 9th Edition, according to which PVA is produced by alcoholysis or hydrolysis of polyvinyl acetate which alone is a product of polymerisation. The process of manufacture of PVA involves replacement of the acetate groups with hydroxyl groups, and the alcolysis proceeds most rapidly in a methanol methyl acetate mixture in the presence of catalytic amounts of alkali or mineral acids, ..... X X X X Extracts X X X X X X X X Extracts X X X X ..... es of application : By C.A. FINCH, it is written The starting material for the production of polyvinyl alcohol is not the monomer, but a polymerised ester. The polymerizations by which such esters are prepared are well known to be exothermic". 7. The learned counsel produced letters from Dr. H.L. Jindal and Dr. J.K. Parasher of Delhi University who confirmed that polyvinyl alcohol is a product of modification. 8. One argument that the learned counsel Mr. Krishnamurthy repeated a number of times was that polyvinyl acetate was not similar to any of the items listed in item 15(A)(l)(ii) and that it was not a product of polymerisation and co-polymerisation. On the principle of EJUSDEM GENERIS, it is not a polyvinyl derivative of the types mentioned in that sub-item and, therefore, does not fall with them since the scheme of the items lays stress on the process of manufacture. The learned counsel also pressed the fact that polyvinyl alcohol is an article made by hydrolysis of polyvinyl acetate, an item listed in 15A(l)(ii), and, therefore, by virtue of explanation below Item 15A(1), it is an article of plastic qualifying for benefit of exemption from additional duty under notifica ..... X X X X Extracts X X X X X X X X Extracts X X X X ..... because of its high cold flow, poly (vinyl acetate) is of little value in the form of moulding and extrusions. However, because of its good adhesion to a number of substrates, and to some extent because of its cold flow a large quantity is produced for use in emulsion paints, adhesive and various textile finishing operations. A minor proportion of the material is also converted into poly (vinyl alcohol) and poly (vinyl acetal) which are of some interest to the plastics industry. 15. Below, we reproduce the section article on Poly (Vinyl Alcohol) from the same book with the structure and process. The passages speak for themselves. Vinyl alcohol does not exist in the free state and all attempts to prepare it have led instead to the production of its tautomer, acetaldehyde, CH 2 = CH CH 2 CHO | OH Poly (vinyl alcohol) is thus prepared by alcoholysis of a poly (vinyl ester) and in practice poly (vinyl acetate) is used CH- - CH + CH 30H - CH 2 - CHOH | OOC.CH 3 + CH 3 COOH 3 The term hydrolysis is sometimes incorrectly used to describe this process. In fact, water does not react readily to yield poly (vinyl alcohol) and may actually retard reaction where ..... X X X X Extracts X X X X X X X X Extracts X X X X ..... kers have been known to develop fibre from polyvinyl alcohol. 17. The behaviour of polyvinyl alcohol results from the presence of the hydroxyl groups attached to the main chain the this has a number of significant effects. The polymer is hydrophilic and will readily dissolve in cold water. The structure of polyvinyl alcohol is atactic like poly vinyl acetate, but the former exhibit crystallinity whereas the latter is amorphous. Polyvinyl alcohol has the same crystal lattices as polyethlene, resulting from the fact that the hydroxylsis groups can fit into the lattice without disrupting it. 18. Hawley s THE CONDENSED CHEMICAL DICTIONARY defines polyvinyl alcohol as a water soluble synthetic polymer made by alcoholysis of polyvinyl acetate. It is to be noted that the Dictionary refers to it as a synthetic polymer. There seem to have been misunderstanding in the mind of the learned counsel for M/s. Sun Exports that because polyvinyl alcohol results from modification of polyvinyl acetate, it is not a polyvinyl derivative. 19. We have seen how Hawley s Dictionary defines Modification. It is only a chemical reaction in which some radicals of high polymer are replaced by other chemi ..... X X X X Extracts X X X X X X X X Extracts X X X X ..... be considered as too brittle a polymer. Because of this, polystyrene manufacturers have made a number of attempts to modify their products. The methods of approaching this problem include : 1. Use of higher molecular weight polymers. 2. Use of plastisizers. 3. Incorporation of fillers such as glass fibre, wood flour etc. 4. Deliberate orientation of polymer molecules. 5. Co-polymerisation. 6. The uses of orubber additives. Some of the books quoted on behalf of appellants also support this. 23. In PRINCIPLE OF POLYMER SYSTEM by Ferdinand Rodigvez on Polymer Modification we read : Whenever a polymer is formed in a several stages, each subsequent stage is a kind of polymer modification. All cross-linking reactions (the Vulcanisation) (rubber) would fall in this category together with the moulding of network polymer like the phenol formaldehyde resins. However, the term polymer modification is used here to mean changes wrought by the polymer manufacturer in an operation separate from the final moulding. Modifications are feasible when a polymeric raw material is available which can have its value enhanced substantially by the operation. Modification results in ..... X X X X Extracts X X X X X X X X Extracts X X X X ..... alcohol which is to unstable to have an independent existence. Polyvinyl alcohol is a polymer of the monomer vinyl alcohol although it had been arrived by circuitous routes, because the monpmer vinyl alcohol is impossible to isolate and to utilise in its free state. By modifying the chemical structure after the polymer, polyvinyl acetate has been made, a poly vinyl alcohol is obtained. Polyvinyl alcohol is a derivative of polyvinyl acetate, itself derived from vinyl alcohol. 26. The learned counsel for M/s. Sun Export would divide Item 15A(1) into virtually watertight Sub-items like (i) and (ii), the first carrying additions and poly-additions, condensation groups and the second polymerisation and. co-polymerisation products. Such a division is unscientific as will be shown by the following words at page 720 of Vol. 18 of Kirk-Othmer Encyclopaedia of Chemical Technology, which lay out the mechanism and processes of polymerisation: A polymerisation reaction is the conversion of a particular compound to a large chemical multiple of itself. There is some confusion resulting from the use of the term polymerization for reactions that form small cyclic compounds molecular weight ..... X X X X Extracts X X X X X X X X Extracts X X X X
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