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The work is mainly to study the chlorination of
thermoplastic rubberswhich is styrenic copolymer.The experiment
will be divided into three parts anddiscussed as follows
seperately. First,the synthesis of high molecular weight
near-monodisperse poly(p-methylstyrene)is described.The
polymerizations were conducted using n-butyllithiumas the
initiator,cyclohexane as the solvent,and a little
tetrahydrofuran as the cosolventThe reaction doesn't take much
time and attains 90% conversion.When the reaction temperature is
lower than 30C ,the polydispersityis low.In the overall reaction
chain transfer or termination doesn't occure. The living
poly(p-methylstyrene)synthesized above is ,then,reacted with
isoprene to synthesized the poly(p-methylstyrene-isoprene-p-
methylstyrene).The molecular weight distribution is analogous to
typical synthetic rubber such aspoly(styrene-isoprene-styrene).
The coupling efficiency attains 60%.
ts.The reactionswere carried out
in mixtures of organic solvent and aqueous sodium
hypochloritethat was neutralized to PH=8.5 with HCl,in the
presence of the phase-transfer-catalystbenzyltriethylammonium
chloride.Accordingspectrum,the chlorinated position would be
different in different solvent.The most probably positions
thatwere chlorinated are :the allylic position,the benzylic
position and the methylgroup in isoprene.The addition reaction
wasn't found.
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