| Summary: | 碩士 === 國立成功大學 === 化學工程學系 === 84 === From the development history of polyester PET,
transesterification process using DMT has been replaced by the
direct esterification process using TPA.The trend will be
applicable to polyester PBT,however during the direct
esterification TPA(Pka=3.5)can release H+ that will cyclize BDO
to THF,the TPA Process can't compete with DMT process.Ti is a
good catalyst for the synthesis of PBT,but the yield of
byproduct of THF is still high.In order to reduce the amount of
THF,some basic catalyst was added to neutrialize the released
H+.The experimentalresults indicated that ceriain basic catalyst
with suitable Pka can reduce THF formation.Next,in order to
improve the heat resistance and modulus of phenyl polyester,some
naphthyl polyester have been developed ,such as ,polyethylene
2,6-naphthalate(PEN),polybutylene 2,6-naphthalate(PBN).However
the price of starting naphthalene material is pretty high,
therefore,copolymers containing both naphthalene and phenylene
unit were developed.From DSC,TGA and DMA analysis,PBNT have
exhibited better thermal and mechanical properties than PBT.From
NMR,we can determine its composition and find its sequence as
random.
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