臺灣博碩士論文加值系統

本研究第一部分為合成3,3- 雙(氯甲基)環氧丙烷(3,3 -bis (chloro-
methyl)oxetane;BCMO)作為主幹單體(back-bone monomer), 和四種液晶
基團:A1:4-methoxybenzyl-idene-4'-aminophenol, A2:4-
cyanobenzylidene -4'-aminophenol,B1:4-methoxyphenylazo-4'-
phenol,B2:4-cyanophenyl- azo-4'-phenol, 及具有不同亞甲基烷鏈(-(
CH )n-; n=0,4,6)連結在BCMO與液晶基(A1-B2) 間的3,3-雙(甲基衍生
物) 環氧丙烷液晶單體。證明BCMO擁有同一碳上可掛接兩個液晶基團藉以
提升單位單體液晶的特性 , 和四元環為有利於液晶性質呈現的結構。本
研究第二部分以自行合成的BCMO單體,以1,4-丁二醇為分子量控制劑(起始
劑)、BFETO 為催化劑及控制活性單體與起始劑的進料比例為條件之下 ,
聚合得窄分布低分子量的均一聚合物 3,3-雙(氯甲基)聚環氧丙烷(poly
3,3-bis(chloromethyl)oxetane ;PBCMO ), 再利用化學接枝法合成兩系
列 (PB-0及PB-6系列) 側鏈型聚環氧丙烷液晶聚合物。證明導入柔軟鏈(
spacer)於高分子主鏈和側邊液晶基之間時,有助於抵消高分子主鏈本身的
擾動 , 並表現出小分子液晶的特性及玻璃轉移溫度(Tg)、結晶熔點(Tm)
、等方向液體溫度 (Ti) 等轉移溫度(transition temperature ) 會隨液
晶基取代度之增加而有所提昇, 且當取代度達50%以上時有利於液晶性質
的呈現。本研究第三部分為合成 BCMO -THF 的共聚物作為高分子主鏈,
利用化學接枝法取代液晶基, 而得側鏈型液晶共聚物。證明共聚物本身可
提供柔軟性極佳的高分子主幹, 低玻璃轉移溫度,並有助於降低化學接枝
反應進行時的立體障礙, 提昇液晶基取代度, 更有利於液晶性質的呈現。

In the first part of this study, 3,3-bis(chloromethyl)oxetane
(BCMO) was synthesized as the backbone monomer . Four
different mesogenic groups: A1 - B2 and various methylene
groups were used with BCMO to prepare several LC monomers. The
characteristic of two mesogens attached on the same carbon atom
of BCMO can raise the density of unit liquid crystalline
monomer has been proved . The structure of oxetane ring is
in favor of the appearance of LC property has also been
studied. In the second part,1,4- butandiol was used as the
molecular weight controller and BF3- ET2O as the catalyst.
BCMO monomer was polymerized to obtain the PBCMO, which is a
homopolymer with low Mw and narrow M.W. dispersity by
changing the feeding ratio of active monomer vs.
initiator. The polymer was usedto synthesize two series of
side chain LC polyoxetanes by chemical modification. The
incor- poration of methylene groups betwwen PBCMO and mesogens
indicate the characteristic of LC molecule due to the
decoupling of pertubation of polymer backbone. Increasing the
degree of sub- stitution of mesogen, the obtained polymer
showed higher glass transition temperature, melting
temperature, and clearing tem- perature. In addition, as the
amount of substitution of mesogen up to 50 %, the polymer can
be easily to exhibit LC property. In the third part, (BCMO/
THF) copolymer used as the polymeric backbone was reacted to
attach the mesogen to polymer backbone by chemical
modification. The steric hindrance of chemical graft reaction
is reduced due to these obtained SCLCPs with more fle- xible
polymer backbone. Therefore, the degree of substitution of
mesogen into these polymers can be increased easily , which is
in favor of the appearance of LC property.