Synthesis and Physical Properties of UV Curable Liquid-Crystalline Acrylate Nanocomposites
Date Issued
2010
Date
2010
Author(s)
Wang, Ying-Da
Abstract
In this research, we have synthesized and utilized a liquid crystalline(LC) acrylate, 4,4''-bis(3-Hydroxy- alkyloxy) biphenyl diacrylates(B3A). We have photo cured the B3A either at LC state or at isotropic state and compared the difference of cured properties between two state. Hardness of the sample with LC structure after photocure exhibits 20% higher than the amorphous one. The result is due to the self reinforcing effect from the LC structure remained in the sample after cured.
We further improved the physical properties of the B3A by incorporating nanofiller to from nanocomposite. We studied the effect of nanofiller on the formation of LC state in the cured sample. In the first part of this work, we added SiO2 particle which modified with 3-(Trimethoxysilyl) propylmethacrylate (MPS) in acrylate resin. SiO2 enhances its decomposition temperature (Td), storage modulus and glass transition temperature (Tg) effectively. But when the content of SiO2 is further increased, the increase in mechanical property is less significant. In the XRD study, the peak of LC structure is broader as increasing the content of SiO2. It shows that the increased amount of SiO2 decrease the domain size of LC structure. In the second part, nanofillers with different aspect ratios, TiO2 nanorod(TNR) and TiO2 nanoparticle(TNP) are added to acrylate resin to investigate their effect on the LC structure formation and self-reinforcing effect. In TNR nanocomposite series, when we increase TNR contain to 2wt%, that is difficult to find large domain LC structure under POM analysis. Due to the increased amount of TNR limit the formation of LC structure. The trend in TNP nanocomposite series matched up with the trend in SiO2 composite series, but the effect on the physical properties by TNP is less obvious.
In conclusion, we observe that the nanocomposites are dependent on the inorganic nanofiller’s shape and the interface interaction of polymer-inorganic. Additionally, the properties of nanocomposites are also affected by the presence of LC structure.
Subjects
self-reinforcing
acrylic resin
liquid crystalline
nanocomposites
SiO2
TiO2
photo-cure
mechanical property
Type
thesis
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