Photonic crystals in biology

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P
P and
Poster Session, Tuesday, June 15
Synthesis and Characterization of Polymers with Triptycene Unites by Photopolymerization and
Polystyrene Possessing Triptycene Units in The Main Chain by Combination of Atrp and Click
Chemistry Processes
1
ULokman TorunUP
1,2
P*, Sahin AtesP
P, Binnur AydoganP P, Yasemin D. YukselP
1
PChemistry Institute, TUBITAK MRC, Gebze, Kocaeli, 41470, Turkey
PIstanbul Technical University, Department of Chemistry, Maslak, 34469, Istanbul, Turkey
2
2
2
2
Yusuf YagciP
Theme A1 - B702
Abstract-We predict that a single ethylene molecule can form a stable complex with two transition metals (TM) such as Ti. The resulting TMethylene
complex then absorbs up to ten hydrogen molecules, reaching to gravimetric storage capacity of ~14 wt%. Our results are quite
remarkable and open a new approach to high-capacity hydrogen-storage materials discovery.
In this work, we herein report synthesis, characterization and
photocuring behavior of a new cross-linker based on triptycene
molecule. Photopolymerizations were performed with the formula
tions containing triptycene hydroquinone diacrylate (THDA)
together with monofunctional monomers glycidyl methacrylate
(GMA), 2-hydroxyethyl acrylate (HEA), 2-hydroxyethyl
ethacrylate (HEMA), and 2-ethylhexyl methacrylate (EHMA), by
using 2,2-dimethoxy-2-phenylacetophenone (DMPA) as the
photoinitiator. Comparative photopolymerization studies were
also performed by using structurally similar cross-linker,
hydroquinone diacrylate (HDA) which does not possess
triptycene unit. Photopolymerization kinetics was analyzed for
different compositions of monofunctional monomers and crosslinked
agents by using photo-differential scanning calorimeter
(photo-DSC). Each monofunctional monomer was reacted with
varied percentages of a difunctional monomer HDA and THDA
respectively to observe the influence of triptycene based crosslinker
on rate of polymerization [1].
Figure 2. Synthesis of the cross linkers.
Photopolymerizations of several monomers using either HDA
or THDA were followed by DSC under identical conditions of
2
temperature (30 °C) and UV light intensity (18.4mWcmP P).
Schematic representation of photoinduced cross-linking is shown
in Figure 3. As can be seen triptycene units are chemically
incorporated to the network after photocuring process.
Figure 1. Overall process for copolymerization of azide terminated
bifunctional polystyrene (NR3R-PS-NR3R) by “click” chemistry.
In addition, In this work, we report synthesis of polystyrene
possessing triptycene unit in the main chain by the combination of
ATRP and click chemistry process. Bromine terminal groups of
polystyrene obtained by ATRP converted to azide functionality
by simple nucleophilic substitution by using NaNR3R. Bisalkyne
functional triptycene compound was independently synthesized
for the subsequent click reaction. Bisazide and bisalkyne
functional compounds with long alkyl chain were also prepared
and used as comonomers [2]. The cross-linkers were synthesized
by the acylation of the respective hydroquinone compounds with
acryloyl chloride (Figure 2).
The H NMR spectrum of HDA showed characteristic peaks for
acrylic protons at 5.6 ppm, 6.0 ppm and 6.4 ppm, and aromatic
protons at 7.1 ppm. In the spectrum of THDA, while the signal at
8.9 ppm corresponding to –OH protons of the precursor TH
completely disappeared, new signals originating from acrylic
protons appeared at 6.1 ppm, 6.5 ppm and 6.7 ppm.
Figure 3. Schematic representation of photoinduced cross-linking of vinyl
monomers using triptycene hydroquinone diacrylate (THDA).
In conclusion, in the first part we report synthesis of polystyrene
possessing triptycene moiety in the structure by combination of
ATRP and “click” chemistry. The intermediates and the resulting
polymers were caharacterized by spectral and thermal analyses
methods. The effect of the triptycene moiety on the thermal
properties was demonstrated. In the light of present study and the
general behavior of triptycene molecules in polymer chains it is
expected that polymers with enhanced properties such as ductility
and stiffness can be obtained by ATRP combined with “click”
chemistry. Further studies on the investigation of these properties
are now in progress.
In the second part, we report synthesis of a new cross-linker
possessing triptycene moiety in the structure and characterized.
Moreover, its photopolymerization behavior in the UV curable
formulations containing different monofunctional monomers was
studied. Comparative kinetic studies revealed that the
polymerization kinetics are governed mainly by the structure of
the monofunctional monomer employed in the formulation and
triptycene type cross-linker acts in a manner similar to the
conventional cross-linkers. In the light of present study and the
general behavior of triptycene molecules in polymer chains it is
expected that cross-linked networks with enhanced properties
such as ductility and stiffness can be obtained by photoinitiated
free radical polymerization.
*Corresponding author: lokman.torun@mam.gov.tr
[1] Sahin Ates, Binnur Aydogan, Lokman Torun, Yusuf Yagci Polymer 51
(2010) 825–831.
[2] Sahin Ates, Yasemin Yuksel Durmaz, Lokman Torun, Yusuf Yagci, In
press. Journal of Macromolecular Science.
6th Nanoscience and Nanotechnology Conference, zmir, 2010 309