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Smart Materials Congress 2019
Nano Research and Applications
ISSN: 2471-9838
Page 36
August 01-02, 2019
Dublin, Ireland
Smart Materials and
Structures
8
th
International Conference on
Sonia Norouzi Esfahany et al., Nano Res Appl 2019, Volume 05
Tunning switch temperature of shape memory
polyacrylamide hydrogel
Sonia Norouzi Esfahany, Mehrdad Kokabi
and
Ghazaleh Alamdarnejad
Tarbiat Modares University, Iran
I
n this work, chemically cross-linked polyacrylamide
(PAAm) hydrogel prepared by free radical polymeriztion.
Theeffectofwatercontentonglasstarnsitiontemperature
(Tg) of hydrogel, as switch temperature of shapememory
system, was investigated using dynamic mechanical
analysis (DMA). The transition temperature, i.e. the
desired switch temperature for our work, was chosen
around ~ 30
o
C by tunning thewater content of hydrogel at
25%, Fig. 1. Shapememory behaviour of chosen hydrogel
was investigated for a full cycle, i.e. four steps, by DMA.
The four steps procedure performed at a constant
heating/cooling rate of 5
o
C.min-1. First, the sample
was heated to 50
o
C (above the switch temperature) and
stretched to a certain strain (ε) under a constant force
(Step 1). Then, the deformed sample was cooled to -50
o
C
under the fixed force (Step 2). The force then removed
and the temporary strain was measured (Step 3). Finally,
the sample was reheated to 50
o
C and kept for 50 min in
this temperature, then the recovery strain recorded (Step
4). The shape fixing ratio and shape recovery ratio as the
main characteristics of shape memory polymeric system
calculated from Fig. 2. The results indicated that the
shape fixing ratio and shape recovery ratio of the system
were 96% and 78%, respectively. Recovering to orginal
shape was started around 10
o
C. The sample showed
good shape fixity because of existence the hydrogen
bonds between PAAm and water. Hydrogen bonds as
physical cross linkers could improve structural strength
of the sample.
Biography
Miss S. Norouzi Esfahany has just completed her MSc from
Tarbiat Modares University. This article is a portion of her MSc
thesis.
Snes.69@gmail.comFig 1. DMA curve PAAmwith 25% water.
Fig 2. Shape memory behavior of PAAm
with 25% water.