In this paper shape memory effect of shape memory composite in magnetic field was studied. The shape memory
composite was filled by nickel powder, and the nickel powder was treated by silane coupling agent. The Tg of shape
memory composite was measured by dynamic mechanical analyzer. The surface element of treated nickel powder was
analysized with FT-IR. Furthermore, the dispersion of nickel powder in polymer was observed by SEM. The results
indicated that the shape of composite filled by untreated nickel powder did not change in the magnetic field, while the
composite filled by treated nickel powder was drawn in the magnetic field. The tensile stretch was decrease with the
increase of nickel powder content in the shape memory composite. The addition of silane coupling agent onto nickel
powder surface was helpful for the dispersion of nickel in polymer.
This paper is concerned about the influence of radialization dosage on performance of shape memory styrene copolymer.
In this paper, the glass transition temperature (Tg) of styrene copolymer was measured by Dynamic Mechanical Analysis
(DMA). The shape memory performance of styrene copolymer before and after radiation was also evaluated. Results
indicated, the gel content of radiated styrene copolymer decreased by 14.3%, tensile strength reduced by 16.7% and
slightly increase in elongation break. The storage modulus decrease sharply and the range of glass transition become
narrower; the loss modulus reduces. In radiated styrene copolymer was not new peaks and the just height of the previous
peaks varies in the spectra. It indicates, there are no oxidized reaction in the process of radiation. The shape recovery is
conducted at different temperature for the SMP and radiated SMP. Below 85°C, the recovery speed of radiated SMP is
faster than that of SMP without radiation. Above 85°C, the recovery speed of SMP is faster than that of radiated SMP. It
can be explained as: after the radiation, the degradation of the polymer occurs, the chain of the molecule become shorter,
the Tg decreases, and the storage modulus reduces consequently.
This paper is concerned about the drive of shape memory styrene copolymer through an infrared optical fiber carrying
infrared laser. The infrared laser was chosen to drive the SMP through the optical fiber embedded into the SMP. The
working frequency of infrared laser was installed in 3-4μm, the working band of optical fiber was 1-6μm. An optical
fiber was embedded into the SMP for delivery of 3-4μm laser light for activation. The surface of the optical fiber was
etched by the aqueous solution of sodium-hydroxide in order to increase transmission efficiency of the optical fiber. We
synthesized thermoset SMP based on styrene copolymer, and measured Tg of SMP is the 53.7oC by the DMA. The
thermally activated SMP is possible to initiate an originally shape by a touchless and highly selective infrared laser
stimulus. The infrared laser-activated SMP could be recovered its original shape by less temperature than Tg, it was
proved this driving method of SMP is more effective than conventional external heaters. Therefore infrared laser-activated
method was advantageous for using in the low temperature condition. The increase in temperature of SMP
which was embedded treated optical fiber indicated that the infrared laser irradiated into the SMP from here and heated
the SMP. The optical fiber was treated by the aqueous solution of sodium-hydroxide, transmission efficiency of the
optical fiber increased, and the total contact area between SMP and the optical fiber. The infrared laser stimulation of
SMP was interest for actuator systems as well as medical applications.
Shape memory polymer (SMP) can recover its original shape under the effect of the external stimuli. Its primary
advantages over other smart materials are the high strain capacity (200% reversible strain), low density and low cost. The
series of SMP based on styrene with the different cross linking agent were synthesized and the influences of cross
linking agent on the shape memory effect (SME), thermo mechanical properties and gel contents were investigated.
The investigation was conducted with experimental methods: swelling method, Dynamic Mechanical Analyzer (DMA),
static, FT-IR spectra and shape recovery tests. The glass transition temperature (Tg) of SMP based on styrene increased
from 35°C to 55°C, and the gel content increased from 0% to 35% with increasing the dosage of cross-linking agent from 0% to 1%. The shape memory behavior of SMP with different mass fraction cross-linking agent was investigated.
SMP could fully recovery its original shape as the activate temperature of SMP was above or equal to Tg. The recovery
rate of SMP became faster with increase of active temperature, and SMP with more cross-linking agent is faster than
other SMP.
This paper is concerned about the synthesis of shape memory styrene copolymer and the investigation of the influence of
cross-linking degree on its shape memory effect. As one of novel actuators in smart materials, shape memory polymers
(SMPs) have been investigated intensively. Styrene copolymer with proper cross-linking degree can exhibit shape
memory effect (SME). In this paper, the influence of cross-linking degree on shape memory effect of styrene copolymer
was investigated through altering the dosage of cross-linking agent. The cross-linking degree of styrene copolymer was
determined by measuring the gel content. The glass transition temperature (Tg) of styrene copolymer, which is
determined the cross-linking degree, was measured by Dynamic Mechanical Analysis (DMA). The shape memory
performance of styrene copolymer with different cross-linking degrees was also evaluated. Results indicated that the
shape memory polymer (SMP) was synthesized successfully. The Tg increased from 55°C to 80.7°C followed by
increasing the gel content from 0% to 80% through increasing the dosage of cross-linking agent from 0% to 4%.
Moreover, the SMP experienced good SME and the largest reversible strain of the SMP reached as high as 150%. When
heating above Tg+30°C (different copolymers performed different Tg), the shape recovery speed of the copolymers
increased with increasing the gel content. However, the recovery speed decreased with increasing the gel content at the
same temperature of 95°C.
This paper is concerned about an investigation of mechanical and electrical conductive properties of carbon fiber fabric
reinforced shape memory polymer composite (SMPC). The shape memory polymer (SMP) is a thermoset styrene-based
resin. SMP is a promising smart material, which is under intensive investigation at present. Its primary advantages over
other smart materials are the high strain capacity (200% reversible strain), low density and low cost etc.. But its major
drawbacks are low strength, low modulus and low recovery stress. So the fiber reinforced SMPC was naturally
considered to be investigated in this paper, which may overcome the disadvantages mentioned above. The investigation
was conducted with experimental methods: Dynamic Mechanical Analyzer (DMA), static and mechanical cycle loading
tests, microscope observation of microstructural deformation mechanism, conductivity and shape recovery tests. Results
indicated that SMPC showed higher glass transition temperature (Tg) than neat SMP and improved the storage modulus,
bending modulus, strength and resistance against relaxation and creep. Both fiber microbuckling and fracture of SMPC
were observed after the static 3-ponit bending test at the constant room temperature. SMPC showed favorable recovery
performances during thermomechanical cycles of the bending recovery test and the fiber microbuckling was obvious.
Moreover, the conductive SMPC of this study experienced low electrical resistivity and performed a good shape memory
effect during numerous thermomechanical cycles.
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