| With the rapid development of the aerospace and other fields, the material requirements which researchers have for are increasingly demanding. In response to this demand, the smart materials become an important direction of development. The shape memory material which is the darling of the smart materials has attracted wide attention.But how to enhance the uniformity good dispersion in the shape memory polymer is a big problem in the years of exploration. At the same time, the shape memory process of most shape memory polymers is one-way. This problem also led its application to be limited. In order to solving the above two problems, this article makes use of enhancing carbon nanotubes uniform dispersed in the shape memory polymer composites as the way, utilize the polymer composite microstructure, is based on cross-scale design. And this article makes the use of carbon nanotube sponge perfusion mode designing shape memory polymer composite materials. At the same time, composite materials have been prepared, characterized and the drive mechanism has been analyzed. The target is to enhance the shape memory polymer composites response speed and bi-directional drive. The composite physical state, chemical status and performance were characterized. This article analyzed and explained the shape memory drive mechanism. Its main contents are as follows:In order to the carbon nanotubes can be dispersed in a good shape memory polymer without forming agglomerates, This article prepared in advance macroscopic threedimensional CNT sponge with good dispersion characteristics by chemical vapor deposition. We know that CNT sponge consists of nanotubes with a diameter of 20 nm and the wall thickness of 5 nm and is overlap one another, staggered from a porous interconnected network by SEM, TEM characterization. And measuring the surface area and the macroscopic properties of electrical conductivity, the results show that the specific surface area of the carbon nanotube sponge is 35 m2/g, and electrical conductivity is 364.5 S/m.The CNT sponge conductivity good macroscopic three-dimensional porous material. It also happens to provide the basis for good performance and build electroluminescent shape memory polymer improved.In order to obtain a carbon nanotube sponge reinforced shape memory polymer composites which has mass fraction of 97.8 % and a density of 0.1 g / cm3, this article adopts immersing method which shape memory polymer was poured into a carbon nanotube sponge, and eventually fabricated out of the composite material by the gradient solidification method. SEM characterization showed that the mutual overlapping between the carbon nanotubes cannot be destroyed. The electrical properties tests indicated that the conductivity of the composite material 123.5 S / m.Through the study of response times under different response voltage unidirectional composites, this law which with the voltage increases, the composite response time becomes shorter and the response time constant after loading 17 V, was revealed. This article utilized composite surface temperature distribution using infrared cameras to analyze the shape memory composite fast driving mechanism which time is within 8 s. DMA characterization experiments show that the composite material which highest storage modulus was 2.96 GPa, enhanced 0.6 GPa than the pure shape memory polymer. Composite glass transition temperature was 98.9 ℃, increase 8.1 ℃ than the pure shape memory polymer. The restoring force of the composite material is 14.07 N, improve 11.3 N than pure shape memory polymer. This article established the bi-directional electric drive model while to build a two-way shape memory composite. The law which with the conversion cycle voltage increasing, moving distance of composite materials becomes larger and larger, and finally the voltage conversion period after 120 s reply is not changed, was disclosed. The robot which imitated motion of inchworm and has 0.8 mm / min steady moving speed was manufactured... |
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