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Study On Graphene Aerogels And Graphene/Nature Rubber Composites

Posted on:2016-10-03Degree:MasterType:Thesis
Country:ChinaCandidate:H S YangFull Text:PDF
GTID:2271330461993492Subject:Materials Processing Engineering
Abstract/Summary:PDF Full Text Request
By reading many papers and sufficient understanding of the fields of studies on graphene aerogels and graphene/NR composites, we found there are many shortcomings in the matter of preparation methods and technology. Therefore, this paper mainly innovated in the preparation methods of graphene aerogels and graphene/NR composites to introduce some new kinds of graphene aerogels and graphene/NR composites. Then, with the aid of various characterization methods, we had a systematic analysis and discussion on three aspects include material preparation, structure and properties. The three main aspects of our paper were showed as follows.First, we introduced a new method for the preparation of graphene aerogels, i.e., firstly using ambient pressure drying method instead of freeze drying and supercritical drying successfully fabricated superelastic graphene aerogels. In detail, by controlling the degree of reduction of graphene oxide, we used the freeze-melt method to reassemble the internal structure of graphene hydrogels, and obtained a structure can resist of the capillary force generated by the ambient pressure drying. SEM results show that the internal structure of aerogel is similar to cellular structure and has the largest aperture currently, which are the main reasons for the success of the ambient pressure drying. In the field of material performance, our graphene aerogels have ultralight and superelastic properties (density,2.5~8.3 mg cm-3; compressive strain, the biggest 93%), good energy dissipation ability, obvious anisotropy and good compression ability (more than 1000 times). In addition, in the process of cyclic compression, the change of its resistance is circular response, and it has the cyclic ability to absorb organic solvent. Therefore, our graphene aerogels have great application prospect. Comparing with freeze drying and supercritical drying, ambient pressure drying is a more economic, environmental method, more suitable for industrial production. Thus, our method is expected to realize the industrial production of graphene aerogels.Second, we proposed a new fabrication route to prepare NR nanocomposites with high graphene contents via vacuum-assisted self-assembly. In detail, we blend stable graphene suspension and NR latex to form the uniform mixture, then obtaining a membrane in the filter paper via vacuum-assisted self-assembly, finally drying and vulcanizing the composites. First, our preparation method achieved the aim that high content (> 10 phr) graphene evenly fill in the rubber matrix, which cannot achieved at the current preparation methods. Second, we researched on the effect of high content graphene on the structure and properties of NR composites, and got the high conductive and strong graphene/NR composites. Detailedly, the electrical conductivity (104 S m-1) of high content (30 phr) graphene/NR composites is two orders of magnitude higher than that low content (10 phr) composites. We also find the phase inversion in nanocomposite when the filler content is over 10 phr, and the tensile strength (48 MPa) and modulus (1.2 GPa) of the composites with 30 phr are significantly increased compared with NRThird, we introduced a kind of latex process to prepare of graphene/natural rubber composites, i.e., using dipping and after-reduction method successfully prepared the graphene/NR composite. In detail, we dipped the mould in the NR latex blended with high concentrations of GO solution to get the wet film and then dried the film. Finally, we after-reducted GO and vulcanized the composite membrane. By DSC and TG analysis and the composite membrane conductivity, we know that the after-reduction method is feasible even for low content graphene (2 phr) filled in the composite. In the rubber industry, there is a certain type of products which the traditional rubber process cannot produce, namely latex products. The current composite method cannot achieve graphene modifieding the latex products. Therefore, we first successfully prepared the graphene/NR composite used the immersion method most commonly used in the latex technology and make it into reality to get graphene/NR latex products.
Keywords/Search Tags:graphene, aerogel, ambient pressure dry, superelasticity, NR, high content, dipping method
PDF Full Text Request
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