Doping Modification Of Poly(Ether-B-Amide 12) And Its Research Of Thermoelectric Performance

Energy is the foundation for the development of human society,while the novel green and renewable energy will be the direction in the future.Thermoelectric(TE)power generation is an appealing,eco-friendly energy harvesting technology capable of converting temperature gradients into electricity.In this thesis,we studied and explored the TE properties of the poly(ether-b-amide)(PEBA),which has been produced industrially with good flexibility and have not any relate reports in TE field.PEBA is a semi-crystalline block polymer containing crystalline polyamide(PA)and amorphous polyether(PE),which gives PEBA a lot of unique properties between thermoplastic and rubber.In this work,we prepared the flexible TE thin films used PEBA as the matrix.The research content is as follows:1.The film-forming methods of the PEBA were firstly discussed and the solvent evaporation way was regarded as the best.After doping PEBA with Lithium chloride(PEBA-Li+),we obtained the PEBA-Li+ composite.The samples before and after dopping were characterized,which confirmed the complexation between Li+ and the ether oxygen([EO])induced the micro phase separation.Which is beneficial to the movement of the soft segment and the transportation of ions.Finally,the conductive performance of PEBA will be improved.The morphology characteristics show that the PEBA-Li+sample is orderly lamellar morphology and the fractured molecular chain connected to formed the network,while the PEBA sample is disordered microstructure.The conductivity testing results show that the conductivity increased from 10-10 to 10-6S·m-1 with the[EO]unit to[Li+]mass ratio of 12.2.The Lithium salt doped PEBA as the matrix via blending P type high purity carbon nanotube(CNT),the P type PEBA-CNT bilayer heterogeneous film(BHF)was obtained.Next,we prepared the N-type DETA-CNT by diethylenetriamine(DETA)doping,and then,The N type PEBA-CNT BHF was also obtained.The micromorphology of two types CNT were characterized by SEM and TEM.The results show the modified DETA-CNT disorder increased,turn into bent and present the bamboo shaped structure.FTIR-ATR,XRD and RAMAN are also confirmed that the graphitization degree of DETA-CNT is decresed.These results show the P type CNT successfully converted into N type.A series of characterizations were performed to show the Top(T)and Bottom(B)layers of the two types BHF.The results indicate that the T layers of both BHFs show polymer matrix properties,while the B layers equipped with CNT properties.The Seebeck coefficient(S)and electrical conductivity(a)(under the application of temperature gradient 20 K)for the obtained P type BHF are 36.88 ?V·K-1 and 456 S·m-1,for the N type BHF are-33.25?V·K-1 and 492 S·m-1,respectively.We constructed a novel TE device by integrating P and N type elements.The results showed that generated TE voltages for the module made of 3 TE couples was able to reach 120 mV for a temperature gradient of 60 K.3.The GOx-PA6 composites were prepared by in-situ polymerization(x represent the content of GO).Chracterization techniques such as SEM,FTIR-ATR,XRD,DSC,et al.demonstrate the GOx-PA6 composites have been fabricated successfully and graphene has been obtained by oxidation-reduction method via in-situ polymerization.The micromorphology of GOx-PA6 composites show that the bright strips in the SEM images are graphene bundles coated with the polymer.The bright strips increased with the increasing of x and starts to bend.The PEBA-GOx-PA6 films are obtained via the GOx-PA6 composites as the dopants which introduce both conductive phase and the compatible phase.The SEM characterizations indicate that the bright strips became brighter and the bent degree increased with the increasing of x.These rusults are beneficial to build more effective conductive networks and to improve the conductivity of the PEBA matrix.The conductivity tests of the PEBA-GOx-PA6 films are performed and the conductivity of the PEBA-GO0 6-PA6 film is 10-5 S·m-1.