Synthesis and Applications of Polymer Composites and Derivatives

聚合物複合物及衍生物的製備與應用

Student thesis: Doctoral Thesis

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Author(s)

  • Wei CHEN

Detail(s)

Awarding Institution
Supervisors/Advisors
  • Feng WANG (Supervisor)
  • Xianfeng CHEN (Supervisor)
Award date25 Aug 2016

Abstract

Polymer composites and derived materials are two types of materials used in a variety of applications, ranging from household stuff to aerospace items. In this thesis, several types of polymer composites and coordination polymer (MOFs) derived materials were developed and used in biomedical and energy fields.
We first describe a class of polyvinylpyrrolidone (PVP)/cyclodextrin (CD) complex. PVP has been used in food and pharmacy industry for decades. Using PVP as a material to prepare microneedles has a biocompatible advantage. However, the high water absorption and weak mechanical properties limit its application. In Chapter 4, we solve these problems by adding cyclodextrin to form PVP/CD complexes. PVP/CD complexes were formed by mixing non-stoichiometric CD to the PVP solution. The formation of complexes not only leads to the decreased water absorption but also results in the improved mechanical and thermal properties. Compared with PVP microneedles, the complexes microneedle has a more competitive advantage in drugs, vaccines, and macromolecules delivery. Another type of polymer composite is ZIF-8/PVA (Chapter 5). Coordination polymer can be used in gas separation because of their high porosity and small pore size. Preparation of coordination polymer composite is an important step in its practical application. A polymer is a good matrix candidate for its easy processability and film-forming ability. To develop a ZIF-8/PVA film, ZIF-8 nanorods were prepared as high aspect ratio will promote MOFs’ overlap and reduce the defects. ZIF-8 nanorods were synthesized using the F127 as a capping agent for the first time. Through controlling the F127 concentration, various sizes of nanorods could be obtained. Then, a ZIF-8/PVA composite with a layered structure was formed by a vacuum filter method. This composite has potential applications in gas separation and barrier.
We also prepared graphitic carbon nanocubes and Fe3O4/carbon nanohybrids by pyrolysis of coordination polymer precursors. As is known, carbon materials including carbon nanotubes and reduced graphene oxide could be used in photothermal therapy. But the non-porous structure and wide size distribution are their limitations. Hence, new graphite carbon nanocubes (GCNCs) with a porous structure and a narrow size distribution were prepared by pyrolysis of ZIF-8 nanocubes (Chapter 6). The graphite structure promotes its photothermal performance. In vitro tests demonstrate that the GCNCs are highly biocompatible and can induce an effective photothermal therapy under an 808-nm irradiation. Considering the high flexibility of designing metal-organic frameworks, this work paves a convenient way for synthesizing novel porous photothermal agents with various morphologies and pores. In a separate investigation, we demonstrate that porous carbon/metal oxide composite electrode can be prepared by a one-step pyrolysis of Fe-MIL-88B-NH2 under N2 atmosphere (Chapter 7). Temperature dependent performance studies reveals a dramatically enhanced specific capacitance of the composite electrode at elevated temperatures. Additionally, the composite electrode can hold the capacitance even the temperature changing rapidly. This work may provide a convenient route for fabricating porous carbon/metal oxide electrode with excellent electrochemical performance.