Fabrication of Crosslinked Block Copolymer Nanoparticles Using Cold Vulcanization
- PDF / 603,658 Bytes
- 6 Pages / 595 x 842 pts (A4) Page_size
- 34 Downloads / 254 Views
1135-CC03-12
Fabrication of Crosslinked Block Copolymer Nanoparticles Using Cold Vulcanization
Sungwon Ma and Yonathan Thio School of Polymer, Textile and Fiber Engineering, Georgia Institute of Technology, 801 Ferst Dr. NW, MRDC 1, Atlanta, GA 30332-0295, USA
ABSTRACT The aim of this study is to understand the crosslinked system of poly(styrene)-bpoly(isoprene) copolymer using cold vulcanization process as a facile method to produce anisometric nanoparticles. The morphologies of block copolymers could be controlled by the type of monomers, block junction, composition, and block size. A systematic methodology, utilizing cylindrical and lamellar morphologies of PS-b-PI copolymer, was used for producing fiber and sheet shaped nanoparticles. The cold vulcanization process was accomplished using sulfur monochloride (S2Cl2) as crosslinking agent. The microstructures and crosslinking density of crosslinked PS-b-PI copolymers were imaged and characterized. This study demonstrated the crosslinking of microphase separated block copolymer as a method to create particles with controlled size, shape, and physical properties.
INTRODUCTION Block copolymer self-assembly techniques have been used for many applications during the last 30 years1-4. By controlling length, shape, and number of blocks, various morphologies can be generated and designed5. Block copolymer is defined as a polymer which consists of two or more distinct blocks linked by covalent bond. One of the advantages of block copolymer is that two or more physical properties can be involved in one macromolecule. Theoretical and experimental research have been conducted for understanding their structure and properties6-9. This study shows nanoparticle structures generated from PS-PI block copolymer. The particles are formed by phase separation of PS-PI block copolymer and maintained by crosslinking of the polyisoprene block, which acts as a core structure. These anisometric nanoparticles have potential applications as nanocomposite, membrane, tissue engineering material etc. Liu et al.10 published nanofiber form of PS-PI block copolymer from cold vulcanization process. Based on his method we have generated nanofiber and nanosheet structures and we will investigate other geometries.
EXPERIMENT Two PS-b-PI copolymers were purchased from Polymer Source Inc. All reagents were purchased from Aldrich and used without further purification. PS-b-PI diblock copolymers were dissolved in 10 wt% toluene solution with stirring for 12 hrs. The solutions were poured into a glass Petri dish for making film. The cast films were dried under a nitrogen condition in a glass chamber for evaporating the solvent. After 3 days, the films and S2Cl2 were placed into same glass chamber. The crosslinking reaction was occurred by S2Cl2 vapor. In order to get different exposure condition, the films were taken out by different time (1hr, 3hr, 7hr, 12hr, 24hr, and 49hr). Composite samples were prepared to predict the mechanical properties of PS-PI nanoparticles indirectly. Solvent casting method
Data Loading...
