"Preparation and characterization of polystyrene- B-poly (Ethylene-Co-Butylene) - B-Polystyrene thermoplastic elastomer"

Date

10-2011

Degree

Bachelor of Science in Applied Physics

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Lou Serafin M. Lozada

Abstract

Graphite is one of the widely used inorganic fillers in polymer matrices because of its desirable properties and structure. The most ideal filler must have a very small particle size but a high aspect ratio, of which are characteristics of expanded graphite nanocomposites (xGnP). There is also a demand on improving the mechanical properties of thermoplastic elastomers like polystyrene-b-poly (ethylene-co-butylene)-b-polystyrene triblock copolymer or SEBS. SEBS/graphite nanocomposite films were prepared in different weight percentage xGnP (0.0wt%, 1.0wt%, 2.5wt% and 5.0wt%). xGnP was prepared via acid treatment, heat treatment and ultrasonic powdering technique. The composite was prepared via solution blending in chloroform (CHC13) and the composite film was prepared via compression moulding. The SEM verified the presence of graphite in the SEBS matrix. Sizes of particles ranged from 80 to 850 nm. Structural flaws in form of cracks and folds were present in SEBS/xGnP composite films. The intensity of these flaws tend to lessen in increasing xGnP loadings. The FTIR spectra verified the functional groups present in pure SEBS. SEBS/xGnP films contain C — 0 and 0 — H that verified oxidation of some carbon bonds on the graphite surface. These functional groups facilitate physical and chemical interactions between SEBS and xGnP. Tensile properties were obtained following ASTM D412. xGnP acted as impurities to the SEBS matrix which decreased its tensile properties. However increasing loadings of xGnP increases the tensile strength. In line with SEM and FTIR results, there was an increased physical and mechanical interaction brought upon by lessened fracture propagation in higher xGnP loadings, thus fixing individual chains in position to resist deformation and matrix break up.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

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Document Type

Thesis

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