Abstract/Details

Nano-particulate dispersion and reinforcement of nanostructured composite materials


2005 2005

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Abstract (summary)

This research investigated the feasibility of reinforcing polymer composites using 30 nm SiC nanoparticles in a vinyl ester resin. The SiC nanoparticles were examined using transmission electron microscopy and thermogravimetric analysis. Gamma-methacryloxy propyl trimethoxy silane (MPS) was chosen as the coupling agent. Both mixing procedures with (1) the nanoparticles pretreated with a dilute MPS solution in an acid 5% (v/v) water-ethanol mixture and (2) the MPS sonicated as an integral blend with the filled vinyl ester, were attempted. Fourier transform infrared spectroscopy was used to study the silanol condensation between MPS and the SiC nanoparticles. The results show that ultrasonic mixing did not fully disperse the particles. Hence the composite strength did not improve although the modulus increased. The use of MPS improved the dispersion quality and hence the composite strength.

The rheological behavior of SiC nanoparticle-filled vinyl ester resin systems was evaluated in terms of the Bingham, power law, Herschel-Bulkley, and Casson models. Even when the particle loading was less then 4% by weight, the viscosity of the nanoparticle suspension was found to increase much more than that of a microparticle suspension. This phenomenon may be the result of association between nanoparticles and polymer molecules, effectively making the nanoparticles larger. The resulting reduction in the mobility of polymer molecules also led to delayed curing. The maximum particle loading corresponding to infinite viscosity was determined as 0.1 volume fraction using the (1 − η r−1/2) − &phis; dependence. The experimental optimum fractional weight per cent of the dispersants (wt. % dispersant/wt. % SiC) was found to be around 40% for 30 nm SiC nanoparticles, which is in close agreement with the theoretically calculated monolayer coverage dosage of 67%.

Indexing (details)


Subject
Materials science
Classification
0794: Materials science
Identifier / keyword
Applied sciences; Composite materials; Dispersion; Nanoparticulate; Nanostructured; Reinforcement
Title
Nano-particulate dispersion and reinforcement of nanostructured composite materials
Author
Yong, Virginia Hiu-Hung
Number of pages
109
Publication year
2005
Degree date
2005
School code
0031
Source
DAI-B 66/05, Dissertation Abstracts International
Place of publication
Ann Arbor
Country of publication
United States
ISBN
054213456X, 9780542134562
Advisor
Hahn, H. Thomas
University/institution
University of California, Los Angeles
University location
United States -- California
Degree
Ph.D.
Source type
Dissertations & Theses
Language
English
Document type
Dissertation/Thesis
Dissertation/thesis number
3175201
ProQuest document ID
305002773
Copyright
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
http://search.proquest.com/docview/305002773
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