Thesis-2005-Sukhummek.pdf (37.87 MB)
Polyurethane/poly(ethyl methacrylate) interpenetrating polymer network organoclay nanocomposites
thesis
posted on 2014-02-19, 14:44 authored by Boonnak SukhummekA number of polyurethane (PU) I poly(ethyl methacrylate) (PEMA) interpenetrating
polymer network nanocomposites were investigated with regard to morphology and
energy absorbing ability. The nanoclays used were umnodified sodium
montmorillonite clay and three different types of organically-modified clays: CI5A,
C20A and C30B. The nanoclays were incorporated into the lPNs by using an in-situ
polymerisation method. The clay dispersions were characterised by wide angle X-ray
diffraction (W AXD) and transmission electron microscopy (TEM). The morphologies
of the lPNs were determined with dynamic mechanical thermal analysis (DMTA),
TEM and modulated-temperature differential scanning calorimetry (M-TDSC), while
the mechanical properties were investigated using tensile testing and hardness
measurements.
Firstly, the original synthesis procedure and formulation was adjusted by varying the
nanoclay C20A content, lPN composition ratio, nanoclay mixing time and PU catalyst,
including a study of the PU and PEMA homopolymer composites. AlIlPN composites
showed only partially intercalated nanocomposites as revealed by W AXD and TEM
results. 70PU/30PEMA (70:30 composition ratio) lPN nanocomposites exhibited
potential as materials for damping applications as it had a broad loss factor;::: 0.3
spanning a wide temperature range. Secondly, the synthesis procedure was modified
by changing the order of nanoclay mixing with homopolymer components. All lPN
composites were based on a composition ratio of 70PU/30PEMA, 5 wt% C20A
content, 1.2 wt% of PU catalyst and 30 min mixing time. High intensity ultrasonic
waves were also introduced in the nanoclay mixing step for one hour. However, the
ultrasonication showed only a marginal change in damping properties. Finally, a
number of other nanoclays were incorporated into the 70PU/30PEMA lPN. All lPN
composites achieved only a partial intercalation, except for the C30B-filled lPN where
no changes were revealed by W AXD. All nanoclays caused a decrease in the glass
transition of both homopolymers. IPN nanocomposites tended to reveal a higher extent
of phase separation with increased clay content, but only the Na clay-filled lPN still
showed a broad loss factor value, even at higher clay content. Improved modulus of
elasticity was shown by all nanoclays, with increased clay loading. Whereas a
moderate increase in the tensile strength was only shown at 1 wt% clay content.
History
School
- Aeronautical, Automotive, Chemical and Materials Engineering
Department
- Materials
Publisher
© Boonnak SukhummekPublication date
2005Notes
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.EThOS Persistent ID
uk.bl.ethos.428915Language
- en