Friday, April 16, 2010

Crystalline PMMA? Really??

This is one of those articles where the reviewers must have been asleep. This new report (open access for the first 30 days) has this abstract:

Optically transparent and electrically conductive thin films composed of multi-walled carbon nanotube (MWCNT) reinforced polymethyl methacrylate/acrylic acid (PMMA/AA) were fabricated using a wire coating technique. Poly(acrylic acid) controls the level of MWCNT dispersion in aqueous mixtures and retains the well-dispersed state in the polymer matrix after solidification resulting from extended polymer chains by adjusting the pH value. The exfoliating the MWCNT bundles by extended polymer chains results in the excellent dispersion of MWCNT. It causes a lower surface electrical resistance at the same MWCNT content. The hydrophilic functional groups (−COO − NA + ) also caused a decrease in the crystallization of PMMA and led to an increase in the transmittance.

PMMA is not crystalline unless special steps are taken to control the tacity of the material - and adding acid comonomers will only make the situation worse. The only evidence to supplied to support the claims of crystallinity is an XRD plot showing a peak. This is not enough as the XRD of PMMA normally shows peaks anyway.

For such a statement to pass through in the abstract is incredible.

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