Surface topography of kenaf (Hibiscus cannabinus) sized papers.

Bleached kenaf handsheets sized with different polymers such as chitosan, polyvinyl alcohol and cationic starch, were used for the determination of surface topography. A non-contact profilometer, the AltiSur 500, was used to characterize the topography of structural details in the paper surface. Numerical and visual characterization of surface roughness indicated that the surface of chitosan-sized paper was less rough than other surfaces, and all the sized papers were commonly smoother than the unsized paper.

Conformational polymorphism in N-(4'-methoxyphenyl)- 3-bromothiobenzamide.

Three conformational polymorphs of N-(4'-methoxyphenyl)-3-bromothiobenzamide, yellow alpha, orange beta, and yellow gamma, have been identified by single-crystal X-ray diffraction. The properties and structure of the polymorphs were examined with FT Raman, FTIR (ATR), and UV/Vis spectroscopy, as well as differential scanning calorimetry. Computational data on rotational barriers in the isolated gas-phase molecule indicate that the molecular conformation found in the alpha form is energetically preferred, but only by around 2 kJ mol(-1) over the gamma conformation.