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Wood polymer composites (WPC) are sensitive to moisture because of the hydrophilic nature of the wood fibers. The main objective of this study was to improve the dimensional stability of WPCs by coating. Polypropylene and polylactic acid were reinforced by three pulp fibers (kraft, thermomechanical (TMP), and chemothermomechanical (CTMP)) at three fiber contents (50, 60, and 70% w/w). The resulting WPCs were coated using two commercial coatings, epoxy and acrylic. Kraft fiber WPCs were less sensitive to moisture than TMP and CTMP WPCs. These differences were explained by the crystallinity of the kraft fibers and their better interfacial adhesion to the polymers. The epoxy coating proved to be more effective than the acrylic coating and significantly reduced the water absorption and the thickness swell for all formulations. Negative relationships between the contact angle and water absorption were obtained. These relationships depend on the fiber content and type, the matrix nature, and the coating.

We present the effect of vacancy in Pr0.6Sr0.4MnO3via dc magnetisation measurements. Using various techniques such as modified Arrott plots, the Kouvel-Fisher method, and Widom scaling relationship the values of TC (ferromagnetic transition temperature), as well as the β, γ and δ (critical exponents) are estimated. Critical exponents for the stoichiometric sample and the strontium deficient sample match well with those predicted for the tricritical mean field model. The vacancy in Pr0.5□0.1Sr0.4MnO3 changes the universal class. The estimated critical exponents of the praseodymium deficient sample are close to those found out by the 3D-Ising model.

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