Search

One of the main concerns in using natural materials in construction, such as bamboo, regards their durability. Ultra violet (UV)irradiation is claimed as a damaging agent; therefore, it is important to study its effect. Several studies have shown that bamboo components such as lignin are subjected to photochemical degradation, but it is not well understood how this affects the mechanical properties of bamboo. The aim of this paper is to explore the correlation between photodegradation and bamboo mechanical performance. Bamboo samples were exposed to accelerated UV ageing for different times (from 6 to 360 h) and then subjected to a four-point bending test. Since one of the ways to stabilize bamboo is to thermally treat it, the tests were conducted on natural untreated bamboo and treated bamboo with a traditional flame treatment. Modifications of the chemical features of the material were analyzed with Fourier Trasform Infra Red (FTIR) spectroscopy, while modifications of the morphological features were analyzed byEnvironmental Scanning Electron Microscopy ESEM and optical microscopy observations. The results show that the bending behavior of bamboo is not compromised by UV exposure up to 360 h. In fact, although a progressive degradation of lignin is reported and cracks in the fiber walls are highlighted from micrographs, no effects were found on the fiber length. [ABSTRACT FROM AUTHOR]

Particulate composites based on poly(lactic acid) (PLA) and poly(butylene succinate) (PBS) biopolymers have been formulated. Silver skin (SSK), the by‐product derived from the roasting of coffee beans, has been milled to micrometric size and added up to a 30 wt% of loading, without any previous treatment. The dynamic mechanical properties of the composites have been investigated, as well as the stability toward UV and IR radiation. The filler improves some mechanical properties such as the elastic modulus (E′) mostly in PBS. Photoaging experiments demonstrate that SSK, due to its polyphenols content and antioxidant activity, is able to protect both PLA and PBS from UV degradation, highlighting an added value of SSK waste‐based composites. [ABSTRACT FROM AUTHOR]

The synthesis and the structural, thermal and electrical characterization of haloplumbate(II) systems revealed three different types of these polymeric systems. These are the strictly monodimensional, (2meptH2)(Pb(sub 1.5)I(sub 5)); ribbon-like, (pnH2)2(Pb(sub 1.5)Br(sub 7))*H2O; and perovskite-like structures, (pnH2)(PbCl4) and (2meptH2)(PbX(sub 4)). One remarkable observation is the presence of organic dications in their extended form, intercalated between the inorganic anions, which are at different distances, depending on the amine length.

Particulate composites with polylactide (PLA) as a matrix and wastes deriving from the wine production have been formulated at different compositions. The microstructure and the mechanical properties of the composites, as well as the thermal stability and water uptake have been evaluated. The results showed that the wine waste residue does not compromise the thermal stability of the matrix while improves the impact strength and influences tensile properties. Specifically, tensile strength progressively decreases on addition of the winery waste, while the elastic modulus slightly increases. This behavior was attributed to the inhomogeneity of the filler particle size and morphology, which can partially induce a discontinuous interface at high filler loading and affect the water uptake. An increase in the value of the water contact angle is obtained below a 10% wt content and the mechanism of water uptake is not modified below the 20 wt% of filler. In any case, up to a content of 15 weight percent, winery wastes can be used in the plain matrix as an extender. Since simple and low cost operations are requested to obtain suitable fillers, an overall decrease in the material cost can be envisaged thus partially solving the drawbacks of PLA exploitation in the packaging industry, and leading to cost‐effective application. Moreover, the conversion of lignocellulosic wastes as filler in biocomposites would be in favor of waste reduction while adding value to the agro‐food chain. POLYM. COMPOS., 40:1378–1383, 2019. © 2018 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]