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Previous work revealed the possibility of controlling the nanostructuration of maleic anhydride plasma polymer (MAPP) by adjusting the plasma process parameters or adding cellulose nanocrystals (CNCs) previously on the substrate. This work aimed to evaluate the stability of MAPP coating to water drop evaporation. The evaporation process was followed by optical microscopy and the effects of substrate surface chemistry and presence of CNCs were investigated. The presence of CNCs affected not only the MAPP adhesion under wet condition, leading to an impressive morphological reconstruction of MAPP coating, but also the evaporation kinetics. Therefore, this work exhibits a simple way to obtain functional surface patterns by changing the coating wet adhesion and opens new opportunities for the utilization of CNCs. [ABSTRACT FROM AUTHOR]

The understanding concerning structure formation during maleic anhydride plasma polymerization is focused based on growth kinetics study and chemical force titration through atomic force microscopy. Growth kinetics suggested that beads were formed initially and acted as intermediate for the random formation of needle-like and branched structures. The structures surface area followed a linear trend, except for the beads surface area that levels-off. Chemical force titration revealed that all the samples exhibited two pKa values, but the shifting of the values and the different trends indicated differences in the global chemistry of the films, associated to the presence of the structures. [ABSTRACT FROM AUTHOR]

We report for the first time the formation of spherical and branched structures when polymerizing maleic anhydride under very low power with pulsed plasma polymerization. A factorial experimental design evidenced duty cycle, frequency and their interactions as decisive factors for the formation and growth of these structures. A mechanism involving the decoupling of deposition (nucleation) and diffusion rates of active species was proposed to relate structure formation to processing parameters. While differences in surface chemistry were not detectable by surface spectroscopy (PM-IRRAS, XPS), AFM force measurements on a carefully designed sample evidenced differences in adhesion and thus surface chemistry between the different film morphologies. [ABSTRACT FROM AUTHOR]

The structure of condensed tannins (CTs) from Pinus pinaster bark extract and their hydroxypropylated derivatives with four degrees of substitution (DS 1, 2, 3 and 4) has been characterized for the first time using negative-ion mode electrospray ionization tandem mass spectrometry (ESI(−)-MS/MS). The results showed that P. pinaster bark CTs possess structural homogeneity in terms of monomeric units (C15, catechin). The oligomer sizes were detected to be dimers to heptamers. The derivatives showed typical phenyl-propyl ether mass fragmentation by substituent elimination (58 amu) and inherent C15 flavonoid fissions. The relative abundance of the product ions revealed a preferential triple, tetra-/penta- and octa- hydroxypropylation substitution pattern in the monomer, dimer and trimer derivatives, respectively. A defined order of -OH reactivity towards propylene oxide was established by means of multistage experiments (A-ring ≥ B-ring > C-ring). A high structural heterogeneity of the modified oligomers was detected. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The article explores the mechanisms that result in differences in the mechanical behavior of formulations of polypropylene blended with maleated polypropylene (MAPP) copolymers. MAPP lowered the melting temperature of PP, which suggests that less stable crystals were formed possibly due to cocrystallization of PP and MAPP. Crystallization kinetics showed that copolymers do not alter the rate of crystal growth, but may hamper nucleation resulting in a more spherulitic morphology.

To our knowledge, xylary reaction tissue has never been reported in a forage crop species. Here we report the discovery of reaction tissue in a transgenic line of Medicago sativa (pC3H, for the gene for p-coumarate-3-hydroxylase) with reduced lignin content and in the wild-type (WT) line. Based on microscopy and biomechanical testing of intemodal alfalfa branch sections, the transgenic (pC3H-1) line, relative to the WT (1) apparently formed more reaction tissue containing gelatinous fibers with adjacent thick-walled fibers (presumed to be ‘intermediate’ tissue) more rapidly, (2) had more xylem tissue, and (3) had comparable tensile dynamic modulus properties. These findings thus establish the (limited) ability of this perennial angiosperm to form (inducible) reaction tissue in a manner somewhat analogous to that of woody arborescent angiosperms. The potential of effectuating reductions in lignin amounts in (woody) angiosperms with increased formation of reaction (tension wood) tissue is discussed because reaction tissues are often viewed as a deleterious trait in processing for many agronomic/industrial applications, especially with the current interest in biofuels. [ABSTRACT FROM AUTHOR]