A fairly simple yet efficient quantitative protocol was developed to investigate plant composition using Fourier-transform infrared spectroscopy (FTIR), through biomass analysis arising from the whole shoot system of Cardoon (Cynara cardunculus L.), Cannabis (Cannabis sativa L.) and Switchgrass (Panicum virgatum L.). An analytical compositional report of the biomasses, serving as a standard method to identify the different chemical groups present, was compared with relevant FTIR spectra and Thermogravimetric Analysis (TGA) thermographs. In order to interpret the highly convoluted absorption spectra, not only a series of reference materials were examined but also extraction protocols were implemented to sequentially isolate the compositional units allowing a spectroscopic monitoring of their progressive removal from the biomass. This approach enabled the assignment and distinction of a series of vibrational peaks and regions identified in the lower wavenumber region. These peaks/regions, were found to be capable of quantitating different chemical units, such as lignin, fats and lipids, even in the case of structural polysaccharides, like cellulose, hemicellulose and pectin, which are the primary constituents of plant cells. Fats and lipids were easily detected at the 3050–2800 cm⁻¹ region, with their concentration determined by the isolated 720 cm⁻¹ and the 728 cm⁻¹ peaks, when present. Lignin concentration was determined via the 1508 cm⁻¹ peak. Hemicellulose is contributing to the 1640, 1245 cm⁻¹ as well as the 1740 cm⁻¹ peak, with its concentration determined in the 850–750 cm⁻¹ region. Cellulose content was quantified via the 895 cm⁻¹ peak, while pectin appeared at the 915 cm⁻¹ peak and also contributed to the 1640 cm⁻¹ signal. Consequently, a better understanding of the vibrational convolution could thus be achieved when studying plant cells where multiple structural units contribute to the spectra. It is therefore expected that plant cellular composition can be adequately revealed with a single FTIR spectrum, without the need for intensive analysis methods, offering a faster and more efficient approach.

BaTiO₃ is one of the most widely used ceramic components in capacitor formulation due to its exceptional ferroelectric properties. The structural transition from the ferroelectric tetragonal to the paraelectric cubic phase has been studied in both nano- and micro-BaTiO₃ particles. Several experimental techniques were employed for characterization purposes (X-ray diffraction-XRD, laser Raman spectroscopy-LRS, differential scanning calorimetry-DSC and broadband dielectric spectroscopy-BDS). All gave evidence for the structural transition from the polar tetragonal to the non-polar cubic phase in both nano- and micro-BaTiO₃ particles. Variation of Full Width at Half Maximum (FWHM) with temperature in XRD peaks was employed for the determination of the critical Curie temperature (T_c). In micro-BaTiO₃ particles (T_c) lies close to 120 °C, while in nanoparticles the transition is complicated due to the influence of particles’ size. Below (T_c) both phases co-exist in nanoparticles. (T_c) was also determined via the temperature dependence of FWHM and found to be 115 °C. DSC, LRS and BDS provided direct results, indicating the transition in both nano- and micro-BaTiO₃ particles. Finally, the 15 parts per hundred resin per weight (phr) BaTiO₃/epoxy nanocomposite revealed also the transition through the peak formation at approximately 130 °C in the variation of FWHM with temperature. The present work introduces, for the first time, a qualitative tool for the determination and study of the ferroelectric to paraelectric structural transition in both nano- and micro-ferroelectric particles and in their nanocomposites. Moreover, its novelty lies on the effect of crystals’ size upon the ferroelectric to the paraelectric phase transition and its influence on physical properties of BaTiO₃.

Hybrid polymeric materials incorporating carbon nanostructures or inorganic constituents stand as a promising class of materials exhibiting distinct but also complementary features. Carbon nanotubes have been proposed as unique candidates for polymer reinforcement; however, sustained efforts are further needed in order to make full use of their potential. The final properties of the reinforced polymer are controlled in part by the morphology and the eventual molecular orientation of the polymer matrix. In the present study, multiwall carbon nanotubes (MWCNTs) were utilized in order to reinforce polyethylene terephthalate (PET) composites. The effect of CNTs on the crystallization and the orientation of the structurally hybridized polymeric material has been investigated from the perspective of assessing their impact on the final properties of a relevant nanocomposite product. Functionalized MWCNTs were used to achieve their optimal dispersion in the polymer matrix. The physical properties of the composites (i.e., crystallinity and orientation) were characterized via differential scanning calorimetry, X-ray diffraction, and polarized Raman microscopy. The addition of well-dispersed CNTs acted as a nucleation agent, increasing the crystallization of the polyethylene terephthalate matrix and differentiating the orientation of both CNTs and macromolecular chains.

Cotton cationization with low molecular weight or polymeric cationic modifiers allows the effective dyeing of cotton substrates with reactive dyes under salt-free and more environmentally friendly conditions. The current work focuses on the spectroscopic study of the intermolecular interactions, which dictate the physicochemical process associated with fabric dyeing. Water-soluble cationic copolymers of vinyl benzyl chloride (VBC) and vinyl benzyl triethylammonium chloride (VBCTEAM) have been used as cellulose cationic modifiers. Dye uptake was assessed using Remazol Brilliant Blue R and Novacron Ruby S-3B dyes. The study involves ATR-FTIR, UV-Vis, fluorescence, and XPS spectroscopy. The results of binary polymer-rich dye-polymer aqueous solutions or dye-polymer precipitates at stoichiometric charge-ratio revealed that the sulfonate/sulfate anions of the dyes interact with the cationic VBCTEAM units of the polymer via electrostatic interactions. Moreover, the comparative study of dye application on modified and unmodified fabrics suggests that, unlike the latter, where dyes are chemically bound to cellulose, electrostatic forces dominate the interaction of modified fabrics with dye molecules.

Bio-nanocomposites based on poly (vinyl alcohol) (PVA) and cellulosic nanostructures are favorable for active food packaging applications. The current study systematically investigates the mechanical properties, gas permeation, and swelling parameters of PVA composites with cellulose nanocrystals (CNC) or nano lignocellulose (NLC) fibers. Alterations in these macroscopic properties, which are critical for food packaging applications, are correlated with structural information at the molecular level. Strong interactions between the fillers and polymer host matrix were observed, while the PVA crystallinity exhibited a maximum at ~1% loading. Finally, the orientation of the PVA nanocrystals in the uniaxially stretched samples was found to depend non-monotonically on the CNC loading and draw ratio. Concerning the macroscopic properties of the composites, the swelling properties were reduced for the D1 food simulant, while for water, a considerable decrease was observed only when high NLC loadings were involved. Furthermore, although the water vapor transmission rates are roughly similar for all samples, the CO₂, N₂, and O₂ gas permeabilities are low, exhibiting further decrease in the 1% and 1–5% loading for CNC and NLC composites, respectively. The mechanical properties were considerably altered as a consequence of the good dispersion of the filler, increased crystallinity of the polymer matrix, and morphology of the filler. Thus, up to ~50%/~170% enhancement of the Young’s modulus and up to ~20%/~50% enhancement of the tensile strength are observed for the CNC/NLC composites. Interestingly, the elongation at break is also increased by ~20% for CNC composites, while it is reduced by ~40% for the NLC composites, signifying the favorable/unfavorable interactions of cellulose/lignin with the matrix.