Abstract:In this paper, the influence of the various degradation conditions, on the molecular and supramolecular structure of polybutylene succinate (PBS) and polybutylene succinate adipate (PBSA) copolymer during degradation is described. The experiment was carried out by the use of injection molded samples and normalized conditions of biodegradation in soil, composting and artificial weathering. Materials were studied by size-exclusion chromatography (SEC) coupled with multiangle laser light scattering (MALLS) detection and wide-angle X-ray diffraction (WAXD). Additionally, the physical and mechanical properties of the samples were determined. The performed experiments clearly show difference impacts of the selected degradation conditions on the macroscopic, supramolecular and molecular parameters of the studied aliphatic polyesters. The structural changes in PBS and PBSA explain the observed changes in the physical and mechanical properties of the obtained injection molded samples.

Abstract:In this paper, the influence of the molecular structure of polylactide (PLA)-characterised by its molar mass and content of D-lactide isomer-on the molecular ordering and α'-α form transition during fibre manufacturing by the wet spinning method is described. Fibres were studied by wide-angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC). Additionally, the physical and mechanical properties of the fibres were determined. This study also examines the preliminary molecular ordering and crystallisation of PLA fibres at various draw ratios. The performed experiments clearly show the dependence of the molecular ordering of PLA on the molar mass and D-lactide content during the wet spinning process. The fibres manufactured from PLA with the lowest content of D-lactide and the lowest molar mass were characterised by a higher tendency for crystallisation and a higher possibility to undergo the disorder-to-order phase transition (α' to α form). The structural changes in PLA explain the observed changes in the physical and mechanical properties of the obtained fibres.

The unique properties of graphene, such as the high elasticity, mechanical strength, thermal conductivity, very high electrical conductivity and transparency, make them it an interesting material for stretchable electronic applications. In the work presented herein, the authors used graphene and carbon nanotubes to introduce chemical sensing properties into textile materials by means of a screen printing method. Carbon nanotubes and graphene pellets were dispersed in water and used as a printing paste in the screen printing process. Three printing paste compositions were prepared—0%, 1% and 3% graphene pellet content with a constant 3% carbon nanotube mass content. Commercially available materials were used in this process. As a substrate, a twill woven cotton fabric was utilized. It has been found that the addition of graphene to printing paste that contains carbon nanotubes significantly enhances the electrical conductivity and sensing properties of the final product.

The general objective of this research is to use melt electrospinning to design and fabricate semibiodegradable and multilayered fibrous structures that have potential applications for cardiovascular implants, including small-diameter (<6 mm) blood vessels replacements. In the first stage of the study, as described in this article, flat fibrous structures from polypropylene and polylactide polymers were fabricated. The fabrication stage was necessary to determine the effect of the polymers' melt mass flow rate, melt electrospinning processing parameters (as a working distance and spinning voltage) on the resulting fiber diameter and on other physical and structural properties of the fibrous structures. An analysis of the effects of the processing parameters on the fabrication of the fibrous structures and the selection of the appropriate polymers for the final multilayered tubular structure were also performed.

We evaluated a solvent vapor-sensitive, non-woven fabric made from a biodegradable, poly(lactic acid) (PLA) polymer loaded with multi-walled carbon nanotubes. The sensory properties of the fabric were obtained by optimizing the process parameters for manufacturing the melt-blown, non-woven fabric composed of 98% PLA 4060D (Nature Works) and 2% multi-walled carbon nanotubes (Nanocyl®). The diffusion of polar and non-polar solvent molecules influenced the electron flow between the separated carbon nanotubes in percolation paths built into the PLA, resulting in an increase of the resistance of the melt-blown, non-woven fabrics. The statistically significant differences between the mean values of electrical resistance before and after the influence of the tested solvent vapors were achieved for the non-woven fabrics manufactured at high air velocity and low extruder screw speed, taking the values of 30 m3/h and 20 rpm, respectively. The results obtained for the non-woven fabric manufactured in the optimal conditions show that methanol vapor response has the lowest amplitude of 15%, whereas for benzene, acetone and toluene sensitivity reaches values of 60%, 40%, and 35%, respectively. The values of the relative resistance amplitude correspond with Flory–Huggins interaction parameters κPLA\benzene < κPLA\acetone < κPLA\toluene < κPLA\methanol.