The Effect of Chitosan on the Chemical Structure, Morphology, and Selected Properties of Polyurethane/Chitosan Composites

Materials science is an interdisciplinary area of studies. This science focuses on the influence of the physico-chemical properties of materials on their application in human everyday lives. The materials’ synthesis should be developed in accordance with sustainable development. Polyurethanes (PUR) represent a significant consumption of plastic in the world. Modification of PUR, e.g., with polysaccharide of natural origin (chitosan, Chit), should have a positive effect on their functional properties and degradability in the natural environment. The basic parameters affecting the scope and direction of changes are the size and quantity of the chitosan particles. The impact assessment of chitosan on the chemical structure, morphology, thermal properties, crystallinity, mechanical properties, flammability, water sorption, adsorption properties, degradability, and biological activity of PUR/Chit composites (without other additives) is discussed in this article. To the best of our knowledge, recent literature does not contain a study discussing the direct impact of the presence of chitosan in the structure of PUR/Chit composite on its properties, regardless of the intended uses. This paper provides an overview of publications, which presents the results of a study on the effect of adding chitosan in polyurethane/chitosan composites without other additives on the properties of polyurethane.

Percolating conductive networks in multiwall carbon nanotube-filled polymeric nanocomposites: towards scalable high-conductivity applications of disordered systems

Disordered polymeric composite systems ordinarily exhibit poor bulk electronic transport properties, restricting their use to low-conductivity applications. In this work, highly electroconductive multi-walled carbon nanotube (MWCNT)/polyurethane (PU) nanocomposites were assembled via an aqueous solvent-blending method. Low percolation thresholds of 0.001 wt% and 0.093 wt% were obtained using pristine MWCNTs (P-MWCNTs) and mildly oxidized MWCNTs (O-MWCNTs), respectively. Corresponding critical values of dimensionality of 2.067 ± 0.094 and 2.304 ± 0.114 were calculated for P-MWCNT/PU and O-MWCNT/PU composites, respectively, strongly suggesting the formation of three-dimensional percolating conductive networks permeating the PU host matrix above the percolation threshold. Saturated direct current conductivities as high as 839 ± 72 S cm-1 were measured for O-MWCNT/PU composites at a filler-loading of 30.9 wt%. MWCNT/PU composite surfaces functionalized with superhydrophobic perfluoroalkyl moieties via chemical vapor deposition of (tridecafluoro-1,1,2,2-tetrahydrooctyl)trichlorosilane exhibited sessile contact angles as high as 154° without adversely affecting electroconductivity.

A novel high-content CNT-reinforced SiC matrix composite-fiber by precursor infiltration and pyrolysis process

A novel carbon nanotube (CNT)-reinforced SiC matrix composite-fiber with excellent mechanical, electrical, and thermal resistant properties was fabricated.