How the Nonwoven Polymer Volume Microstructure Is Transformed under Tension in an Aqueous Environment

Abstract

The fibrous porous structure of polymers can mimic the extracellular matrix of the native tissue, therefore such polymers have a good potential for use in regenerative medicine. Organs and tissues within the body exhibit different mechanical properties depending on their functionality, thus artificial scaffolds should have mechanical behaviors similar to the extracellular matrix in conditions like living organisms, primarily in aqueous media. Several methods have been investigated in aquatic environments, including noninvasive techniques based on ultrasonic focused beams for biological objectives. In this study we explored the tensile behavior of poly(L-lactide) nonwoven polymer scaffolds using high-frequency ultrasound microscopy combined with a horizontal testing machine, which provided a visualization of the reorganization and transformation of the dynamic volume microstructure. The mechanisms of unwinding, elongation, orientation, and deformation of polymer fibers under uniaxial tension were revealed. We observed an association between the lined plastic deformation from 100 to 400% and the formation of multiple necks in the fibers, which caused stress relaxation and significant rarefaction of the fibrous microstructure. It was shown that both peaks on the stress–strain curve corresponded to the microstructure of aligned fibers in terms of initial diameter and thinning fibers. We discuss the possible influence of these microstructure transformations on cell behavior.

Structure and Performance of All-Green Electrospun PHB-Based Membrane Fibrous Biomaterials Modified with Hemin

“…However, the addition of even minor amounts of Hemin to PHB provided positive changes in the mechanical characteristics of the PHB/Hmi materials. Information on the mechanical characteristics of the PHB/Hmi membranes (tensile strength and elongation at break) is presented in Table 3 [ 59 , 60 ]. Stress-strain curves are given in the Supplementary Materials (Figure S1) .…”

“…This evidence can be explained by a better organization and a more uniform supramolecular structure of the nonwoven PHB/Hmi materials. Hence, the introduction of Hemin provides improved mechanical properties of the modified materials and this advantage seems to be of particular importance for their practical use as membranes and filters [ 59 ].…”

Assessing the Biodegradability of PHB-Based Materials with Different Surface Areas: A Comparative Study on Soil Exposure of Films and Electrospun Materials

“…Polymers 2023, 15, x FOR PEER REVIEW 9 of 15 elongation at break of fibrous material is higher by almost 50%. Despite the fact that individual fibers tear more easily than a monolithic film, fibers provide higher flexibility in a whole system of nonwoven material [38]. Fibers have a certain degree of freedom, the restriction of which depends on gluing, thickening and other morphological defects [39].…”

Development of Nonwoven Fibrous Materials Based on Poly-3-Hydroxybutyrate with a High Content of α-Tricalcium Phosphate

“…Previously, we have established how the mechanical deformation of nonwovens electrospun materials based on PHB occurs [59]. First of all, the most stressed areas of the fibrous structure are torn [60]. In general, two aspects of the fibrous structure in such materials contribute to the strength properties of the entire material: macrodefects by which the material can tear (thickening, gluing, and snagging of fibers) and the ability of fibers to move freely relative to each other.…”