Structure and permeability of lamellar polypropylene strained in air and in liquid media

Shmatok, Ye.A.; Stakhanova, S.V.; Аржакова, О.В.; Yarysheva, L. M.; Volynskiĭ, A. L.; Bakeyev, N.F.

doi:10.1016/0032-3950(91)90066-y

Cited by 2 publications

(3 citation statements)

References 9 publications

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“…The improved air permeability or, in other words, breathability of the PHB/Hmi membranes can be explained by the fact that modification of PHB with Hemin at the stage of electrospinning provides the formation of a more uniform and ordered structure of the filter materials and development of numerous open interconnected pores. Hence, the introduction of Hmi, even in low concentrations, makes it possible to control both HLB and breathability of the PHB/Hmi membranes [ 64 , 65 ].…”

Section: Resultsmentioning

confidence: 99%

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

et al. 2023

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This work addresses the challenges concerning the development of “all-green” high-performance biodegradable membrane materials based on poly-3-hydroxybutyrate (PHB) and a natural biocompatible functional additive, iron-containing porphyrin, Hemin (Hmi) via modification and surface functionalization. A new facile and versatile approach based on electrospinning (ES) is advanced when modification of the PHB membranes is performed by the addition of low concentrations of Hmi (from 1 to 5 wt.%). Structure and performance of the resultant {HB/Hmi membranes were studied by diverse physicochemical methods, including differential scanning calorimetry, X-ray analysis, scanning electron microscopy, etc. Modification of the PHB fibrous membranes with Hmi allows control over their quality, supramolecular structure, morphology, and surface wettability. As a result of this modification, air and liquid permeability of the modified electrospun materials markedly increases. The proposed approach provides preparation of high-performance all-green membranes with tailored structure and performance for diverse practical applications, including wound healing, comfort textiles, facial protective masks, tissue engineering, water and air purification, etc.

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Section: Resultsmentioning

confidence: 99%

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

et al. 2023

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“…In contrast to amor phous polymers, PP is able to undergo both modes of solvent crazing and the mode of solvent crazing depends on the type of crystalline structure of the ini tial polymer [11]. As was shown in [12][13][14], isotactic PP with its highly disordered smectic crystalline struc ture (initial PP) undergoes deformation in the pres ence of adsorptionally active liquid environments (AALE) via classical solvent crazing. Annealing of iso tactic PP increases its degree of crystallinity and assists its gradual transition into the monoclinic crystalline modification [15].…”

Section: Resultsmentioning

confidence: 99%

“…The above structural rearrange ments of PP entail concomitant changes in the mech anism of its deformation in AALE. Annealed PP [12][13][14] is characterized by its relatively high degree of crystallinity and experiences so called delocalized sol vent crazing [11].…”

Section: Resultsmentioning

confidence: 99%

Visualization of structural rearrangements during annealing of solvent-crazed isotactic polypropylene

et al. 2009

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Structural rearrangements taking place upon the annealing of solvent crazed isotactic PP are studied by the direct microscopic method. Independently of the type of its crystalline structure, solvent crazed PP undergoes shrinkage in a wide temperature interval, starting even from room temperature and up to its melting temperature. This shrinkage is a result of the structural processes in crazes and proceeds via shutting down of the walls of individual crazes. This low temperature shrinkage of solvent crazed PP is assumed to have an entropy nature. This process involves the contraction of extended polymer chains and their transition into thermodynamically favorable conformations. This contraction is allowed because, upon annealing, the entropy contracting force increases. As a result, the crystalline framework of oriented PP melts down (amorphization), extended chains appear contracted, stored stresses relax, and subsequent recrystalli zation in the unstressed state takes place.

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Structure and permeability of lamellar polypropylene strained in air and in liquid media

Cited by 2 publications

References 9 publications

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

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

Visualization of structural rearrangements during annealing of solvent-crazed isotactic polypropylene

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