scholarly journals Ethylene oxide sterilization of electrospun poly(l-lactide)/poly(d-lactide) core/shell nanofibers

MRS Advances ◽  
2021 ◽  
Author(s):  
Axel T. Neffe ◽  
Quanchao Zhang ◽  
Paul J. Hommes-Schattmann ◽  
Andreas Lendlein
Keyword(s):  
Ethylene Oxide ◽  
Molar Mass ◽  
Shell Morphology ◽  
Material Structure ◽  
Core Shell ◽  
Elongation At Break ◽  
X Ray ◽  
H Nmr ◽  
X Ray Scattering ◽  
Ethylene Oxide Sterilization

Abstract The application of polymers in medicine requires sterilization while retaining material structure and properties. This demands detailed analysis, which we show exemplarily for the sterilization of PLLA/PDLA core–shell nanofibers with ethylene oxide (EtO). The electrospun patch was exposed to EtO gas (6 vol% in CO2, 1.7 bar) for 3 h at 45 °C and 75% rel. humidity, followed by degassing under pressure/vacuum cycles for 12 h. GC–MS analysis showed that no residual EtO was retained. Fiber diameters (~ 520 ± 130 nm) of the patches remained constant as observed by electron microscopy. Young’s modulus slightly increased and the elongation at break slightly decreased, determined at 37 °C. No changes were detected in 1H-NMR spectra, in molar mass distribution (GPC) or in crystallinity measured for annealed samples with comparable thermal history (Wide Angle X-Ray Scattering). Altogether, EtO emerged as suitable sterilization method for polylactide nanofibers with core–shell morphology. Graphic abstract

scholarly journals Hydrogel networks by aliphatic dithiol Michael addition to glycidylmethacrylated gelatin

MRS Advances ◽  
2021 ◽  
Author(s):  
Axel T. Neffe ◽  
Candy Löwenberg ◽  
Andreas Lendlein
Keyword(s):  
Network Formation ◽  
Molar Ratio ◽  
Elongation At Break ◽  
X Ray ◽  
H Nmr ◽  
X Ray Scattering ◽  
Ft Ir ◽  
Triple Helices ◽  
Hydrogel Swelling ◽  
Ft Ir Spectroscopy

AbstractFunctionalization of gelatin with glycidylmethacrylate (GMA-gelatin) enables network formation employing the double bond, so that the reaction is orthogonal to the inherent functional groups in the biomacromolecule. Here, network formation by crosslinking of GMA-gelatin with hexane 1,6-dithiol or nonane 1,9-dithiol to tailor properties and enable a shape-memory effect is shown by 1H NMR and FT-IR spectroscopy. Hydrogel swelling (460–1900 vol%) and mechanical properties (Young’s modulus E = 59–512 kPa, elongation at break εb = 44–127%) depended on the molecular composition of the networks and temperature. Increased crosslinker length, thiol:methacrylate molar ratio, and precursor concentrations led to denser networks. Change of properties with temperature suggested adoption of triple helices by gelatin chains, forming physical netpoints at lower temperatures (< 20 °C). However, the limited freedom of the gelatin chains to move allowed only a minimal extent of triple helices formation, as it became apparent from the related signal in wide-angle X-ray scattering and the thermal transition associated to triple helices in some networks by DSC. The presented strategy is likely transferable to other biomacromolecules, and the results suggest that too short crosslinkers may result in a significant amount of grafting rather than network formation. Graphic abstract

scholarly journals Synthesis and Advanced Characterization of Polymer-Protein Core-Shell Nanoparticles

Catalysts ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 730
Author(s):  
Erik Sarnello ◽  
Tao Li
Keyword(s):  
Particle Size ◽  
Small Angle ◽  
Core Shell ◽  
Assembly Process ◽  
Shell Nanoparticles ◽  
X Ray ◽  
X Ray Scattering ◽  
Wide Range ◽  
Core Shell Nanoparticles ◽  
Ray Scattering

Enzyme immobilization techniques are widely researched due to their wide range of applications. Polymer–protein core–shell nanoparticles (CSNPs) have emerged as a promising technique for enzyme/protein immobilization via a self-assembly process. Based on the desired application, different sizes and distribution of the polymer–protein CSNPs may be required. This work systematically studies the assembly process of poly(4-vinyl pyridine) and bovine serum albumin CSNPs. Average particle size was controlled by varying the concentrations of each reagent. Particle size and size distributions were monitored by dynamic light scattering, ultra-small-angle X-ray scattering, small-angle X-ray scattering and transmission electron microscopy. Results showed a wide range of CSNPs could be assembled ranging from an average radius as small as 52.3 nm, to particles above 1 µm by adjusting reagent concentrations. In situ X-ray scattering techniques monitored particle assembly as a function of time showing the initial particle growth followed by a decrease in particle size as they reach equilibrium. The results outline a general strategy that can be applied to other CSNP systems to better control particle size and distribution for various applications.

scholarly journals Trends in anomalous small-angle X-ray scattering in grazing incidence for supported nanoalloyed and core-shell metallic nanoparticles

2012 ◽  
Vol 208 (1) ◽  
pp. 231-244 ◽  
Author(s):  
P. Andreazza ◽  
H. Khelfane ◽  
O. Lyon ◽  
C. Andreazza-Vignolle ◽  
A. Y. Ramos ◽  
...  
Keyword(s):  
Small Angle ◽  
Metallic Nanoparticles ◽  
Grazing Incidence ◽  
Core Shell ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

scholarly journals Preparation and Characterization of HPMC/PVP Blend Films Plasticized with Sorbitol

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
H. Somashekarappa ◽  
Y. Prakash ◽  
K. Hemalatha ◽  
T. Demappa ◽  
R. Somashekar
Keyword(s):  
Mechanical Properties ◽  
Hydroxypropyl Methylcellulose ◽  
Solution Casting ◽  
Casting Method ◽  
Elongation At Break ◽  
X Ray ◽  
Blend Films ◽  
X Ray Scattering ◽  
Solution Casting Method

The aim of this present work is to investigate the effect of plasticizers like Sorbitol on microstructural and mechanical properties of hydroxypropyl methylcellulose (HPMC) and Polyvinylpyrrolidone (PVP) blend films. The pure blend and plasticized blend films were prepared by solution casting method and investigated using wide angle X-ray scattering (WAXS) method. WAXS analysis confirms that the plasticizers can enter into macromolecular blend structure and destroy the crystallinity of the films. FTIR spectra show that there are a shift and decrease in the intensity of the peaks confirming the interaction of plasticizer with the blend. Mechanical properties like tensile strength and Young’s Modulus decrease up to 0.6% of Sorbitol content in the films. Percentage of elongation at break increases suggesting that the plasticized films are more flexible than pure blend films. These films are suitable to be used as environmental friendly and biodegradable packaging films.

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