scholarly journals Printable Alginate Hydrogels with Embedded Network of Halloysite Nanotubes: Effect of Polymer Cross-Linking on Rheological Properties and Microstructure

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4130
Author(s):  
Svetlana A. Glukhova ◽  
Vyacheslav S. Molchanov ◽  
Boris V. Lokshin ◽  
Andrei V. Rogachev ◽  
Alexey A. Tsarenko ◽  
...  
Keyword(s):  
3D Printing ◽  
Rheological Properties ◽  
Shear Thinning ◽  
Halloysite Nanotubes ◽  
Polymer Chains ◽  
Cross Linking ◽  
Saxs Data ◽  
Nanocomposite Hydrogels ◽  
Embedded Network ◽  
The Cross

Rapidly growing 3D printing of hydrogels requires network materials which combine enhanced mechanical properties and printability. One of the most promising approaches to strengthen the hydrogels consists of the incorporation of inorganic fillers. In this paper, the rheological properties important for 3D printability were studied for nanocomposite hydrogels based on a rigid network of percolating halloysite nanotubes embedded in a soft alginate network cross-linked by calcium ions. Particular attention was paid to the effect of polymer cross-linking on these properties. It was revealed that the system possessed a pronounced shear-thinning behavior accompanied by a viscosity drop of 4–5 orders of magnitude. The polymer cross-links enhanced the shear-thinning properties and accelerated the viscosity recovery at rest so that the system could regain 96% of viscosity in only 18 s. Increasing the cross-linking of the soft network also enhanced the storage modulus of the nanocomposite system by up to 2 kPa. Through SAXS data, it was shown that at cross-linking, the junction zones consisting of fragments of two laterally aligned polymer chains were formed, which should have provided additional strength to the hydrogel. At the same time, the cross-linking of the soft network only slightly affected the yield stress, which seemed to be mainly determined by the rigid percolation network of nanotubes and reached 327 Pa. These properties make the alginate/halloysite hydrogels very promising for 3D printing, in particular, for biomedical purposes taking into account the natural origin, low toxicity, and good biocompatibility of both components.

Photoresins based on acrylated epoxidized soybean oil and benzenedithiols for optical 3D printing

2019 ◽  
Vol 25 (2) ◽  
pp. 378-387 ◽  
Author(s):  
Greta Miezinyte ◽  
Jolita Ostrauskaite ◽  
Egidija Rainosalo ◽  
Edvinas Skliutas ◽  
Mangirdas Malinauskas
Keyword(s):  
3D Printing ◽  
Soybean Oil ◽  
Real Time ◽  
Insoluble Fraction ◽  
Polymer Chains ◽  
Epoxidized Soybean Oil ◽  
Cross Linking ◽  
Content Type ◽  
Cross Links ◽  
Acrylated Epoxidized Soybean Oil

Purpose The purpose of this paper is the design and investigation of novel acrylated epoxidized soybean oil-based photocurable systems as candidate materials for optical 3D printing. Design/methodology/approach Aromatic dithiols, benzene-1,3-dithiol or benzene-1,4-dithiol, were used as cross-linking agents of acrylated epoxidized soybean oil in these systems. Kinetics of photocross-linking was investigated by real-time photorheometry using two different photoinitiators, 2, 2-dimethoxy-2-phenylacetophenone or 2-hydroxy-2-methylpropiophenone, in different quantities. The effect of the initial composition on the rate of photocross-linking, mechanical, thermal properties and swelling of obtained polymers was investigated. Findings The rate of photocross-linking was higher, more cross-links and shorter polymer chains between cross-linking points of the network were formed when benzene-1,4-dithiol and 2, 2-dimethoxy-2-phenylacetophenone were used in compositions. The higher yield of insoluble fraction, glass transition temperatures and values of compressive modulus were obtained when benzene-1,3-dithiol and 2, 2-dimethoxy-2-phenylacetophenone were used in compositions. Originality/value This is the first study of acrylated epoxidized soybean oil-based thiol-ene system by real-time photorheometry. The designed novel photocurable systems based on acrylated epoxidized soybean oil and benzenedithiols are promising renewable photoresins for rapid optical 3D printing on demand.

scholarly journals Extrusion-Printing of Multi-Channeled Two-Component Hydrogel Constructs from Gelatinous Peptides and Anhydride-Containing Oligomers

Biomedicines ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 370
Author(s):  
Jan Krieghoff ◽  
Johannes Rost ◽  
Caroline Kohn-Polster ◽  
Benno Müller ◽  
Andreas Koenig ◽  
...  
Keyword(s):  
3D Printing ◽  
Peripheral Nerve ◽  
Nerve Regeneration ◽  
Peripheral Nerve Regeneration ◽  
Organic N ◽  
Cross Linking ◽  
Two Component ◽  
The Cross ◽  
Small Channels

The performance of artificial nerve guidance conduits (NGC) in peripheral nerve regeneration can be improved by providing structures with multiple small channels instead of a single wide lumen. 3D-printing is a strategy to access such multi-channeled structures in a defined and reproducible way. This study explores extrusion-based 3D-printing of two-component hydrogels from a single cartridge printhead into multi-channeled structures under aseptic conditions. The gels are based on a platform of synthetic, anhydride-containing oligomers for cross-linking of gelatinous peptides. Stable constructs with continuous small channels and a variety of footprints and sizes were successfully generated from formulations containing either an organic or inorganic gelation base. The adjustability of the system was investigated by varying the cross-linking oligomer and substituting the gelation bases controlling the cross-linking kinetics. Formulations with organic N‑methyl-piperidin-3-ol and inorganic K2HPO4 yielded hydrogels with comparable properties after manual processing and extrusion-based 3D-printing. The slower reaction kinetics of formulations with K2HPO4 can be beneficial for extending the time frame for printing. The two-component hydrogels displayed both slow hydrolytic and activity-dependent enzymatic degradability. Together with satisfying in vitro cell proliferation data, these results indicate the suitability of our cross-linked hydrogels as multi-channeled NGC for enhanced peripheral nerve regeneration.

Micro-Indentation Test and Morphology of Electron Beam Irradiated HDPE

2015 ◽  
Vol 662 ◽  
pp. 189-192
Author(s):  
Martin Ovsik ◽  
Petr Kratky ◽  
David Manas ◽  
Miroslav Manas ◽  
Michal Stanek ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Indentation Test ◽  
Polymer Chains ◽  
Cross Linking ◽  
Thermal Treatments ◽  
X Ray Diffraction ◽  
Irradiation Dosage ◽  
The Cross ◽  
Micro Indentation ◽  
Different Doses

Cross-linking is a process in which polymer chains are associated through chemical bonds. The cross-linking level can be adjusted by the irradiation dosage and often by means of a cross-linking booster. The polymer additional cross-linking influences the surface nanoand micro layers in the way comparable to metals during the thermal and chemical-thermal treatments. The aim of this paper is to study the effect of ionizing radiation with different doses (33, 66 and 99 kGy), on micro-mechanical properties of polyethylene (HDPE) and compare these results with those of non-irradiated samples. Influence of the cross-linking by β – radiation of the tested HDPE on micro-indentation test and morphology was investigated. Micro-mechanical properties increased with increasing value of the dose of irradiation material. The changes were examined and confirmed by X-ray diffraction.

3D Printing of Shear-Thinning Hyaluronic Acid Hydrogels with Secondary Cross-Linking

2016 ◽  
Vol 2 (10) ◽  
pp. 1743-1751 ◽  
Author(s):  
Liliang Ouyang ◽  
Christopher B. Highley ◽  
Christopher B. Rodell ◽  
Wei Sun ◽  
Jason A. Burdick
Keyword(s):  
Hyaluronic Acid ◽  
3D Printing ◽  
Shear Thinning ◽  
Cross Linking

3D printing of thermoreversible polyurethanes with targeted shape memory and precise in situ self-healing properties

2019 ◽  
Vol 7 (12) ◽  
pp. 6972-6984 ◽  
Author(s):  
Yue Zhang ◽  
Xiang-Yu Yin ◽  
Mingyue Zheng ◽  
Carolyn Moorlag ◽  
Jun Yang ◽  
...  
Keyword(s):  
3D Printing ◽  
Shape Memory ◽  
Critical Role ◽  
Smart Devices ◽  
Cross Linking ◽  
Self Healing ◽  
3D Structures ◽  
The Cross

3D printable thermoreversible polyurethanes (PDAPUs) are synthesized, which facilitate the manufacturing of smart devices with 3D structures. The cross-linking of aniline trimer in PDAPUs plays a critical role in realizing light controllable precise selfhealing and targeted shape memory.

A Well-Defined Amphiphilic Polymer Conetwork from Sequence Control of the Cross-Linking in Polymer Chains

2014 ◽  
Vol 53 (49) ◽  
pp. 19239-19248 ◽  
Author(s):  
Chao Zhou ◽  
Linhong Deng ◽  
Fang Yao ◽  
Liqun Xu ◽  
Jian Zhou ◽  
...  
Keyword(s):  
Amphiphilic Polymer ◽  
Polymer Chains ◽  
Cross Linking ◽  
The Cross

Mechanical and Structural Consequences of Associative Dynamic Cross-Linking in Acrylic Diblock Copolymers

2019 ◽  
Author(s):  
Jacob Ishibashi ◽  
Yan Fang ◽  
Julia Kalow
Keyword(s):  
Block Copolymers ◽  
Rheological Properties ◽  
Diblock Copolymers ◽  
Cross Linking ◽  
Statistical Copolymer

<p>Block copolymers are used to construct covalent adaptable networks that employ associative exchange chemistry (vitrimers). The resulting vitrimers display markedly different nanostructural, thermal and rheological properties relative to those of their statistical copolymer-derived counterparts. This study demonstrates that prepolymer sequence is a versatile strategy to modify the properties of vitrimers.</p>

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