scholarly journals Oxazoline-based crosslinking reaction for coatings

2021 ◽  
Author(s):  
Philipp Knospe ◽  
Patrick Böhm ◽  
Jochen Gutmann ◽  
Michael Dornbusch
Keyword(s):  
Mechanical Properties ◽  
Loss Modulus ◽  
New Technology ◽  
Sol Gel ◽  
Polymer Network ◽  
Time Dependent ◽  
Crosslinking Reaction ◽  
Coating Materials ◽  
Rheological Measurements ◽  
Excellent Adhesion

AbstractNowadays, coating materials must meet high demands in terms of mechanical, chemical and optical properties in all areas of application. Amongst others, amines and isocyanates are used as crosslinking components for curing reactions, meeting the highly demanding properties of the coatings industry. In this work, a new crosslinking reaction for coatings based on oxazoline chemistry is investigated with the objective to overcome disadvantages of established systems and fulfill the need for sustainable coating compounds. The oxazoline-group containing resin, synthesized from commercially available substances, undergoes cationic self-crosslinking polymerization to build up a network based on urethane and amide moieties. NMR-, IR- and ES-mass spectroscopy are suitable techniques to characterize the synthesized oxazoline monomers, which are linked to polyisocyanates and polymerized afterwards via self-polymerization. The progress of crosslinking is followed by changes in IR spectra and by rheological measurements to calculate time dependent values for storage and loss modulus. The glass transition temperature of the resulting coating is determined, too. Furthermore, sol–gel-analysis is performed to determine the degree of crosslinking. After application on steel and aluminium panels, application tests are performed. In addition to excellent adhesion to the substrate, the polymer network shows promising mechanical properties and with that it could represent a new technology for the coatings industry.

Tailoring of Mechanical Properties of Diisocyanate Crosslinked Gelatin-Based Hydrogels

2013 ◽  
Vol 1569 ◽  
pp. 3-8 ◽  
Author(s):  
Axel T. Neffe ◽  
Tim Gebauer ◽  
Andreas Lendlein
Keyword(s):  
Mechanical Properties ◽  
Network Formation ◽  
Polymer Network ◽  
Polymeric Materials ◽  
Toluene Diisocyanate ◽  
Crosslinking Reaction ◽  
Young’S Moduli ◽  
Physical Interactions ◽  
Reaction In Water ◽  
Full Conversion

ABSTRACTPolymer network formation is an important tool for tailoring mechanical properties of polymeric materials. One option to synthesize a network is the addition of bivalent crosslinkers reacting with functional groups present in a polymer. In case of polymer network syntheses based on biopolymers, performing such a crosslinking reaction in water is sometimes necessary in view of the solubility of the biopolymer, such as gelatin, and can be beneficial to avoid potential contamination of the formed material with organic solvents in view of applications in biomedicine. In the case of applying diisocyanates for the crosslinking in water, it is necessary to show that the low molecular weight bifunctional crosslinker has fully reacted, while tailoring of the mechanical properties of the resulting hydrogels is possible despite the complex reaction mechanism. Here, the formation of gelatin-based hydrogel networks with the diisocyanates 2,4-toluene diisocyanate, 1,4-butane diisocyanate, and isophorone diisocyanate is presented. It is shown that extensive washing of materials is required to ensure full conversion of the diisocyanates. The use of different diisocyanates gives hydrogels covering a large range of Young’s moduli (12-450 kPa). The elongations at break (up to 83%) as well as the maximum tensile strengths (up to 410 kPa) of the hydrogels described here are much higher than for lysine diisocyanate ethyl ester crosslinked gelatin reported before. Rheological investigations suggest that the network formation in some cases is due to physical interactions and entanglements rather than covalent crosslink formation.

scholarly journals Preparation and Characterization of pH Sensitive Chitosan/3-Glycidyloxypropyl Trimethoxysilane (GPTMS) Hydrogels by Sol-Gel Method

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1326 ◽  
Author(s):  
Chi-Ping Li ◽  
Mao-Chi Weng ◽  
Shu-Ling Huang
Keyword(s):  
Mechanical Properties ◽  
Water Content ◽  
Diffusion Mechanism ◽  
Sol Gel ◽  
Swelling Kinetics ◽  
Water Molecules ◽  
Crosslinking Reaction ◽  
Buffer Solution ◽  
Scanning Calorimetry ◽  
Hybrid Hydrogels

pH responsive chitosan and 3-Glycidyloxypropyl trimethoxysilane (GPTMS) hydrogels were synthesized by the sol-gel crosslinking reaction. GPTMS was introduced to influence several behaviors of the chitosan hydrogels, such as the swelling ratio, mechanical properties, swelling thermodynamics, kinetics, and expansion mechanism. The functional groups of Chitosan/GPTMS hybrid hydrogels were verified by FT-IR spectrometer. Differential scanning calorimetry (DSC) and the thermogravimetric analysis (TGA) were used to analyzed the thermal behavior of water molecules, the expansion of thermodynamics, and the content of water molecules in the hydrogel. The results show that hydrogel consists of 50 wt.% GPTMS (CG50) and has good mechanical properties and sensitivity to pH response characteristics in the acidic/alkaline buffer solution. The increase of GPTMS content leads to the increase of hydrophobic groups in the hydrogel and causes the decrease of the overall water content and the freezing bond water content. When the hydrogels were immersed in acid solution, the interaction force parameter was smaller than that of DI-water and alkaline. It means that the interaction forces between hydrogel and water molecules are relatively strong. The swelling kinetics of hybrid hydrogels were investigated to inspect the swelling mechanism. The result is consistent with the Fisk’s diffusion mechanism, meaning that the rate of water penetration is adjustable. The biodegradable hydrogel (CG50) in this study has good environmental sensitivity and mechanical properties. It is suitable to be applied in the fields of drug release or biomedical technology.

scholarly journals An aligned fibrous and thermosensitive hyaluronic acid-puramatrix interpenetrating polymer network hydrogel with mechanical properties adjusted for neural tissue

2022 ◽  
Author(s):  
Negar Abbasi Aval ◽  
Rahmatollah Emadi ◽  
Ali Valiani ◽  
Mahshid Kharaziha ◽  
Anna Finne-Wistrand
Keyword(s):  
Mechanical Properties ◽  
Hyaluronic Acid ◽  
Brain Tissue ◽  
Polymer Network ◽  
3D Structure ◽  
Interpenetrating Polymer Network ◽  
Great Promise ◽  
Sem Images ◽  
Rheological Measurements ◽  
Cell Material Interactions

AbstractCentral nervous system (CNS) injuries such as stroke or trauma can lead to long-lasting disability, and there is no currently accepted treatment to regenerate functional CNS tissue after injury. Hydrogels can mimic the neural extracellular matrix by providing a suitable 3D structure and mechanical properties and have shown great promise in CNS tissue regeneration. Here we present successful synthesis of a thermosensitive hyaluronic acid-RADA 16 (Puramatrix™) peptide interpenetrating network (IPN) that can be applied in situ by injection.Thermosensitive hyaluronic acid (HA) was first synthesized by combining HA with poly(N-isopropylacrylamide). Then, the Puramatrix™ self-assembled peptide was combined with the thermosensitive HA to produce a series of injectable thermoresponsive IPNs. The HA-Puramatrix™ IPNs formed hydrogels successfully at physiological temperature. Characterization by SEM, rheological measurements, enzymatic degradation and swelling tests was performed to select the IPN optimized for neurologic use. SEM images of the optimized dry IPNs demonstrated an aligned porous structure, and the rheological measurements showed that the hydrogels were elastic, with an elastic modulus of approximately 500 Pa, similar to that of brain tissue. An evaluation of the cell–material interactions also showed that the IPN had biological characteristics required for tissue engineering, strongly suggesting that the IPN hydrogel possessed properties beneficial for regeneration of brain tissue.

Sunlight exposure: the effects on the performance of paragliding fabric

2018 ◽  
Vol 69 (05) ◽  
pp. 381-389
Author(s):  
MENGÜÇ GAMZE SÜPÜREN ◽  
TEMEL EMRAH ◽  
BOZDOĞAN FARUK
Keyword(s):  
Mechanical Properties ◽  
Aging Process ◽  
Air Permeability ◽  
Sunlight Exposure ◽  
Test Results ◽  
Coating Materials ◽  
Strength Tests ◽  
Before And After ◽  
The Relationship ◽  
Dark Blue

This study was designed to explore the relationship between sunlight exposure and the mechanical properties of paragliding fabrics which have different colors, densities, yarn counts, and coating materials. This study exposed 5 different colors of paragliding fabrics (red, turquoise, dark blue, orange, and white) to intense sunlight for 150 hours during the summer from 9:00 a.m. to 3:00 p.m. for 5 days a week for 5 weeks. Before and after the UV radiation aging process, the air permeability, tensile strength, tear strength, and bursting strength tests were performed. Test results were also evaluated using statistical methods. According to the results, the fading of the turquoise fabric was found to be the highest among the studied fabrics. It was determined that there is a significant decrease in the mechanical properties of the fabrics after sunlight exposure. After aging, the fabrics become considerably weaker in the case of mechanical properties due to the degradation in both the dyestuff and macromolecular structure of the fiber

scholarly journals Hard Coating Materials Based on Photo-Reactive Silsesquioxane for Flexible Application: Improvement of Flexible and Hardness Properties by High Molecular Weight

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1564
Author(s):  
Jong Tae Leem ◽  
Woong Cheol Seok ◽  
Ji Beom Yoo ◽  
Sangkug Lee ◽  
Ho Jun Song
Keyword(s):  
Molecular Weight ◽  
Surface Morphology ◽  
High Molecular Weight ◽  
Sol Gel ◽  
Xrd Analysis ◽  
Polyhedral Oligomeric Silsesquioxanes ◽  
Coating Materials ◽  
Pencil Hardness ◽  
Coated Film ◽  
Flexible Application

EPOSS of polyhedral oligomeric silsesquioxanes (POSS) mixture structure and LPSQ of ladder-like polysilsesquioxane (LPSQ) structure were synthesized via sol–gel reaction. EPSQ had a high molecular weight due to polycondensation by potassium carbonate. The EPSQ film showed uniform surface morphology due to regular double-stranded structure. In contrast, the EPOSS-coated film showed nonuniform surface morphology due to strong aggregation. Due to the aggregation, the EPOSS film had shorter d-spacing (d1) than the EPSQ film in XRD analysis. In pencil hardness and nanoindentation analysis, EPSQ film showed higher hardness than the EPOSS film due to regular double-stranded structure. In addition, in the in-folding (r = 0.5 mm) and out-folding (r = 5 mm) tests, the EPSQ film did not crack unlike the EPOSS coated film.

scholarly journals Thermal, Physical and Mechanical Properties of Poly(Butylene Succinate)/Kenaf Core Fibers Composites Reinforced with Esterified Lignin

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2359
Author(s):  
Harmaen Ahmad Saffian ◽  
Masayuki Yamaguchi ◽  
Hidayah Ariffin ◽  
Khalina Abdan ◽  
Nur Kartinee Kassim ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Loss Modulus ◽  
Physical And Mechanical Properties ◽  
Weight Percent Gain ◽  
Weight Percent ◽  
Esterification Reaction ◽  
Butylene Succinate ◽  
Kenaf Core ◽  
Modified Lignin

In this study, Kraft lignin was esterified with phthalic anhydride and was served as reinforcing filler for poly(butylene succinate) (PBS). Composites with different ratios of PBS, lignin (L), modified lignin (ML) and kenaf core fibers (KCF) were fabricated using a compounding method. The fabricated PBS composites and its counterparts were tested for thermal, physical and mechanical properties. Weight percent gain of 4.5% after lignin modification and the FTIR spectra has confirmed the occurrence of an esterification reaction. Better thermo-mechanical properties were observed in the PBS composites reinforced with modified lignin and KCF, as higher storage modulus and loss modulus were recorded using dynamic mechanical analysis. The density of the composites fabricated ranged from 1.26 to 1.43 g/cm3. Water absorption of the composites with the addition of modified lignin is higher than that of composites with unmodified lignin. Pure PBS exhibited the highest tensile strength of 18.62 MPa. Incorporation of lignin and KCF into PBS resulted in different extents of reduction in tensile strength (15.78 to 18.60 MPa). However, PBS composite reinforced with modified lignin exhibited better tensile and flexural strength compared to its unmodified lignin counterpart. PBS composite reinforced with 30 wt% ML and 20 wt% KCF had the highest Izod impact, as fibers could diverge the cracking propagation of the matrix. The thermal conductivity value of the composites ranged from 0.0903 to 0.0983 W/mK, showing great potential as a heat insulator.

scholarly journals Optical, electrical and mechanical properties of TiN thin film obtained from a TiO2 sol-gel coating and rapid thermal nitridation

2021 ◽  
pp. 127089
Author(s):  
Arnaud Valour ◽  
Maria Alejandra Usuga Higuita ◽  
Gaylord Guillonneau ◽  
Nicolas Crespo-Monteiro ◽  
Damien Jamon ◽  
...  
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Sol Gel ◽  
Tio2 Sol ◽  
Thermal Nitridation
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