scholarly journals The Effects of Monomer, Crosslinking Agent, and Filler Concentrations on the Viscoelastic and Swelling Properties of Poly(methacrylic acid) Hydrogels: A Comparison

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2305
Author(s):  
Claudia Mihaela Ninciuleanu ◽  
Raluca Ianchiş ◽  
Elvira Alexandrescu ◽  
Cătălin Ionuţ Mihăescu ◽  
Cristina Scomoroşcenco ◽  
...  
Keyword(s):  
Water Absorption ◽  
Methacrylic Acid ◽  
Crosslinking Agent ◽  
Monomer Concentration ◽  
Fold Increase ◽  
Crosslinking Density ◽  
Swelling Properties ◽  
Swelling Degree ◽  
Reinforcing Agent ◽  
Swelling Studies

The present work aims at comparatively studying the effects of the concentrations of a monomer (10–30 wt% based on the whole hydrogel composition), crosslinking agent (1–3 mol% based on the monomer), and reinforcing agent (montmorillonite-MMT, 1–3 wt.% based on the whole hydrogel composition) on the swelling and viscoelastic properties of the crosslinked hydrogels prepared from methacrylic acid (MAA) and N,N′-methylenebisacrylamide (BIS) in the presence of K2S2O8 in aqueous solution. The viscoelastic measurements, carried out on the as-prepared hydrogels, showed that the monomer concentration had the largest impact, its three-time enhancement causing a 30-fold increase in the storage modulus, as compared with only a fivefold increase in the case of the crosslinking agent and 1.5-fold increase for MMT in response to a similar threefold concentration increase. Swelling studies, performed at three pH values, revealed that the water absorption of the hydrogels decreased with increasing concentration of both the monomer and crosslinking agent, with the amplitude of the effect of concentration modification being similar at pH 5.4 and 7.4 in both cases, but very different at pH 1.2. Further, it was shown that the increased pH differently influenced the swelling degree in the case of the hydrogel series in which the concentrations of the monomer and crosslinking agent were varied. In contrast to the effect of the monomer and crosslinking agent concentrations, the increase in the MMT amount in the hydrogel resulted in an increased swelling degree at pH 5.4 and 7.4, while at pH 1.2, a slight decrease in the water absorption was noticed. The hydrogel crosslinking density determinations revealed that this parameter was most affected by the increase in the monomer concentration.

scholarly journals Effect of nature and degree of crosslinking agent of poly(hydroxy-butyl-methacrylate-co-2-ethyl-hexyl-acrylate) networks on the swelling properties in nematic liquid crystal 5CB

2020 ◽  
Vol 66 (5 Sept-Oct) ◽  
pp. 617
Author(s):  
T. Mellal ◽  
M. Habchi ◽  
B. Dali Youcef
Keyword(s):  
Liquid Crystal ◽  
Propylene Glycol ◽  
Crosslinking Agent ◽  
Crosslinking Density ◽  
Butyl Methacrylate ◽  
Swelling Properties ◽  
Ethyl Hexyl ◽  
Face Centered ◽  
Poly Propylene ◽  
Liquid Crystal 5Cb

We experimentally measured the effect of nature and concentration of crosslinker on the photopolymerized time of the poly(hydroxy-butyl-methacrylate-co-2-ethyl-hexyl-acrylate)/5CB system. Initial mixtures are composed of monofunctional monomers hydroxy-butyl-methacrylate (HBMA) and 2-ethyl-hexyl-acrylate (2-EHA), and one of the three bifunctional monomers, poly-propylene-glycol-di-acrylate (PPGDA), tri-propylene-glycol-di-acrylate (TPGDA), or 1,6-hexane-diol-di-acrylate (HDDA), and 2-hydroxy-2-methylpropiophenone (Darocur 1173) as a photoinitiator. The copolymers were elaborated via UV irradiation of reactive formulation. The central composite face-centered design of experiments (DoE) has been used to determine the influence of temperature, crosslinking density and their interactions on swelling behavior of poly(HBMA-co-EHA/crosslinker) networks in liquid crystal 5CB. The experimental results and the predicted responses indicate a good correlation and therefore the validity of the used model.

scholarly journals Poly(urethane-siloxane)s based on hyperbranched polyester as crosslinking agent: Synthesis and characterization

2012 ◽  
Vol 77 (7) ◽  
pp. 919-935 ◽  
Author(s):  
Marija Pergal ◽  
Jasna Dzunuzovic ◽  
Sanja Ostojic ◽  
Miodrag Pergal ◽  
Aleksandra Radulovic ◽  
...  
Keyword(s):  
Ethylene Oxide ◽  
Crosslinking Agent ◽  
Crosslinking Density ◽  
Hyperbranched Polyester ◽  
Scanning Calorimetry ◽  
Polyurethane Networks ◽  
Swelling Studies ◽  
Step Growth ◽  
Step Growth Polymerization ◽  
Two Stages

A series of novel polyurethane crosslinked structures (PUs) was prepared from ?,?-dihydroxy-(ethylene oxide-poly(dimethylsiloxane)-ethylene oxide) (EO-PDMS-EO), 4,4?-methylenediphenyl diisocyanate and Boltorn? hyperbranched polyester of the third pseudo generation. The hydroxyfunctional hyperbranched aliphatic polyester with 26 end groups was used as crosslinking agent. In order to improve the compatibility of all reactants during the synthesis, PU samples were prepared by a step-growth polymerization in two stages in solution. The soft EO-PDMS-EO segment content was varied in the range from 15 to 40 wt.%. The influence of the EO-PDMS-EO content on the swelling behavior, crosslinking density, hardness, thermal and surface properties of the synthesized PUs was investigated. The structure of the synthesized polyurethanes was confirmed by the presence of specific bands in Fourier transform infrared spectra. Swelling studies were carried out to determine the crosslinking density and polyurethane networks with lower EOPDMS- EO content revealed higher crosslinking density. The glass transition temperature of the synthesized PUs, determined by differential scanning calorimetry, slightly increased from 50 to 58?C by decreasing EO-PDMS-EO content as a consequence of higher crosslinking density of samples. The increase of EO-PDMS-EO content leads to the better thermal stability, as it was confirmed by the value of the starting temperature of thermal degradation. The surface of the polyurethane networks became more hydrophobic with increasing EO-PDMS-EO content. The surface morphology of synthesized polyurethanes was analyzed by scanning electron microscopy.

Preparation and swelling properties of poly(acrylic acid-co-acrylamide) composite hydrogels

e-Polymers ◽  
2017 ◽  
Vol 17 (1) ◽  
pp. 95-106 ◽  
Author(s):  
Wei-Min Cheng ◽  
Xiang-Ming Hu ◽  
Yan-Yun Zhao ◽  
Ming-Yue Wu ◽  
Zun-Xiang Hu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Salt Tolerance ◽  
Acrylic Acid ◽  
Water Absorption ◽  
Crosslinking Agent ◽  
Salt Resistance ◽  
Composite Hydrogel ◽  
Swelling Properties ◽  
Unfavorable Effect ◽  
Poly Acrylic Acid

AbstractIn order to study the effect of composite clays on the mechanical properties, water absorption and salt tolerance of a hydrogel, a poly(acrylic acid-co-acrylamide)/bentonite/kaolin composite hydrogel was prepared. Acrylic acid and acrylamide have been used as water absorbent monomers. N,N′-methylene bisacrylamide was used as a crosslinking agent while potassium persulfate was used as an initiator. The water preserving capability, repeated water absorption, salt resistance and the mechanical properties of the composite hydrogel are analyzed and discussed. The results show that a small quantity of bentonite can increase the storage modulus of the composite hydrogel, whereas the excess clay had an unfavorable effect on the mechanical strength of the composite hydrogel. Both bentonite and kaolin significantly improved the water preserving capability, repeated water absorption and salt resistance of the composite hydrogel. Optimum values for the amounts of bentonite and kaolin were found to be 10% and 5%, respectively.

scholarly journals N,N-DIMETHYLACRYLAMIDE HYDROGELS FOR CONTROLLED DRUG DELIVERY. INFLUENCE OF NETWORK STRUCTURE AND DRUG SOLUBILITY ON THE LOAD AND RELEASE MECHANISMS

2019 ◽  
Vol 49 (2) ◽  
pp. 83-91
Author(s):  
Veronica D.G. GONZALEZ ◽  
V. S. GARCIA ◽  
Luis M. GUGLIOTTA
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Water Absorption ◽  
Water Solubility ◽  
Crosslinking Agent ◽  
Monomer Concentration ◽  
Release Mechanisms ◽  
Aqueous Solution Polymerization ◽  
Load Release

The aim of the present work was to synthesize sustained-release hydrogels based on N,N-dimethylacrylamide (DMA) to study the effect of the polymer matrix structure and the solubility of drugs on the load and release mechanisms. A series of crosslinked DMA hydrogels were synthesized with different monomer concentration and crosslinker to monomer ratio by free radical aqueous solution polymerization at 37ºC using N,N-methylen-bis-acrylamide as crosslinking agent. The effect of total monomer concentration and degree of crosslinking on the water absorption, glass transition temperature values, mechanical properties, and load/release of different drugs was studied. Main results showed that: a) the structure of the network, obtained by varying the monomer and crosslinking agent concentration, is a factor that governs the chemical and physical properties of the hydrogel (water absorption, glass transition temperature, storage and loss moduli, network parameters), b) the rate and amount of drug released from swellable hydrogels depend on both the degree of hydrogel crosslinking and the water solubility of the drug. In all cases, as the concentration of the crosslinker agent increased, the swelling capacity of the hydrogels was reduced and drugs with high solubility in water were more easily released, probably due to their greater affinity for the medium.

scholarly journals Development of Novel Superabsorbent Hybrid Hydrogels by E-Beam Crosslinking

Gels ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 189
Author(s):  
Ion Călina ◽  
Maria Demeter ◽  
Anca Scărișoreanu ◽  
Marin Micutz
Keyword(s):  
Sol Gel ◽  
Absorbed Dose ◽  
Crosslinking Density ◽  
Mechanical Analysis ◽  
Hybrid Hydrogel ◽  
Beam Radiation ◽  
Swelling Properties ◽  
Superabsorbent Hydrogel ◽  
Swelling Degree ◽  
Hybrid Hydrogels

In this study, several superabsorbent hybrid hydrogel compositions prepared from xanthan gum (XG)/sodium carboxymethylcellulose (CMC)/graphene oxide (GO) were synthesized by e-beam radiation crosslinking. We studied and evaluated the effects of GO content from the chemical structure of the hydrogels according to: sol-gel analysis, swelling degree, diffusion of water, ATR-FTIR spectroscopy, network structure, and dynamic mechanical analysis. The gel fraction and swelling properties of the prepared hydrogels depended on the polymer compositions and the absorbed dose. The hybrid XGCMCGO hydrogels showed superabsorbent capacity and reached equilibrium in less than 6 h. In particular, the XGCMCGO (70:30) hydrogel reached the highest swelling degree of about 6000%, at an irradiation dose of 15 kGy. The magnitude of the elastic (G′) and viscous (G″) moduli were strongly dependent on the absorbed dose. When the degree of crosslinking was higher, the G′ parameter was found to exceed 1000 Pa. In the case of the XGCMCGO (80:20) hydrogel compositions, the Mc and ξ parameters decreased with the absorbed dose, while crosslinking density increased, which demonstrated that we obtained a superabsorbent hydrogel with a permanent structure.

Interaction of Poly(methacrylic acid) Brushes with Metal Ions:  Swelling Properties

2005 ◽  
Vol 38 (10) ◽  
pp. 4345-4354 ◽  
Author(s):  
Rupert Konradi ◽  
Jürgen Rühe
Keyword(s):  
Metal Ions ◽  
Methacrylic Acid ◽  
Swelling Properties

Preparation of Carbon Fiber-Polyacrylamide Composite Hydrogel Based on Surface Electric-Initiated Polymerization

2021 ◽  
Vol 16 (6) ◽  
pp. 861-868
Author(s):  
Mengge Lv ◽  
Xinfang Wei ◽  
Liwen Peng
Keyword(s):  
Composite Material ◽  
Carbon Fiber ◽  
Electrochemical Polymerization ◽  
Crosslinking Agent ◽  
Monomer Concentration ◽  
Conductive Filler ◽  
Composite Effect ◽  
Conductive Hydrogel ◽  
Graft Modification ◽  
Conductive Hydrogels

Conductive hydrogels have shown excellent application prospects in the fields of bioelectronics, tissue engineering, wearable devices, etc. However, its poor compatibility at the organic-inorganic interface affects its mechanical strength and limits its wide application. We prepared carbon fiber-polyacrylamide organic-inorganic composite material by electrochemical polymerization using N,N-methylenebisacrylamide as the crosslinking agent, acrylamide as the monomer, and carbon fiber as the conductive filler. It forms a conductive hydrogel after absorbing water. The effects of monomer concentration, reaction time, and current on the composite material were investigated in this article. The experimental results show that a large number of irregular bumps are produced on the surface of carbon fiber, and various characterization tests show that it is polyacrylamide (PAM) that successfully attached to carbon fiber. Under the same electrochemical polymerization time, the current density and monomer concentration have little effect on the molecular weight which mainly concentrated around 6.2 × 105. The graft modification of PAM reduces the defects on the surface of the carbon fiber, and the composite effect is good.

scholarly journals Preparation and characteristics of gelatin sponges crosslinked by microbial transglutaminase

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3665 ◽  
Author(s):  
Haiyan Long ◽  
Kunlong Ma ◽  
Zhenghua Xiao ◽  
Xiaomei Ren ◽  
Gang Yang
Keyword(s):  
Cell Proliferation ◽  
Water Absorption ◽  
Crosslinking Agent ◽  
Microbial Transglutaminase ◽  
High Porosity ◽  
Cell Compatibility ◽  
High Viability ◽  
Good Biocompatibility ◽  
The Stability

Microbial transglutaminase (mTG) was used as a crosslinking agent in the preparation of gelatin sponges. The physical properties of the materials were evaluated by measuring their material porosity, water absorption, and elastic modulus. The stability of the sponges were assessed via hydrolysis and enzymolysis. To study the material degradation in vivo, subcutaneous implantations of sponges were performed on rats for 1–3 months, and the implanted sponges were analyzed. To evaluate the cell compatibility of the mTG crosslinked gelatin sponges (mTG sponges), adipose-derived stromal stem cells were cultured and inoculated into the scaffold. Cell proliferation and viability were measured using alamarBlue assay and LIVE/DEAD fluorescence staining, respectively. Cell adhesion on the sponges was observed by scanning electron microscopy (SEM). Results show that mTG sponges have uniform pore size, high porosity and water absorption, and good mechanical properties. In subcutaneous implantation, the material was partially degraded in the first month and completely absorbed in the third month. Cell experiments showed evident cell proliferation and high viability. Results also showed that the cells grew vigorously and adhered tightly to the sponge. In conclusion, mTG sponge has good biocompatibility and can be used in tissue engineering and regenerative medicine.

scholarly journals Preparation, Characterization and Swelling Studies of Carboxymethyl Sago Starch Hydrogel

2019 ◽  
Author(s):  
Normastura Sulta ◽  
Norhazlin Zainuddin ◽  
Mansor Bin Ahmad ◽  
Mas Jaffri Masarudin
Keyword(s):  
Reaction Time ◽  
Absorption Band ◽  
Acid Solution ◽  
Sago Starch ◽  
Additional Absorption ◽  
Sem Image ◽  
Swelling Degree ◽  
Swelling Studies ◽  
Ft Ir ◽  
Additional Absorption Band

Abstract Carboxymethyl sago starch (CMSS) hydrogel was prepared by dissolving CMSS in HCl solution under vigorous stirring to form gel. The parameter studied were the effect of the percentage of CMSS, concentration of the acid solution, reaction time and reaction temperature to identify the optimum condition of preparation of CMSS hydrogel. 60% of CMSS in 2.0M acid solution for 12 hours reaction time at room temperature were the optimum conditions for CMSS hydrogel. The hydrogel was characterized by using Fourier Transform Infrared (FT-IR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). FTIR spectrum of CMSS shows an additional absorption band at 1597 cm-1 indicating the substitution of CH2COO-Na+ group on the starch molecular chain during carboxymethylation, while the spectrum of CMSS hydrogel shows an additional sharp absorption band at 1723 cm-1 indicating that the Na in CMSS being exchanged to H from hydrochloric acid solution. SEM image of CMSS hydrogel shows pores in structure and connected to each other to form networks. TGA curve shows that the maximum rate of thermal decomposition of CMSS hydrogel is higher than CMSS at 330.22 ºC with 60.22% major weight loss. This could be due to the presence of the cross-linkages in the CMSS hydrogel. CMSS hydrogel gives high swelling degree in PBS solution at pH 7 and low swelling degree in acidic medium.

scholarly journals Bio-Based Epoxy Shape-Memory Thermosets from Triglycidyl Phloroglucinol

Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 542 ◽  
Author(s):  
David Santiago ◽  
Dailyn Guzmán ◽  
Francesc Ferrando ◽  
Àngels Serra ◽  
Silvia De la Flor
Keyword(s):  
Shape Memory ◽  
Shape Recovery ◽  
Memory Performance ◽  
Crosslinking Agent ◽  
Shape Memory Polymers ◽  
Crosslinking Density ◽  
Mechanical Analysis ◽  
Diglycidyl Ether ◽  
Partial Substitution ◽  
Scanning Calorimetry

A series of bio-based epoxy shape-memory thermosetting polymers were synthesized starting from a triglycidyl phloroglucinol (3EPOPh) and trimethylolpropane triglycidyl ether (TPTE) as epoxy monomers and a polyetheramine (JEF) as crosslinking agent. The evolution of the curing process was studied by differential scanning calorimetry (DSC) and the materials obtained were characterized by means of DSC, thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), stress-strain tests, and microindentation. Shape-memory properties were evaluated under free and totally constrained conditions. All results were compared with an industrial epoxy thermoset prepared from standard diglycidyl ether of Bisphenol A (DGEBA). Results revealed that materials prepared from 3EPOPh were more reactive and showed a tighter network with higher crosslinking density and glass transition temperatures than the prepared from DGEBA. The partial substitution of 3EPOPh by TPTE as epoxy comonomer caused an increase in the molecular mobility of the materials but without worsening the thermal stability. The shape-memory polymers (SMPs) prepared from 3EPOPh showed good mechanical properties as well as an excellent shape-memory performance. They showed almost complete shape-recovery and shape-fixation, fast shape-recovery rates, and recovery stress up to 7 MPa. The results obtained in this study allow us to conclude that the triglycidyl phloroglucinol derivative of eugenol is a safe and environmentally friendly alternative to DGEBA for preparing thermosetting shape-memory polymers.

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