scholarly journals Synthesis and characterization of temperature-sensitive and biodegradable hydrogel based on N-isopropylacrylamide

2010 ◽  
Vol 8 (2) ◽  
pp. 426-433 ◽  
Author(s):  
Yueqin Yu ◽  
Yanshun Li ◽  
Chunjing Zhu ◽  
Lingxiu Liu
Keyword(s):  
Enzymatic Degradation ◽  
Molar Ratio ◽  
Solution Temperature ◽  
Swelling Kinetics ◽  
Swelling Ratio ◽  
Nacl Solution ◽  
Equilibrium Swelling ◽  
Cross Linker ◽  
The Cross ◽  
Equilibrium Swelling Ratio

AbstractBased on a biodegradable cross-linker, N-maleyl chitosan (N-MACH), a series of Poly(N-isopropylacrylamide) (PNIPAAm) and Poly(N-isopropylacrylamide-co-acrylamide) [P(NIPAAm-co-Am)] hydrogels were prepared, and their lower critical solution temperature (LCST), swelling kinetics, equilibrium swelling ratio in NaCl solution, and enzymatic degradation behavior in simulated gastric fluids (SGF) were discussed. The LCST did not change with different cross-linker contents. By altering the NIPAAm/Am molar ratio of P(NIPAAm-co-Am) hydrogels, the LCST could be increased to 39°C. The LCST of the hydrogel was significantly influenced by the monomer ratio of the NIPAAm/Am but not by the cross-linker content. In the swelling kinetics, all the dry hydrogels exhibited fast swelling behavior, and the swelling ratios were influenced by the cross-linker content and NIPAAm/Am molar ratios. Equilibrium swelling ratio of all the hydrogels decreased with increasing NaCl solution concentration. In enzymatic degradation tests, the weight loss of hydrogels was dependent on the cross-linker contents and the enzyme concentration.

Effect of Salinity and Temperature on Swelling Behavior of Nano/Micro Polymer Particle

2013 ◽  
Vol 448-453 ◽  
pp. 3993-3997
Author(s):  
Yu Lou ◽  
Wei Yao Zhu ◽  
Xue Ling Zhang ◽  
Yun Qian Long
Keyword(s):  
Oil Recovery ◽  
Polymer Particle ◽  
Swelling Behavior ◽  
Swelling Kinetics ◽  
Swelling Ratio ◽  
Polymer Particles ◽  
Equilibrium Swelling ◽  
Swelling Characteristics ◽  
Equilibrium Swelling Ratio ◽  
Kinetics Of

Nano/micro polymer particles of acrylamide (AM), acrylic acid (AA), methyl methacrylate (MMA) are used to enhance oil recovery. Swelling kinetics of nano/micro polymer particles were investigated through experimental analysis and statistical analysis. The effect of salinity and temperature on swelling behavior over time is studied experimentally. The swelling kinetics of nano/micro polymer particle was described by second order kinetics. Equilibrium swelling ratio and swelling rate were obtained through nonlinear regression. The quantitative relationships between equilibrium swelling ratio and salinity, temperature were presented. Results show that the swelling ratio increases with increasing temperature or decreasing salt concentration. The study provides a direct perspective of swelling characteristics of nano/micro polymer particles for oil recovery enhancement.

Preparation and Swelling Dynamics Characterization of Poly(N, N-Diethylacrylamide-Co-Itaconic Acid) Intelligent Hydrogels

2012 ◽  
Vol 490-495 ◽  
pp. 3382-3386
Author(s):  
Xiao Qi Li ◽  
Nai Yan Zhang ◽  
Jun Hai Zhang
Keyword(s):  
Itaconic Acid ◽  
Monomer Concentration ◽  
Molar Ratio ◽  
Solution Temperature ◽  
Temperature Changes ◽  
Different Temperatures ◽  
Total Monomer Concentration ◽  
Equilibrium Swelling Ratio ◽  
Composition Ratios ◽  
Response To Temperature

Poly(N,N-diethylacrylamide) (PDEA) hydrogel is known for their intelligent reversible swelling/deswelling behavior in response to temperature changes across a lower critical solution temperature (LCST) at around 31oC. In this study, itaconic acid (IA) was co-polymerized with N, N-diethylacrylamide (DEA) monomer to improve the swelling behavior and the total absorbing water. These copolymer hydrogels were prepared by changing the initial DEA/IA molar ratio and total monomer concentration. The chemical structure of hydrogels was characterized by fourier transform infrared (FTIR) spectroscopy. In comparison with the PDEA hydrogel, the equilibrium swelling ratio (ESR) of the hydrogels increase with the increase of IA content in the feed and the swelling dynamics behaviors of the different composition ratios of the P(DEA-co-IA) hydrogels on the different temperatures was investigated in detail.

scholarly journals Interlayer-free Glucose Carbonised Template Silica Membranes for Brine Water Desalination

2019 ◽  
Vol 280 ◽  
pp. 03010 ◽  
Author(s):  
Dwi Rasy Mujiyanti ◽  
Muthia Elma ◽  
Mufidah Amalia
Keyword(s):  
Sol Gel ◽  
Tetraethyl Orthosilicate ◽  
Water Desalination ◽  
Molar Ratio ◽  
Solution Temperature ◽  
Nacl Solution ◽  
Silica Membranes ◽  
Salt Ions ◽  
Sol Gel Process ◽  
Free Glucose

Interlayer-free glucose carbonized template silica membranesbased on tetraethyl orthosilicate (TEOS) and glucose were successfullyprepared using an acid-base catalysed sol-gel method for artificial brinewater desalination (7.5% wt NaCl solution %) at temperatures range from25, 40 and 60 °C. These membranes calcined at 250 and 400 °C. Themembranes were fabricated through sol-gel process by using TEOS(tetraethyl orthosilicate); ethanol; nitric acid; ammonia; aquadest andglucose as a template. By molar ratio is 1: 38: 0.0007: 0.0003: 5 and0.25%; 0.5%, 1% w/v glucose as template. The results show the highestwater fluxes of 1.8, 2.2 and 4.8 kg m−2 h−1 for 25, 40 and 60 °Cdesalination process with excellent salt rejections of 99.5, 99.5 and 99.7%, respectively. It was found that the higher the NaCl solution temperature asfeed solution as well as glucose concentration (0.25% to 1% wt) astemplate attached in the silica matrixes, the higher water fluxes eventhough the salt rejection remain the same. This study demonstrates that theorganosilica membranes offered the carbonized silica mesostructuremembranes with excellent separation of water from the hydrated salt ions, particularly for processing brine salt solutions.

scholarly journals Influence of Cross-Linking Degree on Hydrodynamic Behavior and Stimulus-Sensitivity of Derivatives of Branched Polyethyleneimine

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1085
Author(s):  
Alina Amirova ◽  
Tatyana Kirila ◽  
Mikhail Kurlykin ◽  
Andrey Tenkovtsev ◽  
Alexander Filippov
Keyword(s):  
Aqueous Solutions ◽  
Mole Fraction ◽  
Solution Temperature ◽  
Linear Polymers ◽  
Intermolecular Hydrogen Bonds ◽  
Critical Solution Temperature ◽  
Cross Linker ◽  
The Cross ◽  
Derivatives Of ◽  
Constant Characteristics

Cross-linked derivatives of acylated branched polyethyleneimine containing 2-isopropyl-2-oxazoline units were investigated in chloroform and aqueous solutions using methods of molecular hydrodynamics, static and dynamic light scattering, and turbidity. The studied samples differed by the cross-linker content. The solubility of the polyethyleneimines studied worsened with the increasing mole fraction of the cross-linker. Cross-linked polyethyleneimines were characterized by small dimensions in comparison with linear analogs; the increase in the cross-linker content leads to a growth of intramolecular density. At low temperatures, the aqueous solutions of investigated samples were molecularly dispersed, and the large aggregates were formed due to the dehydration of oxazoline units and the formation of intermolecular hydrogen bonds. For the cross-linked polyethyleneimines, the phase separation temperatures were lower than that for linear and star-shaped poly-2-isopropyl-2-oxazolines. The low critical solution temperature of the solutions of studied polymers decreased with the increasing cross-linker mole fraction. The time of establishment of the constant characteristics of the studied solutions after the jump-like change in temperature reaches 3000 s, which is at least two times longer than for linear polymers.

Study on the Effect of [Al13]7+ over the Free Swelling Ratio of Expansive Soil

2017 ◽  
Vol 748 ◽  
pp. 341-345 ◽  
Author(s):  
Liang Liu ◽  
Hai Lin Yao ◽  
Zheng Lu ◽  
Zhong Wen Yin ◽  
Xing Wen Luo ◽  
...  
Keyword(s):  
Expansive Soil ◽  
Swelling Behavior ◽  
Molar Ratio ◽  
Cross Linking ◽  
Swelling Ratio ◽  
Free Swelling ◽  
The Cross ◽  
Alkali Neutralization

The hydroxy-aluminum solution is prepared by alkali neutralization titration and the subsequent cross-linking tests are designed by mixing the hydroxy-aluminum solution and expansive soil, followed by the discussion on the influence of the molar ratio of OH- to Al3+ and ratio of total aluminum to expansive soil on the swelling behavior of the cross-linked soil. The free swelling ratio of the cross-linked soil decreased significantly, indicating that the main aluminum species that changes the expansion properties of the cross-linked soil is [Al13]7+.

Preparation of pH Sensitive Polyacrylic Acid(PAAc) Macroporous Hydrogels in Aqueous NaCl Solutions and their Characterization

2009 ◽  
Vol 79-82 ◽  
pp. 1999-2002
Author(s):  
Yu Hua Xue ◽  
Wen Yuan Zhao ◽  
Shou Feng Sun ◽  
Hu Yu
Keyword(s):  
Polyacrylic Acid ◽  
Response Rates ◽  
Ph Sensitive ◽  
Swelling Ratio ◽  
Ph Changes ◽  
Nacl Concentration ◽  
Equilibrium Swelling ◽  
Swelling Studies ◽  
Equilibrium Swelling Ratio

In this study, macroporous, pH sensitive polyacrylic acid hydrogels were prepared by using different concentration of aqueous NaCl solutions as the polymerization medium. The optical photos showed that the pore morphologies of the hydrogels were dependent on the concentration of NaCl. Swelling studies showed an increase in equilibrium swelling ratio as the NaCl concentration in the polymerization medium increased from 0 to 0.7mol/L. The hydrogels exhibited stronger sensitivity to pH changes, and showed much faster reswelling and deswelling response rates with the NaCl concentration increasing in the polymerization medium.

Studies on Surface Hydroxypropylation and Swellability of Bacterial Cellulose

2012 ◽  
Vol 601 ◽  
pp. 12-15 ◽  
Author(s):  
Tong Wan ◽  
Li Ying Liu ◽  
Wei Zeng ◽  
Yong Zhu
Keyword(s):  
Surface Modification ◽  
Sodium Hydroxide ◽  
Bacterial Cellulose ◽  
Propylene Oxide ◽  
Acetobacter Xylinum ◽  
Swelling Ratio ◽  
Freeze Dried ◽  
Equilibrium Swelling ◽  
Equilibrium Swelling Ratio

Bacterial Cellulose (BC) consisting of hydrophobic ultra-fine fibers was produced by Acetobacter xylinum. Hydroxypropyl bacterial celluloses (HPBC) were synthesized by surface modification of nano-fibrils via hydroxypropylation using two modifier systems, sodium hydroxide/ propylene oxide as system (I) and sodium hydroxide/urea/propylene oxide as system (II) respectively. The equilibrium swelling ratio (ESR) of HPBC was studied. ESR of HPBC obtained from system (I) was significantly higher than that obtained from system (II). The maximum ESR of HPBC was nearly 70 times larger than that of air dried BC and 10 times larger than that of freeze dried BC.

scholarly journals Preformed particle gel: evaluation and optimization of salinity and pH on equilibrium swelling ratio

2012 ◽  
Vol 2 (2) ◽  
pp. 85-91 ◽  
Author(s):  
Asefe Mousavi Moghadam ◽  
Mohsen Vafaie Sefti ◽  
Mahsa Baghban Salehi ◽  
Ahmad Dadvand Koohi
Keyword(s):  
Swelling Ratio ◽  
Preformed Particle Gel ◽  
Equilibrium Swelling ◽  
Equilibrium Swelling Ratio

MESHED SCAFFOLDS MADE OF α, α′ -BIS(2-HYDROXYETHYL METHACRYLATE) POLY(ETHYLENE GLYCOL) THROUGH 3D STEREOLITHOGRAPHY

2013 ◽  
Vol 25 (05) ◽  
pp. 1340002 ◽  
Author(s):  
Ren-Jei Chung ◽  
Ming-Fa Hsieh ◽  
Li-Hsiang Perng ◽  
Yih-Lin Cheng ◽  
Tuan-Jung Hsu
Keyword(s):  
Ethylene Glycol ◽  
Rapid Prototyping ◽  
Molar Ratio ◽  
Main Body ◽  
Hydroxyethyl Methacrylate ◽  
Poly Ethylene Glycol ◽  
Synthetic Process ◽  
Cross Linker ◽  
The Cross ◽  
Poly Ethylene

Recent development of tissue engineering scaffolds that mimic anatomical structures exhibits a tendency to use rapid prototyping technology, because it can be applied to precisely manufacture the designed objects from the computer-generated model. Among all of rapid prototyping approaches, combining with lithography is characterized with a high throughput of fabrication, especially for the fabrication of polymeric scaffolds. In this study, the aims were to: (1) synthesize the 2-hydroxyethyl methacrylate (HEMA)-capped poly(ethylene glycol) (PEG), which served as the cross-linker of the continuous phase of a poly(lactide-co-glycolide) (PLGA) scaffold and (2) fabricate the composite scaffolds through stereolithography. The synthetic process of the cross-linker was traced, and the end-point of the process was found to lie in 3 to 4 h depending on the molecular weight of the PEG used. The chemical structure of the cross-linker was found to be linear and symmetric to PEG and with a 1:2 molar ratio of PEG and HEMA. It was anticipated to form an interpenetrating network upon irradiating under UV light with PLGA serving as the main body of the scaffold. PEG1000–HEMA had better biocompatibility than those with shorter PEG chains. Scaffolds with two structural variants, square and hexagonal pores, designed by computer were demonstrated. It may further combine medical images to reconstruct tissues and organs for regenerative medicine.

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