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.

Synthesis and Deswelling Behavior of Intelligent Thermosensitive Poly(N, N-Diethylacrylamide-Co-Itaconic Acid) Hydrogels

2012 ◽  
Vol 490-495 ◽  
pp. 3667-3671 ◽  
Author(s):  
Nai Yan Zhang ◽  
Yue Guo Shen ◽  
Xiao Qi Li
Keyword(s):  
Itaconic Acid ◽  
Monomer Concentration ◽  
Molar Ratio ◽  
Solution Temperature ◽  
External Temperature ◽  
Critical Solution Temperature ◽  
Different Temperatures ◽  
Total Monomer Concentration ◽  
Equilibrium Swelling Ratio ◽  
Composition Ratios

Poly(N,N-diethylacrylamide) (PDEA) hydrogels possess a lower critical solution temperature (LCST) at around 31oC. When the external temperature is raised above the LCST, the hydrogels experience abrupt and drastic shrinkage. This unique property makes them very useful for biomedical applications such as on-off switches for modulated drug delivery and tissue engineering. In this study, itaconic acid (IA) was co-polymerized with N, N-diethylacrylamide (DEA) monomer to improve the LCST to the physiologic temperature about 37oC. These copolymer hydrogels were prepared by changing the initial DEA/IA molar ratio and total monomer concentration. The interior morphologies of hydrogels were characterized by scanning electron microscopy (SEM). In comparison with the PDEA hydrogel, the equilibrium swelling ratio (ESR) and LCST of the hydrogels increase with the increase of IA content in the feed. The deswelling dynamics behaviors of the different composition ratios of the P(DEA-co-IA) hydrogels on the different temperatures was investigated in detail.

Dynamic Characterization and Drug Release of Thermosensitive Poly(N, N-Diethylacrylamide-Co-Itaconic Acid) Copolymer Hydrogels

2011 ◽  
Vol 117-119 ◽  
pp. 1239-1242
Author(s):  
Xiao Qi Li ◽  
Nei Yan Zhang ◽  
Yue Guo Shen
Keyword(s):  
Itaconic Acid ◽  
Monomer Concentration ◽  
Drug Carriers ◽  
Molar Ratio ◽  
Solution Temperature ◽  
Acid Copolymer ◽  
Total Monomer Concentration ◽  
Model Drug ◽  
Equilibrium Swelling Ratio ◽  
Mechanical Performances

In this study, poly(N,N-diethylacrylamide-co-itaconic acid) (P(DEA-co-IA)) copolymer hydrogels were synthesized by changing the initial DEA/IA molar ratio, N,N-methylenebisacrylamide and total monomer concentration. The thermo-sensitive and mechanical performances were optimized by altering the above parameters. In comparison with the PDEA hydrogel, the equilibrium swelling ratio (ESR) and lower critical solution temperature (LCST) of the hydrogels changed with the alternation of the above parameters. The swelling and deswelling kinetics was also studied in dital. The release behaviors of the model drug, aminophylline, are found dependent on hydrogel composition and environmental temperature, which suggests that these materials have potential application as intelligent drug carriers.

Study on Superabsorbent Material in Thermal Infrared Camouflage

2014 ◽  
Vol 941-944 ◽  
pp. 370-373
Author(s):  
Nai Yan Zhang ◽  
Jiang Yu ◽  
Juan Zhang
Keyword(s):  
Chemical Structure ◽  
Monomer Concentration ◽  
Thermal Infrared ◽  
Molar Ratio ◽  
Object Temperature ◽  
Different Temperatures ◽  
Total Monomer Concentration ◽  
Equilibrium Swelling Ratio ◽  
Composition Ratios ◽  
Infrared Camouflage

Objectives, which is motional on the batter field, such as vehicles, tanks, planes, warships, firing cannons, etc. They are all active objects. On the surface of these objects there have very higher temperatures than around background, they have special pictures, and are easy found by thermal infrared reconnaissance systems. 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 materials were prepared by changing the initial DEA/IA molar ratio and total monomer concentration. The chemical structure of materials was characterized by fourier transform infrared (FTIR) spectroscopy. In comparison with the PDEA hydrogel, the equilibrium swelling ratio (ESR) of the materials 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) materials on the different temperatures was investigated in detail. Using the big hot-inertia of water, the superabsorbent material of the object surface is propitious to debase the object temperature, which suggests that these materials have potential application as thermal infrared camouflage materials.

Preparation and Characterization of Thermosensitive Submicron Particles for Gene Delivery

2006 ◽  
Vol 6 (9) ◽  
pp. 2804-2810 ◽  
Author(s):  
Nalan Özdemir ◽  
Ali Tuncel ◽  
Myungchan Kang ◽  
Emir Baki Denkbş
Keyword(s):  
Gene Delivery ◽  
Plasmid Dna ◽  
Aqueous Media ◽  
Monomer Concentration ◽  
Mouse Fibroblast ◽  
Submicron Particles ◽  
Dna Adsorption ◽  
Different Temperatures ◽  
Total Monomer Concentration

In this study, a new thermosensitive material was proposed as a carrier for gene delivery. The thermosensitive submicron particles were synthesized by the dispersion copolymerization of N-isopropylacylamide (NIPA) with a relatively new, cationic comonomer, N-3-dimethylamino-propylmethacrylamide (DMAPM) with higher ionization ability with respect to the commonly used cationic comonomers. To achieve particle sizes smaller than 1 μm, suitable for gene delivery, the total monomer concentration in the dispersion copolymerization was kept at a sufficiently low level. The size of poly(NIPA-co-DMAPM) particles was determined as 454 nm, by AFM in dry state. The poly(NIPA-co-DMAPM) particles showed both temperature and pH sensitivity in the aqueous media. The plasmid DNA adsorption onto the thermosensitive cationic particles was investigated at different temperatures and pHs. The adsorbed amount of plasmid DNA onto the particles was significantly increased by the introduction of cationic comonomer. The equilibrium plasmid DNA adsorptions up to 13 mg/g dry particles were achieved at physiological pH. Approximately 36% w/w of adsorbed plasmid could be desorbed from the cationic nanolatex. The results of biocompatibility studies performed with mouse fibroblast cells showed the suitability of thermosensitive cationic particles for intended application.

Synthesis of Ultra-High Molecular Weight Polyacrylonitrile (UHMWPAN) by Aqueous Suspension Polymerization

2015 ◽  
Vol 1120-1121 ◽  
pp. 615-619
Author(s):  
Hui Yu Jiang ◽  
Mei Hua Zhou ◽  
Ding Pan
Keyword(s):  
Molecular Weight ◽  
Suspension Polymerization ◽  
Aqueous Suspension ◽  
Average Molecular Weight ◽  
Monomer Concentration ◽  
Polymerization Process ◽  
Polymerization Temperature ◽  
Different Temperatures ◽  
Total Monomer Concentration ◽  
Ultra High Molecular Weight

Acrylonitrile (AN) and itaconic acid (IA) were used to synthesize UHMWPAN by aqueous suspension method with 2,2’-azobisisobutyronitrile (AIBN) as the initiator and polyvinylalcohol (PVA) as the disperser at different temperatures (55°C~75°C) for different timings (1.0h~3.0h). The usage amounts of AN, IA, AIBN and PVA were also technical polymerization parameters used to obtain the optimal polymerization process. We found that the conversion and the viscosity average molecular weight both achieved the optimum levels when the conditions were as follows: the total monomer concentration (21wt%), the monomer ratio (AN: IA=98:2), the usage amount of the initiator (AIBN, 0.01wt%), the usage amount of the disperser (PVA, 0.1wt%), the polymerization temperature (70°C) and the polymerization time (2h).

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.

Effects of Polymerization Parameters on Aqueous Deposited Copolymerization of Acrylonitrile and Itaconic Acid

2013 ◽  
Vol 774-776 ◽  
pp. 508-511
Author(s):  
Ya Qi Zhao ◽  
Qiao Feng ◽  
Ling Zhi Du
Keyword(s):  
Molecular Weight ◽  
Reaction Time ◽  
High Molecular Weight ◽  
Reaction Temperature ◽  
Itaconic Acid ◽  
Temperature Region ◽  
Monomer Concentration ◽  
Initiator Concentration ◽  
Molecular Weights ◽  
Total Monomer Concentration

Pure powdery high molecular weight polyacrylonitrile (HMW-PAN) copolymers were firstly synthesized by aqueous deposited polymerization (ADP) technique employing 2,2'-Azobis (isobutyramidine) dihydrochloride (AIBA) as initiator and itaconic acid (IA) as comonomer. Various PAN polymers were obtained through changing different polymerization parameters. It is indicated that with the increase of total monomer concentration, initiator concentration, reaction temperature and reaction time, polymerization conversions of PAN copolymers all increased. While the molecular weights become greater with the increase of total monomer concentration. With the increase of initiator concentration and reaction temperature (under higher reaction temperature region), the molecular weights decreased. However, the molecular weights only had very little decrease at the end of long extension of reaction time.

Rolling Resistance Calculation Procedure Using the Finite Element Method

2019 ◽  
Vol 48 (3) ◽  
pp. 224-248
Author(s):  
Pablo N. Zitelli ◽  
Gabriel N. Curtosi ◽  
Jorge Kuster
Keyword(s):  
Finite Element ◽  
Energy Dissipation ◽  
Rolling Resistance ◽  
Element Model ◽  
The Finite Element Method ◽  
Temperature Changes ◽  
Rubber Compounds ◽  
Different Temperatures ◽  
Materials Used ◽  
Account Temperature

ABSTRACT Tire engineers are interested in predicting rolling resistance using tools such as numerical simulation and tests. When a car is driven along, its tires are subjected to repeated deformation, leading to energy dissipation as heat. Each point of a loaded tire is deformed as the tire completes a revolution. Most energy dissipation comes from the cyclic loading of the tire, which causes the rolling resistance in addition to the friction force in the contact patch between the tire and road. Rolling resistance mainly depends on the dissipation of viscoelastic energy of the rubber materials used to manufacture the tires. To obtain a good rolling resistance, the calculation method of the tire finite element model must take into account temperature changes. It is mandatory to calibrate all of the rubber compounds of the tire at different temperatures and strain frequencies. Linear viscoelasticity is used to model the materials properties and is found to be a suitable approach to tackle energy dissipation due to hysteresis for rolling resistance calculation.

scholarly journals Preparation and Characterization of High-Efficiency Magnetic Heavy Metal Capture Flocculants

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1732
Author(s):  
Yuanyuan Yu ◽  
Yongjun Sun ◽  
Jun Zhou ◽  
Aowen Chen ◽  
Kinjal J. Shah
Keyword(s):  
Heavy Metal ◽  
Reaction Time ◽  
High Efficiency ◽  
Removal Rate ◽  
Low Cost ◽  
Monomer Concentration ◽  
Synthesis Process ◽  
Response Surface Optimization ◽  
Metal Capture ◽  
Total Monomer Concentration

In this study, a high-efficiency magnetic heavy metal flocculant MF@AA was prepared based on carboxymethyl chitosan and magnetic Fe3O4. It was characterized by SEM, FTIR, XPS, XRD and VSM, and the Cu(II) removal rate was used as the evaluation basis for the preparation process. The effects of AMPS content, total monomer concentration, photoinitiator concentration and reaction time on the performance of MF@AA flocculation to remove Cu(II) were studied. The characterization results show that MF@AA has been successfully prepared and exhibits good magnetic induction characteristics. The synthesis results show that under the conditions of 10% AMPS content, 35% total monomer concentration, 0.04% photoinitiator concentration, and 1.5 h reaction time, the best yield of MF@AA is 77.69%. The best removal rate is 87.65%. In addition, the response surface optimization of the synthesis process of MF@AA was performed. The optimal synthesis ratio was finally determined as iron content 6.5%, CMFS: 29.5%, AM: 53.9%, AMPS: 10.1%. High-efficiency magnetic heavy metal flocculant MF@AA shows excellent flocculation performance in removing Cu(II). This research provides guidance and ideas for the development of efficient and low-cost flocculation technology to remove Cu(II) in wastewater.

scholarly journals LPEATs Tailor Plant Phospholipid Composition through Adjusting Substrate Preferences to Temperature

2021 ◽  
Vol 22 (15) ◽  
pp. 8137
Author(s):  
Sylwia Klińska ◽  
Kamil Demski ◽  
Katarzyna Jasieniecka-Gazarkiewicz ◽  
Antoni Banaś
Keyword(s):  
Growth Regulation ◽  
Phylogenetic Analyses ◽  
Phospholipid Composition ◽  
Expression Ratio ◽  
Temperature Changes ◽  
Substrate Preferences ◽  
Thermal Changes ◽  
Biochemical Evaluation ◽  
Response To Temperature ◽  
Acyl Donors

Acyl-CoA:lysophosphatidylethanolamine acyltransferases (LPEATs) are known as enzymes utilizing acyl-CoAs and lysophospholipids to produce phosphatidylethanolamine. Recently, it has been discovered that they are also involved in the growth regulation of Arabidopsis thaliana. In our study we investigated expression of each Camelina sativa LPEAT isoform and their behavior in response to temperature changes. In order to conduct a more extensive biochemical evaluation we focused both on LPEAT enzymes present in microsomal fractions from C. sativa plant tissues, and on cloned CsLPEAT isoforms expressed in yeast system. Phylogenetic analyses revealed that CsLPEAT1c and CsLPEAT2c originated from Camelina hispida, whereas other isoforms originated from Camelina neglecta. The expression ratio of all CsLPEAT1 isoforms to all CsLPEAT2 isoforms was higher in seeds than in other tissues. The isoforms also displayed divergent substrate specificities in utilization of LPE; CsLPEAT1 preferred 18:1-LPE, whereas CsLPEAT2 preferred 18:2-LPE. Unlike CsLPEAT1, CsLPEAT2 isoforms were specific towards very-long-chain fatty acids. Above all, we discovered that temperature strongly regulates LPEATs activity and substrate specificity towards different acyl donors, making LPEATs sort of a sensor of external thermal changes. We observed the presented findings not only for LPEAT activity in plant-derived microsomal fractions, but also for yeast-expressed individual CsLPEAT isoforms.

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