scholarly journals Synthesis and characterization of PIL/pNIPAAm hybrid hydrogels

2016 ◽  
Vol 2 (1) ◽  
pp. 1-4
Author(s):  
Sylvia Pfensig ◽  
Daniela Arbeiter ◽  
Klaus-Peter Schmitz ◽  
Niels Grabow ◽  
Thomas Eickner ◽  
...  
Keyword(s):  
Mechanical Characterization ◽  
Heating Temperature ◽  
Controlled Drug Release ◽  
Solution Temperature ◽  
Scanning Calorimetry ◽  
Critical Solution Temperature ◽  
Temperature Range ◽  
Hybrid Hydrogels ◽  
Higher Temperature

AbstractIn this study, varying amounts of NIPAAm and an ionic liquid (IL), namely 1-vinyl-3-isopropylimidazolium bromide ([ViPrIm]+[Br]−), have been used to synthesize hybrid hydrogels by radical emulsion polymerization. Amounts of 70/30%, 50/50%, 30/70%, 15/85% and 5/95% (wt/wt) of PIL/pNIPAAm were used to produce hybrid hydrogels as well as the parental hydrogels. The adhesive strength was investigated and evaluated for mechanical characterization. Thermal properties of resulting hydrogels have been investigated using differential scanning calorimetry (DSC) in a default heating temperature range (heating rate 10 K min−1). The presence of poly ionic liquids (PIL) in the polymer matrix leads to a moved LCST (lower critical solution temperature) to a higher temperature range for certain hybrid hydrogels PIL/pNIPAAm. While pNIPAAm exhibits an LCST at 33.9 ± 0.3°C, PIL/pNIPAAm 5/95% and PIL/pNIPAAm 15/85% were found to have LCSTs at 37.6 ± 0.9°C and 52 ± 2°C, respectively. This could be used for controlled drug release that goes along with increasing body temperature in response to an implantation caused infection.

scholarly journals Synthesis and characterization of copolymer hydrogels of chitosan, itaconic acid and N-isopropilacrylamide

2011 ◽  
Vol 65 (6) ◽  
pp. 657-666
Author(s):  
Nedeljko Milosavljevic ◽  
Nikola Milasinovic ◽  
Jovanka Filipovic ◽  
Melina Kalagasidis-Krusic
Keyword(s):  
Itaconic Acid ◽  
Polymer Chains ◽  
Solution Temperature ◽  
Critical Solution Temperature ◽  
Ionic Groups ◽  
Reaction Solution ◽  
Degree Of Swelling ◽  
The Matrix ◽  
Higher Temperature

This paper deals with synthesis of copolymer hydrogels of N-isopropilacrylamide, itaconic acid and chitosan. During synthesis, pH of the reaction solution and temperature were varied. It was found that reaction at higher temperature, above lower critical solution temperature (LCST) value of N-isopropilacrylamide resulted in a formation of polymer rich domains or aggregates in the matrix of loosely tied network, which cause a higher degree of swelling. Moreover, reaction pH also affects the degree of swelling and contraction of hydrogels owing to the different ionization of the ionic groups presence in hydrogel. The values of diffusion exponent, n, indicate non-Fickian kinetics corresponding to diffusion and relaxation of polymer chains. These hydrogels could be classified as macroporous hydrogels. Hence, it is possible to synthetize hydrogels of desired functionality which allow their application in different fields.

scholarly journals STRUCTURAL AND MECHANICAL CHARACTERIZATION OF DEFORMED POLYMER USING CONFOCAL RAMAN MICROSCOPY AND DSC

2016 ◽  
Vol 3 ◽  
pp. 47-50
Author(s):  
Birgit Neitzel ◽  
Florian Aschermayer ◽  
Milan Kracalik ◽  
Sabine Hild
Keyword(s):  
Differential Scanning Calorimetry ◽  
Raman Spectroscopy ◽  
Mechanical Characterization ◽  
Polymer Chains ◽  
Polymer Materials ◽  
Confocal Raman Microscopy ◽  
Micro Structure ◽  
Scanning Calorimetry ◽  
Confocal Raman

Polymers have various interesting properties, which depend largely on their inner structure. One way to influence the macroscopic behaviour is the deformation of the polymer chains, which effects the change in microstructure. For analyzing the microstructure of non-deformed and deformed polymer materials, Raman spectroscopy as well as differential scanning calorimetry (DSC) were used. In the present study we compare the results for crystallinity measurements of deformed polymers using both methods in order to characterize the differences in micro-structure due to deformation. The study is ongoing, and we present the results of the first tests.

Systematic Characterization of Different Quaternary Ammonium Salts to be Used in Organoclays

2012 ◽  
Vol 727-728 ◽  
pp. 1552-1556
Author(s):  
Renata Barbosa ◽  
Dayanne Diniz Souza ◽  
Edcleide Maria Araújo ◽  
Tomás Jefférson Alves de Mélo
Keyword(s):  
Thermal Stability ◽  
Quaternary Ammonium ◽  
Chemical Structure ◽  
Quaternary Ammonium Salts ◽  
Ammonium Salts ◽  
Degradation Mechanisms ◽  
Scanning Calorimetry ◽  
Higher Temperature ◽  
Thermal Stability Of

Studies of degradation have verified that the decomposition of some quaternary ammonium salts can begin to be significant at the temperature of about 180 ° C and like most thermoplastics are processed at least around this temperature, the thermal stability of the salt in clay should always be considered. Some salts are more stable than others, being necessary to study the degradation mechanisms of each case. In this work, four quaternary ammonium salts were characterized by differential scanning calorimetry (DSC) and thermogravimetry (TG). The results of DSC and TG showed that the salts based chloride (Cl-) anion begin to degrade at similar temperatures, while the salt based bromide (Br-) anion degrades at higher temperature. Subsequently, a quaternary ammonium salt was chosen to be used in organoclays, depending on its chemical structure and its thermal behavior.

scholarly journals Development and Characterization of Sustainable Composites from Bacterial Polyester Poly(3-Hydroxybutyrate-co-3-hydroxyhexanoate) and Almond Shell Flour by Reactive Extrusion with Oligomers of Lactic Acid

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1097 ◽  
Author(s):  
Juan Ivorra-Martinez ◽  
Jose Manuel-Mañogil ◽  
Teodomiro Boronat ◽  
Lourdes Sanchez-Nacher ◽  
Rafael Balart ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Mechanical Characterization ◽  
Linear Thermal Expansion ◽  
Reactive Extrusion ◽  
Thermomechanical Analysis ◽  
Almond Shell ◽  
Scanning Calorimetry ◽  
Filler Reinforcement ◽  
Lignocellulosic Filler

Eco-efficient Wood Plastic Composites (WPCs) have been obtained using poly(hydroxybutyrate-co-hexanoate) (PHBH) as the polymer matrix, and almond shell flour (ASF), a by-product from the agro-food industry, as filler/reinforcement. These WPCs were prepared with different amounts of lignocellulosic fillers (wt %), namely 10, 20 and 30. The mechanical characterization of these WPCs showed an important increase in their stiffness with increasing the wt % ASF content. In addition, lower tensile strength and impact strength were obtained. The field emission scanning electron microscopy (FESEM) study revealed the lack of continuity and poor adhesion among the PHBH-ASF interface. Even with the only addition of 10 wt % ASF, these green composites become highly brittle. Nevertheless, for real applications, the WPC with 30 wt % ASF is the most attracting material since it contributes to lowering the overall cost of the WPC and can be manufactured by injection moulding, but its properties are really compromised due to the lack of compatibility between the hydrophobic PHBH matrix and the hydrophilic lignocellulosic filler. To minimize this phenomenon, 10 and 20 phr (weight parts of OLA-Oligomeric Lactic Acid per one hundred weight parts of PHBH) were added to PHBH/ASF (30 wt % ASF) composites. Differential scanning calorimetry (DSC) suggested poor plasticization effect of OLA on PHBH-ASF composites. Nevertheless, the most important property OLA can provide to PHBH/ASF composites is somewhat compatibilization since some mechanical ductile properties are improved with OLA addition. The study by thermomechanical analysis (TMA), confirmed the increase of the coefficient of linear thermal expansion (CLTE) with increasing OLA content. The dynamic mechanical characterization (DTMA), revealed higher storage modulus, E’, with increasing ASF. Moreover, DTMA results confirmed poor plasticization of OLA on PHBH-ASF (30 wt % ASF) composites, but interesting compatibilization effects.

Synthesis and Characterization of Comb-Type Grafted Hydrogels

2012 ◽  
Vol 602-604 ◽  
pp. 1274-1284
Author(s):  
Ping Zhang ◽  
Shi Pu Li ◽  
Xin Yu Wang ◽  
Hong Lian Dai
Keyword(s):  
Aqueous Solution ◽  
Fluorescence Spectroscopy ◽  
Lower Critical Solution Temperature ◽  
Ammonium Persulfate ◽  
Solution Temperature ◽  
Synthesis And Characterization ◽  
Critical Solution Temperature

The grafted hydrogels of N-isopropylacrylamide (IPAAm) with 2-hydroxyethylacrylate (HEA) was prepared in an aqueous solution using ammonium persulfate (APS) and N,N,N’,N’-tetramethylethylene diamine (TEMED) as an accelerator. Lower critical solution temperature (LCST) and swelling ratios were measured as a function of temperature. The properties of the hydrogels contained pyrenyl probe in water were investigated by fluorescence spectroscopy.

scholarly journals Multiresponsive micellar block copolymers from 2-vinylpyridine and dialkylvinylphosphonates with a tunable lower critical solution temperature

RSC Advances ◽  
2016 ◽  
Vol 6 (82) ◽  
pp. 78750-78754 ◽  
Author(s):  
F. Adams ◽  
P. T. Altenbuchner ◽  
P. D. L. Werz ◽  
B. Rieger
Keyword(s):  
Block Copolymers ◽  
Lower Critical Solution Temperature ◽  
Ph Sensitivity ◽  
Solution Temperature ◽  
Critical Solution Temperature ◽  
Temperature Range

Tailor-made, multi-responsive micellar AB and ABB′ block copolymers show a pH-sensitivity and a tunable LCST within an expanded temperature range.

scholarly journals Oligomeric epoxide–amine adducts based on 2-amino-N-isopropylacetamide and α-amino-ε-caprolactam: Solubility in presence of cyclodextrin and curing properties

2013 ◽  
Vol 9 ◽  
pp. 2803-2811 ◽  
Author(s):  
Julian Fischer ◽  
Helmut Ritter
Keyword(s):  
Differential Scanning Calorimetry ◽  
Lower Critical Solution Temperature ◽  
Setting Time ◽  
Diglycidyl Ether ◽  
Solution Temperature ◽  
Scanning Calorimetry ◽  
Critical Solution Temperature ◽  
Lcst Behavior ◽  
Oscillatory Rheology ◽  
Amine Adducts

2-Amino-N-isopropylacetamide and α-amino-ε-caprolactam were reacted with glycerol diglycidyl ether to give novel oligomeric thermoresponsive epoxide–amine adducts. These oligomers exhibit a lower critical solution temperature (LCST) behavior in water. The solubility properties were influenced with randomly methylated β-cyclodextrin (RAMEB-CD) and the curing properties of the amine–epoxide mixtures were analyzed by oscillatory rheology and differential scanning calorimetry, whereby significant differences in setting time, viscosity, and stiffness were observed.

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