Stimuli sensitive copolymer poly(N-tert-butylacrylamide-ran-acrylamide): processing into thin films and their transitional behaviour

Save, Ninad S.; Jassal, Manjeet; Agrawal, Ashwini K.

doi:10.1016/j.polymer.2003.10.029

Cited by 26 publications

(22 citation statements)

References 24 publications

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“…Specifically, the G′ of P(DEAAm-NVP) synthesised using 0.1 wt% crosslinker was 82±24 Pa but increased to 658±150 Pa at 0.25 wt% crosslinker concentration, and at 0.4 wt% crosslinker content the G′ reached 1030±187 Pa. This is as a result of the increased crosslink density of the matrices as put forward in previous studies [50,51]. The hydrophilic component (NVP or DMAAm) in the copolymer also influenced the mechanical properties of the hydrogel.…”

Section: Rheometrymentioning

confidence: 56%

Photopolymerised thermo-responsive poly(N,N-diethylacrylamide)-based copolymer hydrogels for potential drug delivery applications

et al. 2012

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Novel thermo-sensitive N,N-diethylacrylamide (DEAAm) based copolymer hydrogels were prepared via UV-induced free radical bulk polymerisation. UV polymerisation was employed to avoid the use of potentially toxic solvents; solution polymerisation has been the most common means for the preparation of PDEAAm-based hydrogels in the literature to date. The resultant hydrogels were analysed using nuclear magnetic resonance, Fourier transform infrared spectroscopy and modulated differential scanning calorimetry. Parameters such as the crosslinking degree and the nature of the incorporated hydrophilic component, N-vinyl-2-pyrrolidone (NVP) or N,N-dimethylacrylamide (DMAAm) were found to impact hydrogel structure, mechanical properties and swelling kinetics. Pulsatile swelling studies indicated that the hydrogels had thermo-reversible properties which were greatly affected by test temperature, nature of hydrophilic monomer used and crosslinker content. Aminophylline was selected as a model solute for drug loading and release studies by thermal deswelling in HCl buffer (pH 1.4) and phosphate buffer media (pH 6.8). The observed lag time prior to significant drug release from the more crosslinked P(DEAAm-NVP) hydrogels could make them suitable for delayed specific release in the intestine and potential alternatives to layers or membranes in timespecific and site-specific swelling-controlled drug delivery systems.

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Section: Rheometrymentioning

confidence: 56%

Photopolymerised thermo-responsive poly(N,N-diethylacrylamide)-based copolymer hydrogels for potential drug delivery applications

et al. 2012

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“…Thus, these materials can be used as artificial muscle‐like actuators,1, 2 valves,3 and drug delivery systems 4. Interest in hydrogels has gained momentum because these materials can be actuated by a variety of stimuli such as pH,5, 6 salinity,6 electrical current,7 temperature,8–12 and antigens 13…”

Section: Introductionmentioning

confidence: 99%

“…Thus, these materials can be used as artificial muscle-like actuators, 1,2 valves, 3 and drug delivery systems. 4 Interest in hydrogels has gained momentum because these materials can be actuated by a variety of stimuli such as pH, 5,6 salinity, 6 electrical current, 7 temperature, [8][9][10][11][12] and antigens. 13 So far, the stimuli sensitive polymers (SSP) are used in the hydrogel form for diverse applications; however, the potential application of these SSP polymers have not been fully exploited because of their slow response as well as low magnitude of swelling.…”

Section: Introductionmentioning

confidence: 99%

pH‐responsive fibers based on acrylonitrile acrylic acid block copolymers: Effect of spinning conditions and postspinning operations on response and mechanical properties

Sahoo

Jassal

Agrawal

2008

J of Applied Polymer Sci

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pH sensitive poly(acrylonitrile-co-acrylic acid) having $ 50 mol % acrylic acid with block type structure (AA50B) was synthesized by controlled dosing method of free radical polymerization. The polymer was converted into fibers by wet solution spinning technique in DMF-water system. The resulting block type copolymer could generate a domain type morphology with segregated domains of acrylonitrile and acrylic acid on heat-setting. The drawing ratio and heat-setting temperature had a significant effect on the formation of these domains and their stability. The domain formation was more pronounced when the fibers could be drawn to higher draw ratios during coagulation or heat-set at higher temperature. The stability of the fibers, which is influenced by domain formation, was lowest (at few cycles of transitions) when the fibers were heat-set at 1008C, while it is improved significantly to more than 50 cycles as the heat-setting temperature was increased to 1508C. The coagulation conditions, drawing and the heat-setting also greatly influenced the mechanical properties, transition behavior, and retractive stresses of the responsive fibers. The tenacity improved by 6.6 times in swollen state and 1.4 times in deswollen state, while the retractive stresses during deswelling were significantly increased to about 4.7 times. However, the increased heat-setting temperature was also found to have a negative effect on the equilibrium swelling values as well as the response rate. The effect of heat-setting on chemical structure of the copolymer was also investigated.

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“…The linear copolymers could be readily processed into thin films using available amide side groups. The approach for processing of these copolymers has been separately studied 18…”

Section: Introductionmentioning

confidence: 99%

Stimuli sensitive copolymer poly(N‐tert‐butylacrylamide‐ran‐acrylamide): Synthesis and characterization

Save

Jassal

Agrawal

2004

J of Applied Polymer Sci

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Temperature sensitive random linear and crosslinked copolymers of N-tert-butylacrylamide (NTBA) and acrylamide (Am) were synthesized by the solution polymerization method, using regulated dosing of comonomer Am having a higher reactivity ratio (r Am ϭ 1.5) than NTBA (r NTBA ϭ 0.5). Copolymers with varying feed ratios of NTBA and Am (80 : 20 to 20 : 80 mol %) were synthesized and characterized. For the synthesis of copolymer hydrogels, NЈ, N-methylene bisacrylamide (MBA) (1.13 mol %) was used along with monomers. The effect of composition on transition properties was evaluated for the linear copolymers and their hydrogels. A definite trend was observed. The incorporation of a higher percentage of the hydrophilic comonomer Am in the structure resulted in the shifting of the transition temperature towards a higher value. The transition temperatures of the copolymers synthesized with feed compositions of 80 : 20, 70 : 30, 60 : 40, 50 : 50, 40 : 60, 30 : 70, and 20 : 80 mol % were found to be 2, 10, 19, 27, 37, 45, and 58°C, respectively. Differential scanning calorimetry (DSC) studies confirmed the formation of random copolymers. The copolymers synthesized with a monomer feed ratio of 50 : 50 with regulated dosing showed a single glass transition temperature (T g ) at 168°C, while the copolymer synthesized with full dosing of Am at the beginning of the reaction showed two T g s, at 134 and 189°C. The copolymer samples were analyzed by Fourier transform infrared spectroscopy (FTIR) for ascertaining the composition. The composition of the copolymers followed the trend of the feed ratio, but the incorporation of NTBA in the copolymers was found to be lower than the feed ratio because of lower than quantitative yields of the reactions.

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Stimuli sensitive copolymer poly(N-tert-butylacrylamide-ran-acrylamide): processing into thin films and their transitional behaviour

Cited by 26 publications

References 24 publications

Photopolymerised thermo-responsive poly(N,N-diethylacrylamide)-based copolymer hydrogels for potential drug delivery applications

Photopolymerised thermo-responsive poly(N,N-diethylacrylamide)-based copolymer hydrogels for potential drug delivery applications

pH‐responsive fibers based on acrylonitrile acrylic acid block copolymers: Effect of spinning conditions and postspinning operations on response and mechanical properties

Stimuli sensitive copolymer poly(N‐tert‐butylacrylamide‐ran‐acrylamide): Synthesis and characterization

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