Aloe vera gel has been extracted from A. vera leaves and pasteurized at 60 °C to prepare concentrate. The A. vera gel concentrate has been incorporated separately at different doses in the copolymer hydrogel of N-vinylpyrrolidone and acrylamide. The copolymer gel has been found to loose its swelling ability and pH responsiveness, in particular. However the incorporation of A. vera enhances its storage modulus and mean pore size of the hydrogel. Temperature responsiveness also is found to be enhanced with the increase in the A. vera percentage in the gel. An attempt also has been made to correlate the rheological and morphological characteristics of the hydrogels to its swelling abilities. This work is aimed at exploring the possibilities of using the hydrogel in applications requiring protection against harmful UV-C rays. © 2015 Elsevier B.V.

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University of Calcutta (informally known as Calcutta University or CU) is a collegiate public state university located in Kolkata, West Bengal, India.&nbsp;Within India it is recognized as a &quot;Five-Star University&quot; and accredited &quot;A&quot; Grade by National Assessment and Accreditation Council.

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The University of Calcutta has secured the Fifth position among the Universities of India in the prestigious &quot;Indian University Ranking 2019&quot; list, released by the NIRF of the Ministry of Human Resource Development, Government of India.

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It was established on 24 January 1857, and was one of the first institutions in Asia to be established as a multidisciplinary and Western-style university. Its alumni and faculty include several heads of state, heads of government, social reformers, prominent artists, only academy award winner and Dirac medal winner in India, many Fellows of the Royal Society and five Nobel laureates as of 2019 which is highest in South Asia.

University Of Calcutta

Materials Chemistry and Physics

Poly(ethylene glycol) (PEG 1500) is functionalized using itaconic acid by melt esterification reaction to obtain a bi-functional co-monomer crosslinker, Poly(ethylene glycol) di-itaconate. The resulting product has been copolymerized with acrylamide in presence of methylene bis-acrylamide as crosslinker (in varying proportions) so as to prepare hydrogel which is mostly recommended for dye removal from textile effluents. FTIR-ATR, Solid state 13-C NMR and WAXS techniques are used to ensure grafting of the PEG diitaconate on the polyacrylamide backbone. The intermediate products are also characterized using FTIR and 1H NMR spectroscopy. This study reveals that a significant improvement in gel characteristics particularly in respect of swelling properties may be achieved with the hydrogel having only ester type crosslinks. However this is attained at the cost of yield stress. The ester based gel shows better storage modulus, dye sorption ability and the anti-fungal properties in relation to semi-IPN type gels. © 2017

Polymer

Synthesis of poly(ethylene glycol) di-itaconate and investigation of its influence on acrylamide based hydrogels meant for water treatment

Interpenetrating polymer networks (both full and semi) and ester crosslinked hydrogels have been synthesized from acrylic acid and 2-hydroxyethyl methacrylate by using various monomer feed compositions. No crosslinkers have been used in case of ester crosslinked gel, instead the neighboring polymer chains are crosslinked by esterification reaction, which is established by FTIR and 13C NMR spectroscopy. Swelling of the hydrogels has been found to be strongly dependent on the pH, temperature and ionic strength of the medium. The rheological properties of the hydrogels are found to be dependent on the mode of crosslinking and composition of the gel (only in the case of ester crosslinked gel) as well. The flexibility of the gel is also dependent on the method of preparation of the hydrogel. Rheological study in normal force sweep mode reveals the high shape and size regain ability of the gel. The cryo SEM images show the porous structure of the gels. The hydrogels, especially ester crosslinked gels, have been found quite effective in the separation of cationic dyes and heavy metal ions (copper and iron) from their corresponding aqueous solutions. © 2015 The Royal Society of Chemistry.

RSC Advances

Synthesis and characterization of acrylic acid-2-hydroxyethyl methacrylate IPN hydrogels

Polyvinyl alcohol (PVA) is etherified with ethane-1,2-diol to obtain smart etherified polyvinyl alcohol (EPVA) having improved mechanical and gelling characteristics. Linear EPVA is deficient in swelling compared to PVA and follows first order swelling kinetics. EPVA when converted to gel with 5% crosslinker (EPVA5) shows maximum swelling and mechanicals. Sustained solvent releasing ability of the EPVA gel is evident from the deswelling study. EPVA gels demonstrate an increase in storage modulus with increase in crosslinker dose. Ultraviolet resistance ability of the EPVA gel is maximum in the UV range of 280-320. nm. EPVA5 exhibits cells of nanometric dimensions. © 2014 The Korean Society of Industrial and Engineering Chemistry.

Journal of Industrial and Engineering Chemistry

Smart superabsorbent UV resistant etherified PVA gel: Synthesis and characterization

Pore structure plays a great role in determining the physical and mechanical properties of a gel. In this study, a polyvinyl alcohol (PVA) based hydrogel has been synthesized using glyoxal as crosslinker, and the influence of diethylene glycol (DEG) as a porogen in modifying its properties has been investigated. The resulting hydrogel possesses a unimodal distribution of nanopores, the content &amp; sizes of which are controlled by using various dosages of porogen. The hydrogel has been characterized using FTIR spectroscopy which confirms the acetal linkage formation caused by the crosslinking reaction. The presence of DEG influences its rheological properties &amp; decreases its glass transition temperature (Tg). Cyclical swelling-deswelling of the hydrogel samples leads to their improvement. DEG also assists in modifying the thermo-responsive nature of the crosslinked PVA matrix. This journal is © the Partner Organisations 2014.

Journal	Data powered by TypesetMaterials Chemistry and Physics
Publisher	Data powered by TypesetElsevier Ltd
ISSN	0254-0584