Cryogels of cellulose derivatives prepared via UV irradiation of moderately frozen systems

Synthesis of biodegradable hydroxyethylcellulose cryogels by UV irradiation

“…The cryogels obtained are opaque materials and a significant part of water (capillary-bound water) can be easily separated by compression. The influence of the irradiation dose and the amount of BBTMAC on the cross-linking efficiency of moderately frozen systems based on cellulose derivatives were described elsewhere [25]. It is established that 2 min irradiation at an irradiation dose rate of 5.7 J/cm 2 min is adequate for cross-linking of semidilute polymer solutions containing at least 2 wt.% BBTMAC.…”

“…The advantages of the UV irradiation are the very low capital outlay and the extremely short time for efficient gel formation. Very recently, Petrov et al [25] reported on the first effective cross-linking of various cellulose derivatives via UV irradiation of moderately frozen systems on the basis of semidilute aqueous solutions of the polymers. It was suggested that due to the cryoconcentration effect, the polymer concentration in the non-frozen liquid microphase is very high and the reaction conditions resemble the conditions in the paste-like state.…”

Cryogels via UV Irradiation

“…Therefore, under such conditions the probability for recombination of two macroradicals is increased. This fact explains why cellulose derivatives, which degrade in solution upon UV irradiation, were successfully crosslinked via cryogenic treatment [11,12]. Figure 2 shows the storage (G 0 ) and loss (G 00 ) moduli in the 0.1-10 Hz frequency range of 3 mass% aqueous 2-hydroxyethylcellulose (HEC) solutions irradiated with UV light in the frozen state (À30 C) and at room temperature.…”

“…An appropriate strategy for increasing the GF yield and enhancing the mechanical strength of cryogels based on cellulose derivatives is to incorporate suitable crosslinking agents into the polymer network [11]. For instance, the storage modulus of HPMC cryogel prepared in the presence of 3 mass% N,N 0 -methylenebisacrylamide (BisAAm) is an order of magnitude higher than that of HPMC cryogel obtained without crosslinking agent.…”

Biosurfactant Production by Pseudomonas aeruginosa BN10 Cells Entrapped in Cryogels

“…In particular, the synthesis of cryogels via UV irradiation appears to be a very fast and effi cient approach which can be set up at low cost (Doycheva et al, 2004;Petrov et al 2006Petrov et al , 2007. This method allows preparation of various biocompatible, biodegradable, and/or thermosensitive supermacroporous cryogels by irradiation of moderately frozen aqueous systems with UV light (irradiation dose rate of 950 J m -2 s -1 ) for 2 -5 minutes in the presence of a photoinitiator.…”