Pullulan/Poly(2-Hydroxyl Ethyl Methacrylate) Cryogels

Pullulan – polyHEMA cryogel systems were synthesized by using radical chain polymerisation with the aid of chemical crosslinkers. Pullulan- ECH-graftpolyHEMA cryogels and pullulan-ECH-graft-polyHEMA-EGDMA cryogels were prepared from various different concentrations of starting monomer; 2-hydroxy ethyl methacrylate (HEMA) and natural polymer; pullulan. For all the cryogel systems epichlorohydrin (EPC) was used as crosslinker and for some of them in addition to EPC , ethylene glycol dimethacrylate was used. For the initiation of polymerization, the redox couples of ammonium persulfate (APS) and N,N,N’,N;-tetramethelen diamine (TEMED) were used. Swelling characteristics of the cryogel systems were analysed in three different conditions; acidic, neutral and basic conditions at 25 ℃. The concentrations of monomers and crosslinkers were altered to synthesize different cryogels with different swelling characteristic features. In addition, scanning electron microscopy (SEM) and FT-IR spectroscopy analyses were used for structural and morphological characteristic features determination. Based on dynamic swelling tests, it was found that pullulan-ECH-graft-polyHEMA-EGDMA cryogels bears the highest equilibrium swelling capacity characteristics with 97 %. These cryogels has got the highest degree of porosity among all the other types of cryogels. Keywords: Pullulan- ECH-graft-polyHEMA cryogels, epichlorohydrin (EPC), ammonium persulfate (APS) and N,N,N’,N;-tetramethelen diamine (TEMED).