Effect of molecular weight of PEO on the structure and properties of PDMAEMA/PEO hydrogels

A new kind of binary hydrogels composed of poly(dimethylaminoethylmethacrylate) (PDMAEMA) and poly(ethylene oxide) (PEO) with varying weight average molecular weights ((M) over bar)(w) = 5 x 10(4), 1 X 10(5) and 2.5 x 10(6)) were prepared by gamma-irradiation technology. The properties of PDMAEMA/PEO hydrogels obtained were evaluated in terms of gel fraction, gel strength, thermal characterization and swelling behavior. The gel strength and swelling degree of the hydrogels could be improved obviously after adding PEO into the PDMAEMA system, while the degree of improvement decreased with increasing (M) over bar (w) of PEO. The temperature sensitivity of PDMAEMA/PEO was retained only in the sample with PEO of (M) over bar (w) = 5 x 10(4), and the pH sensitivity was retained in samples with PEO of (M) over bar (w) = 5 x 10(4) and 1 x 10(5). When DMAEMA/PEO mixtures containing PEO of (M) over bar (w) = 5 x 10(4) were irradiated, the main reaction could be the cross-linking of DMAEMA, and the linear PEO molecular chains could penetrate into the cross-linked network of PDMAEMA. With increasing (M) over bar (w) of PEO, some side reactions were induced, such as grafting of DMAEMA onto PEO molecules, the scission or cross-linking of PEO.Polymer ScienceSCI(E)EI中国科技核心期刊(ISTIC)中国科学引文数据库(CSCD)1ARTICLE135-402