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ảnh hưởng của nhiệt độ lên khả năng khâu mạch của carboxymethylcellulose Sức đẻ trứng của ong chúa được xác định thông qua tính số lượng nhộng bình quân của đàn ong, bằng cách vào thời điểm ong chúa đẻ ổn định, dùng khung cầu căng dây thép chia ô 5 x 5 cm để đo phần nhộng vít lắp của đàn ong. Sức đẻ trứng một ngày đêm của ong chúa được tính theo công thức: | TẠP CHÍ KHOA HỌC VÀ CÔNG NGHẸ Tập 46 số 6 2008 Tr. 103-108 EFFECT OF TEMPERATURE ON THE RADIATION CROSSLINKING OF CARBOXYMETHYLCELLULOSE PART 1. EFFECT OF ELEVATED TEMPERATURE ON THE RADIATION CROSSLINKING OF CARBOXYMETHYLCELLULOSE PHẠM THỊ LỆ HÀ N. NAGASAWA T. YAGI M. TAMADA TRẰN THỊ THÙY 1. INTRODUCTION Carboxymethylcellulose CMC is the most popular cellulose ether. It is an anionic linear polymer in which original H atoms of cellulose hydroxyl groups are replaced by carboxymethyl substituent - CH2COO 1 2 Some attempts for chemical crosslinking of CMC in order to get hydrogel were conducted with divinylsulphone as a crosslinking agent 3 4 However CMC can not be used as itself because a poor efficiency of crosslinking has been achieved. Pure CMC hydrogel without admixture of other polymer and without addition of low molecular weight contaminant can be produced using y-rays 5 6 . Hydrogels prepared by radiation technique are not only crosslinked but also sterilized 7 Hydrogel of CMC can absorb and hold amount of solvent in its network structure and in the point of view of environment it still retains good property of cellulose to be biodegradable 8 . The results of the interaction of high energy radiation with polymers depend on many parameters including radiation itself irradiation conditions and the nature of polymer. Only one study of the effect of temperature during irradiation on the crosslinking of CMC was found in the literature 9 In this research the effect of temperature on the radiation crosslinking of CMC samples was investigated in part 1 we study about the effect of elevated temperature during the time of irradiation on the gel fraction and swelling ratio of CMC. 2. MATERIALS AND METHODS 2.1. Materials CMC - Na is provided by Daicel Chemical Industry Ltd. Its degree of substitution is 1.36. The viscosity and molecular weight of CMC are 1820 m.Pa.s and 1.11 X 1 o6 respectively. 2.2. Gamma irradiation and preparation of CMC-Na hydrogel Deionized water .
