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صفحه اصلی
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بیست و نهمین کنفرانس شیمی آلی ایران
Synthesis of polytetrahydrofuran
نویسندگان :
Seyedmojtaba Keshavarz ( دانشگاه جامع امام حسین (ع) ) , Alireza Banan ( دانشگاه جامع امام حسین (ع) )
کلید واژه ها :
polytetrahydrofuran،polymerization،heteropolyacid
چکیده مقاله :
High molecular weight poly tetrahydrofuran (PTHF) was prepared in the bulk polymerization at ambient temperature by using Acetic anhydride as initiator. The physical, mechanical, and degradation properties of the resulting polymer were investigated. The experimental results show that poly tetrahydrofuran is a semi crystalline polymer with a melting temperature of 35 °C. The degradation study revealed that PTH F degrades both in solution and in bulk. The degradation kinetics was studied by using various kinetic methods and product analysis. The results showed that the degradation proceeds via a random chain scission process. The random chain scission occurs primarily at the ether linkages. Under thermo-oxidative degradation conditions, the random chain scission may proceed via the weak side link s of hydroperoxide groups formed in the presence of oxygen, which results in a low activation energy. Under thermal degradation conditions, the ether linkages are thermally broken by the random chain scission process, which leads to a high activation energy. Oxygen plays a very important role in the degradation of PTHF. The presence of oxygen changes the degradation process from endo thermic to exothermic and accelerates the degradation. The use of acetic anhydride increases the possibility of adjusting the molecular weight to an acceptable level.
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