نوع مقاله : مروری
نویسندگان
1 تهران ، پژوهشگاه پلیمر و پتروشیمی، پژوهشکده مهندسی، گروه کاتالیست، صندوق پستی 112-14975
2 تهران ، پژوهشگاه پلیمر و پتروشیمی، پژوهشکده علوم ، گروه پلیمرهای زیستسازگار صندوق پستی 112-14975
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Cyclic olefinic copolymers (COC) are an important class of polyolefins with special properties as soft or hard materials, depending on the content of norbornene monomer in the final copolymer composition. The norbornene content in common commercial copolymers is more than 20 percent, which is randomly distributed in throughout the polymer microstructure and its result is an ending to amorphous and optically transparent copolymers as can be expected. An increase in norbornene content in the copolymer structure leads to a corresponding increase in glass transition temperature (Tg) of the final copolymer. The remarkable optical properties of this type of COCs is strongly depend to their amorphous structure, which are not limited to the visible light wavelength range, so COCs can be used as transparent polymers in the ultraviolet and vislible wavelengths to acheive suitable optically clear products. Due to higher resistance against chemicals especially polar solvents, COCs are used for producing laboratory equipments in a competitive manner with other polymers. On the other hand, COCs are inert biological materials making them suitable candidates in packaging appicationes for medicines including pre-filled syringes. Water is the main solvent used to produce the injectable products, so low water absorption by these copolymers ensures dimensional stability of the final product under ambient conditions. In a highly humid environment, water absorption capacity for COCs is limited to 4 and 10 times less than polycarbonate and poly methyl methacrylate polymers, respectively. In this study, after a brief introduction on COCs, polymerization methods by different catalysts are discussesd then, optical, mechanical and thermal characteristics of these copolymers are discussed. Finally, COC processing details and their applications are mentioned.
کلیدواژهها [English]
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