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Radiation Modification of Natural Polymers Lecturer : Assoc. Prof. Dr. Murat Şen

1. H.U. Radiation Modification of Natural Polymers Lecturer : Assoc. Prof. Dr. Murat Şen Hacettepe University Department of Chemistry, Polymer Chemistry Division, 06532, Beytepe, Ankara , TURKIYE. Topic: Radiation Modification of Natural Polymers. 2. H.U.

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Radiation Modification of Natural Polymers Lecturer : Assoc. Prof. Dr. Murat Şen

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  1. 1 H.U. Radiation Modification of Natural Polymers Lecturer : Assoc. Prof. Dr. Murat Şen Hacettepe University Department of Chemistry, Polymer Chemistry Division, 06532, Beytepe, Ankara, TURKIYE

  2. Topic:Radiation Modification of Natural Polymers 2 H.U. Major Processes For the Radiation Modification of Natural Polymers Cross-linking Natural rubber latex Crosslinking of polysaccharides Degradation Cellulose fibers obtained from wood pulp Degradation of polysaccharides Preparation of blends Preparation of synthetic-natural polymer blends

  3. Topic:Radiation Modification of Natural Polymers[1] 3 H.U. Radiation vulcanization of natural rubber latex Various research works have been performed on radiation vulcanization of natural rubber latex (RVNRL) since it possesses several advantages over sulfur vulcanization such as the absence of nitrosoamines compounds better transparency very low cytotoxicity and less rubber proteins that causes allergic response Polyfunctional monomers which contain more than two polymerizable CC double bonds in a molecule, and monofunctional acrylic monomers were used as vulcanization accelerators. Among the monofunctional monomers, n-butyl acrylate (n-BA) is the most effective vulcanization accelerator because it not only imparts much better physical properties at lower Dv but also unreacted n-BA is not retained in the final product The low glass transition temperature of poly(n-BA) and a high probability of chain transfer reaction of n-BA during polymerization are closely related to its highsensitizing effect

  4. Topic:Radiation Modification of Natural Polymers[2] 4 H.U. Many attempts were made to investigate analternative accelerator to be used in radiation vulcanization of natural rubber latex (RVNRL) Trimethylol propane tri-methacrylate (TMPTMA) Phenoxy polyethylene glycol acrylate (polyfunctional monomer) (PPEGA) Phenoxy ethyl acrylate (PEA), Variation of tensile strength of NR vs dose Gelation dose Variation of tensile strength of RVNRL prepared using TMPTMA at various doses of radiation.

  5. Topic:Radiation Modification of Natural Polymers[17] 5 H.U. VISCOSE - RAYONAND CELLOPHANE Rayon is produced from viscose, a polymer made from cellulosic materials such as wood pulp Cellulose fibers extracted from wood pulp can be converted to a thick liquid called viscose, which is used to make commercial products such as rayon fabrics and cellophane films. The molecular weight of the natural cellulose is reduced by treatment with sodium hydroxide and heat. Then this material is dissolved in carbon disulfide to make viscose Initial irradiation of the cellulose causes a reduction in molecular weight, and enables the rest of the process to be completed in less time with less chemical treatment This reduces the cost and also reduces the environmental pollution. The dose requirement is about 15 kGy

  6. Topic:Radiation Modification of Natural Polymers[16] 6 H.U.

  7. Topic:Radiation Modification of Natural Polymers 7 H.U. POLYSACCHARIDES • ALGINATES Food stabilizer,gelling agent, encapsulation matrix, plant growth stimulator • CARRAGEENANS Food processing, thickening agent, film forming, agriculture, horticulture, anti-HIV activities • CHITOSAN Food processing, paper and textile industries, photographic processing, biomedical applications due to antifungal, antibacterial, antitumor activities as well as immuno-enhancing effects and protective effects against infection

  8. Topic:Radiation Modification of Natural Polymers 8 H.U. Possible gelation mechanism of -carrageenan in aqueous solution:(----), ionic bonding; (),electrostaticforces of attraction.

  9. Topic:Radiation Modification of Natural Polymers 9 H.U. • Gigartina (France, Argentina/Chili, Morocco) • Chondrus (France, North Atlantic) • Iridaea (Chili) • Eucheuma (Philippines/Indonesia)

  10. Topic:Radiation Modification of Natural Polymers 10 C O O N a O H H.U. H O O H O O O C O O N a O H D-mannuronate (M) • Natural polysaccharides from seaweeds (brown algae) • Alginate is phycocolliod • Consists of linear chains composed of two monosaccharides; • D-mannuronic acid (mannuronate) (M) • L-guluronic acid (guluronate) (G) D-guluronate (G) Sodium Alginate G G M M G Sodium Alginate

  11. Topic:Radiation Modification of Natural Polymers 11 H.U. Carrageenans • Water-soluble gums sulfated polysaccharides • 1,3 linked β-D- galactose and 1,4 linked α-D- galactose units. • Anionic poly-electrolytes. • Three main branches. • Kappa • Iota • Lambda κ-carrageenan ι-carrageenan λ-carrageenan

  12. Topic:Radiation Modification of Natural Polymers 12 H.U. Chitosan It occurs in the shells of crabs, shrimps, prawns, lobsters, insects as well as some fungi wall cells. • The most essential medical applications of chitosan are as follows • - wound healing promoting dressings • - dermatological agents • biodegradable carriers for slow release • drugs • - anticoagulant agents • optimological, dentistical and orthopedic • agents • - tumor cell metabolism reducing agents

  13. Topic:Radiation Modification of Natural Polymers 13 H.U. DEGRADATION OFPOLYSACCHARIDES • Chemical • Microwave • Enzymatic • Photolysis • Ultrasound • Radiation

  14. Topic:Radiation Modification of Natural Polymers 14 H.U. RADIATION-INDUCED DEGRADATION OF ALGINATE • Radiation cause the breakage of glycosidic bonds • Molecular weight, viscosity,gel strength decreases • Alginates were irradiated as solid state or in aqueous solutions

  15. Topic:Radiation Modification of Natural Polymers[3] 15 H.U. Alginate degradation under N2and O2conditions

  16. Topic:Radiation Modification of Natural Polymers[3] 16 H.U. Color Change of Irradiated Alginate

  17. Topic:Radiation Modification of Natural Polymers[3] 17 H.U. UV Spectra of Alginate Irradiated with Various Doses

  18. Topic:Radiation Modification of Natural Polymers[8] 18 H.U. Mango treated with irradiated chitosan Appearance of mango treated with irradiated chitosan after 12 and 17 days storage Fresh mangoes were dipped into the irradiated chitosan solution (1%) and dried for surface coating.

  19. Topic:Radiation Modification of Natural Polymers[9] 19 H.U. Growth of rice with alginate irradiated in liquid and dry Effect of concentration of degraded alginate on rice growth Effect of irradiated alginate on rice growth • Without alginate • (2) 20 ppm alginate irradiated • at100 kGy in 4% solution • (3) 20 ppm alginate irradiated • At 500kGy in solid state. Alginate was irradiated at 100 kGy in 4% solution and rice was cultivated for 9 days Rice was cultivated for 9 days in hydroponic solution with 20 ppm alginate irradiated in 4% solution

  20. Topic:Radiation Modification of Natural Polymers [9] 20 H.U. Effect of degraded alginate on peanut growth Effect of concentration of degraded alginate on peanut growth. Alginate was irradiated at 100 kGy in 4% solution and peanut was sprayed with alginate solution for 15 days after 30 days cultivation Change in net photosynthesis of peanut plant by foliar spraying of irradiated alginate. : without alginate, :sprayed with irradiated alginate.

  21. Topic:Radiation Modification of Natural Polymers[10] 21 H.U. Rice was cultivated for 9 days in hydroponic solution with 100 mg/ml chitosan shoot; root; shoot without chitosan root without chitosan. Effect of radiation-degraded chitosan on plants stressed with vanadium Change in rice growth with treatment of irradiated chitosan. Effect of irradiated chitosan for rice growth Rice was cultivated for 9 days in hydroponic solution with 100 mg/mlchitosan. From left, (1); control (without chitosan), (2); with unirradiated chitosan, (3)–(5); 20, 50 and 100 kGy-irradiated chitosan

  22. Topic:Radiation Modification of Natural Polymers [10] 22 H.U. Rice and soybean plants were damaged at 2.5 mg/ml V (in VCl3). These damages were reduced by application of radiation-degraded chitosan. Bioimaging analyzer system (BAS) images of 48V in rice under V stress (10 mg/ml) with 50 mg/ml of irradiated chitosan. Left: with chitosan right:without chitosan.

  23. Topic:Radiation Modification of Natural Polymers 23 H.U. New topics Lipid+cholesterol binding A composite material for dietary applications Microgel particles (swelling) Radiation-modified chitosan (effective lipid+cholesterol binding) Crosslinking Matrix Fat-bindingagent Synthetic biocompatible polymer Microgels Action

  24. Topic:Radiation Modification of Natural Polymers 24 H.U. New topics Lipid+cholesterol binding Binding of lipids: ca. 20 g per 1 g of our composite substrate Fat binding Preliminary animal studies under way (with positive results).

  25. Topic:Radiation Modification of Natural Polymers[11-12] 25 H.U. Polysaccharides undergo degradation by irradiation Irradiation of polysaccharides at paste-like condition will led to crosslinking and form hydrogel.

  26. Topic:Radiation Modification of Natural Polymers[13] 26 H.U. Crosslinked CMC is suitable for healthcare product such as surgical operation mats for prevention of bedsores High viscous solution of 20% CMC was pressed into a plastic bag and irradiated with 10 kGy CMC gel Such mats were tested by 68 patients in a hospital. No bedsores were observed in 64 patients and only red spots appeared on 4 patients immediately after surgical operation This result reveals that the crosslinked CMC mat is extremely effective to preventbedsores during surgical operation This CMC gel mat is considered to disperse the body pressure and to maintain the best circulation of blood during operation plastic bag containing CMC gel, commercialized as‘‘Non-bedsore’’ in Japan. crosslinked CMC mat in the surgical operation room

  27. Topic:Radiation Modification of Natural Polymers[14-16] 27 H.U. Preparation of synthetic-natural polymer blends PVP-kappa carrageenan PVP-agar PVA-agar Chitosan-grafted N-isopropylacrylamide Chitosan/pHEMA membranes Synthesis of antibacterial PVA/CM-chitosan blend hydrogels

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