No abstract available

[en] Radiation induced degradation technology is a new and promising application of ionizing radiation to develop viscose, pulp, paper, food preservation, pharmaceutical production, and natural bioactive agents industries. Controlling the degree of degradation, uniform molecular weight distribution, saving achieved in the chemicals (used in conventional methods) on a cost basis, and environmentally friendly process are the beneficial effects of using radiation technology in these industries. However, for some development countries such technology is not economic. Therefore, a great efforts should be done to reduce the cost required for such technologies. One of the principle factors for reducing the cost is achieving the degradation at low irradiation doses. The addition of some additives such as potassium per-sulfate (KPS), ammonium per-sulfate (APS), or H₂O₂ to natural polymers (carboxymethylcellulose (CMC), chitosan, carrageenan and Na-alginate) during irradiation process accelerates their degradation. The highest degradation rate of polysaccharides obtained when APS was used. The end product of irradiated CMC, chitosan, carrageenan and Na-alginate may be used as food additive or benefited in agricultural purposes. On the other hand, radiation crosslinking of PAAm or PNIPAAm is affected by the presence of natural polymer like CMC-Na and carrageenan due to their degradability which could be controlled according to its concentration in the bulk medium and irradiation dose. Accordingly, the gel content, thermo-sensitivity (LCST) and swelling properties of PNIPAAm based natural polymers could be controlled. The swelling of the prepared copolymer hydrogels was investigated for its possible use in personal care articles particularly diapers or as carriers for drug delivery systems. The prepared crosslinked copolymers possessed high and fast swelling properties in simulated urine media and the swelling ratios of CMC-Na/PAAm gels in urine are acceptable for diaper application. (author)

[en] For commercial any product in agriculture, it must be carried out in several steps. The basic research should be done at first. The interesting results on irradiated alginate and chitosan were obtained. In particular, alginate with Mw ca. 9.04 x 10⁵ was irradiated at 75 kGy (Mw - 1.43 x 10⁴Da) had the highest positive influence for growing of flower plants, namely limonium, lisianthus and chrysanthemum. The product of chitosan with 80% degree of deacetylation and Mw approx. 4.8 x 10⁴ irradiated at 100 kGy (Mw - 1.6 x 10⁴ Da) showed the strongest growth promotion effect on the mentioned plants in vitro. The survival ratios of the transferred plantlets treated with irradiated alginate were almost the same as the control value in the green house condition, while the treatment of irradiated chitosan improved the survival ratio and growth of transferred plantlets acclimatized from 10 to 30 days in a greenhouse condition. Based on above results, a plant growth promotion product prepared from irradiated alginate namely T and D. To get the certificate for commercialization, the toxicity tests and trial field tests must be done to satisfy the Department of Plant Protection, Ministry of Agriculture and Rural Development. (author)

[en] Radiation processing technology has been proven to enhance industrial efficiency and productivity, improve product quality and competitiveness. For many years, varieties of radiation crosslinkable materials based on synthetic polymers have been studied at the Malaysian Nuclear Agency either in the form of thermoplastic resins, polymer blends or composites. At present, effort is focused towards developing new materials based on natural polymers such as natural rubber and rubber based products, palm oil and palm oil based products and polysaccharide. Hydrogel based on sago starch has been developed and commercialized for face mask. As for wound dressing application, sago hydrogel is still subjected to the clinical evaluation. Sago starch has also been modified for biodegradable products such as bio-film and bio-foam for packaging purposes. On the other hand palm oil based acrylate resins have been synthesized at the Nuclear Malaysia for pressure sensitive adhesive and printing ink applications. Meanwhile, natural rubber is used in a polymer blend and composites for automotive components. All of these products are at various stages of commercialization. (author)

[en] The fishery industry in Pakistan is well established and is growing very fast. The annual production of shrimp is ∼45,000 metric ton, out of which ∼20,000 metric ton is exported. The annual production of crab is 250 metric ton. The estimated production of waste from these materials is approximately 20,000 metric ton, which is a huge quantity. This crustacean waste generated by fishery industries containing chitin, a natural polymer, can be extracted by chemical treatments. Deacetylation of chitin gives chitosan which is soluble in dilute mineral acids. Presently, the main consumer of this waste is animal feed industries. Pakistan Atomic Energy Commission (PAEC) has started research program on Radiation Processing of Natural Polymers in cooperation with IAEA and RCA in order to convert this sizable waste into value added products. This report describes some of our obtained results on radiation processing of natural polymer and its applications. (author)

[en] Under the Vietnam Atomic Energy Commission there are 5 research and development institutions for radiation processing; Nuclear Research Institute (NRI), Institute for Nuclear Science and Technology (INST), Institute for Technology of Radioactive and Rare Elements (ITRRE); Center for Nuclear Technique (CNT), Research and Development Center for Radiation Technology (VINAGAMMA). NRI has Gamma Co-60 cell (2,000 Ci) and Gamma Co-60 chamber (10,500 Ci). Research activities of the Radiation Technology Department of NRI on radiation processing are as follows: (1) Degradation of natural polymers, (2) Crosslinking, (3) Grafting polymerization. (author)

[en] The electron beam processing (EB processing) has been started in 1950's in the field of crosslinking of polyethylene for the purpose to adding the high temperature durability and to giving memory effects on the products. In nowadays, the EB processing technologies are applied to wide fields of the manufacturing such as the tires, the plastic forms and the poly-electrolyte membranes for button type batteries, etc. The EB processing has been well-known as the technology for the high production rate and the highly functionalized material production. This is true; however, the technology should be noted as the one of the most promising technology with low emission of CO₂ (i.e. so-called green technology) by the high efficiency conversion from wall-plug electricity to electron beam and the high reaction efficiency in the materials. In the viewpoint of this fact, EB processing is one of the key technologies for the various kinds of manufacturing processing. In this paper, the applications and advantages of low energy electron beam below 300keV and especially, extremely low energy electron beam with the energy of several tens of keV are described. (author)

[en] Radiation grafting can introduce the aiming function to the trunk polymer. This technique gave the separator membrane for a button-shaped battery and the gas adsorbent for fabrication facility as commercial products. This commercialization was realized by the excellent properties which were imparted by graft polymerization into the trunk polymer. As ongoing R and D, the fibrous adsorbent has been synthesized by using fibrous trunk polymer. The metal ion adsorbent is promising materials for removal of toxic metals and the recovery of significant metals from the point of environmental preservation view. (author)

[en] Radiation processing either by gamma of e-beam has been applied in many fields and has been widely accepted for use in many areas of the global economy. Among the well established technologies are sterilization, polymer crosslinking/grafting, tire component curing, conservation of art objects and irradiation of selected food items. The International Atomic Energy (IAEA) through its technical co-operation programs, coordinated research projects, consultants and technical meetings and conferences is promoting the peaceful use of nuclear science and radiation technologies. Due to the IAEA's support, some new radiation technologies (e.g. hydrogel dressings, sulfur-free radiation vulcanized latex, growth promoting oligomers, superabsorbents) were developed and transferred to Member States over the past decade. Other promising applications the IAEA has supported are flue gas, waste water and sludge treatment. The IAEA has been organizing many meetings and research coordinated research projects (CRP) in which trends and new developments have been discussed and technical work conducted along this field. Special attention was given to the radiation processing of natural polymers under the framework of the Regional Cooperative Agreement (RCA) for Research, Development and Training Related Nuclear Science and Technology for East Asia and the Pacific. This region is especially rich in respect to wide variety of indigenous natural polymers such as rubber, chitin/chitosan, carrageenans, alginates and silk. It has organized the following research and technical cooperation projects since 1998. (J.P.N.)

[en] Research on radiation processing of natural polymer such as polysaccharides of chitosan, cellulose, carrageenan has been carried out in Sri Lanka since the year 2004. The research group have been involving in development activities on application of chitin and chitosan for wound dressing, irradiated chitosan on shelf life extension of fruits such as papaya, banana, mangoes, radiation crosslinked super-absorbent hydrogel from sodium carboxymethyl cellulose by radiation processing. Hydrogels prepared with PVA/Carrageenan/Agar has been studied on guinea pigs to determine the wound healing effect. Irradiated chitosan powder and chitosan solution was studied in vitro and found chitosan solution (1%) directly subjected to irradiation dosages even at 5 kGy was highly effective in control of anthracnose causing organism of papaya. In vivo studies with irradiated 1% chitosan solution on Rathana and red lady variety of papaya shows better control of spoilage of papaya to a considerable extent. The government of Sri Lanka (Ministry of Science and Technology and Atomic Energy Authority) is in the process of establishing the first government owned Multipurpose Gamma Irradiation Facility and it will be helpful to transfer the output of R and D in radiation processing. (author)