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In this study, acrylic tri‐block‐copolymers of different compositions and constituents were used to modify an epoxy resin. In epoxy the block‐copolymers self‐assembled to generate different nanostructured phases. Spherical micelles and vesicles were formed due to preferential interactions among constituents of the blends. The effect of modifier concentration and morphology on the resulting mechanical properties was investigated. At a modifier content of 5 wt% a more than threefold increase in strain energy release rate was observed relative to the unfilled epoxy for the block‐copolymer/epoxy systems studied. This improvement was accompanied by slight reductions in tensile stiffness, strength and glass transition temperature of developed epoxy blends. Microstructural studies revealed that during crack propagation, vesicle and micelle structures respectively underwent debonding and cavitation followed by shear yielding of the substrate matrix. POLYM. ENG. SCI., 54:1047–1055, 2014. © 2013 Society of Plastics Engineers

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Five pathogenic fungi viz., Alternaria alternata (Fr.) Keissler, Curvularia lunata (Wakker) Boedijn, Drechslera oryzae Breda de Haan (Subramanian and Jain), Fusarium moniliforme Sheldon and Pestalotiopsis guepinii (Desm.) Stay. were isolated from two rice varieties viz., BRRI 29 (Boro) and Pajam (Aman) by Blotter and Tissue planting methods. Ten fungicides i.e. Bavistin 50 WP, Salcox 50 WP, Dithane M-45, Indofil M-45, Tall 25 EC, Ridomil MZ Gold, MC Sulphur 80, Greengel, Hayvit 80 WP and Capvit 50 WP at 100, 200, 300, 400 and 500 ppm were evaluated against the above mentioned five pathogenic fungi. Tall 25 EC completely inhibited the radial growth of the test fungi at all the concentrations except Fusarium moniliforme. Antifungal properties of ethanol extract of Artocarpus heterophyllus Lamk., Tagetes erecta L., Datura metel L., Senna alata (L.) Roxb., Azadirachta indica A. Juss., Citrus medica L., Mangifera indica L., Asparagus racemosus Willd., Nerium indicum Mill. and Allium sativum L. at 5, 10 and 20% concentrations were evaluated against the five test pathogens. All the plant extracts completely inhibited the radial growth of the test fungi at 20% concentration except Asparagus racemosus.

Antagonistic potentials of seven rhizoshere soil fungi viz., Aspergillus flavus Link., A. fumigatus Fresen., A. niger Tiegh., A. terreus Thom., Penicillium sp., Trichoderma harzianum Refat. and T. viride Pers. were tested in opposition to six pathogenic fungi viz., Colletotrichum sp., Curvularia lunata, Fusarium moniliforme, F. oxysporum, F. semitectum and Phomopsis sp. isolated from different leaf spots and fruit rots of brinjal. Out of seven soil fungi, Trichoderma harzianum was found most effective to control the growth of all the test fungi in the study of colony interactions and effects of volatile and non-volatile metabolites. This fungus may be exploited commercially to biocontrol the diseases.

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