تهيه مخلوط هاي LDPE- نشاسته گرما نرم ﴿TPCS ﴾ و بررسي خواص رئولوژيكي و مكانيكي آنها

چكيده انگليسي :

Preparation of LDPE Thermoplastic Corn Starch TPCS Blends and Investigation of Their Rheological Mechanical Properties Maryam Sabetzadeh m sabetzadeh@ce iut ac ir Date of Submission 2011 03 15 Department of Chemical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Persian Supervisor Dr Rouhallah Bagheri bagheri@cc iut ac ir Abstract In this thesis the rheological and mechanical properties of LDPE Thermoplastic corn starch TPCS blends and nanocomposites were investigated The compounds containing different amounts 0 40 wt of TPCS and a constant amount 3wt of LDPE grafted maleic anhydride LDPE g MA as a compatibilizer were prepared using a single screw extruder Also composites containing silicate layered nanoparticles using the best compatibilized blend and different amounts 0 5 3 phr of cloisite 15A were prepared through extrusion process and using a twin screw extruder The rheological mechanical and water absorption properties of all the samples were measured by means of standard methods Also modeling of rheological and mechanical properties of the LDPE TPCS blends and nanocomposites was performed by means of adaptive neuro fuzzy inference system ANFIS The results of melt flow index MFI of the blends showed that with increase in starch content the MFI value of all the blends decreased The rheological measurements indicated that as shear rate increased the apparent viscosity of the blends decreased so the samples showed shear thining behavior Also increase in apparent viscosity with increase in starch content was observed Reduction in MFI values of nanocomposites with increase in amount of nanoparticles was achieved These nanocomposites indicated pseudoplastic behavior and when nanoparticles content increased the apparent viscosity of the composites increased Sccaning electron micrographs SEM of the blends showed improvement in dispersion of starch particles in the LDPE matrix and increase in interfacial adhesion between phases in the presence of PE g MA X ray diffraction of nanocomposites showed with increase in cloisite 15A content the diffraction peek was transferred to lower angles and as a result layer distance of nanoparticles was increased Also the XRD results indicated that intercalated structure was achieved in all the nanocomposites The mechanical properties such as ultimate tensile strength elongation at break Young s modulus and relative impact strength of the blends reduced as the starch content increased However as evidenced by standard test method of PE plastics the compatibilized blends containing 25 wt TPCS have required mechanical properties to produce disposable packaging plastics Also increment in ultimate tensile strength and Young s modulus and decrement in elongation at break and relative impact strength of the nanocomposites were achieved with increase in the content of cloisite 15A However the best properties was observed by adding 1phr cloisite 15A nanoparticles The water absorption of the blend increased with increase in both the starch content and time The effective diffusion coefficient of the blends increased with increase in starch content The results of water absorption of the nanocomposites showed that these samples had lower water absorption values rather than the best compatibilized blend as a reference Also the water absorption values of the nanocomposites and subsequently the effective diffusion coefficient of them decreased as nanoparticles content increased The results of modeling showed that there was good relation between

ثابت زاده، مريم

تهيه مخلوط هاي LDPE- نشاسته گرما نرم ﴿TPCS ﴾ و بررسي خواص رئولوژيكي و مكانيكي آنها

پلي اتيلن سبك , جذب آب