Investigation On The Morphology, Properties And In-situ Polymerization Preparation Of Nylonn11/maleic Anhydride Graft Ethylene/octene Copolymer

Nylon, as the most consumable engineering plastics, was widely used in numerous fieldssuch as automobile, electric apparatus, mechanical equipment, aerospace, sports apparatusand so on. Nylon 11 became the centre of attention since its raw materials is made fromrenewable castor plant. Additionally, nylon 11 was mainly used as automobile pipe-laying andmunicipal gas pipe as well as offshore oilfield applications due to its low moisture-sorption,good dimensional stability and excellent cryogenic property. However, the toughness of thepure nylon 11 is not enough to meet with requisitions for the development of hi-technology.One of the most successful methods of improving the toughness of nylon is to blend withthermal palstic elastomer, which is imcompatibile with the polar nylon 11. Therefore, theimprovement of the compatibility between TPE and nylon 11 become the key problem.In view of the above problem, the nylon 11 was prepared by in-situ polymerization inwhich using 11-amino-undecanoic acid as the monomer and melated poly(ethylene-1-octene)(POE-g-MAH) as toughener. The structure and mechanical properties of nylon 11/POE-g-MAH blends were characterized. The rheological properties, melting andcrystallization behavor were also investigated. The major works were listed as following:1. Preparation and characterization of nylon 11/POE-g-MAH blendsThe nylon 11/POE-g-MAH binary blends were prepared by in situ polymerization throughblending 11-amino-undecanoic acid and POE-g-MAH with different ratios. Themorphological structure of blends was characterized by scanned electron microscope;Differential scanning calorimetry was adopted to study the thermal properties; the mechanicalproperties, water absorption and oil absorption were investigated as well. These experimental results showed that in-situ polymerization is suitable for preparation of nylon 11/POE-g-MAHblends. In comparison with the neat nylon 11, both the mechanical and thermal properties ofthe blends were improved.2. Investigation on the rheological behaviors of nylon 11/POE-g-MAH binary blendsThe rheological behaviors of nylon 11/POE-g-MAH binary blends were investigatedusing capillary rheometer. The experimental results showed that both nylon 11 and nylon11/POE-g-MAH binary blends were pseudoplastic also exhibited shear-thinning behavior.Non-newtonian index decreased with the increment of POE-g-MAH content at the sametemperature. At a constant shearing rate, shear stress of blends were all lower than that of purenylon 11 when content of POE-g-MAH was not higher than 10%, however, shear stress of theblends increased as a whole with the increment of POE-g-MAH content, it was a little higherthan that of pure PA11 in case of the loading level of POE-g-MAH is up to 20%. Thereduction of the viscous activation energy of PA11 and its blends with the increment ofshearing stress indicated that blends can be processed over a wider temperature at a constantshearing stress.3. Investigation on the melting and crystallization behaviors of nylon 11/POE g-MAH blendsThe melting and crystallization behaviors of nylon 11/POE g-MAH blends was investigatedusing differential scanning calorimeter. The crystallization kinetics of PA11 and its blendswere analysized using the classical crystallization kinetics equation. It is found thatPOE-g-MAH does not change the crystalline forms of nylon 11 matrix although it acts as thenucleating agent of nylon 11. The analysis of the crystallization kinetics demonstrated that theAvrami equation was proper to describe the isothermal crystallization of PA11 and its blends,and the Avrami equation modified by Jeziorny and Mo's method described well thenonisothermal crystallization kinetics. Some important parameters for the crystallizationkinetics were obtained. Additionally, the equilibrium melting temperature and the activationenergy of nonisothermal crystallization for blends were calculated from Hoffman-Weeksequation and Hoffmann-Lauritzen theory.