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Study On Properties Of PA6/nano-SiO2Composites Synthesized By In-situ Polymerization

Posted on:2013-02-12Degree:MasterType:Thesis
Country:ChinaCandidate:J HeFull Text:PDF
GTID:2231330371489757Subject:Materials science
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The PA6/nano-SiO2composites were synthesized by in-situ polymerization, and the surface ofnanosilca was modified by different modification agents. The interface structure between PA6matrix andnanosilica was analyzed. Moreover, mechanical properties and tribological behavior of nanocompositeswere evaluated. The antistatic properties of PA6and PA6/carbon black composites were studiedelementarily. The results suggested that the different kinds of modifier on the nanosilica surface could reactwith PA6chains, which would form covalent bonds. Consequently, some blend network structures wereformed in the PA6nanocomposite. It had been found that the interfacial interaction between nanosilica andPA6matrix were increased. The results indicated that interfacial interaction could affect the mechanicalproperties and tribological behavior of nanocomposites.In this thesis, the main contents and research results as follows:1. TEM, IR, TG and XPS were used to analyze the PA6/nano-SiO2composite. It showed that thenanosilica with different active groups on surface could react with PA6chains, and it also acted as amonomer in the polymerization of PA6. The surface of nanosilica has multi modifier groups. Therefore, thenanosilica could graft on two or more PA6chains. Finally, the PA6nanocomposite with blend networkstructures via covalent bonding was formed. As a result, the interfacial interaction between nanosilica andPA6matrix were increased.2. The mechanical properties were analyzed. It showed that nanosilica could strengthen and toughenthe PA6matrix. When RNS-A were introduced into the PA6at a dosage of0.5%, the tensile strength ofPA6nanocomposites was stronger by about54%than that of pure PA6. While the content of RNS-A was0.3%, the notched impact strength of PA6nanocomposites was about55%higher than that of pure PA6.However, RNS-E could strengthen the PA6matrix but had little effect on the notched impact strength ofPA6. When the RNS-E was introduced into PA6matrix at a dosage of0.3%, the tensile strength of PA6nanocomposites was increased by about47.5%than that of pure PA6.3. The tribological behavior of PA6and PA6nanosilica composites were evaluated by an MRH-3block-on-ring model friction and wear tester. And the morphologies of the polymer blends samples were observed by the scanning electron microscope (SEM). It had been found that the friction coefficient of PA6and PA6nanocomposites increased with the content of RNS-A or RNS-E increasing. At the same time, thenanosilica could decrease moderately the wear lost of PA6and PA6nanocomposites. However, the frictioncoefficient of block samples was decreased, while the wear lost increased when the loading force wasincreased. In addition, when the sliding speed increased, friction coefficient and wear lost of PA6and PA6nanocomposites were all increased.4. When carbon black and nanosilica were introduced into PA6, the volume resistivity of compositeswas decreased in a certain extent. But the mechanical properties of PA6reduced by added the carbon black.However, the mechanical properties of PA6could be maintained in a certain extent when the nanosilica wasintroduced into the PA6/CB composites. Otherwise, the carbon black and nanosilica were added, it resultedthat the friction coefficient of PA6composites increased while the wear lost decreased. Contrarily, whenloading force increased, the friction coefficient of PA6composites decreased as the wear lost increased.
Keywords/Search Tags:nylon-6, surface modified nanosilica, in-situ polymerization, nanocomposites, mechanicalproperties, tribological behavior
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