To improve the interfacial adhesion between poly(vinyl chloride) (PVC) and bamboo flour in PVC/bamboo flour composites, a novel coupling agent, poly(styrene-co-maleic anhydride)-block-poly(styrene-coacrylonitrile) {P[(SMA)-b-(SAN)]}, was synthesized through living free-radical polymerization in a one-pot reaction. P[(SMA)-b-(SAN)] was synthesized by a nitroxide-mediated polymerization technique in the presence of 2,2,6,6-tetramethylpiperidin-l-oxyl with azobisisobutyronitrile. The conversion of maleic anhydride (>99%) and styrene (>65%) was relatively high and yielded P[(SMA)-b-(SAN)] with a narrow molecular weight distribution (weight-average molecular weight/number-average molecular weight <1.38). PVC was blended with bamboo flours in the presence of the synthesized coupling agent with a two-roll mill. P[(SMA)-b-(SAN)] was added to the PVC matrix at a concentration of 55 or 20 wt %. As the content of P[(SMA)-b-(SAN)] in the wood-polymer composite increased, improved morphological and mechanical behaviors were observed.
Multi-walled carbon nanotubes (MWCNTs) were successfully functionalized with water-soluble poly(2-ethyl-2-oxazoline) (PEOX) through a polymer wrapping process. Pristine MWCNTs were first treated with nitric acid (HNO 3 ) at 120 8C for 24 hours. The resulting carboxylated MWCNTs were then mixed with 10 wt.% PEOX in ethanol, followed by sonication using a horn-type sonicator for 30 min and stirring at room temperature for 24 hours. Thereafter, unreacted free polymer was washed out repeatedly by centrifugation with an excess amount of ethanol. Scanning electron microscopy exhibited that the diameter of MWCNTs increased approximately by 10 nm after the functionalization of MWCNT with PEOX. Thermogravimetric analysis showed that approximately 15 wt.% polymer was incorporated in the functionalized MWCNTs. The functionalized MWCNTs gave excellent and stable dispersion in water as well as other organic solvents such as ethanol and DMF.
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