In-situ grafting

XRD was used to investigate the spacings of silicate layers of montmorillonite (from 1.9 to 4nm) in PP/montmorillonite (MMT) nanocomposites prepared by in situ graft-intercalation in the presence of acrylamide [331]. Similarly, XRD and TEM were used to study the dispersibility of PP/MMT nanocomposites prepared by melt intercalation using organo-montmorillonite and conventional twin screw extrusion [332]. Various delaminated and intercalated polymer (PA6, PA 12, PS,... 

Polymer-Filler Composites thru In Situ Graft Copolymerization Polyethylene-Clay Composites... 

Table 2 Functional monomers used for in situ grafting of ROMP-derived monoliths...

Scheme 17 Immobilization of a NHC precursor on a ROMP-derived monolith via in situ grafting...

After conversion had reached ca. 100%, the graft monomer (methacrylonitrile or styrene) was simply added to the emulsion and the temperature raised to 75 °C 32). This type of grafting is called in situ grafting (see Table 3.14). 

When polymers are to be tethered to surfaces by covalent bonds, there are two fundamental approaches for achieving this grafting from and grafting onto. Grafting from means surface-initiated polymerization, whereby the polymer chains are created in situ. Grafting onto involves formation of covalent bonds between previously formed polymer chains and reactive groups at a surface (Fig. 9). Both methods have specific pros and cons. 

In another approach, a small amount of maleic anhydride was copolymerized with styrene and acrylonitrile during the preparation of ABS by emulsion polymerization. The anhydride modified ABS was then melt blended with polyamide to form a compatibilized ABS/PA blend [Laven-good et al., 1986, 1987 Howe and Wolkowicz, 1987]. Obviously, a reaction between the anhydride functionality of ABS and the amine end group of polyamide leads to an in situ graft copolymer responsible for compatibilizing this blend. Monsanto s ABS/PA blends (Triax 1000... 

Smeets and co-workers reported the synthesis of amphiphilic HBP from the copolymerisation of a vinyl and divinyl monomers [11]. Grafting of HBP has also been reported by other researchers [12]. Hou and Yan reported the synthesis of a star-shaped copolymer using in situ grafting, which contained a hyperbranched poly(3-methyl-3-oxetanemethanol) core and tetrahydrofuran arms [13]. 

Li, W. H., Chen, X. H., Li, S. N., Xu, L. S., and Yang, Z. 2007. Synthesis of polypropylene wrapped carbon nanotubes composite via in situ graft method with maleic anhydride. Materials Science and Technology 23 1181-1185. 

Ruan W, Zhang M, Rong M, Friedrich K (2004) Polypropylene composites filled with in-situ grafting polymerization modified nano-silica particles. J Mater Sci 39(10) 3475-3478... 

NG. Gaylord, H. Ender, L. Davis, A. Takahashi, Polymer-flUer composites thru in situ graft copolymerization polyethylene-clay composites , in Modification of Polymers , CE.Carraher, M. Tsuda, Eds, ACS Symp Ser 121, Washinbton D C, 1980... 

An alternative approach is to incorporate reactive functional groups Into the elastomer, producing an in-situ graft copolymer. This reduces interfacial tension, improving dispersion in processing, and improves the adhesion of the rubber to the thermoplastic In the solid state. A maleated polystyrene/poly(ethylene-co-butylene)/polystyrene triblock copolymer (SEES) has been used successfully to toughen polyamides and polyesters. 

The addition of a block copolymer of 10 phr epoxidized NR into NR/ chlorosulfonated polyethylene blends increased the tensile properties and tear strength of the blended system. The miscibility of the epoxidized NR was enhanced by an in situ grafting reaction of epoxidized NR onto the surface of the chlorosulfonated polyethylene particles. This graft copolymer reduced the interfacial tension between the chlorosulfonated polyethylene particles and the NR matrix, and the epoxidized NR acted as the load transferring agent between the NR and the chlorosulfonated polyethylene."... 

Yan, D. Yang, G. (2009). A novel approach of in situ grafting polyamide 6 to the surface of multi-walled carbon nanotubes. Materials Letters, 63, 298-300. 

Coatings of fabrics is important as it provides flexibility and mechanical strength to the otherwise powdery, unprocessable poly aniline. Undoubtedly, the in-situ grafting of conducting polyaniline onto substrates can be compared with coating of the electrode during polymerization as both these are solid-liquid interfacial reactions, and therefore the mechanism for the formation of polyaniline cannot differ drastically [302-5]. The polymerization reactions mechanism can be written as... 

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