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Montmorillonite was organically modified with distearyldimethyl-ammonium chloride. This organically modified clay mineral and poly(ethylene oxide), (PEO), were solvent-cast blended with chloroform, and the structure and properties of the resulting blends were investigated. The effects of the clay mineral content on the isothermal crystallization of PEO are discussed. From small and wide angle X-ray...
Aqueous polymerisation of acrylamide by Fe(III)-thiourea redox couple has been studied in homogeneous conditions as well as by loading Fe(III) ions in the interlayer spaces of montmorillonite. A dramatic effect was observed in the latter case, resulting in a very high degree of polymerisation and yielding polymers having high intrinsic viscosity due to imposed constraint on linear termination process...
The cationic polymerization of N-vinylcarbazole (NVC) can be initiated directly by montmorillonite (MMT) The polymerization has been studied with MMT in solid phase and NVC at melting temperature (> 64 o C) or in benzene solution at 50 o C. By repeated benzene extraction of the PNVC-MMT reaction product, an intercalcate of PNVC in MMT has been isolated. I.r. spectral analysis...
Montmorillonite (MMT)/Organo-soluble polyimide (PI) hybrids were prepared using a monomer solution intercalation polymerization method. The organo-soluble polyimide was based on pyromellitic dianhydride and 4,4′-diamino-3,3′-dimethyldiphenylmethane. The MMT was organo-modified with three types of intercalation agents: amino acids, primary aliphatic amines and quaternary ammonium salt. The dispersion...
Polybenzoxazine-clay hybrid nanocomposites were prepared from a polybenzoxazine precursor (B-a) and organically modified-montmorillonite (OMMT) as a type of layered silicates. OMMTs were prepared by surface treatment of montmorillonite (MMT) by octyl, dodecyl or stearyl ammonium chloride. The curing behavior of B-a in the presence of dispersed OMMT was followed by IR and DSC. DSC showed that the onset...
A polymerizable cationic surfactant, vinylbenzyldimethyldodecylammonium chloride (VDAC) was synthesized for functionalization of montmorillonite (MMT) and preparation of exfoliated polystyrene–clay nanocomposites. Organophilic MMT was prepared by cationic exchange between inorganic ions of MMT and ammonium cations of VDAC in an aqueous medium. Dispersions of intercalated clay (VDAC–MMT) in styrene...
Polyimide-MMT (montmorillonite) nanocomposites has been prepared by melt blending an organo-modified MMT with a thermoplastic poly(etherimide) (PEI) in an internal mixer. The dispersion of the MMT layers within the PEI matrix was verified using X-ray diffraction and transmission electron microscopy, revealing an exfoliation morphology. Owing to the molecular dispersion of the MMT layers and the strong...
Nylon 6–organoclay nanocomposites were prepared via direct melt compounding using a conventional twin screw extruder. The mechanical properties and morphology of these nanocomposites were determined and compared to similar materials made by an in situ polymerization process. The organoclay was well exfoliated into the nylon 6 matrix when compounded with the twin screw extruder but use of a single...
Epoxy–clay nanocomposites were synthesised using two montmorillonite clays (MMT) with different cation-exchange capacities (CEC) (94 and 140meq/100g). The purpose was to investigate the influence of the CEC of the clay on the synthesis and structure of epoxy–clay nanocomposites. The dispersion of the 1nm thick clay layers was investigated by X-ray diffraction (XRD) and transmission electron microscopy...
Nanocomposites from polyimide and clay were prepared aiming at finding a promising method for enhancing particularly the tensile modulus of polyimide films. Polyimide-clay hybrids were prepared by blending of poly(amide acid) and organically modified-montmorillonite (OMMT) as a type of layered clays. Poly(amide acid) was prepared from the reaction of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA)...
The objective of this work was directed to solve a problem of polymerization shrinkage in acrylic resin polymethylmethacrylate (PMMA) material. Organophilic montmorillonite (claytone) was added up to 1% by weight to one commercial type of PMMA powder to form PMMA–MMT composite. Acrylic specimens were processed by the conventional heat curing method following manufacturer's instructions. Thermogravimetric...
Polysulfone/organoclay nanocomposites were prepared via a solution dispersion technique, and were characterized by X-ray diffraction, transmission electron microscopy, stress-strain measurements in elongation, and thermogravimetric analysis. The X-ray and microscopy results demonstrated that at least at some compositions, the technique employed was successful in exfoliating and widely dispersing the...
Organoclay nanocomposites based on three different molecular weight grades of nylon 6 were prepared by melt processing using a twin screw extruder. Mechanical properties, transmission electron microscopy, wide-angle X-ray diffraction, and rheological measurements were used to characterize the three types of composites. Tensile modulus and yield strength were found to increase with increasing concentration...
Several types of polybenzoxazine/clay hybrid nanocomposites have been prepared from organically modified montmorillonite (OMMT) and mono- or bifunctional benzoxazine, 3-phenyl-3,4-dihydro-2H-1,3-benzoxazine (Pa) or bis(3-phenyl-3,4-dihydro-2H-1,3-benzoxazinyl) isopropane (Ba), respectively. OMMT was prepared by a cation exchange of montmorillonite (MMT) with ammonium salts of amines such as tyramine,...
Ethylene propylene diene methylene linkage rubber (EPDM)–clay hybrids have been prepared by mixing with EPDM and organophilic clay via vulcanization process. When we used thiuram and dithiocarbamate for the vulcanization accelerator, EPDM–clay hybrid was prepared successfully. In this EPDM–clay hybrid, the silicate layers of the clay were exfoliated and almost dispersed to the monolayers. The tensile...
Polyamide-imide (PAI) is a high performance condensation polymer, which has high heat resistance and high radiation resistance. Solvent suspensions of PAI are widely used in magnetic wire coatings. Montmorillonite (MMT) nanocomposites were investigated for the concentration effects on dispersion, glass transition, degradation, and mechanical properties. Samples were prepared using a controlled torque...
Samples of polyurethane and organically modified montmorillonite (OMont) were prepared, covering a wide range of inorganic composition, up to 40wt%. They were obtained by a three step process using diphenylmethane diisocyanate, poly( -caprolactone), di(ethylene glycol) and poly( -caprolactone)-OMont (NPCL) nanocomposites. The NPCL nanocomposites were used as soft segments for a partial replacement...
The preparation and processing of most of polymer/clay nanocomposites need high temperature. This limited the application of commonly used organic modifiers of long carbon-chain alkyl ammonium salts because of their low thermal stability. In this study, we synthesized two novel thermally stable, rigid-rod aromatic amines. Montmorillonite (MMT) treated by these amines exhibited larger layer-to-layer...
A series of polymer–clay nanocomposite (PCN) materials that consist of poly(vinyl alcohol) (PVA) and layered montmorillonite (MMT) clay are prepared by effectively dispersing the inorganic nanolayers of MMT clay in organic PVA matrix via an in situ free radical polymerization with AIBN as initiator. Organic vinyl acetate monomers are first intercalated into the interlayer regions of organophilic clay...
A novel method for preparation of exfoliated/intercalated nanocomposites is reported based on two steps, i.e. preparation of treated-montmorillonite (MMT) solution and solution blending with polymers. After in situ polymerization of dimethyldichlorosilane between layers and separation of most polydimethylsiloxane (PDMS), the treated-MMT solution shows good storage stability. Although elemental analyzer...
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