Polymer in situ polymerization

Nanocomposite polymers In situ polymerization Nanoscopically confined polymers... 

Incoronata Tritto studied stereospecific olefin polymerization in the group of Prof. Adolfo Zambelli at the Institute for Macromolecular Chemistry of the CNR and received her degree in polymer science at the Specialization School Giulio Natta at Politecnico di Milan (Italy) in 1981. In 1982, she joined as permanent researcher the Institute for Macromolecular Chemistry of the CNR In 1988, she spent 1 year in the group of Prof. Robert H. Grubbs at Caltech (USA), where she studied the relationship between metathesis and addition olefin polymerization. She is currently a senior research chemist at ISMAC-CNR. Her research interests focus on (1) synthesis and microstmctural characterization of stereospecific olefin and cyclic olefin homo- and copolymers by transition metal catalysts (2) activation and deactivation reactions ofthe homogeneous catalytic systems by in situ multinuclearNMR analysis and (3) synthesis of block copolymers and nanostructured hybrid polymers, in situ polymerization on clay and carbon nanotubes. 

Conducting polymer nanocomposites consist of a conducting polymer or copolymer having nanofiUers in the form of particulate (OD) or fiber (ID) or flake (2D) dispersed in the conducting polymer matrix. These may be of different shape, but at least one dimension must be in the nanoscale. Nanocomposites of conducting polymers have been prepared by various methods such as colloidal dispersions, electrochemical encapsulation, coating of inorganic polymers, in situ polymerization with nanoparticles and have opened new avenues for material synthesis. 

There are several approaches to the preparation of multicomponent materials, and the method utilized depends largely on the nature of the conductor used. In the case of polyacetylene blends, in situ polymerization of acetylene into a polymeric matrix has been a successful technique. A film of the matrix polymer is initially swelled in a solution of a typical Ziegler-Natta type initiator and, after washing, the impregnated swollen matrix is exposed to acetylene gas. Polymerization occurs as acetylene diffuses into the membrane. The composite material is then oxidatively doped to form a conductor. Low density polyethylene (136,137) and polybutadiene (138) have both been used in this manner. 

Continuous porous polymer rods have been prepared by an in situ polymerization within the confines of a chromatographic column. The column is filled with glycidyl methacrylate and ethylene dimethacrylate monomer mixtures, cyclo-hexanol and dodecanol diluents, and AIBN initiator. They are then purged with nitrogen, stopped, and closed with a silicon rubber septum. The polymerization is allowed to proceed for 6 hr at 70°C with the column acting as a mold (47). 

This is a highly polar polymer and crystalline due to the presence of amide linkages. To achieve effective intercalation and exfoliation, the nanoclay has to be modified with some functional polar group. Most commonly, amino acid treatment is done for the nanoclays. Nanocomposites have been prepared using in situ polymerization [85] and melt-intercalation methods [113-117]. Crystallization behavior [118-122], mechanical [123,124], thermal, and barrier properties, and kinetic study [125,126] have been carried out. Nylon-based nanocomposites are now being produced commercially. 

There are three general approaches to the synthesis of polymer-clay nanocomposites. In the first approach, a monomer or precursor is mixed with organophilic clay and followed by polymerization. This in situ polymerization technique was first developed by the... 

Recently, many synthetic polymers such as urea/formalin resin, melamine/formalin resin, polyester, and polyurethane have been widely used as the wall material for the microcapsule, though the gelatin microcapsule is still used. Microcapsules using a synthetic polymer wall have several advantages over those using a gelatin wall (1) the preparation process is simple, (2) the size of the microcapsules is well balanced, (3) the microcapsule concentration can be increased twofold or more and (4) the microcapsules have a high resistance to water and many chemicals. Synthetic microcapsules are prepared by interfacial polymerization or in situ polymerization. 

Taviot-Gueho C, Leroux F (2005) In situ Polymerization and Intercalation of Polymers in Layered Double Hydroxides 119 121-159 Teitel baum GB, see Kochelaev BI (2005) 114 205-266 Thessing J, see Peng X (2005) 118 137-177 Trommer K, see Roewer G (2002) 101 59-136 TsuzukiS (2005) Interactions with Aromatic Rings 115 149-193... 

The in situ bulk polymerization of vinyl monomers in PET and the graft polymerization of vinyl monomers to PET are potential useful tools for the chemical modification of this polymer. The distinction between in situ polymerization and graft polymerization is a relatively minor one, and from a practical point of view may be of no significance. In graft polymerization, the newly formed polymer is covalently bonded to a site on the host polymer (PET), while the in situ bulk polymerization of a vinyl monomer results in a polymer that is physically entraped in the PET. The vinyl polymerization in the PET is usually carried out in the presence of the swelling solvent, thereby maintaining the swollen PET structure during polymerization. The swollen structure allows the monomer to diffuse in sufficient quantities to react at the active centers that have been produced by chemical initiation (with AIBM) before termination takes place. 

Polymeric conducting systems were also prepared by in situ polymerization of vinyl monomers in ionic liquids [22], with a conductivity of 1 mS/cm. A conductive polymer electrolytes were also prepared by polymerization in liquid EMIm(HF)nF leading to a composite poly(2-hydroxyethyl methacrylate)-EMIm(HF)nF. Recently, polymer electrolytes were prepared in the form of thin foils, by incorporating ionic liquids in a polymer matrix [13-15], Conductivities of polymer-IL or polymer-IL-solvent systems are collected in Table 4. 

Porous polymer materials, especially in particulate form, are of interest in a diverse range of applications, including controlled drug delivery, enzyme immobilization, molecular separation technology, and as hosts for chemical synthesis [101-104]. MS materials have been used as hosts for the template synthesis of nanoporous polymer replicas through in situ polymerization of monomers in the mesopores [105-108]. 

Polymer in situ gels, 9 75 Polymerization, 12 188. See also Bulk continuous polymerization Polymers Radical polymerization ABS, 1 419-123 acetaldehyde, 1 103 acetylene, 1 181 acrolein, 1 279 acrylamide, 1 311 acrylic ester monomers, 1 375-386 acrylic esters, 1 342 of acrylonitrile, 11 197-204... 

Another approach is similar to that used in for the preparation of polymer-layer open tubular GC columns (PLOT). Horvath s group prepared capillaries with a porous polymer layer as shown in Fig. 13 by in situ polymerization of vinylbenzylchloride and divinylbenzene [183]. The reaction of the N,N-di-methyldodecylamine with chloromethyl groups at the surface simultaneously afforded strong positively charged quaternary ammonium functionalities and attachment of C12 alkyl chains to the surface. The unreacted chloromethyl groups... 

There are three methods for synthesizing polymers melt state compounding, in situ polymerization and solvent methods [185-187,177]. 

Solvent methods are similar to in situ polymerizations. During the first stage, the nanomaterial is dispersed in a solvent. In some cases a surfactant can be used as a bridge between the nanomaterials and the matrix (Fig. 4.9). This reaction occurs in a liquid or gel form in the presence of a solvent such as toluene, chloroform, acetonitrile, water, acetone, etc. The solution of modified nanoparticles is then added to a polymeric solution under agitation (at room or elevated temperatures) in order to ensure a homogeneous dispersion of the nanomaterials in the matrix. Finally, the polymer composite... 

Y. Ou, F. Yang, J. Chen, Interfacial interaction and mechanical properties of nylon 6-potassium titanate composites prepared by In-situ polymerization, Journal of Applied Polymer Science, vol. 64, pp. 2317-2322,1998. 

Y. F. Huang, C. W. Lin, Facile synthesis and morphology control of graphene oxide/polyaniline nanocomposites via in-situ polymerization process, Polymer, vol. 53, pp. 2574-2582, 2012. 

In Situ Polymerization and Intercalation of Polymers in Layered Double Hydroxides... 

In this section, we consider the different synthesis routes that have been employed to incorporate polymers into LDH with emphasis on the in situ polymerization process, an approach which gives rise to well-defined nanocomposites. 

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