inorganic polymeric nanocomposites and membranes (advances in polymer science) (advances in polymer science)

[...]... monomer unit B being – (CH3 )(C2 H4 CF3 )SiO – A comparative study of the thermal properties and of the glass transition temperatures of the (A)n and (B)n homopolymers and of the (AB)n random and alternated copolymers and (BAB)n alternated copolymers has been achieved and showed the in uence of the structure of the polymer 16 F Guida-Pietrasanta · B Boutevin Random copolymers may lead to depolymerization... polymer was capped with vinyl silicone functions and the crosslinking was achieved with a special cross-linker containing several Si – H end groups (general type as in Fig 20), in the presence of a platinum catalyst [84, 85] 24 F Guida-Pietrasanta · B Boutevin Fig 20 The product is described as a liquid perfluoroelastomer and it is becoming popular in the industries as a universal material for O-rings,... considered fluorinated hybrid copolymers (cf Scheme 20) These copolymers were prepared by condensation of hybrid bis-silanol monomers and dichloro or diacetamido silanes, in the presence of a monofunctional silane as the chain stopper, according to the following scheme: Scheme 20 For X = Cl, they obtained random copolymers and for X = acetamido, they obtained alternated copolymers (AB)n or (ABA)n depending on... the classical polydimethyl and polytrifluoropropylmethyl siloxanes, and the authors showed that the introduction of perfluoroalkylene segments – C6 H4 – (CF2 )x – C6 H4 – into the main chain of the polysiloxane increased the thermal stability both under inert and oxidative atmosphere The same type of silphenylene siloxane polymers containing perfluoroalkyl groups in the main chain, was described by Patterson... C, increased as the amount of perfluorocyclobutane-containing silphenylene repeat units increased The TGA analysis showed that when the copolymers contained more than 20% of this repeat unit, they displayed less weight loss at elevated temperature than a classical fluorosilicone homopolymer After crosslinking (using a peroxide) of a copolymer containing about 30 wt % of the perfluorocyclobutane-containing... conversion in shorter amounts of time and that, in ScCO2 , the molecular weights of polymers obtained were notably greater than those obtained in benzene Before ending this review, it is worth citing a product that may be seen as a particular hybrid silicone: the SIFEL perfluoro elastomer from Shin-Etsu Actually, it consists of a perfluoroether polymer backbone combined with an addition-curing silicone crosslinker... layered silicate nanocomposites are reviewed The effect of processing conditions on cure chemistry and morphology is examined, and their relationship to a broad range of material properties elucidated An understanding of the intercalation mechanism and subsequent in uences on nanocomposite formation is emphasized Recent work involving the structure and properties of ternary, thermosetting nanocomposite... history [4–6] with polymer intercalation of montmorillonite being first investigated more than 40 years ago using methyl methacrylate and montmorillonite [7] However, it is only since the pioneering work by Toyota researchers with clays and polyamides [8–11] that layered silicates have gained importance as modifiers in improving polymer performance The significant feature of layered silicates, in comparison... high aspect ratio and their ability to be readily dispersible on a nanometer scale As illustrated in Fig 1, layered silicate composite structures fall into three different classes: (a) microcomposites with no interaction between the clay galleries and the polymer, (b) intercalated nanocomposites, where the silicate is well-dispersed in a polymer matrix with polymer chains inserted into the galleries... remains as the dispersed phase Higher rubber concentrations would lead to phase inversion, resulting in a significant decrease in strength and stiffness For the same reason, the cure profile must be adjusted to optimize the overall morphology, and resulting material performance Any soluble rubber remaining in the matrix plasticises the polymer network, decreasing the glass transition temperature and . classical fluorosilicone homopolymer. After crosslink- ing (using a peroxide) of a copolymer containing about 30 wt.% of the perfluorocyclobutane-containing repeating unit, the crosslinked network dis- played. were crosslinked at room temperature with Si(OEt) 4 and dibutyltin diacetate to give thermostable elastomers. Since the beginning of the 1980s and during the 1990s, Dvornic and Lenz and their. C 6 H 4 – into the main chain of the polysiloxane increased the thermal stability both under inert and oxida- tive atmosphere. The same type of silphenylene siloxane polymers containing perfluo- roalkyl