Silica polymer crosslinking

L. Matejka, O. Dukh, and J. Kolarik, Reinforcement of crosslinked rubbery epoxies by in-situ formed silica, Polymer 1449-1459 (2000). 

Silicone polymers, crosslinked by radiation in the absence of fillers, form rubbers with poor tensile and tear strength. Much better properties can, however, be obtained for small doses by the inclusion of a filler such as silica or carbon black [425]. 

The tensile strength of a nonfilled, but crossllnked polydi-methylsiloxane fluid is about 20 psi. The same polymer/crosslink-er mixture with 15% highly functional silica filler could have a tensile strength of >600 psi or a 30-fold increase. 

Capadona LA, Meador MA, Aluimi A, Fabrizio EF, VassUaras P, Leventis N (2006) Flexible low-density polymer crosslinked silica aerogels. Polymer 47 5754-5761... 

Figure 22.3A, B depicts the storage modulus, loss modulus, and loss tangent as a function of temperature for polymer crosslinked silica aerogel (X-SiOx) with density 0.67 g/ cm and polymer crosslinked vanadia aerogel (X-VOx) with density 0.65 g/cm. At room temperature (23°C), the Young s modulus is 611/673 MPa for X-SiOx andX-VOx, respectively. As the temperature becomes lower the storage modulus increases. At — 119°C, the...

Matejka L, Dukh O and Kolarik J (2000) Reinforcement of crosslinked rubba-y epoxies by formed silica. Polymer 41 1449-1459. 

SEC is a widely used technique for the purification and analysis of synthetic and biological polymers, such as proteins, polysaccharides and nucleic acids. Biologists and biochemists typically use a gel medium — usually polyacrylamide, dextran or agarose — and filter under low pressure. Polymer chemists typically use either a silica or crosslinked polystyrene medium under a higher pressure. These media are known as the stationary phase. 

She et al. [128] used rolling contact to estimate the adhesion hysteresis at polymer/oxide interfaces. By plasma oxidation of the cylinders of crosslinked PDMS, silica-like surfaces were generated which could hydrogen bond to PDMS r olecules. In contrast to unmodified surfaces, the adhesion hysteresis was shown to be larger and proportional to the molecular weight of grafted polymer on the substrate. The observed hysteresis was interpreted in terms of the orientation and relaxation of polymer chains known as Lake-Thomas effect. 

As an organic polymer, poly(tetramethylene oxide) was also used for the preparation of ceramers. The mechanical properties in these cases were much improved in comparison with those for hybrids from polysiloxanes. In these poly (tetramethylene oxide)-silica hybrids, the effect of the number of functional triethoxysilyl groups was examined [13]. As shown in Fig. 2, more multifunctional organic polymer produced more crosslinked hybrid networks. This means that the more rigid the structure in the hybrids is, the higher the modulus and the lower swelling property. 

Naphthalenedisulfonate-acetonitrile as the only mobile phase with a silica column coated with a crosslinked aminofluorocarbon polymer has proven to be an effective combination for the separation of aliphatic anionic surfactants. Indirect conductivity and photometric detection modes are used to monitor these analytes. The retention of these surfactants is found to depend on both the ionic strength and the organic solvent content of the mobile phase. The mechanism of retention is considered to be a combination of both reverse phase and ion exchange processes. Selective separation of both alkanesulfonates and... 

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