Micro structure after carbonation

Zeolite materials with tunable size and volume of mesopores can be prepared by using dispersed carbon black particles with narrow distribution of their sizes as inert mesoporous matrix or as secondary template. In such confined space for synthesis the crystallization of zeolite gel occurs inside the interparticle voids of carbon matrix [10,11,12]. In the case of generation of mesopores by secondary templating by means of addition of carbon black into the reaction mixture, zeolite crystals are formed around carbon particles [13]. After burning off a carbon matrix or carbon particles, zeolite crystals with a controlled pore size distribution and a crystalline micro-mesoporous hierarchical structure are prepared. 

In some cases, metal distribution was maintained at the nanometer scale even after high-temperature treatments. This suggests that metal particles were anchored to the carbon structure, preventing their migration and growth. Thus, micro- and mesopores can act as anchorage points for the metal particles, because many of these materials have narrow pore size distributions. 

Ultimately, the cement hardens to form dahllite, a carbonated apatite similar to that found in the mineral phase of bone [27, 47]. The cement has a micro-porous structure with pores smaller than 1 //m [86]. Calcium phosphate cement is available from multiple manufactures, as an example Norian Skeletal Repair System (SRS, Synthes West Chester, PA) consists of a liquid sodium phosphate solution and powder monocalcium phosphate monohydrate, tricalcium phosphate, and calcium carbonate. After mixing, the cement has a working time of approximately five minutes and hardens in approximately ten minutes. The material has a compressive strength of approximately 10 MPa at 10 minutes and maximum compressive strength of approximately 50 MPa within 24 hours. 

Matyjaszewski et al. [2] patented a novel and flexible method for the preparation of CNTs with predetermined morphology. Phase-separated copolymers/stabilized blends of polymers can be pyrolyzed to form the carbon tubular morphology. These materials are referred to as precursor materials. One of the comonomers that form the copolymers can be acrylonitrile, for example. Another material added along with the precursor material is called the sacrificial material. The sacrificial material is used to control the morphology, self-assembly, and distribution of the precursor phase. The primary source of carbon in the product is the precursor. The polymer blocks in the copolymers are immiscible at the micro scale. Free energy and entropic considerations can be used to derive the conditions for phase separation. Lower critical solution temperatures and upper critical solution temperatures (LCST and UCST) are also important considerations in the phase separation of polymers. But the polymers are covalently attached, thus preventing separation at the macro scale. Phase separation is limited to the nanoscale. The nanoscale dimensions typical of these structures range from 5-100 nm. The precursor phase pyrolyzes to form carbon nanostructures. The sacrificial phase is removed after pyrolysis. 

Another functional success has been the potential for drug incorporation and delivery from nano, micro, and macrospheres. During an overseas summer break, I have noticed that the sand that I was walking on the beach looked as perfect spheres and showed quite unique intricate structures (Figure 1.11). I brought some to our laboratories and after SEM and XRD analysis 1 noticed that it was not silica sand but calcium carbonate marine shells. 

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