Core-shell products

The preparation of core-shell nanoparticles of different types from microemulsion tem- 

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It was important to perform capping reactions on the surface of the resulting ester terminated core-shell products in order to pacify the highly reactive... 

In the most common production method, the semibatch process, about 10% of the preemulsified monomer is added to the deionised water in the reactor. A shot of initiator is added to the reactor to create the seed. Some manufacturers use master batches of seed to avoid variation in this step. Having set the number of particles in the pot, the remaining monomer and, in some cases, additional initiator are added over time. Typical feed times ate 1—4 h. Lengthening the feeds tempers heat generation and provides for uniform comonomer sequence distributions (67). Sometimes skewed monomer feeds are used to offset differences in monomer reactivity ratios. In some cases a second monomer charge is made to produce core—shell latices. At the end of the process pH adjustments are often made. The product is then pumped to a prefilter tank, filtered, and pumped to a post-filter tank where additional processing can occur. When the feed rate of monomer during semibatch production is very low, the reactor is said to be monomer starved. Under these... 

An important class of materials that originates from the precursor core-shell particles is hollow capsules. Hollow capsules (or shells ) can be routinely produced upon removal of the core material using chemical and physical methods. Much of the research conducted in the production of uniform-size hollow capsules arises from their scientific and technological interest. Hollow capsules are widely utilized for the encapsulation and controlled release of various substances (e.g., drugs, cosmetics, dyes, and inks), in catalysis and acoustic insulation, in the development of piezoelectric transducers and low-dielectric-constant materials, and for the manufacture of advanced materials [14],... 

Thermoplastic elastomers (TPE), 9 565-566, 24 695-720 applications for, 24 709-717 based on block copolymers, 24 697t based on graft copolymers, ionomers, and structures with core-shell morphologies, 24 699 based on hard polymer/elastomer combinations, 24 699t based on silicone rubber blends, 24 700 commercial production of, 24 705-708 economic aspects of, 24 708-709 elastomer phase in, 24 703 glass-transition and crystal melting temperatures of, 24 702t hard phase in, 24 703-704 health and safety factors related to, 24 717-718... 

Laboratory procedures are presented for two divergent approaches to covalent structure controlled dendrimer clusters or more specifically - core-shell tecto(dendrimers). The first method, namely (1) the self assembly/covalent bond formation method produces structure controlled saturated shell products (see Scheme 1). The second route, referred to as (2) direct covalent bond formation method , yields partial filled shell structures, as illustrated in Scheme 2. In each case, relatively monodispersed products are obtained. The first method yields precise shell saturated structures [31, 32] whereas the second method gives semi-controlled partially shell filled products [30, 33],... 

Molecular weights for the final products were determined by MALDI-TOF-MS or (polyacrylamide) gel electrophoresis (PAGE). They were corroborated by calculated values from AFM dimension data and were found to be in relatively good agreement within this series (Table 27.2). Calculations based on these experimentally determined molecular weights allowed the estimation of shell filling levels for respective core-shell structures within this series. A comparison with mathematically predicted shell saturated values reported earlier [34], indicates these core-shell structures are only partially filled (i.e. 40-66% of fully saturated shell values, see Table 27.2). 

Safety precautions Before this experiment is carried out, Sect. 2.2.5 must be read as well as the material safety data sheets (MSDS) for all chemicals and products used. This example describes the concept of core/shell impact modifiers for thermoplastic polymers (see Sect. 5.51). 

Yu ZG, Piyor CE, Lau WH, Berding MA, MacQueen DB (2005) Core-shell nanorods for efficient photoelectrochemical hydrogen production. J Phys Chem B 109 22913-22919... 

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