Control architecture

Orthmann E and Wegner G 1986 Preparation of ultrathin layers of molecularly controlled architecture from polymeric phthalocyanines by the Langmuir-Blodgett-technique 1986 Angew. Chem. Int. Edn. Engl. 25 1105-7... 

Microprocessor technology permitted these technical issues to be addressed in a cost-effec tive manner. In the mid-1970s, a process control architecture referred to as a distributed control system (DCS) was introduced and almost instantly became a commercial success. A DCS consists of some number of microprocessor-based nodes that are interconnec ted by a digital communications network, often called a data highway. The key features of this architecture are as follows ... 

The new knowledge and understanding of radical processes has resulted in new polymer structures and in new routes to established materials many with commercial significance. For example, radical polymerization is now used in the production of block copolymers, narrow polydispersity homopolymers, and other materials of controlled architecture that were previously available only by more demanding routes. These commercial developments have added to the resurgence of studies on radical polymerization. 

Kwon, Y. and Faust, R. Synthesis of Polyisobutylene-Based Block Copolymers with Precisely Controlled Architecture by Living Cationic Polymerization. Vol. 167, pp. 107-135. 

C. C. Evans, L. Sukarto, M. D. Ward, Sterically controlled architectural reversion in H-bonded crystalline clathrates , J. Am. Chem. Soc 1998,121, 320-325. 

The recognition of the two fundamental mechanisms of reptation and arm fluctuation for linear and branched entangled polymers respectively allows theoretical treatment of the hnear rheology and dynamics of more complex polymers. The essential tool is the renormahsation of the dynamics on a hierarchy of timescales, as for the case of star polymers. It is important to stress that experimental checks on well-controlled architectures of higher complexity are still very few due to the difficulty of synthesis, but the case of comb-polymers is an example where good data exists [7]. 

Following Custelcean and co-workers, this great advantage of dihydrogen bonds opens new avenues to the rational assembly of extended covalent materials with controlled architecture [4]. As examples, we describe in this chapter some derivatives of icosahedral carboranes widely applied as building blocks in supramolecular systems, as well as NaNH4 poly(2-hydroxyethyl)cyclen building blocks. 

But, in the general case, inhomogeneities are induced by fast chemical reactions and are very difficult to control. For this reason, precursors of controlled architectures have been developed for different purposes, such as to decrease the viscosity in high-solids systems, to lower shrinkage, to improve material properties and, for some electronic and nonlinear optical applications, to build nanosized ordered regions in the networks. 

Synthesis of Polyisobutylene-Based Block Copolymers with Precisely Controlled Architecture by Living Cationic Polymerization... 

The synthesis of hetero-arm star-block copolymers with well-controlled architecture such as AnBn- or ABC-type star-block copolymers, recently accomplished by a living anionic process utilizing a novel concept of the living coupling reaction [84], however, has been a challenge by a living cationic process. 

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