N- polymers

Since the total number of polymer chains is proportional to [B"]o, the number of n-mers in a population of N polymer molecules is given b>... 

The total number of ways of placing N polymer molecules in the lattice is given by the product of factors like these, one for each molecule ... 

The emphasis in the approaches to boron nitride [10043-11 -5] BN, precursors has been concentrated on cycHc compounds. There have been recent reports of trimethylsilyl-substituted aminoboranes being evaluated as B—N precursors. These are linear borylamines containing up to four boron atoms. Compounds were also synthesized with free —NH2 groups amenable to condensation with either dihaloboranes or dihaloborazines (65) and offering suitable monomers for linear B—N polymer synthesis and borazine-ring-linking appHcations. 

COGSWELL, p. N., Polymer Melt Rheology, Geo. Godwin, London (1981)... 

Shaw, J. D. N., Polymer concretes-UK experiences, paper presented at the Conference on Polymers in Concrete, Fourth International Congress, September (1984). 

FIGURE 11,1 Ultrasonic velocity versus acrylonitrile-butadiene mbber/ethylene-propylene-diene monomer (NBR-EPDM) blend composition (a) no compatibiUzer, (b) with chloro-sulfonated polyethylene (CSM), and (c) with chlorinated polyethylene (CM). (From Pandey, K.N., Setua, D.K., and Mathur, G.N., Polym. Eng. Set, 45, 1265, 2005.)... 

FIGURE 21.1 Drawing to help explain entropic elasticity. (From Saito, N., Polymer Physics [in Japanese], Syokabo, Tokyo, Japan, 1967.)... 

An unprecedented stereoselective procedure to obtain enantiomerically pure transition cluster M3Q4 complexes consists of the direct excision of the M3Q7X4 n polymers using chiral diphosphanes, namely (+)-l,2-bis[(2J ,5R)-2,5-(dimethylphospholano)]ethane [(R,R)-Me-BPE] and its respective enantiomer [(S,S)-Me-BPE] to afford the trinuclear complexes (P)-[Mo3S4Cl3(J ,J -Me-BPE)3] and (Af)-[Mo3S4Cl3(S,S-Me-BPE)3] , respectively [30]. The structures of both enantiomers are shown in Fig. 7.3. The symbols (P) and (M) refer to the rotation of the chlorine atoms around the C3 axis, with the capping sulfur pointing towards the viewer. 

The synthesis of tractable, linear B-N polymers (RBNR)n is usually prevented by the ready formation of the extremely stable trimeric borazene ring system (RBNR)3. In an attempt to circumvent this problem, we have prepared a series... 

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