Block length distribution

Sorta E. and MeUs L.A., Block length distribution in finite polycondensation copolymers. Polymer, 19, 1153, 1978. 

Critical micelle concentrations for a range of PEO-PBO, PBO-PEO (here the block order reflects the synthesis sequence), PEO-PBO-PEO, PBO-PEO-PBO and cyclo-PBO-PEO ring copolymers are listed by Booth et al. (1997). Polymerization of PEO second (PBO-PEO diblock) leads to a broader PEO block length distribution, which in turn leads to a difference, for example, in surface tension (this is illustrated for PE04iPB08 and PB08PE041 by Booth et al. 

Also, in [86], the block length distribution functions /hp( ) and were calculated. It was found that the/np(f) function decays exponentially with increasing block length oc exp(-i/LHp), where Lrp is the average length of HP blocks. On the other hand, the distribution exhibits... 

One can show that the block length distribution function /b( ) is characterized for asymptotically large l by the power-law decay of its density /bCO a ta with the exponent a = 3/2 [88]. The exponent a estimated from the simulation data (a % 1.6) is, up to the experimental uncertainty, quite close to that predicted by the exact analytical model. As has been noted above, such a power-law decay is a characteristic of the Levy probabilistic processes [36]. 

Figure 9. Plot of heat of fusion vs. weight fraction of hard segment for each random copolymer, assuming k > 1 or k > 6, where k is the number of diisocyanate (hard-segment) units betwen two consecutive macrodiol (soft-segment) units. (Peebles (30) calculation of hard, block-length distribution in segmented polyurethane block copolymer is applied.)...

The observation that broad, bimodal styrene, block length distributions tend to favor continuity of the polybutadiene phase is not confined to 75% styrene content. Thus, a limited study at 50% styrene showed that polybutadiene-continuous compositions could be prepared by broad blending in place of the normal alternating lamellar structures characteristic of this composition. 

Since simple blending of the finished block polymers and coupling blends of SBLi di-block polymers did not produce markedly different results, it seems clear that the block length distribution per se is more... 

Different block length distributions in SBS and (SB)X block polymers and their mixtures can cause wide changes in domain morphology at constant overall monomer composition, which lead to characteristically different linear viscoelastic properties. 

Terreau O, Luo L et al (2003) Effect of poly(acrylic acid) block length distribution on polystyrene-b-poly(acrylic acid) aggregates in solution. 1. Vesicles. Langmuir 19 5601-5607... 

To gain some further insight into the discussed problem, the block length distribution functions and / ( ) were calculated, using both Monte Carlo simulations and the analytical probabilistic model [88]. 

Montaudo, G., Scamporrino, E., and Vitalini, D., Structural Characterization of Butadiene/Styrene Copol5nners by Fast Atom Bombardment Mass Spectrometry Analysis of the Partial Ozonolysis Products, Mactomolecules, 24, 376 (1991). Wilczek-Vera, G., Danis, P.O., and Eisenberg, A., Individual Block Length distributions of Block Copol5nners of poly(alfa methyl styrene)-block-poly(st5rrene) by MALDI-TOF Mass Spectrometry, Macromolecules, 29, 4036 (1996). 

Wilczek-Vera, G., Danis, P. O., and Eisenberg, A., Individual Block Length Distributions of Block Copolymers of Polystyrene-block-Poly(a-methylstyrene) by MALDI/TOF Mass Spectrometry, Macromolecules, 29, 4036, 1996. 

Miller, S. A. Isotactic block length distribution in polypropylene BemouUian vs hemiisotactic. 

In order to rationalize the disagreement between the model of Scheme 7.6 and observation, Polyakov developed a more computable chain/block length distribution model to treat the continuum from a living polymerization (Poisson distribution) to a terminating polymerization (Shulz-Flory distribution... 

Block-length Distributions of Poly(ether ester)s... 

Figure 10.1 Calculated PBT block-length distribution (a - number average b - weight average) in TPEEs with different wt % of PBT hard segments (denoted in the abbreviation) and PTMO (1000 g/mol) soft segment.

Peebles, L.H., Hard Block Length Distribution in Segmented Block Copolymers. Macromolecules, 9(1) p, 58,1976,... 

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