Composition and rheology of polyamide-6 obtained by using bi- and tri-functional coupling agents

Structure and rheology of branched polyamide 6 polymers from their reaction recipe

“…any molecular segment containing only caprolactam monomers (located between two extremities or functional groups A x B y different from A 1 B 1 ) can be described by a Flory distribution with the same average molecular weight M n,Strand , and (2) we know, a priori, that every chain extremity is of type 'A' (real or virtual). [29][30][31][32] In contrast to the actual polycondensation process and to usual Monte Carlo algorithms, the molecules are therefore not built from the different monomers (A 1 B 1 , B 2 , A 3 , . ), but directly from specic sub-chains which can be considered as building blocks of the molecules.…”

“…Some works have already been proposed in this direction for metallocene polyethylene [25][26][27] as well as for polydisperse polyamide samples. [28][29][30][31][32] In the latter case, it has been shown that classical Monte Carlo statistics lead to a good approximation of the sample, which is formed by a condensation reaction process. The objective here is to propose a simplied Monte Carlo approach, which takes advantage -while without losing accuracy -of the fact that we know a priori that every generation will be described by a Flory-type molecular weight distribution and that they will all have the same average molecular weight (whatever their seniority).…”

Step‐Growth Polymerizing Systems of General Type “AfiBgi”: Calculating the Bivariate (Molecular Size) × (Number of Branch Points) Weight Distribution Using Generating Functions and Recurrences

“…The system "B1 + B3 + A2 + A1B1" resembles a randomly branched polyamide and will be used here as an illustrative example. [4][5][6]13 ] The table lists the four ( K = 4) species of monomers that take part in the reaction, their A functionality In the example, the B's are in excess, g tot > f tot . So, some B groups are free, and, hence, not all B3 monomers will act as branch point in a polymer molecule.…”

“…The situation regarding the right A group would be covered by probability P A [6,1], and regarding the other A group, probability P A [8,2] would be applicable. The molecule as a whole contributes to W [15,3].…”

“…[2][3][4][5][6] Instead of "effective number of branch points", Flory uses the terms "molecular complexity" [ 7,8 ] and "cross-linking index", [ 9 ] and for some relative simple systems of limited generality, he derives explicit expressions for the corresponding bivariate distributions: number or weight over size × number of branch points. In connection with systems past their gel-point, some authors work with "active network chains".…”