To deeply understand the dependence of hyperbranched polymerization on the specialties of molecular chain and chemical reaction, the reaction kinetics of nonideal hyperbranched polymerizations considering the chain rigidity and reaction reversibility are studied using the reactive three-dimensional bond fluctuation lattice model. It is found that, with the increase of chain rigidity, the formation probability of intramolecular rings decreases and less intramolecular rings with larger size are formed. It results in the increase of the degrees of polymerization and polydispersity index with the rise of chain rigidity at higher conversion. Furthermore, our simulation shows that the reversibility of reaction has strong influences on the equilibrium state and kinetic process of hyperbranched polymerizations. When the ratio of reverse reaction probability to forward reaction probability is larger, the conversion and degrees of polymerization quickly grow to the equilibrium value simultaneously. At smaller reverse reaction probability, however, the weigh-average degree of polymerization and polydispersity index further increase slowly after approaching the equilibrium conversion. Our results are well-consistent with the experiments to indicate that the introduction of the specialties of macromolecule and chemical reaction are necessary for quantitative analysis of the realistic hyperbranched polymerizations. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

To overcome the deficiency of mean field method in introducing the intramolecular cyclization and the steric effects, the reactive bond fluctuation model was applied to study nonideal hyperbranched A₂ + B₃ polycondensation, which has high sensitivity of gelation to the concentration of monomers, the feed ratio and the reactivity of functional groups. Simulation demonstrated that the mean field theory overestimated hyperbranched polymerization especially at high reaction conversion in the system with low monomer concentration where the intramolecular cyclization and the steric hindrance play crucial influences on molecular weight, molecular weight distribution and gel point (GP). The dependences of GP on the monomer concentration, feed ratio, and the reactivity of groups are clearly shown. We further simulated a specific polycondensation system with aromatic terephthaloyl chloride (TCl, A₂) and 1,1,1-tris(4-trimethylsiloxyphenyl)ethane (TMS-THPE, B₃) (Macromolecules 2007, 40, 6846) using fitting technology, and estimated molecular weight, molecular weight distribution, GPs, and the conformation of hyperbanched polymer. It provides a feasible way to quantitatively understand hyperbranched polymerization with the reaction specificity. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010

The conformation of hyperbranched polymers from one pot polymerization with AB_n (n = 2, 4) type monomers, applying the reactive 3D bond fluctuation lattice model, are systematically studied using scaling relation R ∼ N^λ, where R is the radius of gyration or the hydrodynamic radius of a hyperbranched polymer with the degree of polymerization N. The exponent λ was calculated at various monomer concentrations and group conversions. When the concentration of monomers with the equal reactivity of B groups increases from 0.1 to 0.9, the exponents λ_g and λ_h (corresponding to the radius of gyration and hydrodynamic radius, respectively) are in the ranges of 0.51–0.37 and 0.41–0.34 at the full conversion of A groups. Especially, we find that λ_g decreases linearly with the reaction conversion increasing. The ratio of z-average radius, R_gz/R_hz, ranges from 1.08 to 1.32 and indicates that hyperbranched polymer is soft macromolecule with penetrable structure. In the case of AB₂ type monomer with unequal reactivities, λ displays complicated dependence on the reaction conversion and the reactivity ratio. The results of our simulation are consistent with those of experiments and theories, and valuable in better understanding the fundamental properties of hyperbranched polymers. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 610–616, 2010

The 3D bond fluctuation lattice model is extendedly developed to explore AB_n (n = 2, 4) type hyperbranched polymerizations with the considerations of intramolecular rings, steric factors, diffusion of molecules, and polymer chain relaxation. In the case of zero activation energy, number- and weight-average degrees of polymerization and polydispersity index (PI) increase with the rise of monomer concentration and their maximal values are finite. The average fraction of branching point (FB), initially elevates with the increase of monomer concentration and then decreases at high concentration at full conversion of A groups. In the case of nonzero activation energy, the PI increases slowly with the decrease of reaction activity, but the average FB keeps nearly unchanging. The influence of substitution effect on PI and FB are also confirmed in simulation. The simulation results show excellent agreement with experimental data and are helpful to make great progress in prediction for AB_n type hyperbranched polymerizations. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 523–533, 2009

Self-condensing vinyl hyperbranched polymerization (SCVP) with A-B* type monomer is simulated applying Monte Carlo method using 3d bond fluctuation lattice model in three-dimensional space. The kinetics of SCVP with zero active energy of reaction is studied in detail. It is found that the maximal number–average and weight–average polymerization degrees and the maximal molecular weight distribution, at varying the initial monomer concentration and double bond conversion, are about 52, 190, and 3.93, respectively, which are much lower than theoretical values. The maximal average fraction of branching points is about 0.27, obtained at full conversion at the initial monomer concentration of 0.75. The simulation demonstrated the importance of steric effects and intramolecular cyclization in self-condensing vinyl hyperbranched polymerization. The results are also compared with experiments qualitatively and a good agreement is achieved. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4486–4494, 2008