@inproceedings{01J9VATAM5F2FA0J8SVM3B50TC,
  abstract     = {{Polymers are present in multiple aspects of our daily lives, playing a significant role in commodity applications
and high-technological industries. Nowadays, most polymeric materials are based on copolymers, i.e., they are
composed of repeating units, allowing the combination of desirable properties found in the corresponding
homopolymers into a single material. By playing with reaction conditions and carefully selecting comonomer
pairs it is possible to tailor a broad range of physical properties [1, 2].
A well-known example is the production of high impact polystyrene (HIPS), a heterogeneous thermoplastic with
improved impact resistance compared to general-purpose polystyrene (PS). HIPS consists of a PS matrix with
dispersed polybutadiene (PB) particles, which often contain occluded PS. Bulk industrial production involves the
free-radical induced grafting (FRIG) of polybutadiene (PB) with styrene (St) in presence of a conventional
chemical initiator. The (poly)styrene-g-(poly)butadiene graft copolymer (GC) produced in-situ plays the role of
stabilizer of the otherwise unstable blend of the precursor PB and the forming PS. The properties of this material
are determined by its morphology, and the latter by reactor parameters and conditions, e.g., stirring speed,
reaction temperature, PB molar mass and cis/trans content, chemical initiator concentration [3, 4].
In the present work, we perform multiphase Coupled Matrix-based Monte Carlo (CMMC) [3, 5] simulations (up
to 60% St conversion) to study the impact of initial PB content (5 to 10%) on the overall and per phase (PS
matrix, PB particles and PS occlusions) average properties and log-molar mass distributions (log-MMD), and on
process kinetics and performance. To account for phase equilibria, i.e., to determined phase separation and
inversion points, and phase compositions, a literature-based ternary phase diagram for St-PB-PS mixtures is
utilized [6]. Diffusional limitations are described by means of apparent rate coefficients, using the free volume
theory in the case of the cage- and glass-effect and the composite kt model in the case of the gel-effect [7, 8].
The simulation results show that St graft efficiency (ratio of grafted St to polymerized St) increases with the
increment of initial PB, while the PB graft efficiency (ratio of grafted PB to initial PB) does not vary
significantly. Due to the shape of the phase envelope, a higher initial PB content implies earlier phase separation
but delayed phase inversion (PI), leading to lower volume of occlude PS. This delay of the PI can be associated
to broader log-MMDs for the PS, GC, and the total polymer (TP), with the multimodality of the PS and TP
log-MMDs being more pronounced and appearing at lower conversions. This work demonstrates the usefulness
of CMMC simulations to study the relationship between process conditions and molecular and (overall)
morphological characteristics of multiphase polymerizations.}},
  author       = {{Figueira, Freddy L. and Zhou, Yin-Ning and Van Steenberge, Paul and Luo, Zheng-Hong and D'hooge, Dagmar}},
  booktitle    = {{Annual Meeting of the Belgian Polymer Group (BPG 2024), Abstracts}},
  language     = {{eng}},
  location     = {{Blankenberge, Belgium}},
  pages        = {{1}},
  title        = {{Impact of rubber content on average properties and distributions of high impact polystyrene by means of multiphase coupled matrix-based Monte Carlo}},
  year         = {{2024}},
}