Jürgen Nagel

Monte-Carlo Simulation of Compatibilization by Network-Building and Catalytic Interface Reactions in Two-Component Injection Molding

Adhesion of immiscible polymers during two-component injection molding can be improved by transreactions of properly functionalized molecules in situ by exploitation of the thermal energy of the melts. These reactions must pro- vide a sufficient conversion of reactive monomers in the short cooling time down to the glass temperature. Furthermore, as much as possible interconnecting chemical links on the molecular level have to be created between the components within the small spatial region of the interdiffusion interface width. To investigate these processes, we performed Monte- Carlo (MC) simulations based on the three-dimensional coarse-grained Bond Fluctuation Model (BFM) including a ther- mal interaction potential in r 6 with energy = 0.1 kBT . We compared a simple Split type reaction, which is capable of network-forming, with a catalytic interface reactive process both exhibiting different values of activation energy. The main process of the catalytic reaction system is identical to the simple Split reaction as described in a previous paper, but now a reactive monomer creating process is prefixed. For the reacting systems different physical properties like consump- tion, radius of gyration, concentration profiles or the distribution of the degree of polymerization were calculated as a function of time. Additionally, several functions for the description of the adhesive strength on the molecular level were adopted and calculated depending on reaction type, activation energy and degree of consumption, respectively. From the results, those chemical reaction types were deduced, which should be most suitable for compatibilization intentions in two-component injection molding.

Compatibilization in Two-Component Injection Molding by Means of SplitReactions with Varying Reactive Sites – a Monte-Carlo Simulation

Adhesion of immiscible polymers during two-component injection molding may be improved by transreactions of properly functionalized molecules in situ using the thermal energy of the melts. These reactions must provide a suffi- cient conversion of reactive monomers during the short cooling time down to the glass temperature and within the small spatial region of the interface width to create as much as possible interconnecting chemical links between the components on the molecular level. To investigate these processes, we performed Monte-Carlo (MC) simulations based on the three dimensional coarse-grained Bond Fluctuation Model (BFM) in a two-phase system. We studied split type reactions exhib- iting reactive monomers at different sites (End, Middle, Random) of the polymers governed by activation energies of EA = 0, 1, 3, 5 and 7 T k B. For the reacting systems several physical properties like consumption, radius of gyration, concentra- tion profiles or the distribution of the degree of polymerization were calculated as a function of time. Additionally, differ- ent functions for the description of adhesion on the molecular level were adopted and calculated depending on reaction type, activation energy and degree of consumption. From the results those chemical reaction types were deduced, which should be most suitable for the compatibilization in two-component injection molding.