Reactivity of functional SAN toward coreactive EPR‐g‐MA at planar interface

Abstract

The grafting kinetics of reactive poly(styrene-co-acrylonitrile) (SAN) onto EPR-g-MA was studied under isothermal conditions, at the planar interface of an SAN/ethylene-propylene rubber (EPR) bilayer film in relation to the type of reactive groups, NH 2 versus carbamate (which is an amine precursor), attached to SAN. The amount of SAN chemically bound to EPR chains at the interface was estimated by selectively washing off the unreacted SAN chains before X-ray photon spectroscopic analysis of the released surface. It is clear that the mutual reactivity of the reactive groups, i.e., the NH 2 -MA pair versus the carbamate-MA pair, has a decisive effect on the amount of SAN that reacts with EPR-g-MA at the interface. In case of SAN-carb, the grafting reaction is controlled by the thermolysis of the carbamate groups into primary amines.

Reactive Compatibilization of SAN/EPR Blends. 1. Dependence of the Phase Morphology Development on the Reaction Kinetics

“…The fitting parameters were subsequently used along with the A SAN / A EPR ratio measured from the FTIR spectra of the insoluble material to calculate the weight fraction of SAN grafted to the rubbery phase. It must be noted that the grafting efficiency calculated by IR for blends prepared in the melt was in good agreement with the data collected by ESCA for bilayer assemblies (static conditions) …”

“…In the case of SAN bearing carbamate groups, the interfacial reaction is controlled by the (slow) carbamate thermolysis into primary amine (Scheme ). Indeed, compared to SAN−NH 2 , the grafting of SAN−carbamate has been shown to proceed more slowly at 200 °C under static conditions . This system is ideal to address the question of the mutual reactivity of the functional groups while keeping constant the molecular weight of each polymer (EP and SAN) and the content and distribution of each type of reactive groups in the reactive chains.…”

Reactive compatibilization of poly(methyl acrylate‐ran‐acrylonitrile)/poly(ethylene) blends through amine–anhydride coupling

“…Seeing that hDi vs for the functionalized blends decreased relative to the non-functionalized blend, it shows that morphology was stabilized due to the coupling reaction as was suggested by previous studies. 5,26,27,33,57 Conversely, the small increase in hDi vs after annealing indicates that coalescence was very slow at the temperature used, and that slight variations in hDi vs were more likely to be caused by particle analysis, rather than the coalescence process. 31 To compare the particle sizes with theoretical or semi-empirical predictions, estimates of the blend interfacial were necessary.…”

“…Examples of compatibilization reactions are amine–anhydride, amine–carboxylic acid, amine–epoxy, isocyanate–hydroxyl, oxazoline–carboxylic acid, and epoxy–carboxylic acid . The coalescence rate is dependent on, among other variables, the kinetics of the coupling reaction . It is therefore important to choose a reaction that has a relatively rapid coupling rate compared to the residence time of the extrusion process.…”

“…24 The coalescence rate is dependent on, among other variables, the kinetics of the coupling reaction. 6,[25][26][27] It is therefore important to choose a reaction that has a relatively rapid coupling rate compared to the residence time of the extrusion process. Out of these reactive pairs, the kinetics of the amine-anhydride (primary amine to be specific) coupling is the fastest.…”