Grafting Efficiency in High-Impact Polystyrene by Sec Combined With Theoretical Predictions From a Polymerization–sec Model

Abstract

In high-impact polystyrene (HIPS), the grafting efficiency (GE) is the mass of grafted styrene divided by the total mass of polymerized styrene. The GE along a prepolymerization was determined from the UV size exclusion chromatogram of the total polymer. The UV sensor at 254 nm ''sees'' only the free and grafted polystyrene (PS) chains, but not the polybutadiene (PB) chains. The data processing involves deconvoluting the UV chromatogram into the chromatograms of the free PS and grafted PS by means of polymerization-SEC model. The GE was determined after adjusting (by trial-and-error) the predicted UV chromatogram to the measurement. A single adjustment parameter was used: the ratio between the rate of initiation to the monomer Downloaded by [The University of Manchester Library] at 07:01 12 October 2014 and the rate of initiation to the rubber. The method is quick and accurate, and the estimates were verified by solvent extractiongravimetry. It is also possible to estimate the GE by deconvolution of the differential refractometer chromatogram. However, in this case a detector calibration is required, and the results are less accurate than when employing the UV sensor.

Modelling of the High‐Impact Polystyrene Morphogenesis

“…[3] These experimental studies provide a similar description of HIPS morphology evolution from the initially homogeneous mixture of polybutadiene dissolved in styrene: (i) phase separation at low styrene conversion resulting in precipitation of small PS domains, (ii) grafting reaction stabilizing PS domains by PB-g-PS chains, (iii) phase inversion at medium conversion of styrene resulting in continuous PS þ styrene phase and particulate PB þ styrene phase containing graft-stabilized PS occlusions, thus resulting in salami morphology. Fundamental studies of grafting reactions applicable to HIPS were conducted by Huang and Sundberg [4] and Estenoz et al [5] Number of secondary processes are affecting HIPS morphology, e.g., mixing and Ostwald ripening. The most dramatic change of morphology takes place during the phase inversion at intermediate styrene conversion.…”

A Mathematical Model of the Bulk Copolymerization of Styrene and Acrylonitrile in the Presence of Polystyrene‐block‐Polybutadiene

“…[22,23] Over the last 30 years, the HIPS process has been theoretically investigated through homogeneous and heterogeneous mathematical models. [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] The former assume polymerization taking place in a single phase. Such an assumption is strictly valid for solution polymerizations and for bulk polymerizations at very low conversions.…”