SUMMREThe interdiffusion of poly(oxy-2,6-dimethyl-l,4-phenylene) (PPE) and polystyrene (PS) sequences is the key step in the formation of the commonly called plastic-rubber composite (Kunststoff-Kautschuk-Verbund, K&K-V). This new process bonds PPE and poly(styrene-co-butadiene) rubber (SBR) during the vulcanization of the rubber, without the aid of any adhesive. As PPE and PS are f d y mutually compatible polymers, polymer-polymer interdiffusion takes place readily. PS was therefore used as a model system. Electron microscopy clearly demonstrates that the kinetics of the diffusion process are determined by the faster diffusing PS. This was studied in the temperature range of 180°C to 260OC. The interdiffusion coefficients are of the order of lo-" to lo-'' cm2 * s-'. These are significantly higher than the selfdiffusion coefficients of PPE and PS, which are lo-'' and lo-'' cm2s-', respectively. The interdiffusion coefficients are dependent on temperature and inversely proportional to the PS molecular weight. for PS molecular weights higher than the entanglement value. The diffusion process follows Fick's law. The interdiffusion coefficient is not, or is only weakly, dependent on the concentration. The interdiffusion of PS samples of molecular weights below the entanglement value is observed by a newly developed method based on Fourier transform infrared spectroscopy with attenuated total reflection technique (FT'IR-ATR). In this low-molecular-weight region, interdiffusion coefficients as high as lo-' cm2 * s-' are obtained. 0 1990, HUthig & Wepf Verlag, Basel CCC 0025-1 16X/90/%03.00

Interdiffusion of poly(oxy-2,6-dimethy1-1 ,Cphenylene) (PPE) and polystyrene (PS) sequences is the key step in the formation of the so-called plastic-rubber composite (Kunststoff-Kautschuk-Verbund, K & K-V). This new process links PPE and poly(styrene-co-butadiene) rubber (SBR) during the vulcanization of the rubber, without the aid of any adhesives. Polystyreneblock-polybutadiene (SB) is used as model for SBR. As PPE and polystyrene (PS) are fully mutually compatible polymers, polymer-polymer interdiffusion occurs easily for PPE and the PS blocks. This is shown by electron microscopy. The thickness of the interdiffusion zone correlates to the PS block length. The respective butadiene block forms a layer on top of the interdiffusion zone. SBR with a high styrene content of at least 71 wt.-% is also compatible with PPE. The interdiffusion kinetics of the system PPE-SBR follows Fickian behaviour. The diffusion coefficients are smaller than for the system PPE-PS. Although PPE and SBR with lower PS content, as it is used for the K & K-V, are not compatible, interdiffusion occurs at the phase boundary. The thickness of the diffusion zone depends on the styrene content of the SBR. For SBR samples with 40 and 23,5 wt.-% styrene, zones of SO and 15 nm thickness are found. ~ a) part 1: cf. ' ).