High impact polystyrene morphology

Figure 1. Morphology of rubber modified high impact polystyrene.

In this context numerous changes were made. The chapter Properties of Polymers was revised and a new section Correlations of Structure and Morphology with the Properties of Polymers was added. The chapter Characterization of Macromolecules was revised and enlarged. 15 examples have been deleted as they did no longer represent the state of the art and/or were of minor educational value. Several new experiments (plus background text) were added, as, for example controlled radical polymerization - enzymatic polymerization - microemulsions - polyelectrolytes as superabsorbants - hyperbranched polymers - new blockcopolymers - high impact polystyrene - electrical conducting polymers. 

Figure 1. Typical morphology of high impact polystyrene.

Experimental Examples. An example may be given of the applicability of the forementioned theories to a complex but well defined morphology. It is well known that in commercial high impact polystyrene (HIPS) the dispersed rubber phase, the gel, is filled with up to 75% occluded polystyrene (PS) (15, 16). In principle, we have a three-phase system Keskkula and Turley (17) succeeded in isolating the gel and determining its dynamic mechanical... 

Figure 2. Morphology of high impact polystyrene prepared from various rubbers X5476...

Figure 6.2. Selected morphologies of IPNs based on SBR and polystyrene, SBR stained with osmium tetroxide. Upper left Commercial high-impact polystyrene. Upper right, Ostromislensky s material, with no phase inversion middle left, semi-IPN, SBR crosslinked middle right, semi-11 IPN, PS crosslinked lower left, full IPN lower right, full IPN, higher crosslinking in the SBR.

Fig. 12.7 The morphology of high-impact polystyrene (HIPS) a transmission electron micrograph, showing dispersed eiastomer particies ( 22 pm in diameter) with poiystyrene occlusions. (Courtesy of Dow Chemicai Company.)...

The commercial value of some polymers depends on their morphology. Thus, high-impact polystyrene (HIPS), which has an impact strength 5-10 times that of the neat polystyrene, is a multiphase material in which polybutadiene rubbery domains are distributed within the polystyrene matrix (Figure 1.4). Each of these domains contains polystyrene... 

The focus on visual evidence of morphological forms of filled polymer blends emerged in the literature in conjunction with studies on electron microscopy. Breuer et al. [28] used a series of SEM images to study morphology development in CB-filled linear low density polyethylene (LLDPE)/high impact polystyrene (HIPS) blends. These authors made the following observations. First, CB particles were observed to be localized in LLDPE droplets. Second, the presence of CB particles reduced the size... 

Giuffria, R., Carhart, R.O., and Davis, D.A. (1963) High gloss of extruded high impact polystyrene sheet A microscopical study of sheet morphology. J. pl. Polym. Sd.. 7,1731. 

Initially compounding was mainly performed between amorphous polymers and elastomers, resulting in a polymer matrix with small domains of elastomers. This morphology can increase the mechanical properties considerably. In later developments special attention was paid to better and controlled phase separation, to control the domain size, and to increase the impact strength, as for instance in high-impact polystyrene (HIPS) and in ABS-latex mixtures. The search for better compatibility between the phases leads also to fully compatible combinations of polymers. Although over 300 pairs of miscible polymers are known (2), only a few systems have actually been commercialized, like PS/PPE... 

An analogous microstructure can be produced in amorphous polymers by crazing them. Figure 2b shows the similarity of the craze structure to the crystalline morphology. We have reported that extensively crazed high-impact polystyrene (HIPS) exhibits hard elastic behavior, as the loading cycle illustrated in Figure 3 shows [10,11]. Hence, hard elastic behavior is associated with a bulk-microfibril composite structure... 

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