| Abstract: | It has been found practical to fractionate relatively monodisperse polystyrenes of molecular weights up to 4 × 106 by using a semiautomatic solvent extraction procedure. The fractionators consist of flow-through mixing chambers provided with settling regions for the removal of finely suspended solid material. Provision is made for accurate control of both temperature and solvent–nonsolvent ratio. Two such apparatus, operated in tandem, were used in the present work; in principle, several more stages could be employed if desired for most polymer systems. Results on polystyrenes prepared in well defined ways appear to be in good agreement with predicted distributions. Applicability to other polymer systems is discussed. |
