The morphology of the quenched form of polypropylene was investigated. Thin films of the quenched form consist of small ball‐like structures which we suggest are defective hexagonal crystals. In thicker films they aggregate to form spherulites with no observable fine structure. Quenching of thin films of molten polypropylene to a temperature below 0°C results in the formation of numerous, isolated monoclinic spherulites with a better defined morphology than the smectic spherulites obtained by quenching above 0°C. This result suggests that the films (quenched below 0°C) were quenched to the glass and subsequently crystallized to the monoclinic form upon heating to room temperature.

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Recent morphological studies of plasticized and unplasticified poly (vinyl chloride) (PVC) are reviewed. Suspension polymerized PVC contains particles in a number of different size ranges 100-200A, 1000-5000A, 1~ and larger. The larger size particles are broken down during plasticization but both the 1OOA and the lOOOA suspension articles retain their idenparticles is a function of the processing conditions. In particular, the size of the lOOA particle increases with plasticizer content and is most distinct as characterized both by small angle x-ray scattering and electron microscopy for milling temperatures in the 160-170°C. range. Consideration is given to the effect of these particles, their structure, and interrelationship on the rheological properties of the resins. tity. The visibility, and presumaby, Y coalescence of these