CRYSTALLINITY IN THE POLYPROPYLENE CELLULOSE SYSTEM .1. NUCLEATION AND CRYSTALLINE MORPHOLOGY/

The amount of research on lignocellulosic/thermoplastic composites has increased dramatically. Little attention, however, has been directed towards the subject of crystallinity at the interface (interphase). Op tical microscopy and differential scanning calorimetry were used in th is work to study crystallinity in the cellulose/polypropylene system. The results verify that cellulose acts as a nucleating agent for polyp ropylene, producing a transcrystalline region around the fiber. Treatm ent of the fibers with alkyl ketene dimer (AKD), alkenyl succinic anhy dride (ASA), or stearic acid, inactivates the surface features respons ible for transcrystallinity. These treatments also affect the overall degree of crystallinity of the sample. Morphological features, resulti ng from a transcrystalline or nontranscrystalline interphase, may have a significant effect on mechanical properties. A possible mechanism f or the appearance of transcrystallinity involving crystal structure ma tching is also proposed. (C) 1993 John Wiley & Sons, Inc.