EFFECT OF MOLECULAR-WEIGHT AND CHAIN-END GROUPS ON CRYSTAL FORMS OF POLY(VINYLIDENE FLUORIDE) OLIGOMERS

The micro-structure of poly(vinylidene fluoride) oligomers was charact erized by F-19 and C-13 n.m.r. and the effects of molecular weight and the chain end groups on the crystal forms were studied by i.r. and X- ray methods. One of the oligomers terminated with -CH3 and the fragmen t of an initiator at the chain ends. The other oligomers were terminat ed with -Cl and CCl3- at their chain ends. The larger chain end groups tended to produce the conformational disorder in the molecules yieldi ng the gamma form. The smaller molecular weight of the oligomer gave r ise to the beta form. (C) 1997 Elsevier Science Ltd.