STRUCTURAL STUDY ON SYNDIOTACTIC POLYSTYRENE .2. CRYSTAL-STRUCTURE OFMOLECULAR-COMPOUND WITH TOLUENE

The crystal structure of the syndiotactic polystyrene-toluene molecula r compound was studied by X-ray diffraction. The crystal data are as f ollows: monoclinic system, space group P2(1)/a (no. 14), a = 17.58, b = 13.26, c(chain axis) = 7.71 angstrom, gamma = 121.2-degrees, eight m onomer units (two chains) and two toluene molecules per unit cell, the molar ratio of monomer: toluene being 4:1. The polymer chains take a twofold helical structure of (-TTGG-)2 conformation, and the packing o f the polymer chains enables each toluene molecule to occupy an isolat ed hole between the benzene rings of adjacent polymer chains. The mole cular compounds with benzene, chlorobenzene, p-xylene, 1,2,4-trichloro benzene and so on are isomorphous to the toluene molecular compound. T hese molecular compounds are commonly transformed on heating between 1 20 and 150-degrees-C to another crystalline phase free from the guests , in which the polymer chains retain the helical structure.