Crystal Structure of Form I of Syndiotactic Poly(p ara-methylstyrene)

• Published in: Macromolecules Vol. 39; no. 15; pp. 5037 - 5042
• Main Authors: Esposito, Giuseppe, Tarallo, Oreste, Petraccone, Vittorio
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 25.07.2006
• Subjects: Applied sciences; Exact sciences and technology; Organic polymers; Physicochemistry of polymers; Properties and characterization; Structure, morphology and analysis; Structural model; Styrene(methyl) polymer; Experimental study; Lattice parameters; Syndiotactic polymer; Crystalline structure
• DOI: 10.1021/ma060940p
• ISSN: 0024-9297

The crystalline structure of form I of syndiotactic poly(para-methylstyrene) is described. In this form, the polymer chains assume a s(2/1)2 helical conformation and are packed according to the space group P21/a in a unit cell with a = 24.5 Å, b = 12.4 Å, c = 8.1 Å, and γ = 143.5°. The proposed model may be described by a stacking of layers of alternating right- and left-handed helical chains efficiently packed in an “interdigital structure” in which phenyl rings belonging to one chain interlock with the phenyl rings of the two adjacent chains of opposite chirality. A disorder in the correct succession of the layers is suggested. A possible similarity between this form and the nanoporous δ form of syndiotactic polystyrene, suggested by the fact they are both obtainable by guest removal from α class clathrates, is analyzed.