Structural aspects of suspension poly(vinyl chloride). Small-angle neutron scattering of rigid and plasticized suspension PVC

• Published in: Macromolecules 1993-06, Vol.26 (12), p.3205-3211
• Main Authors: Scherrenberg, Rolf, Reynaers, Harry, Mortensen, Kell, Vlak, Wim, Gondard, Christian
• Format: Article
• Language: English
• Subjects: Applied sciences; Exact sciences and technology; Organic polymers; Physicochemistry of polymers; Properties and characterization; Structure, morphology and analysis
• ISSN: 0024-9297; 1520-5835
• DOI: 10.1021/ma00064a035

A comprehensive SANS study on both rigid and plasticized suspension PVC demonstrates the presence of superstructural order in this polymer. Comparison of the experimental scattering invariant data with a tentative two-phase model points to specific penetration of the plasticizer in the noncrystalline regions of PVC. Thermal experiments manifest the gradual and thermoreversible melting of the crystalline regions at temperatures > 80-90 deg C. Uniaxial deformation experiments on plasticized PVC confirm the existence of a heterogeneous network-structure in PVC where the crystalline tie-points act as physical cross-links. The observed anisotropic "butterfly" scattering pattern of a uniaxially stretched sample indicates the formation of concentration inhomogeneities as a consequence of the random distribution of the crystalline tie-points in plasticized PVC. The anistropy of the scattering pattern gradually disappears on heating, probably resulting from the increasing mobility of the plasticized interstitial medium.