Dynamic rheological behavior and microcrystalline structure of dioctyl phthalate plasticized poly(vinyl chloride)

• Published in: Journal of applied polymer science Vol. 121; no. 3; pp. 1725 - 1733
• Main Authors: Zou, Jiajia, Su, Lin, You, Feng, Chen, Guangshun, Guo, Shaoyun
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 05.08.2011; Wiley; Wiley Subscription Services, Inc
• Subjects: Applied sciences; Chlorides; Compounding ingredients; crystal structures; Crystallites; Differential scanning calorimetry; Dopants; Dynamical systems; Dynamics; Exact sciences and technology; Fireproof agents; gelation; Materials science; Physical properties; poly(vinyl chloride); Polymer industry, paints, wood; Polymers; Polyvinyl chlorides; Properties and testing; PVC; Rheological properties; rheology; Technology of polymers; Viscoelasticity; Melting; rheology; Gelation; Crystallinity; Experimental study; crystal structures; Phthalates; PVC plasticizer; Thermal properties; poly(vinyl chloride); Additive; Dynamic mechanical properties; Concentration effect; Mechanical loss; Polyvinyl chloride; PVC; Rheological properties
• ISSN: 0021-8995; 1097-4628; 1097-4628
• DOI: 10.1002/app.33765

The dynamic rheological behavior of poly(vinyl chloride) (PVC)/dioctyl phthalate (DOP) systems were studied as a function of DOP content and melting temperature. The dynamic rheological behavior of the PVC/DOP systems was found to be remarkably affected by the DOP content. The observed curves of storage modulus (G′) versus frequency were well fitted to an empirical equation (G′ = G′0 + Kωn, where G′0 is the low‐frequency yield value of the storage modulus, the exponent n is a dependent index of frequency, K is a constant coefficient, and ω is the angular frequency). The loss tangent and/or phase angle increased remarkably at a higher DOP content. There was an apparent critical DOP content transition where the dynamic rheological behavior of the PVC/DOP systems changed greatly. Scanning electron microscopy observations revealed the existence of a multiscale particle structure in the PVC/DOP systems. For the PVC/DOP (100/70) system, with increasing melting temperature, its dynamic rheological behavior showed an apparent mutation at about 190°C. Differential scanning calorimetry (DSC) analysis confirmed that the high elastic networks in the PVC/DOP systems were closely related to the microcrystalline structure of PVC. The transitions in the curves of the gelation degree and crystallinity versus the DOP content corresponded well to the DOP content transition in the dynamic rheological behavior. DOP could inhibit the secondary crystallite of PVC and almost had no effect on the primary crystallite of PVC. The coexistence of the microcrystalline structure of PVC and the plasticizer (DOP) resulted in high elastic networks in the PVC/DOP systems. The DSC results explained the DOP content transition and the temperature transition in the dynamic rheological behavior of the PVC/DOP systems well. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011