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Thermodynamic interactions and the properties of PVC–plasticizer systems
Author(s) -
Su C. S.,
Patterson D.,
Schreiber H. P.
Publication year - 1976
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1976.070200414
Subject(s) - plasticizer , chemistry , phthalate , thermodynamics , vinyl chloride , flory–huggins solution theory , volume fraction , polymer , organic chemistry , physics , copolymer
Gas–liquid chromatography (GLC) has been applied to the study of thermodynamic interactions in poly(vinyl chloride) (PVC) plasticized by di‐ n ‐octyl phthalate (D n OP). A number of vapor‐phase “probes” were used to evaluate the Flory‐Huggins thermodynamic parameter for the PVC–D n OP interaction in stationary phase mixtures of the components which covered the entire composition range. Experiments were carried out in the temperature span of 100–130°C. The interaction parameter was strongly negative, indicating high PVC–D n OP compatibility, up to 0.25 volume fraction of plasticizer. It then became less negative and finally positive at 0.55 volume fraction of D n OP, suggesting a lower compatibility limit. The composition dependence of the interaction parameter and its apparent variation with the chemical nature of the vapor‐phase probe may reflect a nonrandom solution of the probe in the stationary phase and/or non‐random mixing of PVC–D n OP, particularly at D n OP contents in the limited compatibility range. Evaluations of the influence of D n OP on zero‐shear melt viscosity and T g of compounds indicate that both thermodynamic interactions and volume‐of‐dilution effects must be taken into account in assessing the effectiveness of the plasticizer.