A simple solvent selection method for accelerated solvent extraction of additives from polymers

Abstract

A simple solvent selection procedure for accelerated solvent extraction (ASE ® ) of polymers is described using Hildebrand solubility parameters. A series of extractions with a solvent with a solubility parameter several Hildebrand units (MPa 1/2 ) different from the polymer are carried out at increasing temperatures until maximum extraction is reached. A second solvent with a solubility parameter close to that of the polymer is then added incrementally at the optimum temperature found from the initial experiments, until a maximum in the extraction rate is reached. This method is used to determine optimum conditions for ASE ® of additives from ground polypropylene (PP), poly(vinyl chloride) (PVC) and nylon. Complete extractions were possible of Irganox 1010 (pentaerythrityl tetrakis (3,5-di-tert-butyl-4-hydroxyphenyl) propionate) from freeze ground PP in 18 min (propan-2-ol-cyclohexane (97.5+2.5) at 140 °C), and dioctyl phthalate (DOP) from PVC in 13 min (hexane-ethyl acetate (60+40) at 170 °C). ASE ® extraction from PVC pellets was possible in reasonable time (1 h) without grinding or cutting the polymer. The results were not significantly different from those obtained by conventional solvent extraction methods. From nylon, 96% extraction of the dimer in 19 min (hexane-ethanol (60+40) at 170 °C) was possible, compared to the total amount extracted by exhaustive ASE ® . The behaviour of poly(ethylene terephthalate) (PET) and poly(methyl methacrylate) (PMMA) was observed with different solvents at high temperature to determine likely optimum extraction conditions. These were ethyl acetate at 190 °C for PET and hexane-ethyl acetate (70+30) at 150 °C for PMMA.

Effect of additives on the morphology and properties of poly(vinylidene fluoride) blend hollow fiber membrane prepared by the thermally induced phase separation method

“…Furthermore, the crystallization temperature decreased to a much greater extent with the addition of PVP in solution than with addition of PMMA. The solubility parameters of PVDF, PVP and PMMA are 19.2 [29], 21.2 [30] and 19.0 MPa 0.5 [31], respectively. In general, when the solubility parameters of two chemicals are similar, two chemicals have good compatibility.…”

Determination of antioxidants in polyolefins by pressurized liquid extraction prior to high performance liquid chromatography

“…Although these methods imply rather simple and inexpensive equipment, they are time and solvent consuming [9]. More recent methodologies involve microwave assisted extraction (MAE) [10,11,12], supercritical fluid extraction (SFE) [13,14] and pressurized liquid extraction (PLE) [15,16,17] which, in turn, offer the possibility to extract at high pressure and temperature, resulting in a considerably lower extraction time and less solvent usage [7,9]. In a second step, the extracted additives are quantified by high performance liquid chromatography (HPLC) in both reversed [18] and normal phase [19].…”

Removal of polyaromatic hydrocarbons from scrap tires by solvent extraction

“…The effectiveness of a solvent is mainly dictated by its polarity and solubility parameters [10]. The current trend is to replace toxic organic solvents with benign solvents in processes ranging from analytical extractions to chemical synthesis and environmental remediation at ambient conditions.…”

“…As a consequence of improvements in quantitation methods, deeper attention is being focused on extraction methods [9]. The literature contains examples of extraction techniques for removing PAHs from environmental solids such as supercritical fluid extraction (SFE), soxhlet extraction, and microwave-assisted extraction (MAE) [7][8][9][10]. A relatively new technique is pressurized fluid extraction (PFE; 2000 psi, >100 o C and pressurized hot water extraction (PHWE; >250 o C) using conventional solvents at high pressure and temperature [9,11].…”