Non-solvent additive

Chen, H Wu, J.-C. and Chen, H.-Y. (1995) Preparation of ethylcellulose microcapsules containing theophylline by using emulsion non-solvent addition method. Journal of Microencapsulation, 12, 137-147. 

For simple coacervation induced by non-solvent addition in aqueous systems, ethanol, acetone, dioxane, isopropanol, and propanol are the most preferred to cause polymer desolvation and phase separation. In organic systems, mainly non-polar solvents. 

Chen, H. Wu, J.C. Chen, H.Y. Preparation of ethyl cellulose microcapsules containing teophylline by using emulsion non-solvent addition method. J. Microencapsulation 1995, 12 (2), 137-147. 

Hollow fiber UF membranes have been prepared from PPESK with a dry/ wet phase inversion technique. Ethylene glycol mono methyl ether, diethylene glycol, and methyl ethyl ketone were used as non-solvent additives and NMP was used as a solvent in membrane preparation. ... 

In general, the fabrication of encapsulation systems via bottom-up approaches is based on the dissolution of the bioactive compound in a suitable organic solvent, followed by its precipitation through a non-solvent addition in the presence of stabilizers, such as surfactants or hydrocol-loids." Eventually, a polymer soluble in the internal solvent but insoluble in the external one may be added to the system." ... 

Jelvehgari M, Atapour F, Nokhodchi A. Micromeritics and release behaviours of cellulose acetate butyrate microspheres containing theophylline prepared by emulsion solvent evaporation and emulsion non-solvent addition method. Archives ofPharmacal Research. July 2009 32(7) 1019-1028. PubMed PMID 19641883. 

ARO Aroon, M.A., Ismail, A.F., Monlazer-Rahmati, M.M., andMatsuura, T., Morphology and permeation properties of polysulfone membranes for gas separation Effects of non-solvent additives and co-solvent. Separation Purification Technol., 72, 194, 2010. 

Miscellaneous Fractionation Methods.—Turbidimetric titration by non-solvent addition has virtually vanished since the advent of GPC, but Hay et have recently shown that the method of turbidimetric titration by temperature decrease can give useful information about the polydispersity of polymers. Nonsolvent induced turbidimetry of fractions eluted from a GPC column has been used by Hoffmann and Urban to examine composition distribution in copolymers. 

R. Naim, A.F. Ismail, and A. Mansourizadeh. (2012). Effect of non-solvent additives on the structure and performance of PVDF hollow fiber membrane contactor for COj stripping, J. Memb. Sci. 423-424 503-513. 

M. Khayet, C.Y. Feng, K.C. Khulbe, and T. Matsuura. (2002). Study on the effect of a non-solvent additive on the morphology and performance of ultrafiltration hollow-fiber membranes, Desalination 148 321-327. 

One of the key components in the enhancement of the performance of a gas separation membrane is the addition of a non-solvent additive. It improves the overall morphology and performance of the membrane. Previous studies have shown that an interaction develops between the nonsolvent additive and polymer resulting in the swelling of the polymer or the formation of supermolecular aggregates. ... 

Dissolution/reprecipitation processes were evaluated for the recycling of poly-epsilon-caprolactam (PA6) and polyhexamethyleneadipamide (PA66). The process involved solution of the polyamide in an appropriate solvent, precipitation by the addition of a non-solvent, and recovery of the polymer by washing and drying. Dimethylsulphoxide was used as the solvent for PA6, and formic acid for PA66, and methylethylketone was used as the non-solvent for both polymers. The recycled polymers were evaluated by determination of molecular weight, crystallinity and grain size. Excellent recoveries were achieved, with no deterioration in the polymer properties. 33 refs. 

The Vinyloop process is based on the selective dissolution of PVC used in composites applications like cable insulation, flooring, tarpaulins, blisters, etc. After removal of insoluble parts like metals, rubber or other polymers, the PVC is reprecipitated with all additives by introduction of a non-solvent component whieh will form with the seleetive solvent an azeotropie mixture. By using typical conditions, the process is able to reeover a pure PVC eompound powder ready for use without any additional treatment like melt filtration or a new pelletisation (speeific characteristics of the powder are average diameter of 400 microns and bulk density above 600 kg/ eub.m). All the solvents used are eompletely reeyeled and reused. PVC compounds recovered in the Vinyloop process can be reused in a closed-loop recycling scheme... 

These thermolysis reactions normally produce polymeric products, free of the cyclic analogs, in essentially quantitative yield and in sufficient purity to give satisfactory elemental analysis upon removal of the sHyl ether byproduct under vacuum. Final purification is generally achieved by precipitation of the polymer into a non-solvent such as hexane. With the exception of poly(diethylphosphazene) (2), which is insoluble in all common solvents (see below), the new polymers are readily soluble in CH CU and CHCU. In addition, the phenyl substituted compounds (3-6) are soluble in THF andvanous aromatic solvents. None of the polymers are water-soluble however, Me2PN]n (1) is soluble in a 50 50 water/THF mixture. 

Following solubilization of the PHA from the defatted plant material, recovery of PHA from the solvent can be accomplished in various ways (Fig. 5) [74-78]. Addition of a PHA non-solvent to the solution would lead to PHA precipitation. If a solvent was used which dissolves PHA only under high temperature and pressure, cooling the solvent may be used to recover the polymer. Alternatively, evaporation of the solvent could also lead to polymer precipitation. Each of these methods have their disadvantages. Precipitation of PHA... 

Dissolve SPDP in dimethylformamide (DMF) at a concentration of 6.2 mg/ml (makes a 20 mM stock solution). Add 50 pi of the SPDP solution to the 1 ml particle suspension and mix to dissolve. Note The small quantity of DMF in a polymeric particle suspension should not affect particle stability, even if the polymer type is susceptible to swelling in pure DMF. Other particle types, such as metallic or silica based, usually are not affected by organic solvent addition, unless their surfaces are non-covalently coated with a dissolvable polymer. 

Besides temperature and addition of non-solvent, pressure can also be expected to affect the solvency of the dispersion medium for the solvated steric stabilizer. A previous analysis (3) of the effect of an applied pressure indicated that the UCFT should increase as the applied pressure increases, while the LCFT should be relatively insensitive to applied pressure. The purpose of this communication is to examine the UCFT of a nonaqueous dispersion as a function of applied pressure. For dispersions of polymer particles stabilized by polyisobutylene (PIB) and dispersed in 2-methylbutane, it was observed that the UCFT moves to higher temperatures with increasing applied pressure. These results can qualitatively be rationalized by considering the effect of pressure on the free volume dissimilarity contribution to the free energy of close approach of the interacting particles. 

The Lewis basicity of the solvents was found to be more important for the solvatochromism than the solvent polarity, since such Si... solvent and Si... F interactions are competitive in the presence of solvents with donor atoms. In contrast, the analogous non-fluorinated polysilane, poly(methyl-/z-propylsilylene), revealed a disordered conformation in both coordinating and non-coordinating solvents. Additionally, the UV spectra of various molecular weight fractions of 87 showed an unusual molecular weight dependency an isosbestic point is apparent, suggesting an equilibrium between globule- and rod-like conformations at room temperature, which was also evident from the... 

Copolymerization reactions Copolymerization experiments with styrene and MMA employed molar fractions of 20, 40, 60, and 80% comonomers, which were reacted in ethanol 1,2-dichIorethane 60 40 (by volume) mixtures and benzoyl peroxide as catalyst. Polymerizations were carried out at 70°C. The reactions were quenched by the addition of methanol as non-solvent, and the copolymer was isolated by centrifugation. Copolymer analysis employed UV spectroscopy for copolymers with MMA, and methoxyl content determination according to a procedure by Hodges et al. (16) in the case of styrene copolymers. Reactivity ratios were determined in accordance with the method by Kelen-Tiidos (17) and that by Yezrielev-Brokhina-Roskin (YBR) (18). Experimental details and results are presented elsewhere (15). 

Reactivity ratios between acrylated lignin model compound (Fig. 2), defined as Mi, with either MM A or S, defined as M2, were determined experimentally in accordance with standard procedures (15). These involve mixing two different vinyl monomers in various molar ratios with catalyst (i.e., benzoyl peroxide) and solvent, heating the mixture to achieve polymerization, and recovering the polymer by the addition of non-solvent, and centrifugation. The respective molar monomer fractions of the copolymer were determined by UV-spectroscopy in the cases where MMA served as M2, and by methoxyl content analysis in those cases in which S was the M2-species. The results were subjected to numerical treatments according to the established relationships of Kelen-Tiidos (17) and Yezrielev-Brokhina-Roskin (YBR) (18), and this is described elsewhere (15). 

Anhydrous theophylline (100 mesh) was incorporated into a homogenous 5% w/w solution of the corresponding Eudragit in its solvent (Table 1) containing 2-7% w/w of polyisobutadiene. The phase separation and subsequent deposition of the polymer was effected by desolvating the polymer (Table 1) under stirred conditions. Hardening of the microcapsules was effected by dropwise addition of the chilled non-solvent. After the formation of embryonic microcapsules, they were separated, washed with chilled non-solvent and air dried at ambient temperature. 

One method is to run the reaction in an aqueous buffer/organic solvent biphasic system. This makes it possible to work at high substrate and product concentrations and at the pH-optimum of the enzyme. In addition, in water-immiscible solvents the non-enzymahc addition of HCN to the carbonyl group is non-existent or extremely slow. Possible disadvantages are enzyme deactivation at the interface and the presence of organic solvent dissolved in the aqueous phase [15, 17, 18]. 

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