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Polymer Solubility (polymer + solubility)
Selected AbstractsUse of Hoy's solubility parameters to predict water sorption/solubility of experimental primers and adhesivesEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 1 2007Yoshihiro Nishitani Self-etching primers and adhesives contain very hydrophilic acidic monomers that result in high water sorption/solubilities of their polymers. However, the chemical composition of these products varies widely. The purpose of this work was to vary the chemical composition of experimental self-etching primers and adhesives to determine if the water sorption/solubility of the polymers were affected in a predictable manner. The Hoy's solubility parameters of these mixtures were calculated to permit ranking of the degree of hydrophilicity of the polymers. Water sorption/solubility was measured according to ISO 4049. The results showed highly significant (R2 = 0.86, P < 0.001) correlations between water sorption and Hoy's solubility parameter for polar forces (,p) of the polymers. Similar correlations were obtained between polymer solubility and ,p. When these results were compared with previously published results obtained with more hydrophobic resins, excellent correlations were obtained, indicating that Hoy's ,p values may be used to predict the water sorption behavior of methylmethacrylate polymers. [source] Synthesis and characterization of copolymers of alkyl- and azo-thiophenes: Chromic properties and photoinduced birefringenceJOURNAL OF APPLIED POLYMER SCIENCE, Issue 2 2009Vanessa C. Gonçalves Abstract Polyazothiophene is a type of polythiophene derivative that combines the electrical and luminescent properties of polythiophenes with the photoisomerization property of azopolymers. Extensive efforts have been made to improve the properties of polyazothiophenes, such as solubility, optical, and chromic properties. We report the preparation of copolymers of an alkylthiophene (3-octylthiophene, 3-OT) and an azothiophene (2-[N -ethyl- N -[4-[(4-(4-nitrophenyl)azo]phenyl]amino]ethyl 3-thienylacetate, 3-AzoT) in different ratios as an alternative route to improve these properties. The azosubstituted monomer contents in these copolymers were 6, 9, 12, and 51% (in mol), as evaluated by elemental analysis. Their chemical structures were confirmed by FTIR and 1H-NMR. HPSEC and thermal analysis were used to characterize the polymers. The presence of thermochromic and solvatochromic properties was demonstrated by UV-Vis spectroscopy. Optically induced birefringence was detected only in polymers with 12 and 51 mol % of azo-units. The introduction of different ratios of the azothiophene in the copolymer alters the polymer solubility and emissive properties. The results indicate that the polyazothiophene copolymers presented are promising active layers for optical devices and sensors. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source] Drug,polymer solubility and miscibility: Stability consideration and practical challenges in amorphous solid dispersion developmentJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 7 2010Feng Qian Abstract Drug,polymer solid dispersion has been demonstrated as a feasible approach to formulate poorly water-soluble drugs in the amorphous form, for the enhancement of dissolution rate and bioperformance. The solubility (for crystalline drug) and miscibility (for amorphous drug) in the polymer are directly related to the stabilization of amorphous drug against crystallization. Therefore, it is important for pharmaceutical scientists to rationally assess solubility and miscibility in order to select the optimal formulation (e.g., polymer type, drug loading, etc.) and recommend storage conditions, with respect to maximizing the physical stability. This commentary attempts to discuss the concepts and implications of the drug,polymer solubility and miscibility on the stabilization of solid dispersions, review recent literatures, and propose some practical strategies for the evaluation and development of such systems utilizing a working diagram. © 2010 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99:2941,2947, 2010 [source] Solid-state solubility influences encapsulation and release of hydrophobic drugs from PLGA/PLA nanoparticlesJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 7 2004Jayanth Panyam Abstract Biodegradable nanoparticles formulated from poly(D,L -lactide- co -glycolide) (PLGA) and polylactide (PLA) polymers are being extensively investigated for various drug delivery applications. In this study, we hypothesize that the solid-state solubility of hydrophobic drugs in polymers could influence their encapsulation and release from nanoparticles. Dexamethasone and flutamide were used as model hydrophobic drugs. A simple, semiquantitative method based on drug,polymer phase separation was developed to determine the solid-state drug,polymer solubility. Nanoparticles using PLGA/PLA polymers were formulated using an emulsion,solvent evaporation technique, and were characterized for size, drug loading, and in vitro release. X-ray powder diffraction (XRD) and differential scanning calorimetry (DSC) were used to determine the physical state of the encapsulated drug. Results demonstrated that the solid-state drug,polymer solubility depends on the polymer composition, molecular weight, and end-functional groups (ester or carboxyl) in polymer chains. Higher solid-state drug,polymer solubility resulted in higher drug encapsulation in nanoparticles, but followed an inverse correlation with the percent cumulative drug released. The XRD and DSC analyses demonstrated that the drug encapsulated in nanoparticles was present in the form of a molecular dispersion (dissolved state) in the polymer, whereas in microparticles, the drug was present in both molecular dispersion and crystalline forms. In conclusion, the solid-state drug,polymer solubility affects the nanoparticle characteristics, and thus could be used as an important preformulation parameter. © 2004 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 93:1804,1814, 2004 [source] Synthesis and Characterization of N -Propargyl Cinnamamide Polymers and CopolymersMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 3 2007Jianping Deng Abstract This paper deals with synthesis and characterization of a novel poly(N -propargylamide) containing cinnamamide groups (poly(1)) in its side chains. Monomer 1, CHCCH2NHCOCHCH(C6H5), was synthesized and polymerized with a rhodium catalyst, (nbd)Rh+B,(C6H5)4 (nbd,=,2,5-norbornadiene). Effects of some factors on polymerization of monomer 1 such as solvent, temperature, and the ratio of monomer/catalyst were investigated in detail; polymers with moderate number-average molecular weights () and low index of polydispersity () were obtained. To improve the polymers' solubility and to elucidate whether poly(1) could form helical conformation, another N -propargylamide monomer 2, CHCCH2NHCOCH(CH2CH3)2, was employed to accomplish copolymerization with monomer 1. Copolymerization with monomer 2 improved obviously the solubility of the (co)polymers; the copolymers with certain monomer ratios could form helices under the examined conditions according to the related UV-vis spectra. [source] | ||||||||||