Freeform Polymer Precipitation in Microparticulate Gels

2021 ◽  
Vol 3 (2) ◽  
pp. 908-919
Author(s):  
Rahul Karyappa ◽  
Michinao Hashimoto
Keyword(s):  
Polymer Precipitation

scholarly journals Sustained Delivery of a Novel Natriuretic Peptide for Three Weeks With In Situ Polymer Precipitation Delivery System

2012 ◽  
Vol 18 (8) ◽  
pp. S63 ◽  
Author(s):  
Soo G. Lim ◽  
Syed Ameenuddin ◽  
John C. Burnett ◽  
Subbu S. Venkatraman ◽  
Horng H. Chen
Keyword(s):  
Natriuretic Peptide ◽  
Delivery System ◽  
Sustained Delivery ◽  
Polymer Precipitation

Carboxymethylchitosan/Calcium Phosphate Hybrid Materials Prepared by an Innovative Auto-Catalytic Co-Precipitation Method

2005 ◽  
Vol 284-286 ◽  
pp. 701-704 ◽  
Author(s):  
S.A. Costa ◽  
J. Miguel Oliveira ◽  
Isabel B. Leonor ◽  
Rui L. Reis
Keyword(s):  
Calcium Phosphate ◽  
Calcium Phosphates ◽  
Precipitation Method ◽  
Porous Scaffolds ◽  
X Ray Diffraction ◽  
Polymer Precipitation ◽  
Acid Bath ◽  
The Fourier Transform ◽  
Xrd Patterns ◽  
Co Precipitation

In this study, it is shown that it is possible to prepare carboxymethyl-chitosan/Ca-P hybrids using an innovative “auto-catalytic” co-precipitation method, namely by using an acid and an oxidant bath. The X-ray diffraction (XRD) patterns evidenced the formation of crystalline calcium-phosphate precipitates when using an acid bath, while amorphous ones were obtained for those produced in the oxidant bath. The Fourier Transform Infrared spectroscopy (FTIR) and Scanning Electron Microscopy (SEM/EDS) studies revealed that the extent of the polymer precipitation and formation of calcium-phosphates is directly dependent on the pH and composition of the baths. Furthermore, by conducting bioactivity tests in a simulated body fluid (SBF) followed by the SEM/EDS analysis it was possible to detect the formation of an apatite layer with a cauliflower-like morphology on the surface of hybrids prepared by the acid bath, after 7 days of immersion. These results are quite promising because they can allow for the production of bioactive and biodegradable 3D porous scaffolds to be used in bone tissue engineering applications.

scholarly journals Carboxymethylated pulp as starting point to prepare hydroxypropylmethyl cellulose with enhanced gel rheological properties in an aqueous medium

BioResources ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. 1453-1468
Author(s):  
Othman Hamed ◽  
Rana Al-Kerm ◽  
Rola Al-Kerm ◽  
Hisham Qrareya ◽  
Abdalhadi Deghles ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Rheological Properties ◽  
Repeat Unit ◽  
Hydroxypropyl Methylcellulose ◽  
Polymer Chains ◽  
Significant Drop ◽  
Hydroxypropylmethyl Cellulose ◽  
Thermal Gelation ◽  
Polymer Precipitation ◽  
Starting Point

Hydroxypropyl methylcellulose in an aqueous solution upon heating tends to undergo thermal gelation, where the polymer chains form a network and precipitate from solution. This occurs at a temperature known as thermal gelation point. Polymer precipitation causes a significant drop in the shear viscosity. This could be a disadvantage in a hot environment or in applications were heat is applied. In this work, a hydroxypropylmethyl cellulose (HPMC) was formed that undergoes thermal gelation with no polymer precipitation and with enhanced rheological properties. The target HPMC was prepared from wood pulp with a low content of carboxymethyl groups. The produced hydroxypropyl methylcellulose (CMHPMC) derivative showed unique physical properties that are not achievable with typical hydroxypropyl methylcellulose. The thermal gelation temperature of an aqueous solution of CMHPMC was increased from 55 °C for commercial HPMC to 85 °C for CMHPMC. A substitution level of carboxymethylation that led to an HPMC with a thermal gelation and with no precipitation was determined to be a 0.15 of carboxyl groups per anhydroglucose repeat unit. In addition, the carboxymethylated pulp showed an enhanced reactivity towards etherification reactions.

Effect of organic solvents on polycondensation in solution accompanied by polymer precipitation

1970 ◽  
Vol 12 (10) ◽  
pp. 2689-2696
Author(s):  
A.N. Zav'yalov ◽  
T.A. Sorokina ◽  
T.B. Shabanova
Keyword(s):  
Organic Solvents ◽  
Polymer Precipitation

Polymer Precipitation Using a Micellar Nonsolvent:  The Role of Surfactant−Polymer Interactions and the Development of a Microencapsulation Technique

1996 ◽  
Vol 35 (9) ◽  
pp. 3100-3107 ◽  
Author(s):  
Sukanta Banerjee ◽  
Ramannair Premchandran ◽  
Murthy Tata ◽  
Vijay T. John ◽  
Gary L. McPherson ◽  
...  
Keyword(s):  
Polymer Precipitation ◽  
Polymer Interactions

Effect of polymer precipitation on chemical reactions—I. Changes of antioxidant efficiency in the polyethylene melt

1997 ◽  
Vol 33 (10-12) ◽  
pp. 1665-1669 ◽  
Author(s):  
Paolo Bruni ◽  
Carla Conti ◽  
Alexander Mar'in ◽  
Yury A. Shlyapnikov ◽  
Giorgio Tosi
Keyword(s):  
Chemical Reactions ◽  
Antioxidant Efficiency ◽  
Polymer Precipitation ◽  
Polyethylene Melt

Ibuprofen–polymer precipitation using supercritical CO2 at low temperature

2014 ◽  
Vol 94 ◽  
pp. 91-101 ◽  
Author(s):  
A. Montes ◽  
M.D. Gordillo ◽  
C. Pereyra ◽  
D.M. De los Santos ◽  
E.J. Martínez de la Ossa
Keyword(s):  
Low Temperature ◽  
Supercritical Co2 ◽  
Polymer Precipitation
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