Ethyl cellulose blends

Krishna Rao KSV, Subha MCS, Vijaya Kumar Naidu B, Sairam M, Mallikarjuna NN, Aminabhavi TM (2006) Controlled release of diclofenac sodium and ibuprofen through beads of sodium alginate and hydroxy ethyl cellulose blends. J Appl Polym Sci 102 5708-5718... 

P. T. Liu, H. Miao, and Z. Liu, Miscibility and liquid crystallinity studies of chitosan/ethyl-cellulose blends. Appl. Mech. Mater. 79, 210-214 (2011). 

Before discussing theoretical approaches let us review some experimental results on the influence of flow on the phase behavior of polymer solutions and blends. Pioneering work on shear-induced phase changes in polymer solutions was carried out by Silberberg and Kuhn [108] on a polymer mixture of polystyrene (PS) and ethyl cellulose dissolved in benzene a system which displays UCST behavior. They observed shear-dependent depressions of the critical point of as much as 13 K under steady-state shear at rates up to 270 s Similar results on shear-induced homogenization were reported on a 50/50 blend solution of PS and poly(butadiene) (PB) with dioctyl phthalate (DOP) as a solvent under steady-state Couette flow [109, 110], A semi-dilute solution of the mixture containing 3 wt% of total polymer was prepared. The quiescent... 

Rowe, R.C. The prediction of compatibihty/incompatibility in blends of ethyl cellulose with hydroxypropyl methylcellulose or hydroxypropyl cellulose using 2-dimen-sional solubility parameter maps. J. Pharm. Pharmacol. 1986, 38, 214-215. 

Figure 14.16. Stability of various types of thickener over different pH ranges MC, methyl cellulose HEC, hydroxy ethyl cellulose CMC, carboxy methyl cellulose , includes blends with anionics...

Separation of hydrazine-water was carried out via PV through various blended membranes (ethyl cellulose (EC) and acrylonitrile-butadiene-styrene (ABS)) as well as pure EC and ABS polymeric membranes (Mandal et al. 2008). Results of PV showed that normalized flux decreases and selectivity increases with increasing ABS in the blended membrane. Through contact angle measurements, it was observed that increasing content of ABS increases the hydrophobic characteristic. 

Cellulosic membranes are developed as a novel dmg delivery system, which is expressed to use on the skin and used as a mucus membrane of stomach, ear, nose, eye, rectum, and vagina. The goal excipients of these preparations are adhesive and film-former polymers. Modified cellulose, especially cellulose ethers, are extensively applied in bio-adhesives such as nasal, vaginal, ocular, buccal, and transdermal inventions only or by blend with additional polymers. Further newly applied ethers of cellulose in bio-adhesives contain anionic ether derivatives such as sodium carboxy-methyl cellulose (NaCMC) and non-ionic cellulose ethers such as hydoxypropyl cellulose (HPC), carboxymethyl cellulose (CMC), hydroxyethyl cellulose, ethyl cellulose (EC), hydroxylpropylmethyl cellulose (HPMC), or methyl cellulose (MC). Capability of polymer to absorb water from mucus and pH of objective area are main features defining the adhesive power of polymers. One benefit of cellulose ethers, such as HPC and NaCMC, is smaller dependence of adhesion period and their adhesion strength to pH of medium than thiolated bio-adhesive polymers and polyacrylate... 

S.M. Maru, M. de Matas, A. Kelly, and A. Paradkar, Characterization of thermal and rheological properties of zidovudine, lamivudine and plasticizer blends with ethyl cellulose to assess their suitabihty for hot melt extrusion, Eur J Pharm Sci, 44 (4), 471-8,2011. 

The research indicates a good compatibihty in the ethylcellulose/cellulose acetate system, whereas the thermal stabihty of mixtiu-es is improved compared to that of pure ethyl cellulose [142], Thus, this blend met the best equilibrium conditions at the membrane-solution interface of membrane separation in liquid chromatography experiments. In this context, knowledge on the interaction force between solute and interface of the membrane is necessary. It is observed that the interfacial adsorption properties and hydrophilidty of ethylcellulose are improved when blending the solution with cellulose acetate, and also that the alloys are superior to ethylcellulose in the separation efficiency for non-dissociable polar organic solutes. The obtained results are useful especially for orientational membrane fabrication. 

S. L. Gao, N. G. Zhou, X. Z. Zhang, and W. Zhang, Interfacial properties of ethyl cellulose/ cellulose acetate blends by HPLC. Chin. J. Process Eng. 7,152-154 (2007). 

PVOH miscibility has been noted with poly(N, N-dimethyl acrylamide) [962] and partial miscibility noted with methyl cellulose [963]. With poly(N, N-dimethyl acrylamide), vinyl alcohol-vinyl acetate copolymers are miscible above 12 mole% vinyl alcohol. Fully hydrolyzed PVOH is not miscible with poly(2-ethyl oxazoline)(PEOx), but ethylene-vinyl alcohol copolymers (68 and 78 mole% vinyl alcohol) are miscible with PEOx [964]. Vinyl acetate-vinyl alcohol copolymers were shown to be miscible with PEOx over a wide range of copolymer compositions [965]. The immiscibility of fully hydrolyzed PVOH was attributed to the hydroxyl self-association dominating the competing hydroxyl-amide association. PVOH blends with sodium polystyrene sulfonate gave flexible, transparent films with good electrical conductivity [966]. Phase separation of PVOH/PEO [967] and PVOH/hydroxypropylmethyl cellulose blends [968] has been reported. PVOH/polyethyleneimine blends have been studied for membrane separations involving isomer separation [969]. PVOH/poly(ethyl oxazoline) blends have noted in a series of patent applications related to proton-conducting membranes [970]. 

---