Rheological properties and microstructures of cellulose acetate phthalate/hydroxypropyl cellulose blends

Abstract

Cellulose acetate phthalate (CAP)/hydroxypropyl cellulose (HPC) blends were investigated by means of attenuated total reflection‐Fourier transform infrared spectroscopy, thermogravimetry/differential thermal analysis, shear viscosity, oscillatory shear tests, and atomic force microscopy (AFM). Effect of solution concentrations in 2‐methoxyethanol, blend compositions, and shear rate on the rheological functions reflects the mobility of the chain segments or their orientation—with thinning behavior in the shear field. Specific interactions, such as the hydrogen bonds between polymer components and 2‐methoxyethanol used in casting solutions of films, influence the resulting morphology. Supernodular aggregates with different intensities and dimensions, which involve the coexistence of an isotropic and an anisotropic phase, typical for lyotropic cellulosic derivative liquid crystals at low concentrations, are evidenced by AFM images. This study is useful for applications of CAP/HPC blends in pharmaceutical domains.POLYM. COMPOS., 33:2072–2083, 2012. © 2012 Society of Plastics Engineers

Biocidal activity of cellulose materials for medical implants

“…Interpretation of surface properties results must be performed starting from CAP 36 The occurrence of hydrogen bond structures in blends can be evidenced from peaks shape and intensity of the absorption band of the hydrogen stretching vibration. 23 The differences observed among the shape, broadening, and shifting of the mentioned peaks for polymer blends suggest the existence of hydrogen bonding, generated by AOH, C@O, and CAOAC groups. The free and associated groups provide the equilibrium in these polymer blends via hydrogen bonds; (b) Quantitative measurements of weight loss from TG/DTG plots show that CAP is less thermally stable than the HPC and CAP/HPC blends, as the anhydroglucose units increase the rigidity of the HPC chain.…”

“…A previous article, 23 has shown that the specific interactions in a blend, including hydrogen bonding, ion-ion pairing, and electron-donor and electron-acceptor complexation, etc., produce a favorable mixing enthalpy and hence may lead to miscibility among components. The presence of a solvent in the blend system introduces the polymers-solvent interactions as a function of polymers composition, concentration of polymers solution and temperature, and determines different conformations.…”

“…A number of requirements should be met for a proper use of polymer scaffolds, such as biodegradability with controllable degradation rate, structure, porosity, and surface properties; these requirements allow cells to be seeded for a successful differentiation and growth. [19][20][21][22] In our previous articles, [23][24][25] it has been shown that the solution properties of CAP and HPC are important for a better understanding and control of polymer blending processes, where miscibility is a result of the specific interactions between polymer segments in casting solutions of organic solvents. In addition, some properties related to the morphological and structuralrheological aspects of their mixtures at various compositions and concentrations have been analyzed.…”

On the Effects of UV Radiation on the Release Ability of Glucose Embedded in Hydroxypropyl Cellulose Films

“…This aspect may be explained if one considers the formation of hydrogen bonds between HPC and glucose, a phenomenon widely observed for sugars. [10,23] When both S1 and S2 are irradiated, the surface polarity of the samples increased with augmentation of the UV Table 3. The surface tension components and interfacial tension with water (in mN/m) of HPC/glucose films before and after UV exposure at different periods of time t UV (in minutes).…”

“…[9] The reasons for its widespread acceptance include (1) great solubility characteristics in gastrointestinal and other organic fluids, (2) non-interference with tablet disintegration and drug availability, (3) flexibility, chip resistance and absence of taste and odor, (4) stability in the presence of heat, light, air or reasonable levels of moisture, and (5) ability to incorporate color and other additives into the film or tablet without difficulty. The HPC good solubility in most polar organic solvents makes it possible to prepare stable aqueous and nonaqueous solutions [10] thus forming thermotropic as well as lyotropic liquid crystalline phases in many solvents [11] . HPC exhibits the appropriate attributes of an ideal polymer for film coating, as required in release oral delivery.…”