Polymers and polymeric composites have steadily reflected their importance in our daily life. Blending poly(vinyl alcohol) (PVA) with a potentially useful natural biopolymers such as hydroxypropyl cellulose (HPC) seems to be an interesting way of preparing a polymeric blends. In the present work, blends of PVA/HPC of compositions (100/0, 90/10, 75/25, 50/50, 25/75, and 0/100 wt/wt%) were prepared to be used as bioequivalent materials. Thermal analyses [differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA)], and X-ray diffraction (XRD) were employed to characterize and reveal the miscibility map and the structural properties of such blend system. The obtained results of the thermal analyses showed variations in the glass transition temperature (T_g) indicating the miscibility of the blend systems. Moreover, the changes in the melting temperature (Tm), shape and area were attributed to the different degrees of crystallinity and the existence of polymer-polymer interactions between PVA and HPC molecules. The X-ray diffraction (XRD) analysis showed broadening and sharpening of peaks at different HPC concentrations with PVA. This indicated changes in the crystallinity/amorphosity ratio, and also suggested that the miscibility between the amorphous components of homo-polymers PVA and HPC is possible. The results showed that HPC doped in PVA film can improve the thermal stability of the film under investigation, leading to interesting technological applications

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T HE PRESENT work focused on modifying the chitosan structure which has noticeable places in advanced research. The effect of UV-ozone irradiation with different exposure doses (9.68 x 10-14 , 19.35 x 10-14 , 29.03 x 10-14 and 38.75 x 10-14 J/m 2) on the microstructural, thermal stability and optical properties of chitosan was studied. X-ray diffraction (XRD), selected area electron diffraction (SAED), high-resolution transmission electron microscopy (HRTEM), optical parameters techniques as well as differential thermal analysis (DTA) and thermogravimetric analysis (TGA and DTG), were performed. The obtained results indicated that, effects on semi-crystalline structures have occurred. Detected variations in XRD, SAED, HRTEM, DTA and TGA analyses under investigation may be attributed to the different degrees of crystallinity, induction of structural changes and molecular configuration of chitosan upon exposure to UV-ozone. The results confirmed that the UV-ozone irradiation plays a role in refining the microstructure and changes occurring in chitosan matrix for future biomedical applications.

Many researches have been devoted for studying poly(vinyl alcohol) (PVA) and hydroxypropyl cellulose (HPC) and their blends as important promising biomaterials. In the present work, thin films of pure PVA, pure HPC and their PVA/HPC blends were prepared using the solution casting method. The mechanical properties of the prepared thin films such as stress-strain curve, tensile modulus and tensile strength as well as elongation at break were investigated. The obtained results show that there is an increase in the elastic range and decrease in the hardness of the resulting blends by increasing the concentration of HPC due to the different molecular morphology. In addition, the range in which it would responds elastically to external stress was decreased to some extent.