Degradation of polymer blends: A brief review

Dispersions of nanosilica in biocompatible copolymers

Blown low density polyethylene (LDPE) films added with oxo-biodegradable additive containing pro-oxidant were subjected to thermo-oxidation in an oven at 70 °C for varying time periods The changes in mechanical and surface properties were studied using tensile strength, elongation at break, wettability, surface morphology using SEM, surface topology by AFM, functional groups by FTIR spectroscopy, absorbance spectra by UV-Vis spectroscopy The thermally aged films with pro-oxidant additive added polyethylene (PE) exhibited a higher level of oxidation as revealed by increase in their carbonyl index than the pristine PE In addition to it, the DSC melting behavior showed a slight increase in crystallinity (%C) and melting temperature (Tm) of the polymer containing oxo-biodegradable additive The SEM micrograph reveals the increase in the size of cracks and grooves, according to the increase in the concentration of pro-oxidant additive The surface roughness also supports the same through AFM image The increase in the wettability and surface free energy of the thermally aged samples were attributed to the formation of hydrophilic groups on the polymer surface by thermo-oxidation The pro-oxidant additive offers a new insight into the thermo-oxidation strategy for PE and can be widely used in packaging industry

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Influence of thermal oxidation on surface and thermo-mechanical properties of polyethylene

Preparation and characterisation of poly (amide-imide) incorporated cellulose acetate membranes for polymer enhanced ultrafiltration of metal ions

In this article, we discuss the phase morphology, thermal, mechanical, and crystallization properties of uncompatibilized and compatibilized polypropylene/polystyrene (PP/PS) blends. It is observed that the Young's modulus increases, but other mechanical properties such as tensile strength, flexural strength, elongation at break, and impact strength decrease by blending PS to PP. The tensile strength and Young's modulus of PP/PS blends were compared with various theoretical models. The thermal stability, melting, and crystallization temperatures and percentage crystallinity of semicrystalline PP in the blends were marginally decreased by the addition of amorphous PS. The presence of maleic anhydride-grafted polypropylene (compatibilizer) increases the phase stability of 90/10 and 80/20 blends by preventing the coalescence. Hence, finer and more uniform droplets of PS dispersed phases are observed. The compatibilizer induced some improvement in impact strength for the blends with PP matrix phase, however fluctuations in modulus, strength and ductility were observed with respect to the uncompatibilized blend. The thermal stability was not much affected by the addition of the compatibilizer for the PP rich blends but shows some decrease in the thermal stability of the blends, where PS forms the matrix. On the other hand, the % crystallinity was increased by the addition of compatibilizer, irrespective of the blend concentration. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42100.

Phase morphology, thermomechanical, and crystallization behavior of uncompatibilized and PP-g-MAH compatibilized polypropylene/polystyrene blends

Thermal degradation and crystallisation studies of reactively compatibilised polymer blends

The mechanical and dynamic mechanical properties of isotactic polypropylene/high density polyethylene (PP/HDPE) blends, as a function of blend ratio and compatibiliser concentration were analysed. Ethylene propylene random copolymers (EPDM) with three different monomer fractions were used as compatibilisers. Compatibilisation improved the mechanical properties (except Young’s modulus) of the blends, considerably. The compatibiliser with 1:1 monomer fraction was found to be most efficient. A detailed discussion on the fundamental reasons responsible for the deterioration of properties in the absence of compatibilisers and the improvement of properties in the presence of compatibilisers was presented. The tensile strength of the uncompatibilised blends was theoretically modelled using Nielsen’s and Nicolais-Narkis models. The Young’s and storage moduli of uncompatibilised blends were compared with those predicted by various theoretical models. Attention was paid to correlate the mechanical properties of both compatibilised and uncompatibilised blends with their phase morphology.

Mechanical and dynamic mechanical properties of polyolefin blends: effect of blend ratio and copolymer monomer fraction on the compatibilisation efficiency of random copolymers

P. K. Biju

Papers

Thermal degradation and crystallisation studies of reactively compatibilised polymer blends

Mechanical and dynamic mechanical properties of polyolefin blends: effect of blend ratio and copolymer monomer fraction on the compatibilisation efficiency of random copolymers