Polyvinyl alcohol (PVA) was blended with starch (S) in presence of glacial acetic acid as crosslinking agent. The effect of blend ratio and molecular weight of PVA on the physical, thermal and mechanical properties of PVA/S blends were investigated using various techniques such as DSC, TGA, SEM, tensile strength, and solubility tests. Furthermore, biodegradability of the blend films was also studied. In addition, FTIR spectroscopy was used to check the hydrogen bonding interaction between PVA and S in the blends. The obtained results showed that the physico-mechanical properties are strongly dependent on the molecular weight and PVA content in PVA/S blends. DSC and SEM analyses of PVA/S blend showed a single glass transition temperature indicating the formation of completely miscible blends with a single phase due to the formation of hydrogen bonds between the hydroxyl groups of PVA and starch. In addition, PVA/S blend films exhibited good mechanical properties, thermal stability as compared with the pure PVA. More interestingly, the results showed enhancement in biodegradability of PVA/S blend films and particularly in moist soil, which can be exploited for manufacturing of biodegradable and environmentally friendly packaging materials at low cost.

Amphiphilic copolymers have been synthesised by free radical copolymerisation of 2‐hydroxyethyl acrylate with butyl acrylate, the reactivity ratios of which indicate practically equal reactivity. The copolymers containing less than 30 mol‐% of BA were soluble in water and exhibited a LCST in aqueous solutions. It was found that the interaction between these copolymers and poly(acrylic acid) in aqueous solutions resulted in the formation of interpolymer complexes stabilised by hydrogen bonds and hydrophobic interactions. This interaction was significantly affected by solution pH and led to modification of the temperature‐responsive behaviour of the copolymers.magnified image

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Amphiphilic random copolymers based on vinyl ether of ethylene glycol and vinyl butyl ether as well as their polycomplexes with poly(acrylic acid) were studied as polymeric reagents for the stabilization of water/n-hexane emulsions. The emulsion stability strongly depended on the content of vinyl butyl ether in the copolymers as well as their concentration in solution. The more hydrophobic copolymers stabilized emulsions more efficiently. An increase in the temperature and the addition of inorganic salts reduced the emulsion lifetime. The formation of interpolymer complexes between the copolymers and poly(acrylic acid) significantly influenced the stability of the emulsions.

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