The thermal characterization of polypropylene (PP) composites containing untreated and treated zeolite with different silane
coupling agents was carried out using thermogravimetric analysis (TG) and differential scanning calorimetry (DSC) to investigate
the effects of natural zeolite and surface modifiers on melting, crystallization and degradation behaviour of PP. 3-aminopropyltriethoxysilane
(AMPTES), methyltriethoxysilane (MTES) and 3-mercaptopropyltrimethoxysilane (MPTMS) were used as surface modifiers at four
different concentrations (0.5–2.0 mass%). Thermal analyses indicated that silane treatment and 2–6 mass% zeolite addition
have no significant effect on the melting and degradation temperatures of the composites. The crystallization temperatures
of the composites were increased due to the nucleating effect of the zeolite. The influence of the modifiers on the interactions
between PP and zeolite was determined by the activities of untreated and treated zeolite. The maximum interactions leading
to good adhesion were observed in the AMPTES treated composites. Also, non-isothermal crystallization kinetics of the composites
was analyzed using Avrami and Kissinger models.
Authors:İsa Doğan Atik, B. Özen, and F. Tıhmınlıoğlu
The novel film structure of corn-zein coated on polypropylene (PP) synthetic film for packaging industry was developed to
examine the feasibility of resulting coated films as an alternative water barrier performance for food packaging. The effects
of coating formulation (solvent, corn-zein, plasticizer concentration and plasticizer type) on final properties of films were
observed. Corn-zein is the most important protein of corn and has good film forming property. Composites structures of PP
films coated with corn-zein were obtained through a simple solvent casting method. Polyethylene glycol (PEG) and glycerol
(GLY) were used as plasticizer to increase film flexibility. Statistical analysis based on full factorial design was performed
to observe coating formulation effects. The high water vapour barriers were obtained for films coated with coating formulation
consisting of higher amounts of corn-zein plasticized by GLY. The lower glass transition temperatures (Tg) of films were obtained by plasticization of films and Tg decreased by increasing plasticizer content. The statistical analysis defined the key parameters of coating formulation that
had major effects on the final properties of coated PP films as corn-zein, plasticizer concentration and plasticizer type.
In conclusion, corn-zein coatings could have potential as an alternative to conventional synthetic polymers used in composite
multilayer structures for food packaging applications.
Authors:D. Berkün, D. Balköse, F. Tıhmınlıoǧlu, and S. Altınkaya
Two types of films consisting of sodium salt of carboxymethyl cellulose (NaCMC) and hydroxypropyl cellulose (HPC) as film
forming materials and glycerin as plasticizer were prepared, characterized and their water vapour sorption properties were
The water sorption isotherms of the films were measured using a magnetic suspension balance. Results show that diffusion of
water vapour in NaCMC based film is faster than that in HPC based films, due to the heterogeneous structure and larger pore
dimensions of the NaCMC films.