Thermoplastic starch (TPS) materials present several advantages to the plastic industry andwhen blended with other materials they can exhibit improved mechanical and moisturesensitivity properties compared to pure TPS materials. Further investigations on TPS: PVAblends are of particular interest due to their excellent compatibility and improved properties suchas tensile strength, elongation, toughness and processability, predominantly due to animprovement in melt strength compared to pure TPS material. The aims of the study were toinvestigate the effect of varying polyvinyl alcohol content within the TPS blends on the rate andextent of starch enzymatic hydrolysis using enzyme alpha-amylase. Analyses the enzymaticdegradation behavior of poly(vinyl alcohol) with starch was based on the determinations ofWeight loss and the reducing sugars. The degraded residues have been examined by FT-IRspectroscopy and scanning electronic microscopy (SEM). پرونده مقاله

The thermal decomposition of 86 % vinyl chloride 14 % vinyl acetate copolymer wasstudied by the conductometry technique in the presence of nitrogen. The kinetics of stability andthermal degradation of vinyl chloride- co- vinyl acetate (PVC- co- PVAc) copolymer withcopper, copper oxide and tricalcium dicitrate (st) were investigated at various temperatures (150-180 oC ) in solution. The rate coefficients for the degradation of the copolymer were determined.The energies of activation, determined from the temperature dependence of the rate coefficientsfor copolymer alone was 63.536 kJ mol-1 and in the presence of copper, copper oxide andtricalcium dicitrate were 44.224, 55.594 and 110.332 KJ mol-1, respectively. The results showthat thermal stability was increased in the presence of tricalcium dicitrate, but its thermalstability was decreased in the presence of copper and copper oxide. پرونده مقاله

Kinetic study of epoxidation of unsaturated ketone of mesityl oxide was studied by usingHydrogen peroxide in the presence of dodecyltrimethyl ammonium bromide (DTAB) as aninverse phase transfer catalyst. The reaction was carried out in the two-phase media of waterheptanewith 1:1 ratio in 25 °C. It was found that the order of reaction for mesityl oxide forketone concentration in the range of 0.03- 0.1 mol L-1 are 0.8906. And also with regard tocatalyst concentrations in the range of 0.07- 0.2 mol L-1, the order of reaction for catalyst is0.1205. The order of reaction of Hydrogen peroxide in the range o of 1.5-4 mol L-1 concentrationfor mesityl oxide is –0.1411. The activation energy of the reaction is 27.51 kJ mol-1 in therestricted temperature between 10-25 °C and it was observed that reaction rate enhances bytemperature increase. As the phase transfer catalyst depends strongly on mass transfer betweentwo phases, it is well understood that ultrasonic waves have a greater efficiency of interfacemixing than conventional agitation. So, in this research the effect of ultrasonic waves incomparison with magnetic stirrer was studied. The results showed that an ultrasonic waveaccelerates on the reaction. پرونده مقاله