Characterization of blends of PP with vitamins “C” and “E” exposed to gamma radiation at sterilization dose

Kinetics of Thermal Degradation of Non‐Woven Plastics: Model‐Free Kinetic Approach

“…The average activation energy calculated by Friedman, FWO and modified Coats-Redfern method are 112.8, 111.8 and 109.8 kJmol À 1 , respectively and are close to the activation energy calculated using Kissinger method (106.50kJ/mole). Literature reports the activation energy of thermal degradation of pure polymers vary between 196 and 259 kJ/mol for PP [5,6,7,17,20] 288-318 kJ/mol for HDPE [5,6,7,17,20] and 204-231 for LDPE. [7,8,17] The significant lowering of activation energy of the thermal degradation of non-woven plastic with major composition PP obtained in our research could be due to the presence of two additives i. e. polyethylene and inorganic filers.…”

“…C. Albano and E. de Freitas report of decrease of activation energy of thermal degradation PP by the addition of HDPE due to the alteration of the degradation mechanism. [6,7] Another reason of decrease of activation energy may be due to the catalytic effect of the inorganic fillers present in the polymer.…”

“…PP was found to reduce the activation energy (E a ) significantly when mixed with non-degraded HDPE. [6] The activation energy and the reaction model of the pyrolysis of HDPE, low density polyethylene (LDPE) and PP have been estimated from non-isothermal kinetic results using iso-conversional methods the activation energy was found to be 238-247 kJ/mol for HDPE, 215-221 kJ/mol for LDPE and 179-188 kJ/mol for PP. [7] Thermal degradation of natural polystyrene (PS), LDPE, acrylonitrile butadiene styrene(ABS), polyenterophthalate of ethylene(PETE), and PP was taken at a temperature of 415-490°C and heating rate of 5-30 K min À 1 to calculate the activation energy (E a ) and pre-exponential factor (A) for plastic materials.…”

Unexpected effects in non crystalline materials exposed to X-ray radiation

“…In the Vacuum UltraViolet (VUV) wavelength range damage is often encountered [17][18][19][20] and even used as a fabrication method in lithography [21,22]. γ-rays are used as a method to induce cross linking in polymeric systems [23][24][25] or as a biological sterilization method which intrinsically implies radiation damage [26,27]. In this text we will limit ourselves to the photon energy range which is commonly used in techniques such as powder diffraction, X-ray absorption spectroscopy and SAXS/WAXS.…”

Thermal degradation behavior of styrene‐butadiene‐styrene tri‐block copolymer/multiwalled carbon nanotubes composites

“…24 One or some of these processes can take place depending on the nature of the filler and polymer, which ultimately could influence the degradation processing of the polymer matrix. [25][26][27] It is reported that the E a of polypropylene filled with acetylated sisal fiber is higher than that of composites filled with untreated ones: a possible explanation of this behavior might be the higher polymer-filler interaction, which results in improved stability of the composites. 25 The interactions between the filler and the polymer could help to develop a hard and compact char layer, which increases the resistance under flame stress.…”