Performance of polylactide against UV irradiation: Synergism of an organic UV absorber with micron and nano-sized TiO2

Kaynak, Cevdet
The main purpose of this study was to investigate mechanical and thermal performance of polylactide specimens against UV irradiation; first when only adding benzotriazole benzotriazole-based organic UV absorber (UVA), micro (200 nm) and nano (50 nm) sized titania (TiO2) particles alone, and then to reveal possible synergism when they are added together. Compounds were prepared by twin-screw extruder melt mixing, while the 2 mm thick specimens were shaped by compression molding. Specimens were exposed to UV irradiation under fluorescent lamps (UVB-313) with 0.50 W/m(2) for the periods of 12 and 24 days. Changes in the performance of UV irradiated specimens were evaluated in terms of % weight loss, changes in color and chemical structure, including the decreases in the mechanical and thermal properties. Various tests and analysis revealed that synergistic benefits of using micro and nano TiO2 particles together with benzotriazole-type UVA were not only due to the effective stiffening, strengthening and toughening actions of titania particles, but also due to their very significant "UV screening" actions absorbing the photons of the UV irradiation, thus decreasing the degree of the detrimental photodegradation reactions leading to chain scissions in their PLA matrix.


Monitoring the Microstructural Evolution in Spheroidized Steels by Magnetic Barkhausen Noise Measurements
DAVUT, Kemal; Gür, Cemil Hakan (Springer Science and Business Media LLC, 2010-12-01)
The aim of this study is to monitor nondestructively the degree of spheroidization in steels by Magnetic Barkhausen Noise (MBN) method. Various series of specimens consisting of either lamellar pearlite or partially/completely spheroidized carbides were produced from AISI 1060 steel by appropriate heat treatments. All specimens were characterized by metallographic examinations, hardness and MBN measurements. The results show that MBN signals are very sensitive to the variations in the microstructure caused ...
Effect of carbon fiber amount and length on flame retardant and mechanical properties of intumescent polypropylene composites
ATABEK SAVAŞ, Lemiye; Mutlu, Aysenur; Dike, Ali Sinan; Tayfun, Umit; DOĞAN, Mehmet (SAGE Publications, 2018-02-01)
The effects of carbon fiber amount and length were studied on the flame retardant, thermal, and mechanical properties of the intumescent polypropylene composites. The flame retardant properties of the intumescent polypropylene-based composites were investigated using limiting oxygen index, vertical burning test (UL-94), and mass loss calorimeter. The mechanical properties of the composites were studied using tensile test and dynamic mechanical analysis. According to the flammability tests results, the antag...
Influences of three different ethylene copolymers on the toughness and other properties of polylactide
MEYVA, YELDA; Kaynak, Cevdet (Informa UK Limited, 2016-01-01)
The aim of this study was to investigate influences of three different ethylene copolymers on the toughness and other properties of very brittle biopolymer PLA (polylactide). For this aim, PLA was melt blended by twin-screw extruder with various amounts of ethylene vinyl acetate (EVA), ethylene-methyl-acrylate (EMA) and ethylene-n-butyl acrylate-glycidyl-methacrylate (EBA-GMA). SEM and DSC analyses indicated that these ethylene copolymers were thermodynamically immiscible with phase separation in the form o...
Effect of spraying rate on microstructure of spray deposited Al-Fe-V-Si alloy
Kalkanlı, Ali (Informa UK Limited, 2003-12-01)
In this study gas atomisation and spray deposition of a series of AlFeVSi alloys were carried out. Traces of transient liquid were observed as lamellar structure in the middle of the specimen. The heat transfer conditions of this structure were modelled by finite difference calculation. Metallographic specimens for optical microscopy were prepared from the preforms formed in these processes. Optical microscopy showed the presence of dispersoids in the specimens. The dispersoids were characterised as AlFeVSi...
Influences of aminosilanization of halloysite nanotubes on the mechanical properties of polyamide-6 nanocomposites
Erdogan, Ali Riza; Kaygusuz, Ilker; Kaynak, Cevdet (Wiley, 2014-07-01)
The main purpose of this study was to explore effects of silanization of halloysite nanotubes (HNT) on the mechanical properties of polyamide 6 by using aminopropyltriethoxysilane. Effects of two silanization parameters; initial silane concentration and pH of reaction solution were also investigated. Nanocomposites were compounded via melt mixing method in a twin-screw extruder, while specimens were shaped by injection molding. Formation of aminosilane molecules on the edges and defected surfaces of HNTs we...
Citation Formats
U. CAN and C. Kaynak, “Performance of polylactide against UV irradiation: Synergism of an organic UV absorber with micron and nano-sized TiO2,” JOURNAL OF COMPOSITE MATERIALS, pp. 2489–2504, 2020, Accessed: 00, 2020. [Online]. Available: