Various combinations of zinc borate (ZB), alumina trihydrate (ATH) and magnesium hydroxide (MH) were used to retard the flammability of PVC composite. Flame retardancy of samples were investigated with limiting oxygen index (LOI) test. Further testing was achieved to expose the individual and synergistic effects of flame retardant additives on heat stability, Vicat softening temperature, fusion time, microstructure, mechanical and thermal characteristics. Microstructural and thermal analyses were performed by scanning electron microscopy and TG/DTA respectively. The LOI results showed that, high levels of ZB-ATH combination provided the highest LOI value of 53.4%. Although ZB and its combinations improved the fire performances of composites, they caused a small reduction at tensile strengths. When compared with plain PVC, flame retardant composites had better thermal stability. In addition to the advantages of ZB, when test results were evaluated with a holistic approach ZB-ATH-MH combination was understood to be an effective flame retardant alternative with this research.

The formation of the first membrane, the swelling of the crystal by incoming water from the semipermeable membrane and the formation of irregular shaped branches were observed by optical microscopy, when zinc sulfate heptahydrate crystals were immersed in saturated borax solution. The powders obtained by mixing dilute aqueous borax and zinc sulfate solutions had B, O, Na, S and Zn elements. Presence of Na Zn 1/2 B 4 O 7 .xH 2 O was indicated by EDX analysis. The molar ratio of B 2 O 3 /ZnO in powders was around 2. FTIR analysis indicated the ratio of absorbance values of asymmetric stretching vibrations of B (3) -O at 1351 cm -1 to that of B (4) -O at 1026 cm -1 increased with their heating time at 90ºC during their preparation. X-ray diffraction patterns indicated the presence of Zn(OH) 2 and Zn 4 (OH) 6 (SO 4 )•4H 2 O. The zinc borate compounds in the powders were not crystalline since no sharp peaks related to zinc borates were present in x-ray diffraction diagram. There were two mass loss steps in TG curves of the powders. The first step at 150-350ºC and the second step at 700-950ºC were due to elimination of water and due to decomposition of sulfate ions respectively. The submicron powders were a mixture of zinc borate, Zn(OH) 2 , Zn 4 (OH) 6 (SO 4 )•4H 2 O and Na Zn 1/2 B 4 O 7 .xH 2 O and they could be used as lubricant additive due to their small particle size of 600 nm.

Deve dikeni (Silybum marianum) tohumuna çözücü ile ekstraksiyon yöntemi uygulanarak %7,3 verimle silimarin tozu elde edilmiştir. Ekstrakte tozun %57,8 silimarin içerdiği bulunmuştur. Silimarin içeriği dikkate alınarak Silybum marianum tohumunun silimarin içeriği %4,21 olarak bulunmuştur. Ekstrakt ve orjinal silimarin, Fourier dönüşümlü kızıl ötesi spektroskopisi (FTIR), Optik Mikroskop, X-ışını kırınımı (XRD) ve taramalı elektron mikroskobu (SEM) ile karakterize edilmiştir. Püskürtme ve enjeksiyon yöntemleri ile ekstrakt ve orjinal silimarin tozları aljinat ile enkapsüle edilmiştir. Silimarin enkapsülasyonu sonrasında mikrokapsüllerin tutuklama verimleri %83,14-%91,27 aralığında bulunmuştur. Simule mide (0,1N HCl) ortamında kümülatif silimarin salımı %13-%71 aralığında, simule bağırsak (PBS) ortamında kümülatif silimarin salımı %28,3-%82 aralığında hesaplanmıştır. Tüm örneklerde simule bağırsak (PBS) ortamında daha yüksek silimarın salımı gözlenmiştir. Salım deneyleri sonrasında örneklerin fonksiyonel gruplarındaki değişikler FTIR ile belirlenmiştir.

Nano particles of zinc borate were obtained by homogeneous precipitation method which is based on dissolving zinc borate in ammonia and precipitating it as nano particles by slow evaporation of ammonia. The synthesized zinc borates were characterized by advanced analytical techniques. Zinc borate nano particles were used as a lubricant additive to spindle oil having Span 60 dispersant. The particles were well dispersed in spindle oil as shown by optical microscopy of the oils. Four ball tests of the lubricants indicated zinc borate lowered (61.8%) the wear scar diameter significantly. The hardness of wear surfaces of test balls was reduced from 688 HV to 618 HV and presence of zinc borate particles embedded on the surface indicated a flexible skin was formed. Therefore the pressure was decreased due to increase of the contact area of the balls. The surface roughness was also decreased from 35.63 nm to 27.60 nm by the addition of zinc borate to spindle oil having Span 60. Zinc borate prepared by homogeneous precipitation technique lowered the wear of the surfaces that rub to each other.