Dehydration,Water Vapor Adsorption and Desorption Behavior of Zn[B3O3(OH)5] · H2O and Zn[B3O4(OH)3]

The dehydration behaviors of two different hydrated zinc borate species, Zn[B₃O₃(OH)₅] · H₂O and Zn[B₃O₄(OH)₃], which are industrially important flame retardants, were studied by thermal gravimetric(TG) analysis and in situ diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy. Dehydration onset temperatures of Zn[B₃O₃(OH)₅] · H₂O and Zn[B₃O₄(OH)₃] were 129 and 320°C, respectively, at a 10°C/min ramp rate. A very small amount of boric acid was volatilized in addition to water vapor when both samples were heated at 250°C. A significant amount of water vapor was adsorbed by Zn[B₃O₃(OH)₅] · H₂O from air at 25°C. However, Zn[B₃O₄(OH)₃] adsorbed a very small amount of water under the same conditions. Both zinc borates did not have a tendency to cake during storage.     

Statistical thermal stability of PVC

Experimental design was used to optimize the processing parameters for the decomposition of poly(vinyl chloride). Factorial design and face centered composite design (FCC) were applied to determine the optimum conditions. A total of 10 g PVC powder was mixed with different amounts of zinc stearate (ZnSt₂) and natural zeolite and tested for thermal stability. Factorial fitted model was explained by first order pattern due to the significant main effect regression constants, and FCC model was described by second order model owing to higher order polynomial coefficients. FCC design was superior to factorial design as FCC considers not only its pure quadratic effects contribution but also its higher overall desirability for thermal stability of PVC. For factorial design the optimum conditions were determined as 163.06 mg for ZnSt₂, 399.99 mg for zeolite, and 140°C for temperature with desirability of 0.933. However, 400 mg for ZnSt₂, 333.24 mg for zeolite, and 140°C for temperature with desirability of 0.956 were obtained as the optimum conditions by FCC design. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparation and Characterization of Copper Borates as Lubricant Additives

The present study attempts the preparation of copper borate as a lubricating oil additive by the reaction of copper nitrate and borax solutions. Effects of borax/copper ratio, surface active agent （Span 60）, pH, temperature and mixing time on properties of the products were investigated. The obtained products were not pure form; therefore they were analyzed in detail. They were characterized by color measurement, X-ray diffraction, SEM, zeta sizer, ICP, EDX, TG, DSC, CHNS analysis and FTIR spectroscopy. Mainly Cu2（OH）3NO3 with nitrate ions partially substituted with borate ions was obtained at pH 3.7. There were borate ions equivalent to 0.32 tools of Cu（BO）2 per tool of CUE（OH）3NO3. The borate ions should have replaced partially the nitrate ions in Cu2（OH）3NO3 without changing its crystal structure. On the other hand, Cu （BO2）l 5（OH）074＇（H20）015 was produced at pH 10.2. It also contained 0.11 mol NO3- per tool. By mixing of dilute solutions at pH 8.2 and drying at room temperature nanopartieles of Cu（BO2）I 5（H20）6 having 0.05 NO3 per tool was obtained. The precipitates obtained at pH 10.1 and 8.2 were tested as lubricant additives. When they were added to lubricating oil with Span 60, the friction coefficient was reduced 28 % and 65 % for the precipitates prepared at pH 10.1 and 8.2, respectively.     

Diesel evaporation as the first step of hydrogen production

Diesel constitutes the major fuel utilized in ships. Hence, diesel reforming is foreseen as one of the options for marine fuel cell applications. Evaporation of diesel fuel is an important stage in the diesel reforming processes. Thermal decomposition of the heavy feedstock that occurs primarily in the high temperature domain of the evaporation process leads to carboneous material formation and may plug the evaporator. Carboneous materials can also accumulate on the catalyst surface and cause serious problems in desulfurization and pre-reformer units. The diesel evaporator design is one of the key parameters to minimize carbon formation. The operating conditions must be optimized as well.     

Synergistic effect of metal soaps and natural zeolite on poly(vinyl chloride) thermal stability

The synergistic effect of metal soaps (zinc stearate and calcium stearate) and/or natural zeolite (clinoptilolite) on PVC thermal stability was investigated. For this purpose, PVC plastisol was prepared by mixing poly(vinyl chloride) (PVC) and dioctyl phthalate (DOP) and stabilized with different amounts of metal soaps and zeolite. Kinetic studies of dehydrochlorination at 140 and 160°C were done for unstabilized and stabilized PVC plastigels using 763 PVC Thermomat equipment. The stabilizing effect of zeolite on the increase in the induction period of the sample was considered to result from the absorption of HCl, a property that was thought to reduce the autocatalytic effect of HCl evolved at the initial stages of dehydrochlorination. Since the induction time of the sample having 0.53% of zinc stearate and 0.53% of zeolite was higher than those of the PVC plastigels having only zinc stearate or zeolite, the synergistic effect on thermal stability was observed at low levels of these additives. J. VINYL. ADDIT. TECHNOL., 11:47–56, 2005. © 2005 Society of Plastics Engineers