Advanced Materials Research Vols. 652-654

Abstract: A zinc hydroxystannate-coated mineral grade Mg(OH)₂ (ZHSCMH) was synthesized as flame retardant and smoke suppressant for flexible poly (vinyl chloride). The powder of ZHSCMH was characterized by the x-ray diffraction (XRD) and scanning electron microscopy (SEM). The flame retardancy, smoke suppression and thermal behavior of PVC treated with ZHSCMH and mineral grade Mg(OH)₂ were comparative studied by means of limiting oxygen index (LOI), smoke density rating (SDR), thermogravimetry (TG), differential thermogravimetry (DTG) and SEM. The results show that, ZHSCMH can be used as a high effective flame retardant and smoke suppressant for PVC. The flame retardant of ZHSCMH can effectively promote the crosslinking reaction of poly (vinyl chloride) (PVC) in the first stage, and improve the stability of the char residue in the second stage.

Abstract: Low density polyethylene (LDPE) was modified by the addition of commercial fire retardants FR01 and aluminium hydroxide (ATH). ATH/FR01/LDPE composites were prepared by melt blending and extrusion in a twin-screw extruder. ATH was first modified by a silane coupling agent KH550 then added to LDPE. The flame retardancy, electrical property and thermal behavior of the LDPE composites were investigated by limiting oxygen index (LOI), volume resistivity and thermogravimetric analysis (TGA), respectively. The results indicated that the surface modification of ATH (M-ATH) could greatly improve the dispersibility and compatibility with LDPE matrix. The mechanical property tests showed good mechanical properties of composite, compared with unmodified one, tensile strength and elongation of M-ATH/LDPE were all improved, and the addition of FR01 improved the flame retardancy of ATH/LDPE remarkably. TGA results demonstrate that char yield of M-ATH/FR01/LDPE (30/15/70) reaches 27 wt% at 600 °C in Ar atmosphere.

Abstract: Using dendritic bromide poly (benzyl ether), G₂-Br, as macroinitiator, dendritic-linear polymer (G₂-PS-NHSO₃Na) was obtained via atom transfer radical polymerization and nucleophilic substitution of G₂-PS-Br. G₂-PS-NHSO₃Na was constructed on cationic silica by both electrostatic attraction and steric effort coming from dendritic block of G₂-PS-NHSO₃Na. ¹H-NMR and differential scanning calorimetry were used to characterize the structure and thermal behavior of G₂-PS-NHSO₃Na; thermo-gravimetric analysis and TEM were applied to analysis the assembly amount of G₂-PS-NHSO₃Na and the dispersibility of silica before and after assembly. The results show that G₂-PS-NHSO₃Na can be synthesized successfully and has exact structure; it can be constructed on cationic silica with 27% assembly amount; the aggregation of silica can be prevented effectively by the dendritic-linear brushes, but the molecular weight of linear segment and the generation of dendritic block will influence the assembly behavior and the amount of the dendritic-linear brushes.

Abstract: The copolymerization processes and the optimal conditions of LASP/AA/AM polymer with initiator, crosslinking agent were studied. The results show that the water absorption ratio and the salt-water absorption ratio of LASP/AA/AM polymer are 1017g/g and 98.02 g/g, respectively. The optimal conditions of LASP/AA/AM copolymerization are: WLASP:WAA+AM=8%, Wcrosslinker :WAA+AM=0.02%, W initiator :WAA+AM=0.5%, WAA:WAM=7 : 3.

Abstract: The nonisothermal crystallization kinetics of isotactic polypropylene (iPP) filled with a novel nucleating agent (TMC328) was studied by using differential scanning calorimetric. The commonly used Arami, Ozawa, and Mo models were used to model the crystallization kinetics, and it appears that Arami and Mo models can well describe the nonisothermal crystallization behaviors of iPP/TMC328 blends. The results indicate that a small amount of TMC328 can obviously enhance the kinetic crystallizability of iPP due to its heterogeneous nucleation effect.

Abstract: Polymers belong to most spread organic flammable materials. They are decisive material – insulator also in cable production. Regarding the safety of buildings it is necessary to know their fire-technical characteristics, which predict their behaviour in case of fire. The article deals with testing cables protected and non-protected with intumescent coating, exposed to heat flux, in dependence on distance. A special equipment was developed for testing the inflammability, allowing objectivisation of critical conditions leading to ignition of tested materials.

Abstract: Removed at authors request.

Abstract: Transparent thin films of Sn-doped ZnO (ZnO:Sn) were deposited onto silica glass substrates by the sol–gel method. The effect of different Sn doping on the crystallinity, structural, optical and electrical properties of ZnO:Sn thin films were investigated by XRD, SEM, UV-VIS spectrophotometer and four-point probe method respectively. Among all of ZnO:Sn thin films in this paper, Sn-doped with 2 at.% exhibited the best properties, the surface demonstrate an accumulative crystallization and hexagonal structure, with a high-preferential c-axis orientation, namely an average transmittance of 90% and the resistivity of 19.6 Ω·cm.

Abstract: The transmittance spectrograms of quartz glass slabs are measured in spectral range 1.34-4.20μm. A new inversion method of optical constants (k is extinction coefficient and n is refractive index) of glass was proposed to calculate the optical constants. The optical constants of selenide glass attained in the references were selected as the true values, and the spectral transmittance radio of the semitransparent solid based on the direct model simulation were regarded as the experimental values, and validation of the new inversion method was investigated. Then the optical constants of quartz glass were achieved by the inverse model.

Abstract: The optical absorption spectra of blended poly (N-carbazole) (PVK) with polyvinylpyrrolidone (PVP) in various compositions are investigated. A doctor blade technique was used to coat the blended polymer on a quartz substrate. The electronic parameters such as absorption edge (E_e), allowed direct band gap (E_d), allowed indirect band gap (E_i), Urbach edge (E_u) and steepness parameter (γ) were calculated using Tauc/Davis-Mott Model. The results reveal that the E_e, E_d and E_i increase with increasing of PVP ratio. There also have variation changing in Urbach energy and steepness parameter.